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108 responses to “Measuring Sprawl”

1. 

   larryg

   April 2, 2014

   I think the concept of trying to quantify a quality has potential but there needs to be a way to validate the ratings.

   for instance if you totaled up the number of miles of streets for a given area – would it be consistent with the rating? how about sidewalks or miles of bike lanes?

   what I noticed was that Fredericksburg has a higher score than quite a few places that are quite a big larger in area.

   but even it has a core area of grid-streets and other areas of less density that the core areas but still way more that suburbs …

   I wonder if some of Luke’s map magic might show graphically how some cities vary in density and how that compares (or not) to road infrastructure.

   on density ‘restrictions” – I’ve seen quite a few higher-density proposals over the years and I’m having a hard time remember ones that got turned down for being “too dense”.

   I’ve seen many rezoned at 8 and 16 du and cannot recall any being rejected.

   VDOT places one of the bigger roles in these decisions in Va as they determined what it will take for a proposed development to get a curb cut.

   one that was done down our way recently required not only right-in-right-out but left turn lanes and a traffic signal but it was 16 du – without sidewalks or bike/ped stuff, just cars. The development is served by transit but it’s lame in terms of frequency and connectivity to other places

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2. 

   Hydra

   April 3, 2014

   The environmental movement in ths US has become so peeverted it classiifies high density areas where food must be imported and sewage must be expoted as “green” .

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   1. 

      Tysons Engineer

      April 3, 2014

      I didn’t realize food and sewage was teleported from suburban homes. This changes everything.

      Another case of seeing the aggregate formation embodied by a skyscraper and thinking it creates more damage than a suburban home. Its not apples to apples. Compare 1000 dwelling units in a high rise to 1000 suburban homes. Add in the fact that not only do suburban homes not make their own food, they also have to be shipped in a much more dispersed fashion meaning more fuel use as well.

      Unless you are a self sustaining farmer with your own septic and rainwater harvesting for water, and your own solar plant in the back yard, then it is likely per capita you use more everything than your urban brethren.

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      1. 

         larryg

         April 3, 2014

         re: ” I didn’t realize food and sewage was teleported from suburban homes. This changes everything.”

         touche!

         rural lands do support both urban and suburban but the impacts are larger from denser parcels and greater impervious surfaces.

         “Another case of seeing the aggregate formation embodied by a skyscraper and thinking it creates more damage than a suburban home.”

         I don’t know if it creates “more” but the point is it IS subsidized as opposed to it not being subsidized and suburban being subsidized per the conventional wisdom.

         “Its not apples to apples. Compare 1000 dwelling units in a high rise to 1000 suburban homes. Add in the fact that not only do suburban homes not make their own food, they also have to be shipped in a much more dispersed fashion meaning more fuel use as well.”

         take how much transportation infrastructure is needed to deliver food to dense urbanized areas. how much transportation infrastructure is needed to move food from everywhere else to the urbanized areas?

         Again it’s not an issue of suburban having subsidies and urban not. the point is they both have them and yes.. on a per capita basis – maybe a MORE valid apples to apples but that’s not what advocates of urban do. They play the “suburban is subsidized and we’re not” game.

         “Unless you are a self sustaining farmer with your own septic and rainwater harvesting for water, and your own solar plant in the back yard, then it is likely per capita you use more everything than your urban brethren.”

         really? my septic and my well are pretty self-sustaining.. for the most part and my prescriptions drugs don’t go into streams and rivers like it does in the cities.

         when it rains – even hard – it soaks in the soil and woods as there is no huge parking lot for it to run off from… not even from 50-100 of us .. there still is not big parking lot or other impervious surfaces.. of the scope and scale you see in urban areas.

         on a per capita basis – between urban and suburban it may be a lot closer than the oft claimed ” suburbs are subsidized and cities are not” narrative.

         next time it rains TE – go look at some of your creeks and see what higher percent of impervious surfaces does to creeks…in urban areas and tell me how you’d fix it. One way to fix it is to not have parking lots but only parking structures… they’re more eco friendly than parking lots by far.

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         1. 

            Tysons Engineer

            April 3, 2014

            I’ve designed stormwater plans for 43 sites personally, including 7 embassies which meet LEED Silver or Gold, all of which incorporate both treatment and rain water harvest controls. I’ve spent a bit of time taking a look at storm runoff in my life 😉

            One way to fix it is definitely to reduce impervious area, but here again you are not comparing apples to apples. You are seeing the focused density of development with its 1000 dwellings for instance, and not taking into consideration the 1000 home equivalents. A 1000 dwelling highrise could fit within a 2.5 acre site. With its extensive structural components it makes more sense for them to incorporate parking internal to the building, instead of sprawled about on the surface. The centralized building is also much easier to incorporate a rainwater cistern into the actual structure of the building, again because you are sharing cost on concrete. 1000 units, within a 2.5 acre impervious area, with full rainwater control. You could actually make the building have a net 0 runoff if you wanted in most cases.

            Compare now to 1000 suburban homes, a standard R-4 will have approximately 5000 sf of impervious area specifically for the lot, not to mention all of the roads, cul-de-sacs, and long stretches of pavement laid down in order to reach it. But lets keep it simple, just the lot. 5000 sf per lot x 1000 lots = 5 million square feet, or about 114 acres of pavement, for 1000 homes. Yes often times new developers in NOVA are required to put down storm water controls, but these are far less likely to be full control, more akin to standard detention basins which work well for quantity and flood control, but are crap for total suspended solids, and most common of all to homes (because of lawns) phosphates and nitrates… thats the stuff that cause fresh water death known as eutrophication.

            Run off is one of the strongest cases for appropriate urban development in fact for this reason.

            On a side note, recent studies show that the filtration process that happens in soil percolation does not remove pharmaceuticals if less than 100′ to the saturated zone when soils are more porous than clays (which if you have a septic field you are not allowed to locate on clay because it will consistently back up). The best way to remove pharmaceuticals from waste water is to have it go to a facility capable of tertiary treatment with polishing or reverse osmosis… of which we have 3 in Northern Virginia because of the urbanization of the area.

            Sorry for the defense tone, I do appreciate that you are interested in this stuff, but perception versus reality are really tough things to show people, and this is the kinda of calculations I do on a daily basis. I’m not saying to take my word for it, but look more into the raw data and research, it will keep leading you to the same conclusion.

            Per acre, suburbs for a long time have been heralded to be environmentally sensitive. But that comparison is garbage because it doesn’t consider the amount of people per acre. It should be people based otherwise you get weird distortions like 2.5 acres with 1000 dwellings is worse than 1000 homes on 250 acres.

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            1. 

               larryg

               April 3, 2014

               re: ” I’ve designed stormwater plans for 43 sites personally, including 7 embassies which meet LEED Silver or Gold, all of which incorporate both treatment and rain water harvest controls. I’ve spent a bit of time taking a look at storm run off in my life 😉 ”

               there’s LEED for stormwater ?

               “One way to fix it is definitely to reduce impervious area, but here again you are not comparing apples to apples. You are seeing the focused density of development with its 1000 dwellings for instance, and not taking into consideration the 1000 home equivalents. ”

               well no… if you have a 1/2 acre lot.. you have a small amount of impervious surfaces… and a large amount of surface land to sequester runoff.

               if you do 1000 home equivalents -you have to recognize that there is a threshold of how much pervious surface you have – per capita and the dynamics of less density assure less impervious surface per capita, less runoff per capita.

               “A 1000 dwelling highrise could fit within a 2.5 acre site. With its extensive structural components it makes more sense for them to incorporate parking internal to the building, instead of sprawled about on the surface.”

               I totally agree. Is that the norm right now? if every structure had a floor or floors for vehicles runoff would be much, much reduced perhaps on par with sprawl.

               ” The centralized building is also much easier to incorporate a rainwater cistern into the actual structure of the building, again because you are sharing cost on concrete. 1000 units, within a 2.5 acre impervious area, with full rainwater control. You could actually make the building have a net 0 runoff if you wanted in most cases.”

               you could. is it? are we comparing what you could do or what you do?

               “Compare now to 1000 suburban homes, a standard R-4 will have approximately 5000 sf of impervious area specifically for the lot, not to mention all of the roads, cul-de-sacs, and long stretches of pavement laid down in order to reach it. ”

               not buying the 5000 square feet of impervious surface on a 1/4 or 1/2 acre suburban lot .. with a driveway that is 20 x 40… and the rest of the yard is in grass.

               yes there is pavement just like there is for cars in NoVa. again.. do you want to claim no subsidies in Nova vs subsidies for sprawl or do you want a real comparison?

               “But lets keep it simple, just the lot. 5000 sf per lot x 1000 lots = 5 million square feet, or about 114 acres of pavement, for 1000 homes. ”

               show me where you got the 500o please.

               “Yes often times new developers in NOVA are required to put down storm water controls, but these are far less likely to be full control, more akin to standard detention basins which work well for quantity and flood control, but are crap for total suspended solids, and most common of all to homes (because of lawns) phosphates and nitrates… thats the stuff that cause fresh water death known as eutrophication.”

               wait.. are you arguing that the current controls are no good? and what are you saying to do instead.. no wiggling here… tell me what you should do about it – and are you right now and if you are not – is that an environmental subsidy?

               “Run off is one of the strongest cases for appropriate urban development in fact for this reason.”

               is that why the urban areas are operating under consent decrees for runoff and trying to evade the regs?

               again – what’s going on right now and is that a subsidy or not?

               “On a side note, recent studies show that the filtration process that happens in soil percolation does not remove pharmaceuticals if less than 100′ to the saturated zone when soils are more porous than clays (which if you have a septic field you are not allowed to locate on clay because it will consistently back up). The best way to remove pharmaceuticals from waste water is to have it go to a facility capable of tertiary treatment with polishing or reverse osmosis… of which we have 3 in Northern Virginia because of the urbanization of the area.”

               give me a cite for you claim please. pharmaceuticals first get sequestered in the septic tank itself then flows to the drain field and gets filtrated like the other things do – which may or may not be 100% complete but I’ve yet to see credible studies on it – and it’s certainly not the same as into your toilet, into the sewer then through the sewage treatment plant and into the river.

               again – are we actually comparing what you do now compared to what suburbs do now as opposed to something you think should be done or claiming that suburbs are subsidized and urban areas are not or less so?

               “Sorry for the defense tone, I do appreciate that you are interested in this stuff, but perception versus reality are really tough things to show people, and this is the kinda of calculations I do on a daily basis. I’m not saying to take my word for it, but look more into the raw data and research, it will keep leading you to the same conclusion.”

               I’ve looked at the data… and I’m skeptical of the claims of no and/or less subsidies because I yet to see a real – objective comparison which, in reality should show subsidies for both – and how they compare …

               it’s not a good vs evil scenario. it’s got shades.. and urban areas have pollution issues and require external subsidies for pollution for them to operate.

               “Per acre, suburbs for a long time have been heralded to be environmentally sensitive. But that comparison is garbage because it doesn’t consider the amount of people per acre. It should be people based otherwise you get weird distortions like 2.5 acres with 1000 dwellings is worse than 1000 homes on 250 acres.”

               I agree.. but it’s true on both sides… and yes.. we should be comparing on a per capita basis.. but honestly … which means at best – urban areas also harm the environment… and the question is to what degree in comparisons and not what you think they could do – but what they actually do ..right now.

               I could play the “we could do this” for suburbs also. For instance, low impact development is a totally doeable thing on most suburban properties – precisely because they’ve got land for detention, cisterns, etc… and it’s cheaper and easier to do –

               I’m basically looking for the truth here.. I have no dog in the urban vs suburban conundrum other than the fact that some claims are bogus and illicit on first blush.

               I just think the comparisons have to be honest and valid rather than propped up unproven, obviously questionable assertions.

               remember, I’m the guy totally in favor of tolls for commuters.. the higher the better especially at rush hour and I would give up major ground for integrated parking structures for density even without detention because you remove the oil/antifreeze/other stuff from the runoff – but not the pet poop.
            2. 

               Tysons Engineer

               April 3, 2014

               No there isnt a LEED for stormwater, but the projects as a whole all incorporated stormwater credits, and in all but 2 of them, received additional credits for full rainwater harvest.

               With the 1/2 acre lot, again you aren’t getting the point. The half acre lot holds 1 family. You are looking at this on a project vs project basis, 1 building vs 1 building. Thats pointless. Unless your point is to massacre most of humanity, then you have to realize people exist, you have to house them. So yes, your 1 parcel might have lower impervious area, but the one skyscraper has 1000 families in it that would otherwise have to live on 1/2 acre lots. Following? So ok let’s play with numbers to make them more as you wish (btw 5000 sqft for most new homes in NOVA is about right when you include the deck, additional patios, detached garages or sheds, pools, pool decks, and yes the driveway).

               So lets say a half acre lot. Well not you have a longer driveway, but lets just say we reduce it down to 3000 sf of impervious. Better?

               1000 families have to now live. Ok well they need 1000 1/2 acre lots now. To house those 1000 families, you end up with (a revised) 3,000,000 square feet. 69 acres of impervious area for 1000 families. The fact that the house is somewhat disconnected helps, but ultimately the lawn uses fertilizers, and the runoff still typically makes it to surface flows (after about 200′ of sheet flow most runoff starts forming channels and is less likely to percolate).

               69 acres vs 2.5.

               Now if those homes had rain barrels for the roofs, if they used non-chemical fertilizer, if they had vegetated buffers that are significant in size, then those things help. The cost to do those decentralized for 1000 homes is insane, which is why you rarely ever see a home builder put roof controls on new homes.

               Yet, as you asked, yes most high rise developments provide rainwater harvest as a given, because it is the most cost effective way to meet the required ches bay regulations. In the era before the ches bay regs I would agree with you. On top of that, skyscrapers often promote their sustainability, its a value added, and stormwater runoff is one of the cheapest ways (compared to for instance, installing 4000 water efficient fixtures) to get LEED points.

               Stormwater management in cities is the typical, it is the ones that don’t provide this that are uncommon and typically in the states that don’t have regulations on stormwater.

               For structures taller than 6 stories, yes parking garages are very common. My typical experience is surface parking only makes sense in areas with land values less than $2.5 million per acre, which is not found in most TOD areas or urban regions. When you see it, it is usually overflow created by local parking minimums, or a holding spot for future buildings to come in future phases of a site.

               On the issue of NOVA developers, I don’t work for developers. I did at Bowman in the mid 2000s. The issue wasn’t that developers were skipping on putting it, its that the state regulations are fairly lax on residential subdivisions in terms of the percentage of nutrient removal needed, and are mum on TSS. And when the developers put these in, these facilities are a lot less effective than practices like rainwater harvesting, full filtration (either with products like filterra or baysaver). Those are the kinds of practices that go above and beyond state regulations and are common place in high density development because those projects find them to be more space saving and therefore more cost effective than ponds which are the minimum, and more typical of subdivisions.

               Urban areas are under consent decrees because of years of not understanding the relationship of impervious area and floods/erosion. This research has only been around for the past 40 years (which the DC metro area was one of the leaders on) and even up until the 90s the research was not fully developed hence why we saw the era of municipal ponds. The new regulations for the ches bay are really less than 15 years old, and have continued to be refined to be stricter(lest the regulators be run out of town for being too heavy handed all at once). Tysons had almost no storm controls when it originally boomed between the 70s and 90s. It was only in the 90s when developments started controlling their runoff, and it is only now with the new requirements that the situation will really be properly addressed with all projects required to meet LEED requirements for Stormwater management. I would add that subdivisions built during that time were also horrifically bad for the streams and water bodies. And of course the worst of all is VDOT who still lags behind private developers in stormwater management. More roads for subdivisions, longer roads, is another case against suburban development vs urban because VDOT often skirts the rules.

               And if you wanna talk about consent decrees on water body pollution, it begins and ends with chicken farmers, but thats a whole other issue.

               Your home septic tank has a treament effluent of over 50 ppm, give me a break. Come on man, that tiny tank and drainfield comes no where close to the treatment level required of municipal waste water treatment plants, typically 20 ppm now and days but the EPA is actually shooting for stricter standards (not gonna get it because of certain anti-regulation folks). That sewer plant you just jumped across in your reference, outputs water at spring water quality, which is why we uptake it up here in the urban north for reuse out of the very streams that they are input into upstream. Thats how clean it is.

               Additionally, unlike thousands and thousands of septic systems (which after 10 years lose about 50% of their efficiency) a waste water treatment plant has to record and report its output on an hourly basis to ensure that they remain with critical thresholds. Being centralized helps in that case. For the county to go around and check on individual septic systems at that frequency would put every jurisdiction in the country into bankruptcy. I could wax poetic for another hour on this subject, but perhaps I’ll save that for another day.

               The comparison is what is done now. The negatives of urban development were under older standards due to a lack of understanding on the impacts of those decisions. That was the era of urban sprawl.

               Urban areas don’t require subsidies because their assessed values are out of control high. Urban areas fuel non-urban areas. In NY the state is propped up by New York City. Hell even in Texas, look at the numbers, the cities are where the funds come from, Dallas, Houston, etc. To say that somehow cities are subsidized by suburbs is to say, the US economy would be better if NYC, LA, Chicago, DC, Boston, and Seattle didnt exist, if instead all areas looked like Hackensack New Jersey. There are lots of countries like that, they are typically considered third world economies though.

               Now, to the place where I agree. There are shades, its not clear cut. Your arguments are the area where there are shades, it is well known that by all measures SWM, Wastewater, and commute footprints are all considerably better with more dense urban development. Where it is a gray area is the components that create skyscrapers, and the environmental impact their manufacturing creates. Concrete, steel, glass, these are things with massive carbon footprints, have harsh chemical processes, require significant indirect environmental impacts.

               When these are included, it becomes much more muddled as to whether a new LEED style high rise building is better than a typical subdivision home. So there are cases where some new high rise buildings are not great for the environment, if they incorporate the minimum, don’t use rapid growth materials, if they source materials from another country, etc. And there are certainly cases where single family homes can be extremely environmental sensitive (even zero footprint) if they use rainwater harvest, have filtered septic systems with polishing which is used to irrigate, if they have renewable energy sourcing, if they have low water and low energy appliances/fixtures; sometimes those things can win out against the negatives of more driving and more roads.

               In the modern era of LEED and environmentally sensitive city designs (because after all most cities in the US are headed by those green hippies) most of the new buildings you see come online in cities are very very efficient and good for the environment. The same can’t be said for many of the sprawl, on the fringe, built on cheap green field, subdivisions that some of the good ole boys that I used to work for skirt by the local jurisdictions (who are trying to balance their budgets with RE taxes and don’t want to hold up any new developments).

               There is no good or evil. Single family homes are just as important as strong cities, and people aren’t evil for living in them. I am just addressing the idea that cities are worse for the environment, which is often not the case. It is to say, we should support better cities, ones that give options that reduce the impacts of suburban sprawl (sprawl being the expansion with out proper controls and regulations, skirted by as a local jurisdictions method for getting quick money).

               This is a tough discussion to have online of course, and my response is extremely long. These kinds of things really are better discussed over beer 😛
            3. 

               larryg

               April 3, 2014

               re: ” No there isnt a LEED for stormwater, but the projects as a whole all incorporated stormwater credits, and in all but 2 of them, received additional credits for full rainwater harvest.”

               how does that relate to state and federal standards for stormwater?

               “With the 1/2 acre lot, again you aren’t getting the point. The half acre lot holds 1 family. You are looking at this on a project vs project basis, 1 building vs 1 building. Thats pointless. Unless your point is to massacre most of humanity, then you have to realize people exist, you have to house them. So yes, your 1 parcel might have lower impervious area, but the one skyscraper has 1000 families in it that would otherwise have to live on 1/2 acre lots. Following? So ok let’s play with numbers to make them more as you wish (btw 5000 sqft for most new homes in NOVA is about right when you include the deck, additional patios, detached garages or sheds, pools, pool decks, and yes the driveway).”

               and I agree with the premise. most homes even with driveway are not 5000 square feet. Unless you have a cite, I think that’s about twice the real number.

               there’s a big range… here.. so again.. we need real numbers.. not hand waving.

               and again – it’s to compare the two .. honestly.. not just 1000 family structures but the typical NoVa structure/SFH home , etc.

               “So lets say a half acre lot. Well not you have a longer driveway, but lets just say we reduce it down to 3000 sf of impervious. Better?”

               2500 unless there is a credible cite and I think if we’re going to use numbers we ought to at least acknowledge when we’re speculating..

               “1000 families have to now live. Ok well they need 1000 1/2 acre lots now. To house those 1000 families, you end up with (a revised) 3,000,000 square feet. 69 acres of impervious area for 1000 families. The fact that the house is somewhat disconnected helps, but ultimately the lawn uses fertilizers, and the runoff still typically makes it to surface flows (after about 200′ of sheet flow most runoff starts forming channels and is less likely to percolate).”

               most suburb subdivisions these days do have storm ponds and the regs just got stricter.. and we’re getting stormwater authorities to upgrade from 2yr storm detention to 10+ year storm detention.

               “69 acres vs 2.5.”

               is 2.5 the norm in Nova now?

               “Now if those homes had rain barrels for the roofs, if they used non-chemical fertilizer, if they had vegetated buffers that are significant in size, then those things help. The cost to do those decentralized for 1000 homes is insane, which is why you rarely ever see a home builder put roof controls on new homes.”

               storm barrels are mostly “feel good” crap. the question is how much water do they capture for a particular storm event. do they capture all the water from a 2yr storm event? how about a 6 month storm event? got a number?

               what happens to the rest? it’s EASY to build runoff detention on most quarter acre lots – you dig a ditch.. put in gravel.. cover with soil.. plant a garden and watch the runoff disappear into the ditch.

               “Yet, as you asked, yes most high rise developments provide rainwater harvest as a given, because it is the most cost effective way to meet the required ches bay regulations. In the era before the ches bay regs I would agree with you. On top of that, skyscrapers often promote their sustainability, its a value added, and stormwater runoff is one of the cheapest ways (compared to for instance, installing 4000 water efficient fixtures) to get LEED points.”

               again.. is this the norm now? do you know how much rainwater there is for 1000 square foot for a 2yr storm event? you should given your credentials.

               what percent of NOVA development harvests storm water?

               “Stormwater management in cities is the typical, it is the ones that don’t provide this that are uncommon and typically in the states that don’t have regulations on stormwater.”

               100% bull hockey and you know it. stormwater is a huge problem for urban areas. you said you looked at creeks? Really? Have you looked at NoVa creeks during rain events? They are literally rolling disasters.. too much impervious surface not enough detention/sequestration.

               “On the issue of NOVA developers, I don’t work for developers. I did at Bowman in the mid 2000s. The issue wasn’t that developers were skipping on putting it, its that the state regulations are fairly lax on residential … ”

               and I would not expect developers to fall on their swords over this unless it was required. they do what is required and nothing more. It’s not about developers.

               are you familiar with the latest storm water regs coming out of Richmond?

               “Urban areas are under consent decrees because of years of not understanding the relationship of impervious area and floods/erosion. This research has only been around for the past 40 years (which the DC metro area was one of the leaders on) and even up until the 90s the research was not fully developed hence why we saw the era of municipal ponds.”

               “only” the last 40 years… 🙂 yes.. EVERYONE is behind on this but the biggest violators are where there are high percentages of impervious surfaces and very little surplus land available for new detention. It’s much, much easier to up the game in areas where impervious surfaces are lower percents.

               “The new regulations for the ches bay are really less than 15 years old, and have continued to be refined to be stricter(lest the regulators be run out of town for being too heavy handed all at once). Tysons had almost no storm controls when it originally boomed between the 70s and 90s. It was only in the 90s when developments started controlling their runoff, and it is only now with the new requirements that the situation will really be properly addressed with all projects required to meet LEED requirements for Stormwater management.”

               I’m ignorant of any comparisons between LEED stormwater standards and EPA/DEQ state standards but I’m skeptical because most urbanized entities have traditionally ignored storm water and it’s the 600 lb gorilla in areas with high percentages of impervious surfaces.

               down our way – they talk in terms of “replicating” the pre-development runoff signature. there is no way in Hades that urbanized areas can come close to that unless they are going to build HUGE underground tunnels or tanks whih is – by the way what they ARE doing for CSOs for Arlington/Alexandria, etc.

               http://www.tunneltalk.com/Anacostia-Aug2009-Anacostia-CSO.php

               ” I would add that subdivisions built during that time were also horrifically bad for the streams and water bodies. And of course the worst of all is VDOT who still lags behind private developers in stormwater management. More roads for subdivisions, longer roads, is another case against suburban development vs urban because VDOT often skirts the rules.”

               not any more.. new roads down this way have SIGNIFICANT storm-water facilities.

               And if you wanna talk about consent decrees on water body pollution, it begins and ends with chicken farmers, but thats a whole other issue.

               that’s more than just storm water.. but interesting you bring it up because those chickens are 90% for NoVa and they leave poop behind to be dealt with.

               “Your home septic tank has a treament effluent of over 50 ppm, give me a break. Come on man, that tiny tank and drainfield comes no where close to the treatment level required of municipal waste water treatment plants, typically 20 ppm now and days but the EPA is actually shooting for stricter standards (not gonna get it because of certain anti-regulation folks). ”

               no..you’d be wrong guy. the well that people drink water from is usually 100-200 feet from the drainfield. capisce? What you have to keep in mind is that in a septic/drainfield – the effluent is sequestered and gradually filtered and in a Municipal WW plant – it’s a matter of hours/days from the toilet to the outflow.

               “That sewer plant you just jumped across in your reference, outputs water at spring water quality, which is why we uptake it up here in the urban north for reuse out of the very streams that they are input into upstream. Thats how clean it is.”

               does not remove pharmaceuticals and no.. it’s not yet tertiary and no you won’t drink it except for “show”. it has so much nitrogen and phosphorous in it that we’re at the limits of technology for treatment and release as effluent.

               do a little reading on TMDLs and see how that affects urban WWT plants.

               “Additionally, unlike thousands and thousands of septic systems (which after 10 years lose about 50% of their efficiency) a waste water treatment plant has to record and report its output on an hourly basis to ensure that they remain with critical thresholds. Being centralized helps in that case. For the county to go around and check on individual septic systems at that frequency would put every jurisdiction in the country into bankruptcy. I could wax poetic for another hour on this subject, but perhaps I’ll save that for another day.”

               if septic systems got compromised after 10 years – no one could live on that property any more , right? are you flinging data here? what’s the reality?
               Isn’t the reality that people live on property with septic tanks for decades?

               what you’re implying is that septic tanks are not sustainable – and if that were true – you’ve have no sprawl.. right?

               “The comparison is what is done now. The negatives of urban development were under older standards due to a lack of understanding on the impacts of those decisions. That was the era of urban sprawl.”

               I just thing when comparing.. need to keep the currency correct.

               “Urban areas don’t require subsidies because their assessed values are out of control high.”

               not true. they’re not paying for their externalities… they’re MORE EFFICIENT than less density but they STILL require enormous subsidies.

               ” Urban areas fuel non-urban areas. In NY the state is propped up by New York City. Hell even in Texas, look at the numbers, the cities are where the funds come from, Dallas, Houston, etc. To say that somehow cities are subsidized by suburbs is to say, the US economy would be better if NYC, LA, Chicago, DC, Boston, and Seattle didnt exist, if instead all areas looked like Hackensack New Jersey. There are lots of countries like that, they are typically considered third world economies though.”

               yadda yadda yadda.

               “Now, to the place where I agree. There are shades, its not clear cut. Your arguments are the area where there are shades, it is well known that by all measures SWM, Wastewater, and commute footprints are all considerably better with more dense urban development. Where it is a gray area is the components that create skyscrapers, and the environmental impact their manufacturing creates. Concrete, steel, glass, these are things with massive carbon footprints, have harsh chemical processes, require significant indirect environmental impacts.”

               until you show me streams running clear in urban areas.. or at least as clear as they run in the suburbs.. you have a problem.

               we get your.. “bio-solids” down our way – every day also.

               “When these are included, it becomes much more muddled as to whether a new LEED style high rise building is better than a typical subdivision home. So there are cases where some new high rise buildings are not great for the environment, if they incorporate the minimum, don’t use rapid growth materials, if they source materials from another country, etc. And there are certainly cases where single family homes can be extremely environmental sensitive (even zero footprint) if they use rainwater harvest, have filtered septic systems with polishing which is used to irrigate, if they have renewable energy sourcing, if they have low water and low energy appliances/fixtures; sometimes those things can win out against the negatives of more driving and more roads.”

               I don’t buy the “rainwater harvest” idea.. unless you’re going to tell me how much rainwater there is in a 2 inch rain event – and what you do with it.
               do you know how much water in gallons a 2inch rainfall generates on an acre of land?

               In the modern era of LEED and environmentally sensitive city designs (because after all most cities in the US are headed by those green hippies) most of the new buildings you see come online in cities are very very efficient and good for the environment. The same can’t be said for many of the sprawl, on the fringe, built on cheap green field, subdivisions that some of the good ole boys that I used to work for skirt by the local jurisdictions (who are trying to balance their budgets with RE taxes and don’t want to hold up any new developments).

               There is no good or evil. Single family homes are just as important as strong cities, and people aren’t evil for living in them. I am just addressing the idea that cities are worse for the environment, which is often not the case. It is to say, we should support better cities, ones that give options that reduce the impacts of suburban sprawl (sprawl being the expansion with out proper controls and regulations, skirted by as a local jurisdictions method for getting quick money).

               This is a tough discussion to have online of course, and my response is extremely long. These kinds of things really are better discussed over beer 😛

               I’m a supporter of more efficient development. I just object to the not really informative lop-sided claims that urban is better and suburban is bad..

               but do agree about the beer…

               😉

               my shtick here in BR to to seek the truth on all issues. I don’t always even do what I say is the goal but that’s the goal anyhow.. and if something is bogus.. then call it out… and get to the bottom of it.
            4. 

               Tysons Engineer

               April 3, 2014

               @Larry

               I can’t keep up the thread. Its too long, its getting to hard to split the stuff. Email me, hell I’ll even talk to you on the phone, but you need to study this stuff if you want to talk about it.

               10 yr vs 2 yr controls isn’t an improvement. 10 yr storm detention mean larger storage area for channel containment, but 2-yr is far more important to stream way erosion. Before you talk about the ineffectiveness of rainwater harvesting I think you should understand it better, for instance 2 and 10 yr control have nothing to do with nutrient removal, extremely minimal efficiency, really relies on settling when you talk ponding, and that means you gotta atleast hold the storm for 24-48 hours to get ANY kind of treatment. Its about half of what you get from filtration, infiltration. By far the best way is to reuse that water however, like with plants, because that is actual vegetated uptake.

               Whether 2.5 acres vs 69 acres are both the norms is inconsequential. You are off by orders of magnitude regardless when you are comparing suburban vs infill urban. But if you don’t believe me

               http://www.fairfaxcounty.gov/tysons/development/

               Follow the rabbit hole yourself. There is nothing that Tysons is doing that is ground breaking in terms of the modern urbanism movement. Its a rehash of whats been done in Arlington with slightly more density.

               Compare that to any other subdivision plan in the state of virginia you’d like. Every county has an public database, some even online. Pull out any plan, compare the impervious areas on a per dwelling or per desk basis, not on a per acre basis. For reference, 2.5 acres for 1000 dwelling units would be a high goal in Tysons, not because land developers want to be wider, but because the county is pushing back against taller. 1000 dwelling units would be about 900,000 sf, so that’d be a FAR of 8, hardly ground breaking for urban projects, but a little steep for long rooted legacy of suburbanism in NOVA. But change it as you like, the numbers will never equal what suburbia has to offer. 69 acres, or 50 acres for 1000 units, or hell 30 acres for really small 1000 units vs lets say 6 acres for 1000 urban dwelling units (now we are talking about pretty much every project in Tysons). You are still off by 5 fold on impervious area per person.

               On the 2yr question, are you asking for volume or peak flow? I assume peak flow since you keep talking about 2 decades old regulations that have been proven to be inadequate for avoiding eutrophication. In order to answer that it depends on your drainage area. Whats the time of concentration from the top of the watershed. In subdivisions, yer usually gonna get about a 15-20 minute for the most part but thats for the overall shed, for any given lot its 5 minutes to the back of most lots so you are talking about a intensity of 5.25 if I remember correctly (its been about 6 years now). So average C factor of 0.55, area of 0.046 acres, 0.13 cubic feet per second, enough to channelize on grass… so your theory that you can just make a ditch and the water disappears before getting to the next lot is incorrect. If you stagnate the water you may be able to get some percolation and uptake, but thats a storage issue, whole other game, you gotta use the total 24-hour event volume to figure that out. I highly doubt on your individual lot you have that in your ditch considering you likely aren’t impounding, unless you have a bioretention basin… then you got a chance.

               Problem with bioretention basins though, as the jurisdictions are finding out after years of me warning them, is that they need to be checked, just like septic tanks, otherwise their efficiency plummets as minerals get deposited at the interface between the mulch/surface and the actually percolating media. So you end up with them falling apart after 5 to 10 years (since most of these started in the early 2000s, we are now seeing exactly that).

               Your interpretation of where it is easiest to retrofit is completely on its head. I worked in land development, and I’m telling you, you couldn’t be more wrong. Whats easier to do, get 500 HOA members to agree to put a bioretention swale in their backyards with an easement to retrofit their outdated stormwater management system for their subdivision, or approaching 1 developer who owns the entire property, who is trying to upzone their property, to build a central facility that adds only $150,000 to the construction cost of a $65 million high rise? Come on man. Its another case of the perceived because of it being clustered versus the far worse condition in dispersion.

               Analogy. Some might say NYC has a ton of trash that is created. My god the piles and piles of trash. Now ask yourself, if your neighborhood had 8.5 million people in it, and 3 million tourists, do you think that your trash output of each of the homes housing these people would be more or less than a bunch of people who live in 800sf apartments?

               Just cause its all piled up in NYC doesn’t mean its more than all the trash being created in suburban florida. You just never get to see all that 8.5 million floridian’s trash in one place.

               I don’t know why you keep asking me about my credentials. I’m a P.E., my credentials are I passed 4 years in a bachelors of science from Virginia Tech, passed an 8 hour long test to get my EIT, worked in the field for 4 years, then passed another 8 hour test to get my P.E., and have continued to work in the field for a decade now. I have designed projects that are case studies in the subject, see Cougar Elementary School in Manassas Park which was one of the first LEED Gold educational facilities in the country.

               You said 2″ storm, again I think you mean 2-yr storm, and again your question is non-sense. If you are asking the peak intensity of a 2-yr storm I answered it above, but I’d like you to know that those intensities are dependent on hydrology of the watershed as well as which area you are in. Northern Virginia has a different one than Blacksburg for instance, and different from Virginia Beach for instance. If you are asking about the 2-yr SCS volume for Fairfax, then your precipitation that actually falls on a 2-yr 24 hour storm is IIRC 3.2″. Which means off of a direct impervious area you’ll usually end up actually have 95% of that in the form of runoff so ~3″. So a 2000sf roof would have about 500cubic feet of runoff. But no one in subdivision design controls for the 2-yr storage, the requirement for the state (the Richmond regulations you alluded to) is for the 90% storm, which is most storms that occur during the year, ie a total storm volume of 1″. Treatment of this volume is the most integral to preserving waterbodies as this type of storm is the one that happens the most, is the one that causes most of the nutrient and pollutant deposit that affects those waterbodies. For the 1″ P, you get ~167cubic feet or 1250 gallons (as you like it, though no one in SWM design uses gallons, thats typically used in plumbing engineering).

               But to my point, rain barrels for subdivisions IS extremely expensive per unit, and hence why you dont see many developers putting in these 1250 gallon tanks for each individual house. However, a 2.5acre high rise (like we keep coming back to for discussion purposes) would have 9075 cubic feet of runoff from the same 1″ storm, which would fit in a 8′ Tall x 30 Wide x 40 Long cistern, quite common in fact for urban projects. In fact I’m currently looking out of my high rise at one right now that serves my building which is located on P1 of my parking garage and has access hatches at the entry way drive to my garage. I can take pictures of it if you’d like, hell I can talk to some of the Clark boys building the high rise next to me tomorrow and see if they’ll let me open it up and take a picture inside to show you the size of it.

               That cistern tank (which I don’t have the full measurements in front of me) usually costs on the order of 250k to 500k (depending on just how big it is. And again, that is negligible cost to a developer if it means they can upzone to be taller on a $50 to 80 million building.

               Have I sufficiently proven my credentials? Do I have the job? Did I just write a dissertation? 😛

               Again, I’d be extremely pleased to discuss this with you, but I can’t keep going in this format.
            5. 

               larryg

               April 4, 2014

               re: thread length – yup.. break it up into discrete parts.

               in terms of “study”.. I can give links if you want to back up what I’m saying.

               re: 2yr vs 10 yr.. check the regs and the reason why the stricter regs, TE.

               10 yr vs 2 yr controls isn’t an improvement. 10 yr storm detention mean larger storage area for channel containment, but 2-yr is far more important to stream way erosion.

               the larger the volume and the longer it flows the more stream erosion you’ll have.

               re: Before you talk about the ineffectiveness of rainwater harvesting I think you should understand it better, for instance 2 and 10 yr control have nothing to do with nutrient removal, extremely minimal efficiency, really relies on settling when you talk ponding, and that means you gotta atleast hold the storm for 24-48 hours to get ANY kind of treatment. Its about half of what you get from filtration, infiltration. By far the best way is to reuse that water however, like with plants, because that is actual vegetated uptake.”

               rainwater ‘harvesting” define the time. what it is is simple sequestering of water for re-use for landscaping, etc but you have to have a large enough place to store large volumes or else it’s just fluff … so you can say you are “harvesting”.
               what are the standards for it to be effective? are you suggesting that it would replace a storm pond? be specific.
               I never said nor implied it was related to nutrients Nutrients come from impervious surfaces – like pet poop, and from fertilizer runoff, but LOT of it in the rivers comes from what does not get taken out at the WWT plant.

               “Whether 2.5 acres vs 69 acres are both the norms is inconsequential. You are off by orders of magnitude regardless when you are comparing suburban vs infill urban. But if you don’t believe me

               http://www.fairfaxcounty.gov/tysons/development/”

               this is a link to development guy not mitigation of development with regard to storm water runoff. what’s the point of the link?

               “Follow the rabbit hole yourself. There is nothing that Tysons is doing that is ground breaking in terms of the modern urbanism movement. Its a rehash of whats been done in Arlington with slightly more density.”

               I’ve never argued otherwise.

               “Compare that to any other subdivision plan in the state of virginia you’d like. Every county has an public database, some even online. Pull out any plan, compare the impervious areas on a per dwelling or per desk basis, not on a per acre basis. For reference, 2.5 acres for 1000 dwelling units would be a high goal in Tysons, not because land developers want to be wider, but because the county is pushing back against taller. 1000 dwelling units would be about 900,000 sf, so that’d be a FAR of 8, hardly ground breaking for urban projects, but a little steep for long rooted legacy of suburbanism in NOVA. But change it as you like, the numbers will never equal what suburbia has to offer. 69 acres, or 50 acres for 1000 units, or hell 30 acres for really small 1000 units vs lets say 6 acres for 1000 urban dwelling units (now we are talking about pretty much every project in Tysons). You are still off by 5 fold on impervious area per person.”

               you’re mixing things up here. the impervious “footprint” of suburban structures is “known” and in fact being incorporated into some storm water ordinances – i.e. compute square feet of impervious surface, rooftop plus driveway..etc and multiply by fee. so storm water has a direct cost and people are going to pay for it..

               What I’ve objected to is the unsubstantiated assertions about suburban subsidies and what I’ve got is not real data but hand-waving which in the case of storm water – is not good when looking at the actual runoff issues.

               both urban and suburban have issues as opposed to one being “subsidized” and the other in compliance …

               stormwater is a huge problem in places where most of the land is impervious surfaces – no matter the density – it just so happens that density pretty much requires impervious surfaces… and right now they are NOT mitigating it – just look at the problems in NoVa with stormwater runoff right now.

               “On the 2yr question, are you asking for volume or peak flow? I assume peak flow since you keep talking about 2 decades old regulations that have been proven to be inadequate for avoiding eutrophication.”

               talking about both but stormwater is about volume AND peak flow AND duration AND intensity – and it’s a separate issue from Eutrophication in the storm pond itself. Eutrophication involves the larger bodies of water – water supply reservoirs like Occaquon, and lower rivers near their mouths with the Bay. Eutrophication is from all sources of nutrients – from beef/poultry, to landscaping fertilizer – both suburban and urban, as well as impervious surfaces not sequestered and storm ponds themselves.

               the new regulations for storm water encompass not only volume/capacity, peak but water quality, i.e. possible treatment before release.

               you need to be thinking about CSOs in urban areas and why they are a problem and what the solution will be.

               when you have a large storm event – the treatment facilities are overrun because they do not have enough capacity storage for the larger storm events.

               the same is true of storm water except they are not point source like the WWTPs

               ” In order to answer that it depends on your drainage area.”

               it’s a calculable number.

               re: ” so your theory that you can just make a ditch and the water disappears before getting to the next lot is incorrect.”

               it’s not a theory – it’s a practice. it’s an engineering solution to determine what kind of structures work and their needed size – to reduce the size of the storm pond relative to how much the LID took care of.

               ” If you stagnate the water you may be able to get some percolation and uptake, but thats a storage issue, whole other game, you gotta use the total 24-hour event volume to figure that out. I highly doubt on your individual lot you have that in your ditch considering you likely aren’t impounding, unless you have a bioretention basin… then you got a chance.”

               it’s a engineering issue.. but in places where you have land – you have those options including the storm pond itself if the land is not suitable for LID.

               we use storm ponds down our water for ball fields now. they catch the runoff then with pumps use it for irrigation … that’s ONE approach, not the only and it’s not a theory -it’s an engineering and compliance issue with the standards.
               and it’s every bit ‘harvesting’ rain as any technique but the issue is not the use of the word “harvest” but in performance. HOW MUCH are you “harvesting” for a given impervious surfaces and how are you holding/sequestering it?

               “Problem with bioretention basins though, as the jurisdictions are finding out after years of me warning them, is that they need to be checked, just like septic tanks, otherwise their efficiency plummets as minerals get deposited at the interface between the mulch/surface and the actually percolating media. So you end up with them falling apart after 5 to 10 years (since most of these started in the early 2000s, we are now seeing exactly that).”

               they don’t “fall apart”. they require maintenance. just like septic tanks do to maintain their performance. If they do “fall apart”, they have to be rebuilt and restored to the performance called for in the permit.

               “Your interpretation of where it is easiest to retrofit is completely on its head. I worked in land development, and I’m telling you, you couldn’t be more wrong. Whats easier to do, get 500 HOA members to agree to put a bioretention swale in their backyards with an easement to retrofit their outdated stormwater management system for their subdivision, or approaching 1 developer who owns the entire property, who is trying to upzone their property, to build a central facility that adds only $150,000 to the construction cost of a $65 million high rise? Come on man. Its another case of the perceived because of it being clustered versus the far worse condition in dispersion.”

               500 HOA members have to agree on what options they can choose from to meet the new regs… the new regs put that on the county – to implement by collecting stormwater fees from owners including HOAs to then use the various options available – for instance, if the HOA does not want swales, they might have to build a bigger storm pond or they might have to buy a share of a new regional storm pond.

               I’m not focusing on what specifically needs to be done or is done – that’s an engineering and enforcement issue that has myriad aspects to it.

               what I’m focusing on is the “suburbs are subsidized” issue with respect to storm ponds and pointing out that it’s not an issue where urban is fine and suburbs need “subsidies”. It’s a big problem in both locales and is going to require substantial remediation which is costlier if you don’t have a lot of available land for more storm ponds.

               “Analogy. Some might say NYC has a ton of trash that is created. My god the piles and piles of trash. Now ask yourself, if your neighborhood had 8.5 million people in it, and 3 million tourists, do you think that your trash output of each of the homes housing these people would be more or less than a bunch of people who live in 800sf apartments?”

               you don’t have to convince me of this .. I agree.. but I’m pointing out to you that they still have to get rid of it – and it’s not taken care of by using the land in their jurisdiction (like it is in the suburbs). It, like the treatment plant bio-solids relies on “external” places to put it… a de-facto land subsidy so that urban can function.

               “I don’t know why you keep asking me about my credentials. I’m a P.E., my credentials are I passed 4 years in a bachelors of science from Virginia Tech, ”

               pretty sure I have not asked you about yours. I’m pointing out that some studies are not well done to relevant and important standards but do a lot of unsubstantiated hand-waving – when instead they could be making much more convincing Prima facie cases using real and honest data and comparisons. I accept and respect your credentials BTW but I also know BS when I see it.

               the assertions about septic tanks and drain fields is a good example. They”ve been around for decades including in areas like Occoquan where you actually COULD run a study to see what comes from the septic tanks/drain fields and into the reservoir – what things and at what rate.

               has anyone actually run a study to see if pharmaceuticals do that or not? They hardly have data for nitrogen and phosphorous transport and much of that is more speculation than actual instrumented results.

               “You said 2″ storm, again I think you mean 2-yr storm, and again your question is non-sense. ”

               I was using short-hand. Let me revise this to say current and proposed standards. So do you know what they are ?

               do you know what a standard that requires pre-development replication of the runoff means?

               http://vwrrc.vt.edu/vwmc/pdfs/lid_followup_presentations/Part_IV_Site_Plan_Review_Handout_format.pdf

               “If you are asking the peak intensity of a 2-yr storm I answered it above, but I’d like you to know that those intensities are dependent on hydrology of the watershed as well as which area you are in.”

               it’s more than intensity – see the standards.

               “Northern Virginia has a different one than Blacksburg for instance, and different from Virginia Beach for instance.”

               you have to meet the defined standard for the site in question which is handled differently for each site depending on factors such as soil, hydrology, slope, etc.

               you need a credentialed scientist and engineer who understand the standards to produce a design appropriate for the site that meets the performance standards in the permit.

               re: ” Treatment of this volume is the most integral to preserving waterbodies as this type of storm is the one that happens the most, is the one that causes most of the nutrient and pollutant deposit that affects those waterbodies. For the 1″ P, you get ~167cubic feet or 1250 gallons (as you like it, though no one in SWM design uses gallons, thats typically used in plumbing engineering).

               cubic feet per second .. 7.48052 gallons in a cubic foot… or use acre feet.

               one is volume but when you add time… per second.. it’s volume flow per time unit.

               “But to my point, rain barrels for subdivisions IS extremely expensive per unit, and hence why you dont see many developers putting in these 1250 gallon tanks for each individual house.”

               how much water from a 2yr or 10yr event do they retain? how much water comes off the roof ?

               “However, a 2.5acre high rise (like we keep coming back to for discussion purposes) would have 9075 cubic feet of runoff from the same 1″ storm, which would fit in a 8′ Tall x 30 Wide x 40 Long cistern, quite common in fact for urban projects.” that’s 9075 x 7.48052.

               thats more than 60,000 gallons, right? I get a 20 foot diameter and 50 foot long or some combination. what happens when you get a 10 or 20 year event? where does the excess that you cannot store go?

               ” In fact I’m currently looking out of my high rise at one right now that serves my building which is located on P1 of my parking garage and has access hatches at the entry way drive to my garage. I can take pictures of it if you’d like, hell I can talk to some of the Clark boys building the high rise next to me tomorrow and see if they’ll let me open it up and take a picture inside to show you the size of it.”

               I LIKE parking structures.. they are the way to go in urban areas.. but how much water are you storing at your site for runoff?

               “That cistern tank (which I don’t have the full measurements in front of me) usually costs on the order of 250k to 500k (depending on just how big it is. And again, that is negligible cost to a developer if it means they can upzone to be taller on a $50 to 80 million building.”

               actually the one’s I’ve see have drains in the bottom to slowly release into the ground layers below. you could have one to keep enough for landscaping, etc and have others that meter out underground if the soil/hydrology work.

               Have I sufficiently proven my credentials? Do I have the job? Did I just write a dissertation? 😛

               Again, I’d be extremely pleased to discuss this with you, but I can’t keep going in this format.

               rather than wide ranging… on smart growth.. smaller bites.. on specifics.. over time.

               you don’t have to prove your credentials but please understand that even highly credentialed folks do blow it out the other end … in person, in writings and in “studies”.

               not saying that about you – just that I respect the credentials but I also respect the argument and the data and I do recognize BS when it gets involved.

               remember – the subject here is comparing the burbs to urban in terms of “subsidies” … like .. in this case ..storm water.

               the more density you have the more efficiencies you have – yes but when it comes to environmental – it’s tougher because the way we primarily mitigate environmental is land and water .. and presumed dilution ..then treatment for water quality but storm water volume and intensity destroys watersheds and most urban areas have watersheds unless they are located in desert locales.
            6. 

               Tysons Engineer

               April 4, 2014

               Larry,

               You are giving me a near impossible task, to translate to the layperson what would typically be covered in a book.

               Honestly, and sincerely, email me through my website and we can set up a time to talk about it on the phone. I am willing to give part of my day to the discussion because it is part of the engineers cannons to help educate the public and because I think it is extremely important to the development process.

               Until then I will continue this.

               The 2 yr vs 10 yr vs larger design storms that you are talking about is really complicated. You keep saying 10 yr is better than 2 yr and bigger storms to control are even better. This is #1 the biggest misconception you have. The bigger the storm that you detain for does not necessarily mean better control. They serve different purposes but before I continue let me explain to you something.

               They are all done already, by state regulations, which by the way have lagged northern virginia requirements by 2 decades. Everything you are saying, has been a requirement of development in Fairfax, Prince William, Loudoun, Stafford and even Fauquier for the past 20 years. You are talking about SWM standards, instead of BMP.

               Every single site in the link I sent you has a stormwater management plan which controls the 2 and the 10 year plan because it is a requirement, hell its a pre-requisite, its the very first thing you must show. But it doesn’t work the way that you say.

               On top of all of that, every plan also has to show pollutant removal, thats where it gets complicated and where subdivision developers cheap out and put in dry ponds, which have the least impact to pollutants. The reason you see ponds isn’t because they are the best, look through any regulation of stormwater (where jurisdictions have instituted) any where in the country, they are the minimum, they are the cheapest to perform.

               Dry ponds by themselves don’t meet standards for urban projects. When you say the 2 yr and 10 yr are more important, subdivisions don’t do anything with those except slowing the flow (not the volume) to a sufficient peak point so that it doesn’t over come the channel below.

               Thats great, thats a good first step to reduce peaks, but its no where near enough to protect water bodies, you still have extended periods of time where the channel experiences increased flow rates.

               I don’t know what I can do to help explain it through this writing, but you really need to read the actual “richmond (cute cause they adopted what NOVA has been doing for a long time) regulations”.

               Regs that are in place since 1999
               http://www.deq.virginia.gov/Portals/0/DEQ/Water/Publications/HndbkVolumeI.pdf

               New discussions in Virginia that model the Maryland model
               http://www.deq.virginia.gov/Portals/0/DEQ/Water/Publications/BetterSiteDesign.pdf

               Marylands regulations which have been in front of Virginia’s (as a state, again NOVA has already incorporated this stuff to a large part)
               http://www.mde.state.md.us/programs/Water/StormwaterManagementProgram/MarylandStormwaterDesignManual/Pages/programs/waterprograms/sedimentandstormwater/stormwater_design/index.aspx

               The Northern Virginia BMP handbook, which has been regulations for the past 2 decades
               http://www.novaregion.org/DocumentCenter/Home/View/1679

               Read those documents. You’ll find time and time again layouts associated with suburban models (cul-de-sac, long roads, decentralized design to ponds) are negatives that are now being mitigated.

               I hope you take up my offer to discuss on the phone.
3. 

   TMT

   April 3, 2014

   Density requires mass transit, which is incredibly expensive. Sprawl requires lots of roads, which are incredibly expensive. Development is costly. Instead of focusing on density or sprawl, we need to look at ways to provide infrastructure on a more fiscally sound basis.

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   1. 

      Tysons Engineer

      April 3, 2014

      But mixed use development near existing TOD is not expensive per return on tax revenue and per capita. I think that is the point of sprawl vs non sprawl. You can’t call infill (around TOD) sprawl, its the opposite of such. So in that way the question isn’t necessarily density or not, but development around existing assets or not.

      If the infrastructure is there, we should leverage it to the greatest extent possible because your dollar to dollar return vs green fields is significant. Tysons is already showing that with the increase from 2000 to today being $7 billion in land value and rising.

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      1. 

         TMT

         April 3, 2014

         TE, Tysons needs a huge amount of expensive infrastructure to work. I am not arguing that the same amount of development could be built in other locations for less or for more. I don’t know. But I do know that Tysons is incredibly expensive from an infrastructure standpoint. Dulles Rail, other transit, massive road improvements, parks, civic facilities, storm water, schools, and on and on. I don’t expect Tysons will ever have any positive impact on residential real estate taxes in Fairfax County.
         Having said this, I agree with you we need to take best advantage of the infrastructure in Tysons. I voted last night at an MCA board meeting to support Cap One’s revised development plans.

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         1. 

            Tysons Engineer

            April 3, 2014

            At a land value of $11.8 billion today, let alone the $20 billion rise if you keep the same ratio psf in todays dollars for future growth already in the pipeline, how do you figure it doesn’t pay for itself?

            I really want to see the numbers that support that statement. I personally have run through every single parcel in the Tysons district and gotten that 11.8 billion.

            11.8 billion with an average RE tax (ignoring C&I) including the special tax comes out to $177 million per year, right now. Show me how that annual amount doesn’t equal what Tysons uses.

            3.1 billion for Phase 1 spread over 35 years (2050 plan) = 88.5 million per year

            2.5 billion (minus the in lieu road grid that is not a public cost, but still includes infrastructure thats not even in Tysons) for “road infrastructure” spread over 35 years (Table 7) = $71.5 million

            That 2.5 billion assumes the needs IF the full build out were to happen, do you not agree it would not fully be needed if only a portion of that were to happen, and surely would be far less if we are talking about just today’s infrastructure needs?

            Thats $160 million per year vs the 177 million per year generated already.

            I suppose you could throw in the school system costs also. $12,000 per child per year, currently there are ~1000 school aged children out of the 19,000 residents, so that is a cost of $12 million.

            So even with all those costs, including future build out of all of the infrastructure in town, despite not considering future build out taxes, becomes a surplus of $5 million. And that doesn’t even consider the state funds that help with education, and not to mention the massive state sales taxes and income taxes generated from Tysons.

            But is that a fair assessment? What if you included reality, of the build out which is tied to that $2.5 billion, what then?

            Total build out in the pipe line (which is still conservative because the 2.5 billion for infrastructure actually allows for another 50% more sf, but I’ll be conservative for you) would mean a land value of 30.8 billion for annual revenue of $462 million.

            With that comes the additional school age population. Lets say magically it rises to the population ratios of the rest of the county (despite this being for multi family which has far smaller school age populations). 16,000 students out of the future population 100,000 in any given year (16% of 1.2 million residents are in public schools in FFX Co per citydata stats).

            The school costs become a fairly sizable $192 million per year.

            Everything else stays the same so total costs annually are $352 million.

            Meaning a net revenue surplus of $110 million PER YEAR from Tysons.

            I have the numbers. Where are yours that back your assertion?

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            1. 

               TMT

               April 3, 2014

               TE, No one argues Tysons doesn’t pay a lot of taxes. But it is also receiving a lot of tax and fee dollars from others. Federal taxpayers funded $900 M for the Silver Line, Phase 1. DTR drivers are paying billions in tolls. 90% of the costs for necessary road improvements outside Tysons, but necessary for Tysons to grow, are paid by regular taxpayers. (For example, the replacement of the Lewinsville Road-Great Falls St. intersection with 123 with an overpass will be paid 90% from general taxpayers.) All non-rail transit costs are being paid for by ordinary taxpayers. The entire C&I tax from the county will be used for Tysons improvements. The business in Annandale is going to pay for Tysons through C&I.

               This is not to say Tysons contributes nothing. It contributes a little less than 10% of county real estate tax revenues. But Tysons is no Prudoe Bay that sends checks to Alaska residents each year. It’s not the Iron Range in Minnesota that provided residents with the lowest real estate taxes in the state, with some of the best school facilities.

               The R-B corridor in Arlington contributes about 25% of all the county’s real estate taxes. And probably very little before it was redeveloped. Tysons produces about 10% as a sprawling office park. No one thinks it will produce 25%. Heck, Ed Long worries that all commercial real estate in the county will not get to 25% – the goal. From that standard, Tysons falls way short of the R-B corridor.

               Finally, I’ve asked county officials whether they think new tax revenue from Tysons will be sufficient to lower residential real estate taxes. To date, no one has said yes. Tysons is important, but far from the County’s savior.
            2. 

               Tysons Engineer

               April 3, 2014

               I hope to goodness you don’t take care of your own finances the way you do public financing.

               You bring up the 900 million in fed funds, and the toll roads (28% of the phase 1 coming to 1.4 billion total. Did you notice I already took that into account with the 3.1 billion (which also includes a private garage btw).

               Its all dollars.

               You want to keep it separate? Whether you include them as one fund counterbalanced by the RE taxes or you exclude it, the revenue from Tysons remains, all you do is change the surplus to be greater.

               I provide hard numbers, CONSERVATIVE ones at that which included ALL numbers. You bring up the 90% of outside etc, that is already part of the 2.5 billion I already stated.

               You are double counting costs and that is a lie to the people on this thread. It is a pure and out right lie. But I’ll do the hard work, and dispute your claims because I unlike you believe that information proves the case.

               Tysons remains generating the $177 million per year which hopefully you do not dispute because I really don’t wish to upload my database of tax assessments within the district.

               In your scenario, you want to remove the contributions that came from non RE sources, and remember I haven’t even included the generation of RE revenue in Reston at Wiehle. Ok, that leaves a silver line phase 1 cost of 1.7 billion (conservative because I still keep the garage cost despite it being private). Over 35 years that is $48.5 million per year.

               Next you want to call the 90% of outside tysons infrastructure which is paid by Billy in Centreville, ok the inside Tysons infrastructure is $1.3 billion per Table 7, again spread over 35 years, at $37.1 million per year.

               Now the schools at $12 million per year, that stays the same. So a total of $97.6 million per year that acts against the $177 million for a surplus of $79.4 million.

               Spread over 35 years that is $2.78 billion in surplus. That counter balances your 1.4 billion paid for by Federal sources and toll road users, with a remainder of $1.38 billion. Then the infrastructure, sub 1.2 billion per table 7, which leaves again, a surplus of $180 million over the next 35 years.

               That money, means yes in fact Tysons does subsidize the remaining real estate funds necessary for the county.

               But wait theres more! Because again, you continue to ignore that Table 7 is development triggered ONLY. Those costs are ghost costs built only if density increases in Tysons. Therefore if you want to include the Table 7 costs, then you also must include the Comp plan density.

               The additional $20 billion in land value increase that occurs from just the projects in the pipe line (constituting 50% of the total possible amount that would trigger all table 7 costs by the way, so I am even helping your argument) comes out to 300 million dollars per year ON TOP of the already existing surplus above that already pays for all of that. Sub the 180 million per year for schools for the extremely conservative 16,000 students from the district, for a total surplus of $120 million.

               That is $4.2 billion dollar increase in revenues coming to Fairfax because of Tysons development over the next 35 years, plus the 180 million that would occur even if table 7 and the silver line were completely paid for by Tysons without new development.

               For a grand total of $4.38 billion coming to the county in the form of surplus over cost. Yes, that does go to counter balance the requirements from all needs around the county. Whether or not a county official will tell you they will lower the tax rate is a specious argument. The 4.38 billion doesn’t disappear, it’s there and it will continue to help fund the county.

               At its heart your argument is shallow. You note that Tysons makes up 10% of the counties revenue. Great. Now show me how the heck the county spends 10% of its costs IN TYSONS. It doesn’t, that would mean 400 million is being funneled into Tysons every year which is flat out not true.

               So once again, I have addressed your arguments with hard numbers. I await your response of “nuh uh big buildings are bad”
         2. 

            Tysons Engineer

            April 3, 2014

            I am glad the MCA has moved forward with Capital One, its going to be an important economic stimulus to our region helping to diversify the business that we do here in Fairfax and the building will put us on the map by being the tallest in the region (and even better its to house more Capital One future employees).

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4. 

   larryg

   April 3, 2014

   there is another indicator of “sprawl” and that is homeowner insurance.

   why? because homeowner insurance for properties that are not near fire hydrants and fire stations is much more expensive.

   so you could probably get a pretty good map of at least some threshold of “sprawl” by looking at a water/sewage system map.

   look at a place like Loudoun or even parts of Fairfax – and ask where the water and sewer is NOT present.

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5. 

   larryg

   April 4, 2014

   TE – I have another post that is awaiting moderation but this is the kind thing I am talking about for storm water:

   http://chesapeakestormwater.net/wp-content/uploads/downloads/2012/02/Intro-for-New-VA-SWM-BMP-Design-Specs_Final-Draft_08Mar2010.pdf

   the point of the 2yr and 10yr is shorthand for the conditions that would have to be accommodated in the design and performance of the facility.

   even then – there is no real standard and provisions for higher storm events.

   the higher the storm event – the more water, volume, longer duration, the more difficult to design a facility to handle and it usually boils down to some kind of surface retention… dry ponds, etc..

   these types of sites are harder to come by in urban areas and more expensive usually than other options that are not available in urban areas.

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   1. 

      Tysons Engineer

      April 4, 2014

      You keep seeing ponds and thinking they are big so they are good. You are not looking at it as a per capita.

      A 1000 person apartment provides the exact same controls, the size is smaller because it has less impervious area therefore less runoff. These are all requirements of ALL developments, not just subdivisions. My building has a cistern that provides more controls than typical subdivision ponds. It has a filtration system that removes TSS as well as a far greater percentage of nitrates and road grit. It has harvesting to irrigate. It not only reduces the 2yr peak and 10 year peak runoff flows (the standard for ponds) but it actually reduces the total volume to be the same as the natural condition. Hydrographs aren’t volume, they are peak amounts, and to date that is the only thing that the state of virginia has required in terms of stream protection.

      Unfortunately that doesn’t go far enough, what you end up with is during storm events there isn’t a massive single plug of water that causes erosion, but the stream does have to control far more water because the volume hasn’t been affected on bit. All of that runoff still is there, it is simply detained (hence the term detention pond). It still exists, it still causes the same amount of pollution essentially, stream water temperature increase, and some levels of channel erosion (though better than if not controlled). Highrises on the other hand are typically following LEED requirements, which are more stringent, require controlling not just flow, but volume and temperature meaning they not only capture and slow, but they actually reduce the total amount that runs in the stream to the natural levels as if no development occurred.

      This isn’t the case in subdivisions. There may be a dozen or so subdivisions in the entire state that have been LEED certified, let alone LEED Silver or Gold. The vast majority of new construction that meets LEED is in urban developments becuase there the cost to provide better design is minimal to the overall cost of the project (1-2.5%) where as in subdivisions it can be quite cumbersome compared to the whole cost of the project.

      A 2.5 acre urban development that meets LEED 6.1 and 6.2 is far FAR FAAAAAAR superior to one that simply meets old Virginia regulations, and still better than even the newest Virginia standards that are in the pipeline (which are an improvement but still a long way from restoring our waterways).

      Your point that “these sites are harder to come by in urban areas” is absolutely on its face not true. Its is false. It is a misconception. I can look out my window and see 5 sites right now implementing LID development with green roofing, cisterns, bioretention, and filtration, and pervious pavement all of which not only reduce the peak flow but the total volume of the development. Now find me a comparable scenario in the suburbs. It doesn’t exist.

      If you follow the link to the tysons development projects, actual click of the FDPs and CDPs, scroll to the storm water management plans which are a requirement for each, you will find the information you are looking for. Its the norm, its the typical, its the requirement for all urban projects in Tysons.

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6. 

   billsblots

   April 4, 2014

   Thank goodness for the scroll down button.

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7. 

   larryg

   April 4, 2014

   re: regs – TE – are you aware that DEQ now has responsibility for storm ponds and that new regs go into effect on July 1 that implement additional standards and counties and places like Richmond are now creating tax districts or assessing storm water fees based on impervious surfaces?

   remember – the issue here is – subsidies for sprawl.

   and what I’ve pointed out is that storm water is a problem both in the burbs and the urban.

   you say NoVa is ahead of other places. Are you aware that Fairfax is suing the EPA over stormwater – that applies to all Va localities?

   to what do you attribute the existing storm water problems in NoVa to if you’re already doing what needs to be done?

   and how would you fix the current issues in NoVa over storm water?

   once you exceed the design capacity of a storm water facility, no matter what 2yr or 10yr standard (or others).. what happens?

   isn’t what happens essentially similar to the CSO issue where water that tops the existing facility capacity – either has to be held/stored or released into the watershed?

   I have no ax to grind here other than represent the facts.

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   1. 

      Tysons Engineer

      April 4, 2014

      I am aware of all of that. But you are confusing existing conditions and current development.

      Sprawl is sprawl. Sprawl can be high density, sprawl can be low density. Sprawl isn’t a measure of density, it is a measure of whether the construction of something new mitigates what is new to ensure no impacts to other parties. Other parties can mean transportation (for instance making sure that new units are tied to proffers and contributions to new roads), to schools (again through proffers and payments to fund the new schools) or to waterbodies (by ensuring that they control runoff to avoid impacts to downstream).

      The problem wasn’t that Fairfax was dense, its that when all of that development occurred in Fairfax, it was sprawl. The county in the 60s and 70s had no requirements for controlling the runoff. In the 80s and 90s they barely had any also. So millions and millions of square feet of suburban development (what was most of the development in Fairfax between 1960 and 1990s) came online with all this new impervious area, and very very few ponds and other measures to actually address it.

      Since that time, countless studies have researched the impacts of not controlling runoff to show how stream beds have become eroded, how pollutnats have caused fish kills, how all sorts of bad things came out of the lack of control.

      Flash forward to current design standards. All new developments in Fairfax in the 2000s required 2yr and 10 year controls, because they learned. Virginia followed on and also made that a requirement, because they learned and didn’t want that kind of stuff to happen elsewhere in the state.

      Thats great, thats a really good first step to help reduce the impacts of new development, and I would say it was the first steps again sprawl impacts on waterbodies. But it doesn’t address anything except peak flow. We still have water body issues now regarding pollutant loads, which are not properly met by simply detaining the 2 and 10 year storm. Those regulations are not yet state wide, though the new regulations would make it so. This requires additional controls, like bioretention, like filters, which can actually remove nutrients from runoff that cause fish kills and dead water bodies etc.

      Those are the next steps.

      However, for the past decade this thing LEED has existed. It incorporates those standards already, and even goes another step further to say, water temperatures are also important to how a water body can handle development. And so is total volume which can (on a slower basis) cause erosion. So in LEED there are now more standards to actually control the volume so that when rain falls on a project (of any kind) it is as if it mimics the existing condition entirely. Volume, runoff peak, temperature, and nutrient loads are ALL addressed this way.

      To date Virginia has not adopted LEED requirements, Maryland is moving close and 99% of the way there. So the only way that LEED gets incorporated in Virginia right now is on a voluntary basis or specifically from jurisdictions that require it. To date, no county has required ALL projects in the county to meet LEED, however, in urban districts like Arlington, Tysons, Reston all new projects (ie urban infills) must be. So in this way, subdivisions that come up in Prince William for instance, only meet a very limited requirement, while skyscrapers in Tysons actually have to go much farther. The reason why this distinction is made is because it can be. If the county were to require all new homes to have LEED, then no new homes would get built. It simply wouldn’t happen, the construction funnel would shut down on those projects because economically it would be very difficult to meet those standards. Whereas with urban projects, the cost is already built in to other functions of the project, whether it be the construction of a concrete vault (which would be a hardship for house builders but quite simple for a high rise) or pervious pavement (which again would be the difference between profit or loss for a home builder, but is fairly insignificant for a high rise road way).

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8. 

   Tysons Engineer

   April 4, 2014

   I think the basic misconception at heart in Larry’s arguments, after having read through all of this again, is that he believes the subdivision storm ponds that go in hold onto the volume difference between pre developed and post developed conditions.

   That is not true.

   They hold onto the peak flow difference between pre-developed and post developed conditions.

   If a developer were developing a 200 lot subdivision with (as you wish 2500 sf impervious per lot) on quarter acre lots.

   2500sf x 200 = 50,000 sf of total impervious cover.

   The 10 year 24 hour rainfall in “Virginia”(depends on each jurisdiction) is about 5.5″ anywhere along the coastal jurisdictions (mountains are less because they don’t typically see Type II tropical storms which set that number).

   Ok 5.5” x 500,000 sf = 229,166 cubic feet. This is actually not the real calculation because what you actually do is set a CN factor to all surfaces, as even grass areas contribute in watersheds to total runoff. But in this scenario Ive simplified it since it is your opinion that a 1/4 lot will have the same hydrology in the post condition in the pervious areas as it did in the original forested case. Again thats not true, lawns actually have about a 30% increase compared to forests, but I’ll play along for you.

   229,166 cubic feet is about 4 times the size of the actual size that the pond would be in order to meet both current and planned regulations. That is because in the current regs (not LEED but state of Virginia) all you have to do is slow the runoff, not hold onto it. So instead of SCS they use rational method.

   http://wgbis.ces.iisc.ernet.in/energy/water/paper/urbanfloods_bangalore/Runoff%20Hydrograph1.jpg

   That is a typical uncontrolled development. So your predeveloped condition has a natural flow, the volume is lets call it X, which is the total area under the curve. When a new development (any kind) comes in, if it doesn’t have any controls you get the post developed condition that is shown. The peak is higher and the volume under the curve is higher.This is because the runoff is both sped up (and concentrated) and you reduce the absorption through natural conditions (from grass, trees, and slow flows).

   Ok still following? So in any project without runoff controls that is what happens. Then when a designer looks at VA SWM requirements, they must reduced that peak height (not the area, but the actual height on the Y-Axis) to be equal to or less than the pre height (not area but actual height on the Y-Axis).

   So a typical VA SWM required facility will then detain the flow to create the following characteristic

   http://www.elibrary.dep.state.pa.us/dsweb/GetRendition/Document-48473/html/index34409.png

   Which ok, great the peak volume has been reduced to pre-developed. This keeps most erosion that occurs on channel banks reduced because it is that initial plug that comes through that can really tear away if its uncontrolled. But notice, that the volume is still much higher than the existing condition. Thats because the pond doesn’t remove any of the flow (unless you have exfiltration through percolation which is a different kind of facility uncommon in Virginia subdivisions).

   So yes, you’ve controlled that flood plug, but you actually have increased the overall volume processed in that stream during large storm events, which still means that you are depositing more pollutants, you are still causing the stream temperatures to rise, you are still causing some levels of change to the natural condition.

   Now review a system which actually reduces volume. Theres really only 3 ways one can remove volume. You can reuse it (either in irrigation or process functions like cooling loads), you can infiltrate it (like infiltration basins or sand filter vaults), or you can biologically transpire it, through sucking it up through roots and natural systems. Volume is the LEED requirement for 6.1. Ponds in subdivisions don’t meet this requirement because to do so you would need to have storage of the 200,000+ cubic feet, it makes for massive land areas and you need to plant them with wetland zones, you need to provide meandering in the system to mimic natural wetlands. Not many sites actually do this, the few that do pay a price cause it is expensive relative to the cost of the 200 homes.

   A LEED projects hydrograph not only de-peaks (detains which is a requirement in all of Virginia for all projects) but it actually reduces the area under neath the post developed conditions to the same volume as the pre-developed condition. IE, down stream, the stream has the exact same conditions as if the development never occurred, not just a mitigation for the worst moment of a storm.

   LEED projects are the norm for urban development. It is. Even in Dallas (the heart of texas) they require LEED Silver for any new high rise. Same in DC. Same in Tysons. And as I’ve said before, the stormwater management credit is one of the easiest to meet for these types of developments, because the increase in cost (with already constructed concrete on site) is minimal. An 80 million dollar high rise spends more in financing interest in a month than it costs to build a cistern, so its easy for them to make the jurisdiction happy and put one in becuase it doesn’t reduce how much density they have, it doesn’t require expensive land.

   A subdivision however, can’t provide the 200,000 cubic feet, because that would likely need to fit on a 2 acre portion of the site for a 200 unit 1/4 acre lot site, thats a loss of 8 units. That, even without the 150k in actual construction, in of itself means a likely loss at the end of the project, or at a minimum a significant drop in profit. So instead, they meet the standard Virginia requirements (in order to get approval) of 2-yr and 10-yr peak detention. That means for 200 lots like the ones we are using in this scenario, a pond of around 50,000 to 60,000 cubic feet. Again, go look up some subdivision plans which are pubicly available in your County’s offices if you don’t believe me. That 50,000 to 60,000 cubic feet means a likely footprint of around 1/2 an acre, or 2 lost units. That is the difference between making money (an extra 6 units could mean an extra $1million in profit for the builder) or taking a loss… or atleast less money. 200 lots after construction costs, in a hot neighborhood, might end up making a builder $5,000,000 after you remove what they have to pay to banks, etc. Losing $1M of that profit is a significant hit. Hence why you don’t see them going above and beyond very often.

   I hope this makes more sense to you.

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9. 

   larryg

   April 4, 2014

   actually, yes.

   on the volume – the idea is to cut the peaks and the tradeoff is to meter out the higher volume over time and if you have enough capacity in the retention facility.. you can keep the increase volume flows lower by metering over even longer times.

   I think we agree on that!

   but I still think the options available to suburban are more than in urbanized areas where land is more expensive and the land that is available for retention is more problematical.

   the water quality issue is additional and new rules pegged to TMDLs and non-point-source developing and ongoing.

   my point remains that stormwater is in issue wherever there is development – burb or urban… and that places with more undeveloped land – have more options for bigger, larger, regional type stormwater facilities whereas in areas that are close to build-out – there are less or more problematical opportunities usually also more expensive.

   we do not sequester in tanks down this way – because raw land is almost always available.. and the use of tanks usually indicates that that is more cost-effective than land-based options.

   I totally agree a 10 story building with 40 families probably does not generate much more runoff than a 1 or 2 acre residential lot does (if there are parking structures).

   storm water facilities in areas where development is built out is more problematical in terms of options to meet the standards no matter what they are – volume or quality because both require some retention capacity.

   I’m intrigued about LEED and it’s relation to the state and fed standards especially with required to storm events more severe than the current 2/10.

   I’m enjoying the conversation ..learning.. even though we’re chewing a little on each other.. I don not question your credentials nor your experience… and actually appreciate your insights.

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   1. 

      Tysons Engineer

      April 4, 2014

      No no no

      You arent listening

      First of all retention basins arent the norm. VA standards require DETENTION BASINS. Please try to use reality in your argument because I can’t take serious someone who isn’t knowledgable in what is actually required versus your own pipe dreams.

      Retention means you hold onto that volume, it never goes to the stream. Detention means you slow that volume (the flow) so it depeaks. Detention ponds, the ones you see in suburban developments DONT REDUCE VOLUME.

      Yeeeeeesh

      I write all of that and you ignore it all

      Here is a break down perhaps that can make more sense

      States without regulation
      No requirements for 2-yr and 10-yr detention

      Virginias 90s requirements, the NOVAs early Ches Bay acts
      Required 2-yr and 10-yr DETENTION

      Virginias new requirements, Maryland and NOVA current standards
      Required 2-yr and 10-yr DETENTION
      Required BMP to reduce pollutant loads, 50% of SOME new pollutants compared to existing conditions

      LEED Requirements, required in high density areas of NOVA, becoming closing to enaction state wide in Maryland
      Requires 2-yr and 10-yr detention
      Requires 2-yr complete removal of new volume, temperature increases
      Requires net zero pollutant loads (100% treatment) compared to existing

      LEED and NOVA requirements didnt remove a single darn thing from what the State is currently proposing, all of these are on top of.

      Sorry for the tone, but I am really trying every avenue to help explain it because you keep going back to urban developments “cant”. Well in fact, urban development DO, because they have to. You can’t build in Tysons unless you do, where as you can build to your hearts content in for instance Goochland, if you wanted meeting only 2 decades old standards as of today.

      So you can understand why its frustrating when people think the opposite is true, that somehow urban areas are skirting by willy nilly, while somehow the opposite that sprawl subdivisions are going above and beyond. Thats not the reality, honestly, truly, I have no dogs in this game, I dont consult any more on these things and I am telling you thats not the reality.

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   2. 

      Tysons Engineer

      April 4, 2014

      On re-read of my post, I really do come off as a jerk. So I will right up front say, I’m sorry. This whole discussion isn’t your fault, the public outreach on the importance of watersheds and mitigation is clearly not there and I blame the regulators for not properly explaining it for the confusion on the subject more than anything.

      So please accept my apology for losing my cool through out this.

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10. 

    Tysons Engineer

    April 4, 2014

    Another argument that I’d like to address is that you believe that suburbs create less impervious area per person than urban areas. Its simply not true.

    Tysons has ~2200 acres within the urban district boundary. Of that 2200 acres, of which approximately 350 acres is within VDOT right of way which for this purpose lets not include just like I won’t include all of the miles of roads that lead to subdivison parcels. If I were to include the roads to the subdivision parcels it would far exceed that of Tysons, so this is a conservative estimate.

    So you have 1850 acres in developable Tysons. The current impervious area of Tysons is 75% which will not be exceeded with the new developments. So the impervious area of Tysons is 1388 acres at full build out, which is for 100,000 residents and 200,000 jobs (as well as a bunch of hotels but we’ll leave that off to again help your case).

    100,000 residents living on parcels in subdivisions would mean 23810 dwellings based on 4.2 people per house (above state average but typical of suburban areas). At 2500 sf per dwelling it comes out to 1366 acres of impervious.

    Now the jobs, each employee at a suburban office park has a parking space (and then some) but lets keep it to 1 spot per employee. A parking space when including the drive aisle comes out to ~300 sf per spot, totalling 1377 acres of parking. Now the office. Lets assume extremely tight fit suburban office space 1 employee per 50sf, even those most jurisdictions believe it is 200sf. Now lets assume by some miracle the suburban office park developer put that in a 2 story building, so effectively its really only 25sf of natural footprint per employee. That comes out to 115 acres of office building.

    Add em all up

    Suburbs for the same amount = 2858 acres of impervious area

    Urban for the same amount = 1388 acres of impervious area

    Hell you could add back all of the VDOT right of way that makes up Tysons as well as calling it all 100% impervious and you still would create less runoff than a similar suburban development.

    This puts aside the issue that both actually control their runoff per state requirements (and in the case of urban to higher standards). On its own, suburban models create more disturbance to nature than urban areas. Not to mention to actually get all of that space, the 1/4 acre homes and all those offices you would need somewhere in the ball park of 8000 acres of disturbance to prestine woodlands, as opposed to focusing it all in a space of 2200 acres (and getting retail, hotels, government buildings).

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    1. 

       James A. Bacon

       April 4, 2014

       In support of T.E. on this particular issue… he’s actually under-estimating the degree to which suburban development contributes to rainwater run-off. Not only does suburban development have more impervious surface per capita (roofs, roads, streets, parking lots, roofs, etc.) it has more grass lawn per capita — by many orders of magnitude. Grass lawns are an ecological disaster. Where do you think most of the nitrogen and phosphorous compounds go? Fertilizer for grass lawns! What’s more, grass lawns absorb little moisture. Heavy rain on grass lawns turns straightaway into run-off. In theory, suburban development could mitigate the run-off with lots of planting designed to absorb rainwater before it hits the rivers and streams, but in practice we see very little of that. Most homeowners are oblivious.

       Suburban development doesn’t look as bad because the impact is so diffused. But when you consider than 10 times the land per capita (order of magnitude) is impacted, the cumulative impact is much worse.

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       1. 

          Tysons Engineer

          April 4, 2014

          Bingo, can suburbs be done better? Sure, but its gonna look like something out of those extreme survivor shows like I originally said. You can make the Wright dream work, but subdivision developers arent required to do so, they don’t mitigate the costs, they pass it on to the people down stream (in the case of transportation and stormwater) because its essentially a revenue game for the county, they need the new home owners to increase the tax revenues so they put up with it, fully knowing that jurisdictions closer in have to foot the bill. Thats not the case of highly visible high rises, they have to mitigate everything because they are so visible and such targets.

          Asking developers on the fringe to pay to mitigate that stuff fully, that is not something that most jurisdictions feel they can ask of home builders without shutting down all development due to the relative cost of these for most subdivisions. Where home values start exceeding $800k and profits can be as much as 400k per unit, you can start seeing some of these “boutique” style projects, but that is almost always relegated to infill projects in urban areas or urban adjacent areas (like McLean for instance). Out in Stafford, someone would laugh at you if you asked them to put volume controls on subdivision plans, and no where in the requirements are they asked to do so, because the house prices are down in the $400k zone, meaning sticks and bricks + land vs market price isn’t enough for those kinds of additional standards.

          If that’s not the definition of subsidization, playing by two separate rules in order to help make one economically viable vs the other, then I don’t know what is. If home builders were to have to do that kind of stuff, the price of homes would need to be higher to address the added costs.

          It is as you say, an issue of perception because yes NYC is polluted but it holds 8.5 million people. Thats the same as Virginia. And I bet you by every metric one could imagine in terms of pollution, NYC generates less, weather it be stormwater, sanitary, aquifer/spring reduction, trash, air pollution.

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11. 

    larryg

    April 4, 2014

    REMEMBER – the issue is burb subsidies.

    what is subsidized if the rules require mitigation facilities and they are paid for by those who live there?

    second – show me data not hand waving arguments.

    where is the data to show that the pollution in Accotink and other creeks and rivers is less per capita than say the Rappahannock in Fredericksburg?

    with all that nasty burb fertilizer ..you should have nitrogen/phosphorous levels in the river – divided by the population of the region to show a much worse per-capita pollution index.

    otherwise – without data – how are you actually “proving” ?

    the argument here is that density is more efficient. I agree. but the more impervious surfaces there are relative to non-impervious surfaces in turn requires higher levels and more expensive levels of mitigation than less intense denuding of vegetation.

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    1. 

       Tysons Engineer

       April 4, 2014

       What hand waving? All I have shown you is literally the data. I’m not hand waving. At this point, I am done. I would suggest you read the links I have provided for you, taking my time to help educate, and make up your own mind. But where you are right now, is the tip of the iceberg in terms of your knowledge on the subject matter.

       Read the links and I think you should go back up and read what I wrote in the post you skipped above about which areas require what. Suburbs are subsidized by being allowed to play by a separate set of rules that are cheaper. End of story, that’s reality, deal with it or don’t, I don’t care anymore I tried to explain and you have clearly your biases against urban areas.

       Thanks

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       1. 

          larryg

          April 4, 2014

          my apologies to you. I do not question your credentials nor your experience but I think we are hand waving.

          What I have asserted is that I’m skeptical about the burbs are subsidized argument with respect to storm water runoff.

          and what this devolved into was a discussion about how efficient denser development is – with respect to storm water than the burbs.

          that’s a totally different argument from saying the burbs are being subsidized especially if the burbs pay for their storm water facilities that end up meeting the same standards applied – statewide.

          I AGREE the burbs are subsidized with commuting roads AND I advocated tolls for them to pay their fair share.

          but for stormwater – where is that dynamic? how are the burbs subsidized on storm water?

          they are not subsidized because they are ‘less efficient” …as long as they pay for the costs – which they do.

          they might be subsidized if they actually have more runoff per capita that more dense settlement patterns but that’s not at all proven with real data at this point.

          not proven either is the claim that runoff per capita is higher in the burbs.

          the more impervious surfaces you have the higher, longer and more intense the runoff – per capita no matter WHERE those impervious surfaces are.

          but on the whole the more higher percentage impervious surfaces you have compared to the same number of people on more acreage with a far lower percent of impervious surfaces.. I’d like to see some specific comparative data before I buy that premise.

          they use land to mitigate runoff in the burbs.. how do they mitigate runoff in places that are built-out and land is scarce and expensive?
          where are you going to store runoff in built-out areas?

          ” Combined Sewer Overflow (CSO) Locations in Virginia”

          ” In Alexandria, Ashland, Bristol, Cape Charles, Colonial Heights, Covington, Fredericksburg, Lynchburg, Newport News, Radford, Richmond, Roanoke, and Waynesboro, some pipes for carrying stormwater to the nearest stream were connected to the old wastewater pipes, creating a Combined Sewer Overflow (CSO) infrastructure. When stormwater systems were first developed in those communities, downspouts from gutters on houses in old neighborhoods or from buildings downtown were connected to the sewers. In addition, some inlets from gutters carrying water off streets in urban areas were also connected to pre-existing sewer pipes.1

          The combination of wastewater/stormwater systems simplified the construction process. Just one set of pipes was placed underground, saving money and minimizing disruption from digging up streets to install a second set of pipes. Combining waste and stormwater flows also ensured a complete flushing of the sewer system during storms.

          http://www.virginiaplaces.org/waste/cso.html

          if the problem were so easy to fix just by retrofitting cisterns.. and such they would have done that.

          instead – they’re using giant tunnel boring machines to great tunnels to hold the runoff – very expensive tunnels… likely far more expensive per capita that the per-capita costs of mitigating in the burbs by using surface land-based structures.

          again, I’m not biased against urban areas. I just refuse to buy the premise that impacts are less and cheaper to mitigate on a per capita basis.

          but if someone has actual data that shows per-capita stormwater costs between urban areas and burbs.. I’d certainly read it – and .. I’d eat some crow if it actually proves my skepticism wrong.

          and again – I apologize to TE but I don’t get moved on issues by people getting pissed by disputes on the data… just do provide the actual specific real-world data comparisons and we’ll be more than happy to issue a mea culpa.

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          1. 

             Tysons Engineer

             April 6, 2014

             We are really talking strawmen now, when you bring CSO’s into the mix. You are talking about systems that pre-date the modern era in many cases when you bring those up, you do know this yes?

             Again its an issue of there was sprawl in urban build out for many many years (in SWM) because people didn’t know what the heck to do with SWM until atleast in the 1970s, and for many jurisdictions they didn’t start putting in even the simplest controls until the 1990s.

             The reason why the burbs on an aggregate look like they provide more stormwater is because cities were built before the science and burbs were born with the science. Thats the only reason. But that only explains the overall city issue, thats not subsidization.

             Follow here.

             In 1970 some science was figured out linking things like parking lots to things like floods. Before this time no one really understood the relationship. So a few (very liberal and open to regulation) areas of the country started incorporating standards to address it. You can’t go in retroactively to people who have owned a property for 50 years before the science even existed and say, tear down what you got and build it this way. (in fact its a good thing they didnt because those early understandings were flawed).

             So they tied improvements to new construction or modifications to sites. The idea that suburbs led the way is revisionist. No the cities led the way first, and then the suburbs began adopting it also. So when fairfax came along building at insane rates in the 70-90s they like some cities decided to adopt these regulations (although later than some cities which is why we ended up with early Tysons the way we did). In the 70s they had barely 10% of the build out they have now and days, so all of that new construction washed away the fact that the original 10% was not meeting requirements.

             The same cities (the ones that led the charge) also had new construction, but much of it pre-dated, they went from lets say 80% to current 100% of build out (numbers don’t matter in this case). The point is they were built out to now very built out. So the projects, which they required the exact same requirements of (if not more in many cases) than the suburbs didn’t have as much impact because so much of the development simply pre-dated that era.

             Over and over again, the dynamics have remained cities pass the strictest regulation earliest, followed by direct inner suburbs with less strict and later on, followed by the sprawl zone (the fringe where all development is on green sites) who have far less strict regulations and have come later.

             So, in the case of Tysons, even before the State is requiring the new regulations, all projects in the city have to meet TMDL requirements (which are superseded by LEED 6.2). In other words even when the state passes those regulations, projects in Tysons will need to go beyond that because they have been required to do so.

             That is subsidization of outer development, because it isn’t equivalent. The urban one has to go even further on a per capita basis (by far) and even on a per impervious acre basis. On every basis, the urban project has stricter controls.

             You want to bring up CSOs, thats fine, and urban areas are in fact paying for those out of their own pockets in many cases because they realized it was a mistake (DC is spending billions to do so). But the reason for those systems wasn’t because developers cheaped out, the science literally didn’t exist in many ways when they were being created.

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             1. 

                larryg

                April 6, 2014

                TE – remember – you wanted short discussion!

                re:

                ” We are really talking strawmen now, when you bring CSO’s into the mix. You are talking about systems that pre-date the modern era in many cases when you bring those up, you do know this yes?”

                I KNOW as do you that these older settlement patterns as claimed to be the goal of Smart Growth in terms of density unless you want to revise the modern goal of smart growth to be less density than the existing traditional.

                but my point was and is in ANY grid-street type density that if there was a way to “harvest”rainwater and utilizing other things you’ve cited that they’d certainly be doing that rather than boring these huge tunnels.

                what you are citing as modern ways of dealing with runoff apparently does not work for the kind of density associated with grid streets development.

                RE: ” Again its an issue of there was sprawl in urban build out for many many years (in SWM) because people didn’t know what the heck to do with SWM until atleast in the 1970s, and for many jurisdictions they didn’t start putting in even the simplest controls until the 1990s.”

                are you saying that the grid street development of DC can handle the runoff in ways other than the tunnels?

                “The reason why the burbs on an aggregate look like they provide more stormwater is because cities were built before the science and burbs were born with the science. Thats the only reason. But that only explains the overall city issue, thats not subsidization.”

                they have more available land to use cheaper land-based mitigation.. no magic.

                “Follow here.

                In 1970 some science was figured out linking things like parking lots to things like floods. Before this time no one really understood the relationship. So a few (very liberal and open to regulation) areas of the country started incorporating standards to address it. You can’t go in retroactively to people who have owned a property for 50 years before the science even existed and say, tear down what you got and build it this way. (in fact its a good thing they didnt because those early understandings were flawed).”

                again – if there is an older or a modern – grid street settlement pattern are you saying there are ways to handle the runoff without building tunnels? If Tysons goes on to further densify into grid streets – similar to what we see in DC – are you saying there are ways to mitigate without the tunnels – and if so.. why is DC building tunnels instead of retrofitting those more modern approaches?

                “So they tied improvements to new construction or modifications to sites. The idea that suburbs led the way is revisionist.”

                I never said the burbs led the way at all. I said that they have more raw undeveloped, cheaper land to build storm water facilities.

                ” No the cities led the way first, and then the suburbs began adopting it also.”

                this is confusing. How did a place like DC or for that matter Arlington or Alexandria “lead the way” … first?

                re: ” So when fairfax came along building at insane rates in the 70-90s they like some cities decided to adopt these regulations (although later than some cities which is why we ended up with early Tysons the way we did). In the 70s they had barely 10% of the build out they have now and days, so all of that new construction washed away the fact that the original 10% was not meeting requirements.”

                isn’t it the older Fairfax that is causing the most runoff damage right now because their facilities built long ago fail at runoff control?

                Wasn’t Fairfax 40 years ago “sprawl”? and now the storm water controls built then totally inadequate ? and how do you fix it?

                “The same cities (the ones that led the charge) also had new construction, but much of it pre-dated, they went from lets say 80% to current 100% of build out (numbers don’t matter in this case). The point is they were built out to now very built out. So the projects, which they required the exact same requirements of (if not more in many cases) than the suburbs didn’t have as much impact because so much of the development simply pre-dated that era.”

                how do you retrofit “very built out” development?

                “Over and over again, the dynamics have remained cities pass the strictest regulation earliest, followed by direct inner suburbs with less strict and later on, followed by the sprawl zone (the fringe where all development is on green sites) who have far less strict regulations and have come later.”

                is that why the EPA went after Fairfax over Accotink creek?

                “So, in the case of Tysons, even before the State is requiring the new regulations, all projects in the city have to meet TMDL requirements (which are superseded by LEED 6.2). In other words even when the state passes those regulations, projects in Tysons will need to go beyond that because they have been required to do so.”

                then why can’t that same approach be used in older dense places instead of having to bore tunnels? What is the difference between a dense Tysons and a dense Arlington in terms of meeting TMDL and LEED? what keeps Arlington from doing what Tysons is doing instead of boring tunnels?

                “That is subsidization of outer development, because it isn’t equivalent. The urban one has to go even further on a per capita basis (by far) and even on a per impervious acre basis. On every basis, the urban project has stricter controls.”

                what I’ve done is dispute the claim that sprawl is subsidized with respect to storm water. both urban and suburban have to meet the SAME standards guy… if you think urban has to meet stricter standards than the suburbs.. then show me a comparison .

                “You want to bring up CSOs, thats fine, and urban areas are in fact paying for those out of their own pockets in many cases because they realized it was a mistake (DC is spending billions to do so). But the reason for those systems wasn’t because developers cheaped out, the science literally didn’t exist in many ways when they were being created.”

                yes.. it’s paid for by rate payers – at about 4K per ratepayer.. and it’s NOT subsidized – as you say but NEITHER are the burbs who are ALSO paying for storm water facilities which is why I have questioned from the get go why there is a claim
                that the burbs are being subsidized on storm water.

                it don’t matter how “efficient” the urban is on something.. it does not mean the burbs are subsidized – only that they are less efficient. If you can identify something in particular that shows that burbs receive direct subsidies then make the case.

                One for sure is commuter highways.. no question.. but as to other things.. again – just because the burbs do not densify does not constitute a subsidy.

                CSOs basically came about because they used the sanitary sewers to transport storm water.

                we both agree that in retrospect it turned out to be a bad idea.

                but I’m asking you what they should have done instead – and why they can’t do it now by copying the modern approach used by Tysons?

                answer please.
             2. 

                Tysons Engineer

                April 6, 2014

                WRONG! That is simply not true Larry. No where in the Smart Growth principals does it say to return to Combined Sewer systems, that would be stupid. The point is to return to land use PATTERNS. If you actually read any smart growth documents you would know that one of the highest principals is stormwater treatment and controls at HIGHER REGULATION than those of sprawl developments. You are confusing land use with new technology.

                No one is saying we should go back to brick mortar construction also, in case you were wondering, nor do they want coal burning local boilers for hot water in those buildings. Just because smart growth looks to recreate stronger town settings like those in the 1920s to 1950s doesnt mean they also want to ignore all the changes in technology that have happened since then.

                Why make up stuff? Seriously.

                Next

                You are so absolutely confused on what the purpose of the tunnels is, that it is ridiculous. The tunnels are to separate the sanitary flow from the storm because you can’t take large plug storm flows to a sanitary treatment plant without sizing it for that much larger storm volume. If DC was built with separated sanitary and storm sewer then the tunnels would not be necessary at all. You really need to actually understand things before you take such ridiculous stances on them. That has nothing to do with what level of “street grid” whatever you said, it has to do with you should never combined sanitary sewer and storm sewer because you will overload your wastewater treatment plant by forcing it during heavy rain events to release outflows at higher potency than without. That is in no way indicative of “urban areas development” except for those built at the turn of the 1900s because again for the 1000th time, at that time people didn’t understand the stormwater issues.

                If you want to ignore the fact they exist then once again I feel sorry for you for not using reality in your argument.

                What are you talking about street grid development cant do…. That is not correct in any way, you conflate the issue by bringing in the separation of sanitary sewer from DC’s storm water system (which isn’t needed in Tysons I would add because our stormwater and sanitary was built separate due to the era in which the system was built) as some strawman excuse for your argument.

                Good lets talk Tysons.

                Yes, in Tysons our stormwater is better than your neighborhood. For 4000 words I have explained in EVERY WAY how it is why is it even still being questioned. Tysons will not have any of the issues needing your magic tunnels, which HAVE NOTHING TO DO WITH STORM WATER, because we don’t have a stupid antiquated combined sewer system. Who ever told you that urban areas are developed with those in the modern era lied to you.

                Tysons projects going up today not only have to meet the requirements, they must exceed tehm (again for the 1000th time) compared to the rest of the state. The new projects must make flow from their site as if they were never developed at all. If the build out were to occur of Tysons by 2050 then the storm water pollutant load, the runoff volumes by EVERY MEASURE YOU CAN THINK, including Volume, peak flow for 2 yr and 10 yr and 100yr, will all be less in the future than they will be today because that is what is required of areas that are smart and follow LEED stormwater regulations.

                However, fringe zones like Stafford County, will not be. With their new homes, they will only be reducing the peak flow of the 2yr and 10 yr, and minimize the impact of their new development by 50% for pollutants. Which means their pollutant load will increase (though slower than previous eras atleast) and yes the total volume they pump into their streams will increase leading to long term erosion issues.

                Understand?

                “they have more available land to use cheaper land-based mitigation.. no magic.”

                WRONG, their standards are actually less. I provided 400 words, and 30 minutes of my time to explain this to you and it still evidently didn’t sink in. I won’t rehash it again just because you are to lazy to read. Sure it is cheaper land, but if they actually had to do what urban developments had to do, their projects would not be financially viable. End of story. That is why jurisdictions subsidize suburban sprawl because if they didnt no one could afford to build it.

                “this is confusing. How did a place like DC or for that matter Arlington or Alexandria “lead the way” … first?”
                Because they adopted the regulations first and have required it of all developments far before your “new richmond standards”.

                You simply don’t understand SWM at all. You think ponds are storm water management. In fact, reflecting upon this I now realize there’s nothing I can do to explain this to you until you actually educate yourself on the stuff you are talking about. To think that “ponds” are SWM is disturbing to me. It’s like someone walking up to me and telling me about this great thing called cassette tapes. You are waaaaay WAAAAAAAY behind. Guess who isnt? URBAN AREAS.

                Hence why they are leading the way and places like state governments (RICHMOND) are so freakin far behind.

                Fairfax older areas “fail” because our definition of pass or fail are higher than other areas, and only now are other areas finally catching up in Richmond. Great, thats fantastic welcome to damn party, but we already moved on and are starting to implement even stricter standards on ourselves. Maybe in 20 years the rest of you people can implement those as well.

                But you are correct, there were areas of Fairfax built a long time ago in a more sprawl like fashion, and we in Fairfax will be fixing those issues via redevelopment. The kind that comes with LEED controls that mitigate and go beyond the rest of the state’s requirements in order to make up for the suburban areas that will never be redeveloped to better standards.

                About your issue about whether suburbs are less than urban I ALREADY FRICKEN POSTED THT AND YOU SKIPPED IT.

                States without regulation
                No requirements for 2-yr and 10-yr detention

                Virginias 90s requirements, the NOVAs early Ches Bay acts
                Required 2-yr and 10-yr DETENTION

                Virginias new requirements, Maryland and NOVA current standards
                Required 2-yr and 10-yr DETENTION
                Required BMP to reduce pollutant loads, 50% of SOME new pollutants compared to existing conditions

                LEED Requirements, required in high density areas of NOVA, becoming closing to enaction state wide in Maryland
                Requires 2-yr and 10-yr detention
                Requires 2-yr complete removal of new volume, temperature increases
                Requires net zero pollutant loads (100% treatment) compared to existing

                What else do you want?
          2. 

             Tysons Engineer

             April 6, 2014

             Feel free to read this

             http://stuff.mit.edu/afs/athena/dept/cron/project/urban-sustainability/Stormwater_Sarah%20Madden/References/Jacob&Lopez2009.pdf

             I could literally flood this thread with proofs backing my case because really at the end of the day its common sense. Housing more people in a smaller footprint means less runoff from impervious area. You can blame the sins of the past on urban development, but suburban development during that time (where suburbs were at that time like Fairfax) did the same stuff.

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             1. 

                larryg

                April 6, 2014

                from your paper:

                ” The issue of stormwater detention and
                floodwater control is a separate, although not unrelated
                issue from the water quality that is the focus of
                our paper. Nothing we present here suggests that
                higher density alone would absolve cities of the responsibility
                they have always had to address the downstream
                impacts of greater amounts and rates of runoff.
                The data developed here do suggest, however, that per
                capita and thus total volumes of runoff for a given population
                would be reduced, reducing therefore the overall
                energy of the flashiness.”

                we have lots of studies TE – but then we have the obvious reality of creeks like Accotink and the apparent need to bore tunnels in grid-street settlement areas.

                If you are saying that Tysons does not need land to mitigate stormwater than why not DC utilizing Tysons techniques. If you ARE saying that LAND IS NEEDED for Tysons to mitigate then are you agreeing that TYSONS cannot end up like grid-street density similar to Washington or Arlington?
             2. 

                Tysons Engineer

                April 6, 2014

                You don’t know what you are talking about. The tunnel boring has nothing to do with stormwater. Go read about something before you try to use it as a defense for your inaccurate information.

                Good day
             3. 

                larryg

                April 6, 2014

                ” DC Water “Lady Bird” Tunnel Machine Digging 13 Mile Storm Water Storage Tunnel

                The tunnel-boring machine, nicknamed “Lady Bird,” made its debut Tuesday at the Blue Plains Advanced Wastewater Treatment Plant, where DC Water officials heralded it as part of a plan to significantly reduce the amount of raw sewage that flows into local rivers and basements during rainstorms. The tunnel-boring machine was named after Lady Bird Johnson as a tribute to her environmental activism.

                The four-mile tunnel will start beneath the treatment plant just north of the Woodrow Wilson Bridge and then dig beneath the Anacostia, ending near Nationals Park. It will become part of a 12.8-mile tunnel, scheduled for completion in 2022, that will serve as an enormous holding tank during rainstorms. ”

                http://cenvironment.blogspot.com/2013/04/dc-water-lady-bird-tunnel-machine.html

                from USA Today:

                “The workers and their tunnel-boring machine — they call it “Lady Bird,” after Johnson, the environmentally conscious first lady — are trying to solve a problem plaguing cities since the Civil War: raw sewage carried by storm water into rivers, streets and basements.

                More than 700 cities in the United States were built using a combined sewer system, in which wastewater — that’s toilet water, shower water, whatever goes down the drain — and runoff from storms flow into a single pipe. Most of the time, that pipe can transport all of it, but when it rains, raw sewage often overflows into streets, basements, rivers and streams.

                In Washington, about 2 billion gallons of overflow spews into the Anacostia and Potomac rivers and Rock Creek each year. The storm water washes household waste, oil, trash and chemicals into waterways. The toxic brew is so bad that in the 24 hours after an overflow, ”

                so no, we’re not going back to CSOs (never advocated that) but I HAVE asked
                what are we going to do instead – for places that are densifying to a grid-street type density?

                what is the modern solution to stormwater from dense settlement patterns?

                is the answer that Tysons will never really go to a grid-street configuration but instead office towers with enough land not used to build storm water facilities?

                why will a grid-street Tysons be any different than a grid-street Arlington when it comes to how storm water would be handled?

                we don’t do CSOs anymore but we still have the runoff that was put in the sewers so what are we doing with that runoff today in grid-street type developments?
             4. 

                Tysons Engineer

                April 6, 2014

                DC already has the Tysons techniques, Tysons is using DC and Arlington standards.

                DC’s tunnel system has NOTHING TO DO WITH STORMWATER RUNOFF, except for the fact that the combined sewers need to be separated so that stormwater doesn’t over whelm sanitary sewer treatment facilities.

                You are conflating two issues because you don’t understand the science of what you are talking about. You are hearing little tidbits and think you understand.

                DC can’t fix the issue of sanitary sewer being combined by adding ponds larry, or vaults, or roof gardens. They can only do it by splitting the storm drains from the sanitary drains.

                Suburbs (if they were built by the same technology that DC was built on in the 1800s) would ALSO face this issue. In fact the EPA did a report on this, and while big cities like NYC and DC which grew up in the industrial boom have CSOs, most areas in the country which have them and will continue to have them are in populations of less than 10,000. The reason being a scale issue. Cities have the money on hand to correct outdated technology like combined sewers, where as little rural towns with combined sewer dont’

                And by the way, your septic system is just a diffused version of a CSO. The impact of 8 million people on septic would be GREATER than the impacts of the 8 million people in NYC who live with CSO (which is being replaced incrementally also). It’s just that you don’t see the impact because it is diffused, but in fact for most times of the year your septic system is actually worse for the environment. So congrats.

                You can stick your head in the sand, or in this case your poop in the ground, but thats the reality of septic infiltration.
             5. 

                Tysons Engineer

                April 6, 2014

                I am so unbelievably pissed at you for ruining my god damn weekend but I can’t let ignorance continue in the world.

                DEAR GOD LARRY

                the tunnel has nothing to do with storm water. What the hell can I type on here that can explain this to you. People in the 1800s thought, lets put pipes underground instead of letting our crap fill the streets. So they built a bunch of pipes and they connected all the street inlets to the system because they didnt want water ponding up also.

                They let these flow to rivers.

                Then some dead genius realized that, oh crap maybe we shouldnt put our feces in the same place we pull our water. (what a god damn genius he was). So he decided to put a wastewater treatment plant prior to outflow to the river. He didn’t change the piping, he just did that plopped one down.

                Thats great, it was an improvement, far less shit made its way into our lemonades. But every year or two a big rainstorm would happen, and all the tanks and things that are in a WWTP started filling up way too fast, and so just like your sink a little overflow hole released the water before the tanks are overwhelmed. This means during this large event, there was raw sewage being released, only partially dilluted, back into the river.

                Thats bad stuff but for decades most people thought, meh we are dumping it into a river, it only happens a few times a decade so I think its ok. Then the CWA realized that oh wait, dillution isn’t the solution, theres still long periods of resonance that occurs with those outflows, and they cause long term damage (still less than what happened in the 1840s with no treatment) but yea if we want healthy water ways something needs to be done.

                For some cities, they increased the capacity of the sanitary treatment plants to just store more volume to make up for these big events. Some cities did this for a while but then realized, yea we need a better solution, and hell some of these pipes are getting old and we are replacing them anyways.

                So in DC’s case, they said, well if we split out the storm system from the sanitary system, then the treatment plant can properly treat the actual sanitary flow. So they started this tunnel project which will do that, and thats all it will do, it will split the two flows so that sanitary plants won’t get overwhelmed, not to act as treatment of the storm water.

                For stormwater itself, the Non-point source pollution (because of course WWPT are actually Point source) DC for the past 3 decades has established regulations for 2-yr, 10-yr, and nutrient removal which they continue to require of all construction. On top of that they have gone even further to require volume controls all the LEED stuff I keep saying ON TOP OF EVERYTHING because they realize volume is just as bad as flow, especially in terms of pollutant load.

                In fact, from Non Point Source elements, they HAVE reduced their runoff impact over the past decade, and after the rainwater is removed from sanitary water, DC will be one of the cleanest watersheds in our area.

                Tysons doesn’t need to do a tunnel because Tysons DOESNT HAVE A COMBINED SEWER SYSTEM. But Tysons is doing the non-point source controls just like DC has had for a while to ensure that the non-point source pollution actually goes DOWN in total despite more development going UP.
             6. 

                larryg

                April 6, 2014

                TE – the project itself says its to store storm water.

                it’s on their website guy.

                virtually every article about the project says it’s to divert and sequester stormwater.
             7. 

                Tysons Engineer

                April 6, 2014

                Larry that is incorrectly understood on your behalf because you don’t know what you are reading.

                They are holding the water SO THAT the sanitary system will not be overwhelmed. It is not to meet stormwater requirements.

                You simply are not knowledgeable on what you are “debating” with me. And your responses to me are equating down to “but why” like a child. You can imagine how frustrating that can be and especially after I actually provide you time and time again with references.

                The tunnel SPLITS the waters so that they do not impact sanitary treatment. That storm water if it were possible to release to the river would not have the point source pollution, it is only the introduction of sanitary OVERFLOW which makes it the toxic sludge during large storm events.

                That is because over the last couple of decades DC has actually reduced its stormwater impact itself through each development being required to provide controls.

                Heres a question to you, why doesn’t Arlington have this issue smart guy? Arlington is even denser than DC, yet it doesnt need this massive infrastructure.

                The reason is because they don’t have Combined Sewer. The storm is treated and the sanitary is treated and one doesn’t over whelm the other.
             8. 

                larryg

                April 6, 2014

                “They are holding the water SO THAT the sanitary system will not be overwhelmed. It is not to meet stormwater requirements.”

                and I’m asking where are they holding it?

                “You simply are not knowledgeable on what you are “debating” with me. And your responses to me are equating down to “but why” like a child. You can imagine how frustrating that can be and especially after I actually provide you time and time again with references.”

                I think you are the child here since you seem to insist on trading insults for no good reason. why don’t you behave?

                there is storm water runoff – it has to go somewhere. if it does not go into the sewer where does it go? where are they holding it?

                “The tunnel SPLITS the waters so that they do not impact sanitary treatment. That storm water if it were possible to release to the river would not have the point source pollution, it is only the introduction of sanitary OVERFLOW which makes it the toxic sludge during large storm events.”

                please tell me how the tunnel “splits” the combined stormwater and sewage guy. how do they “split” it?

                “That is because over the last couple of decades DC has actually reduced its stormwater impact itself through each development being required to provide controls.”

                and what does the modern development do with the stormwater? are there still drains on the curbs to transport the runoff to ..where? do you have curb drains in Tysons?

                “Heres a question to you, why doesn’t Arlington have this issue smart guy?

                oh stop with the petty insults guy. you’re making yourself look like a jerk.

                Arlington is even denser than DC, yet it doesnt need this massive infrastructure.”

                “The reason is because they don’t have Combined Sewer. The storm is treated and the sanitary is treated and one doesn’t over whelm the other.”

                their sewer system is old.. right.. ? do their curbs drain somewhere else?

                where does the stormwater go in Arlington?

                I don’t know but I’m skeptical if their system is over 50 years old that it
                was built any different …

                “Storm Sewer

                The storm sewer system consists of approximately 365 miles of pipe that range in size from eight to 144 inches in diameter. The system transmits rainwater runoff from streets, sidewalks and buildings to our local streams, preventing flooding during heavy rains. Water flows into “catch basins” (storm drains) located along the street, through storm sewer pipes and local streams. This water is not treated at the Water Pollution Control Plant, so it’s important not to dump chemicals or throw trash in the street or storm drains. Learn more about preventing stream pollution”

                MS4 Permit

                The Virginia Department of Environmental Quality (DEQ) issues permits for the discharge of stormwater into waterways like Four Mile Run and the Potomac River. These permits, called municipal separate storm sewer system (MS4) permits, are good for five years. Arlington’s current MS4 permit (VPDES Permit No. VA 0088579) was issued on June 26, 2013.

                Arlington is the first municipality in Virginia to receive an MS4 permit that includes quantitative pollution reduction requirements to clean up the Chesapeake Bay. The Chesapeake Bay Total Maximum Daily Load (TMDL), which is commonly referred to as the “bay pollution diet,” requires significant reductions in nutrient and sediment pollution across the bay watershed.

                Each MS4 permit is good for five years, and the new permit will be in effect through mid-2018. During this permit cycle, Arlington is required to achieve a 5 percent reduction of its share of these bay TDML pollutants. In the next two permit cycles, Arlington will be required to decrease its share of these bay TDML pollutants by an additional 35 percent (2018-2023 permit cycle) and 60 percent (2023-2028 permit cycle).

                Supporting Programs

                We began preparing for the 2013-issued permit and its more stringent requirements in 2008 with the adoption of the Stormwater Fund. The fund has allowed for the expansion of permit-required watershed management programs. The following programs and projects are among those that are specifically described in the permit:”

                Ballston Pond Restoration Project
                Volunteer Stream Monitoring Program
                Expansion of Arlington’s Water Pollution Control Plant
                Reporting stream pollution
                Green Streets projects
                Sanitary sewer rehabilitation <——
                Stream restoration projects
                Street Sweeping Program
                Stormwater Master Plan <——-
                StormwaterWise Landscapes Program
                Watershed retrofit studies

                so basically Arlington has (mostly) a separate system and shunts it's stormwater directly into local creeks – which is no longer going to be allowed.

                they have a "permit" and will ultimately have to hold the stormwater in some fashion and treat it.
          3. 

             Tysons Engineer

             April 6, 2014

             And just to spike the ball, again don’t take my word for it, here’s the Ches Bay’s actual TMDL statistics site which is well done

             http://stat.chesapeakebay.net/?q=node/130&quicktabs_10=2

             Play around with it, in almost every case you will see the pollutant loads come largely from non-urban sources despite the fact that those urban areas out weigh the population of sprawl zones

             Specifically, on the left side screen for basins(the tab) and then take a look at the Potomac vs York and Rappahanock, then compare the current load/lbs to the population ratios of each.

             Pure stats don’t lie.

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             1. 

                larryg

                April 6, 2014

                it is a nice site.. but not sure how you delineate boundaries but I did notice that stormwater has to be treated for NoVa but not the burbs in Spotsylvania.

                the other thing is that the TMDLs are about the same for NoVa as they are for say Fredericksburg .. and that makes sense because they are indeed supposed to be the total load that the river can sustain and still be healthy.

                the difference is that Fredericksburg and region has to meet those standards for about 300K population whereas NoVa has to do it for 2 million.

                think about on a per capita basis – what the “share” is.

                you’re going to have much, much higher treatment standards because you have 6 times the population – for the same size river.
             2. 

                Tysons Engineer

                April 6, 2014

                I’m tired of you Larry, you have raised my blood pressure with your tip of the iceberg knowledge on the subject and have refused my several offers of actually talking in a better format, using my time to help you understand something.

                I’m done.

                I will not be explaining anything else to you outside of a phone call which you can get from me by emailing me.
12. 

    Tysons Engineer

    April 6, 2014

    LAND IS NOT ALWAYS NEEDED TO TREAT STORMWATER.

    What part of this don’t you understand? A storm detention pond is just a bowl that holds X cubic feet. The same darn thing can be provided in a vault. Thats not magic. Its just a volume. You dont have to put it in dirt, you can put it in concrete. Not only can you put it in concrete, it is cheaper for urban developers to do so because land costs more than concrete.

    Good you have that clear? In that way suburban and urban areas both provide the exact same damn 2yr and 10yr controls. SAME DAMN ONES LARRY. SAME ONES. SAY IT WITH ME THE SAME CONTROLS ARE REQUIRED THERE IS NO MAGIC WAIVERS THAT RELEASE URBAN AREAS FROM THIS.

    Then the pollutant load removals (something the rest of the state has yet to enact). Ok regulated suburbs include things like bioretention, wet swales, constructed pond wetlands, to get the TSS, Phosphorous, and Nitrogen to appropriate effluent levels. Those are land based systems they meet a treatment level of X%.

    URBAN AREAS PROVIDE THE SAME DAMN THINGS. SAY IT WITH ME THE SAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAME things. They have effluent levels of that same X% (in fact less in some cases) through the use of filtration vaults, sand filters, baysaver cartridge systems, and a host of other elements.

    EACH END UP WITH THE SAME LEVELS, the only reason you don’t see ponds do it in urban areas is because someone would have to be a damn moron to use up 2 acres of land instead of building a more efficient structural and underground facility. BUT THEY DO THE SAME DAMN THINGS.

    OK?

    NOW urban areas go EVEN FURTHER. EEEEEEEEEEEEEEEEEEEEEEEEEEVEN FUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUURTHER than even the regulated suburban areas by being required to meet LEED requirements which means not only do they have to meet 2-yr and 10-yr peak runoff reduction, and pollution reduction but ON TOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOP of that they have to actually use the water, in their buildings or for irrigation through harvesting or recharge of the ground water aquifer, for the 2-yr storm. They have to ensure that the released water doesn’t increase the temperature of receiving bodies. AND they have to provide commissioning proof that people will acutlaly be able to monitor those conditions to make sure they continue to operate at that high of a level.

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    1. 

       larryg

       April 6, 2014

       re: ” What part of this don’t you understand? A storm detention pond is just a bowl that holds X cubic feet. The same darn thing can be provided in a vault. Thats not magic. Its just a volume. You dont have to put it in dirt, you can put it in concrete. Not only can you put it in concrete, it is cheaper for urban developers to do so because land costs more than concrete.”

       do you consider a big bored tunnel as one of the options?

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       1. 

          Tysons Engineer

          April 6, 2014

          This is only an issue for cities built before 1950. All modern cities, Arlington and Tysons included, have separate storm and sanitary systems. So this much storage wouldn’t be required, each development provides retention and treatment on their own property, and over mitigate in order to address the public road systems next to them, or provide treatment for those public roadways in some cases as well.

          Suburbs that are only under state regs, get away without having to make up for the existing conditions. All they have to do is make it so that their new impervious area isn’t as bad as it could be if it were untreated. Urban areas have to make the impervious area as if it didn’t exist, far more stringent.

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          1. 

             larryg

             April 6, 2014

             re: ” Suburbs that are only under state regs, get away without having to make up for the existing conditions.”

             then why are they having to levy storm water taxes?

             “All they have to do is make it so that their new impervious area isn’t as bad as it could be if it were untreated.”

             I think whether it has to be treated or not – does not depend on the locality but rather how dirty the runoff water is.

             we are being told down here that some locations with a lot of impervious surfaces that transport oil, antifreeze, pet poop etc probably will have to be treated or at least be permitted and meet water quality standards.

             ” Urban areas have to make the impervious area as if it didn’t exist, far more stringent.”

             my understanding is – it’s based on the water quality of the discharged water.

             if it’s dirty, it has to be treated. if it’s not (or less dirty), it might not.

             think about it this way also.

             if you have a water supply reservoir – what’s in the water that feeds it and where does it come from?

             there is a reason why there are few, if any water supply reservoirs in urban areas whereas where I live we have 6 and all of them are clean enough to require minimal treatment before going into the water system.

             your water up there comes from where?

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             1. 

                Tysons Engineer

                April 6, 2014

                Your understandings are incorrect.

                1st of all you need to recognize there are suburbs like Fairfax and then there are suburbs like Stafford. When I say ” ” Suburbs that are only under state regs, get away without having to make up for the existing conditions.” I mean counties like Stafford, who don’t have their own local stricter standards. These locals don’t usually levy stormwater taxes, it is the ones that are closer in, that have to deal with existing areas that aren’t redeveloping (that are staying in a non-compliant state of low density homes like around four mile run) that need to levy special taxes. Its not because R-B developed that Arlington needs it, its because four mile HASN’t developed that they need it.

                “my understanding is – it’s based on the water quality of the discharged water.”

                And your understanding is incorrect. You are confusing mitigation of existing conditions that pre-date regulation with new development. New development has a requirement to meet effluent numbers on all metrics. That is all. It doesn’t matter if you have a construction vehicle storage facility or a kindergarten, the per acre stuff has to be the same. There is no different set of rules for the goal numbers. The difference occurs in the regulations as a whole. Some jurisdictions have stricter ones than others, the State’s being the weakest escalated based on the more urban you get.

                All development requires treatment up here in Fairfax. All. All development in Tysons requires even stricter treatment in terms of percentage. All. Non-point source pollution and point source pollution are different things.

                In some cases, like gas stations, the county for the purpose of extending the life span of any treatment controls will require things like pretreatment using oil grit separators, but that is only for when it makes sense like exposed fuel possibilities. Whole other issue, lets not complicate an already complicated discussion by bringing pre-treatment into it. Either way, I can assure you that only urban areas require this stuff, fringe zones let people get away with murder.

                We have dozens of reservoirs also. I have no idea where you get this idea as if we what? Pump our water from you guys 😛

                Please

                Our water comes from reservoirs and surface water, but our water is actually much more sustainable because unlike your reservoirs we supplement the flow by treating our wastewater to levels that are better than natural streams upstream of the reservoirs, so unlike you guys are reservoirs are also adaptive to drought. Our water quality levels are better than yours I assure you, there have been case studies on the Fairfax water system and how they achieve the level they do.

                Not sure what this has to do with anything. And btw no your reservoirs are not straight to the tap, you have water treatment plants, so you are horribly mistaken by that.

                Not sure where you live but heres Stafford

                http://stafford.va.us/index.aspx?NID=987

                Raw water is not allowed to be used for potable. It must be treated because all surface waters are above the legal limits for all sorts of stuff, most notably water born disease. ALL areas in the country require this, and have for decades. Wells get away with it because they are in populations that are small, generally away from industrial sites, and because the soil percolation can (key word can, must be proven to the health department for any proposed well) be of the same quality as surface waters.

                But no, as soon as water is on the surface in the US it must be treated to be part of a municipal water system. Sorry to break that to you.
             2. 

                larryg

                April 6, 2014

                re: ” I mean counties like Stafford, who don’t have their own local stricter standards. These locals don’t usually levy stormwater taxes, it is the ones that are closer in, that have to deal with existing areas that aren’t redeveloping (that are staying in a non-compliant state of low density homes like around four mile run) that need to levy special taxes. Its not because R-B developed that Arlington needs it, its because four mile HASN’t developed that they need it.”

                we follow the state regs and yes this year we’re going to start fees. we have hundreds of storm ponds guy and not one of them was “volunteered”.

                “my understanding is – it’s based on the water quality of the discharged water.”

                And your understanding is incorrect. You are confusing mitigation of existing conditions that pre-date regulation with new development. New development has a requirement to meet effluent numbers on all metrics. That is all. It doesn’t matter if you have a construction vehicle storage facility or a kindergarten, the per acre stuff has to be the same. There is no different set of rules for the goal numbers. The difference occurs in the regulations as a whole. Some jurisdictions have stricter ones than others, the State’s being the weakest escalated based on the more urban you get.”

                we do not yet have state-required regs for stormwater water quality but we do have many, many storm pods throughout our region.

                “All development requires treatment up here in Fairfax. All. All development in Tysons requires even stricter treatment in terms of percentage. All. Non-point source pollution and point source pollution are different things.”

                all your development requires treatment? doesn’t that mean you have to sequester it and feed it through a treatment plant?

                “In some cases, like gas stations, the county for the purpose of extending the life span of any treatment controls will require things like pretreatment using oil grit separators, but that is only for when it makes sense like exposed fuel possibilities. Whole other issue, lets not complicate an already complicated discussion by bringing pre-treatment into it. Either way, I can assure you that only urban areas require this stuff, fringe zones let people get away with murder.”

                the water quality of the receiving streams is what kicks off stricter regs – not the jurisdiction or location. they monitor the streams.. when the streams start to degrade – they start requiring stricter regs.

                “We have dozens of reservoirs also. I have no idea where you get this idea as if we what? Pump our water from you guys :P”

                you’ve been telling me for hours/days that ponds are not the only option. right?

                “Please

                Our water comes from reservoirs and surface water, but our water is actually much more sustainable because unlike your reservoirs we supplement the flow by treating our wastewater to levels that are better than natural streams upstream of the reservoirs, so unlike you guys are reservoirs are also adaptive to drought. Our water quality levels are better than yours I assure you, there have been case studies on the Fairfax water system and how they achieve the level they do.”

                come on FE.. can you stop with the BS?

                “In Fairfax County, our water comes from two major sources: the Occoquan Reservoir and Potomac River. The water that flows in the Potomac and Occoquan comes from both groundwater and stormwater runoff.

                Groundwater is cleaned and cooled when it flows through the soil. Runoff, on the other hand, can carry pollution into our drinking water sources, including sediment from the land, contaminants such as pesticides or motor oil, and organic matter from deceased insects, plants, or animals. Water treatment plants remove these impurities and make the water safe for household use.

                The Occoquan Reservoir provides drinking water supply to Northern Virginia through the Fredrick P. Griffith treatment plant. This plant can treat up to 120 million gallons of drinking water per day.

                The Potomac River provides water to area residents through the James J. Corbalis Jr. treatment plant, which can treat 225 million gallons of water per day.”

                “Not sure what this has to do with anything. And btw no your reservoirs are not straight to the tap, you have water treatment plants, so you are horribly mistaken by that.”

                never said straight to the tap.. but if you actually read the Fairfax water authority website they’ll tell you that they seek the cleanest raw water they can so the treatment process is less expensive and more reliable.
13. 

    Tysons Engineer

    April 6, 2014

    Larry

    Over and over again I have told you what projects do with “street grid” developments

    And you have ignored.

    There is nothing different that is done for street grid than suburban cul de sac, other than street grid development, because of people like you that don’t understand diffused reality, are required to do even more.

    Street grid sanitary goes to waste water treatment plants, that unlike your neck of the woods, meet not just EPA standards but are case studies in even higher standards that provide near drinkable water quality. Those WWTP are funded to be so good because the extremely high assessed value of urban areas contribute to the capital needed to create them (unlike the cheap WWTP found in the fringe zones if at all, usually septic).

    Street grid then address storm water by not just capturing the same way suburbs do, but treating at a higher level, and releasing less volume than the suburbs.

    End of story larry, that is subsidization of suburbs becuase they play by looser standards.

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14. 

    Tysons Engineer

    April 6, 2014

    Please stop responding to me, I can’t stop responding when you make uneducated comments. So for my own health so I don’t have a heart attack arguing with you, either stop responding and let me have my damn last word because I am that much of an a-hole that I need it, or call me and I will talk like a human to human with you.

    Thank you, I appreciate it if you could accommodate my pyschosis as such

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15. 

    Tysons Engineer

    April 6, 2014

    Here

    http://thetysonscorner.com/wp-content/uploads/2014/04/CombinedSewer.png

    http://thetysonscorner.com/wp-content/uploads/2014/04/CombinedSewer2.png

    http://thetysonscorner.com/wp-content/uploads/2014/04/CombinedSewer3.png

    I made quick graphics.

    You are conflating two different issues that never again because of technological improvements will ever be an issue. Cities that are encumbered by the old arrangement will need to spend money to make it better but that is because they grew up during a different time not because there is something inherently in the “street grid urban” that you keep talking about that keeps them from being correct.

    Now I’ve been extremely gracious by saying I will talk to you about this stuff on the phone, because typing in technical information is extremely cumbersome for me to explain the stuff that you keep conflating the issue about. Especially since there is a limit to the heirarchical levels allowed by this commenting system which makes the conversation more muddled than any that would occur on a phone.

    I dont know why you won’t take up my offer as you have nothing to lose? My name is all over the internet, hell if you are worried I will harm you in some way my P.E. License number is on the NCEES record database. If I in anyway cause you harm report me.

    I simply want to stop the stupidity of this useless online “discussion” with a 10 minute conversation on the phone instead. What is so wrong with that?

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16. 

    Tysons Engineer

    April 6, 2014

    I have some links awaiting confirmation but before then I want to again offer to speak about this stuff on the phone, we can resolve it, it can be done in a far less frustrating way. I am the one taking the risk by offering this by the way, for all I know you could leak my number out and then I’ll be screwed. But I am willing to discuss it none the less because I care about educating people on this stuff.

    Please stop this non-sense online, and lets just talk on the phone which won’t take more than 10 minutes to explain the science. I think if I can stop having to type this stuff, it can be much more clear to you. When I type technical information, it frustrates me, and I get emotional and irritated and then the points I make are lost in my anger. It is alot easier to have a conversation than this online non-sense.

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    1. 

       larryg

       April 6, 2014

       re: ” Please stop this non-sense online, and lets just talk on the phone which won’t take more than 10 minutes to explain the science”

       right. so you can be even more insulting in private? no thanks.

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       1. 

          Tysons Engineer

          April 6, 2014

          If I insult you on the phone, post my phone number. Deal? I seriously am just getting irritated because of this format.

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          1. 

             larryg

             April 6, 2014

             nope.

             you cannot disagree guy without go after the other guy personally.

             not for me.

             you said you were done. honor your word.

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             1. 

                Tysons Engineer

                April 6, 2014

                Read below. You don’t understand that sanitary and storm systems stay in separate pipes.
             2. 

                larryg

                April 6, 2014

                we’re talking past each other.

                concentrated sewage with no runoff – goes direct to the treatment plant, which is sized to accommodate it, gets treated and released into the receiving stream.

                but in a rain event runoff goes into curb drains and in older urban those curb drains go into the sewer system.

                the treatment plant has some excess capacity to store excess sewage that has been swelled by surface runoff but only for smaller rain events. In the larger rain events the volume of the runoff-diluted sewage is greater than the capacity of the plant and they have no choice by to let it go directly into the river.

                my point here is that if you do not let surface water get into the sewers, you still have to do something with it. it does not evaporate.

                what do we do with it?

                you seem to be saying that there’s not much of it if we use modern methods to capture and diffuse it.

                my view is that – if that were actually true – no one in their right mind would spend 2.6 trillion to bore huge underground tunnels to store it – and that’s effectively what they’ve done is to choose to NOT separate it.. just continue to let it get into the sewage system then store the whole mess in underground tunnels while the treatment plant day, by day, treats what’s essentially stored in the tunnels.

                perhaps it’s not just where to store the surface runoff if you separated it but what you’d have to actually do to separate it. You’d have to tear up every street and and put in new, separate runoff pipe that captures at the curb drains.

                but then where would the other end of the pipe go if not to the sewage treatment plant?

                where would that water go to and what would happen to it?

                what happens to the surface runoff water that goes into separate pipes at Tysons?
          2. 

             Tysons Engineer

             April 6, 2014

             We’re definitely talking past each other, which is why Ithink a 10 minute phone call would be much more productive, theres no such thing as talking past each other on the phone.

             You keep bringing in the sanitary sewage problem.

             I’ve said it a bunch of times. This is specific to cities from the 19th century. Sanitary and storm sewer have as much to do with each other for Tysons and Arlington as does electric supply and storm sewer. They don’t interact in any any way. In fact less so, atleast in the case of electric sometimes you need a submersible pump or electrical sensor to provide the filtration and treatment of stormwater.

             Sanitary goes to WWTP. Storm goes through its own treatment system (depending on the year it was built).

             The same effect that timing had on sanitary and storm, it is having a similar effect on the implementation of non-point source storm water treatment. It depends on the age of the neighborhood.

             If Tysons was a green field today, and through whatever reason the county said, we are gonna build here to super high density, and developers were to say, ya lets do it(without any proof that it could be urban), and that the county would enact the same exact regulations they have currently on Tysons. Then it would be no issue. Stormwater that currently runs in Pimmit Run and Scotts Run would be impacted not at all. Zero. Zero impact, zero new volume, zero new pollutants, zero new anything. The stream would literally not see a change because everything upstream of it is being returned to a natural state.

             The reason why you see urban areas with problems, isn’t becuase their current regulations are weak, its that their older regulations mimic what Richmond is proposing. They implemented standards that weren’t fully understood, and now have to play catch up. But again, new cities don’t have this problem because they are up and running with current standards. In the future maybe we will discover something new that cities have to adjust for also, but that is true also of the exurbs that allow builders to get away with even less than cities do currently.

             In areas like Stafford, builders just do what they want, plop down a pond, and the county does everything else for them. In 20 years those areas of stafford will see the same problems Fairfax experienced because they didn’t listen, but in Fairfax’s defense atleast, the science was still new then, in Staffords this stuff has been around and established for years, at this point it is acknowledged subsidization. I’ve heard outer burb county officials literally say we can’t do that, it will dry up development. How is that not subsidization?

             Again, you keep confusing the purpose of the tunnel.

             The tunnel is to get it to acceptable SANITARY volumes. It has nothing to do with the river, it has to do with what the WWTP can handle, and when that volume is exceeded then the WWTP has to release the dam.

             If the system were separated they wouldn’t have to spend the billions to build the tunnel. So you continue to conflate the two issues. I don’t really know how else to explain that to you other than to say, Arlington and Tysons don’t have that problem. Only old cities do.

             That is your view. Mine is not a view. It is fact. Tysons and Arlington will never need that.

             Like I’ve said now 30 times (I think thats literally) and please stop saying if, don’t make me go into the storm sewer and take a picture. Its not an if, the systems are separated.

             stormwater is non-point source. Take those words apart. NON (isnt) point (from one) source (generated). The water is taken care of before it ever gets to the pipe. Each parcel treats itself and its surrounding roads in its own parcels storm drain piping, so that before it outflows into the main storm water pipe branch that underlies the entire city, it is returned back to the existing condition (like forests were there) for all conditions.

             The net effect of each parcel doing this is that the main collector pipe carries the exact same flow as what existed there before. So then when that pipe eventually gets outside of the city, and to a stream, when it outflows that water is in every way the same as the old tributaries that used to feed that larger water body. Thats already occurring, this isn’t somethign thats new, its been required of all urban developments for decades, its the degree to which that has increased over time.

             But in cities that is the hydrologic process. Parcel is rained on, parcel makes it as if it was never there before releasing to a pipe, pipe goes on its merry way just as a collecting tributary would until it reaches the actual perennial water body at which point the water coming out of it is the same as if nothing ever occurred.

             This isn’t theory, this is what happens.

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17. 

    Tysons Engineer

    April 6, 2014

    Perhaps you are not aware but storm sewers and sanitary sewers are two different things.
    Yikes bikes, I didn’t even consider you didn’t realize this.

    In arlington storm runoff goes into one pipe, and sanitary into another.

    They don’t go to the same place. That hasn’t happened in over a half century, as Isaid, combined sewers are old technology.

    In tysons the curb inlets go to a storm drainage system, the flow that goes into the curb inlets is mitigated by plenty of ways. 1) By actually providing storm inlet filtration boxes, 2) by collecting downstream and treating at a combined point, 3) by over treating other areas more in control of a developer to mitigate the inlets that aren’t treatable thereby creating the same net effluent outflow.

    Btw your subdivisions suburbs also have this same issue of pollutants in inlets so whats your point? What do you think that your ditch at your driveway or cul de sac inlets are different? Atleast in the urban areas the developers actually provide OVER control in order to make up for VDOTs idiocy.

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18. 

    Tysons Engineer

    April 6, 2014

    The tunnel does split the flow. You have to understand what is happening.

    Sanitary pipes are combined with storm. When a ton of water falls from the sky, when they get to the treatment plant they over whelm the plant. One way to split the occurance of a rain fall event, from typically sanitary through put, is to hold on to that combined water long enough that it can be diffused.

    This is because the WWTP is where it is, and theres no way to change that now because people in the 1800s didnt understand this and neither did turn of the 1900s folks as I previously explained.

    So the WWTP being where the WWPT is, and the pipes being what the pipes are, you have to find a way to split the storm even from the sanitary. Split doesn’t mean the physical splitting, it can mean the hydrological splitting.

    This again is not needed in any city after that era. Arlington doesn’t need this. Fairfax will never need this no matter how developed Tysons gets, because they stay in two separate pipes that are accurately sized to carry each type of flow. The sanitary pipes are properly sized and take the sanitary flow to the WWTP which is adequately sized which treats the water to better than EPA levels before release *unlike areas of ROVA*.

    In Fairfax, the stormwater first starts on each property, which requires for that property it is treated to state regulations, and stricter local regulations, before it is tied to any downstream bodies or parcels. So if you take every single parcel in Tysons, and treat water so that the water flows as if it was on a natural forest, then tie each of those parcels into the overall storm sewer system, then when those pipes outfall into the natural water bodies they do not cause damage to those streams and lakes and eventually the bay.

    They are two separate systems in modern days, which is why your argument about combined systems is a moot one and not germane to this discussion, which is why I got so annoyed. It has nothing to do with urban or suburban, it has to do with pre 1950 vs post 1950.

    The DC tunnel is sized in a way that doesn’t mimic natural flow, it has to be even more insanely sized (which is why its so expensive) in order to diffuse the rainwater from the sanitary water throughput.

    If DC had two separate systems where sanitary was the only thing going to the WWTP, they would not need this tunnel. They would continue the process they have been undergoing of letting redeveloped properties come up to compliance with new plans that require they store their own storm water and treat their own storm water, on their parcel to levels of prior to any development.

    Over the past 3 decades DC has successfully reduced their storm runoff as such, and jurisdictiosn around it like Arlington and Fairfax are using this same method to correct for their own lag (from the 50s to 90s) because they didn’t enact quickly enough.

    This in contrast to outer burbs and other areas of Virginia where the regulations still are lagging to those from the 90s.

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    1. 

       larryg

       April 6, 2014

       there is no “splitting”. they’re holding it – the sewage combined with the storm water – in the same tunnel until the plant can process it and they’re doing it this way because it’s cheaper that going back and making a two pipe system which you allude to for Tysons.

       and my question is what happens to the water that is in the storm pipe?

       in Arlington, right now, they say on their website that they are dumping it into local creeks.

       where does Tysons put theirs if not in a storm pond or “vault” or tunnel?

       or are you telling me that modern development like that in Tysons has zero discharge of stormwater?

       if you want to continue – be polite. otherwise go enjoy your day as best you can.

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       1. 

          Tysons Engineer

          April 6, 2014

          Larry, it is hard to be polite when this stuff isn’t sinking in online which is why I want to talk on the phone.

          I will continue to use my time to explain how things in cities work to you.

          Arlington says it “dumps to streams” because literally eventually all outfalls go to streams. It is a matter of what the volume and flow to that stream is.

          Its not that DC is cheaping out by doing the tunnel, it is the cheaper option than the alternative which is to relocate the entire system. You can’t rip out all of the pipes in a 2 century old city. Theres too much there already. It would cost hundreds of billions. This solution turns back the bad decisions of the past by diffusing the flow which is a form of hydrological splitting (that is more technical than I think I can explain to you) but it is the same basis for the TMDL treatment that richmond is taking up in terms of BMP nutrient treatment.

          But again you are really frustrating because you are not understanding all of the timeline of this thing man. Seriously you gotta listen dude.

          1850s people learned poop shouldn’t be on the surface, so they built pipes to take it away and combined it with road inlets and building roofs.

          By the turn of the century cities realized their poop was causing health problems because it was killing off fish and it was being used for water so they built waste water treatment plants near the outflows so as to treat all that collected water before releasing it.

          This worked much better 99% of the time and no one had the kinds of electronic equipment to say otherwise. For the most part, the water looked healthier (which it was better than before) and the fish were doing better.

          In the 1950s people started actually recording information on our waterways though, and they saw, wow we have a lot of bad pollutants in this water that still come from sewage. They saw that those 1% events were causing risidual damage that wasn’t physically observable but was having long term impacts. So many jurisdictions expanded their WWTP to make them bigger so they could handle more flow.

          That was a stop gap, they realized if the population ever grew then that would be just as big of a problem because the plants would keep chasing the population, but they had to do something so they did it.

          Thats sanitary up till the 50s.

          Now at the same time, people were starting to see roads, and automobiles, and post industrial processes and their understanding of water quality started expanding with regard to non-point source. We had known that some industrial processes were bad for rivers (controls on coal, and steel operations) but at that time no one thought about, well what about all this tearing down trees, and fertilizer, and all the extra water that isn’t being sucked up by plants?

          In the 70s the first research on those were starting to form a much better understanding. People were seeing, oh actually its not just industry that causes stream damage, the combined presence of all this pavement and roof causes water way banks to erode, deposits all of our pollutants on those roads into the streams, etc. So some of the more liberal cities in the country started enacting requirements like cisterns and storm water sand filters for any new buildings because at a minimum they wanted to not allow any more growth without proper controls. The existing stuff was still a problem, but atleast it didn’t continue to get worse.

          At the same time, suburbs were becoming big things, so cities were not seeing the growth the experienced before so the redevelopment wasn’t changing the horizon fast enough. Those suburbs at the time, didn’t listen to the cities, they wanted the tax money, so early on they allowed no regulations on stormwater. They were separated systems from sanitary (because they didn’t want to fall for that mistake like early cities) but none of the parcels held onto water or treated water.

          Then 10-20 years later, these suburbs started seeing the effects of their decisions, oh crap we should have listened to cities, our streams are looking terrible, our fishing areas are having problems, and we need to fix this stuff. So inner suburbs (no longer on the fringes of development and in many ways established) in the 90s, like Fairfax and Arlington, started requiring that any new projects provide these kinds of controls that cities 20 years before were requiring. Some of that happened as subdivisions, some happened as higher density, but the requirements were same for either in terms of whatever your impact is, you gotta mitigate for it. Now, by this time, Fairfax and Arlington was largely built out with homes, and since their land planners didn’t want to push for much more than just homes at that time, the fixes didn’t work very quickly. To date there are suburban like parts of Arlington around Four Mile Run which still need mitigation cause no one has redeveloped there for 50 years. But Rosslyn to Ballston where high rises went up, make up for many of those issues by over detaining and over treating their impacts. Arlington county was able to get this concession because those developers really wanted to build there, and it was worth their time to play ball and give them better stormwater.

          Now flash forward to the 2000s. New studies started seeing, hey, we’ve done pretty good, stuff in waterbodies is getting better but we have new measurements we never thought about before like the temperature of the water (which causes fish kills too) and other types of nutrients that can cause other kinds of problems. We should start treating that. So once again, cities started telling their new urban developments, hey if you guys wanna play ball you better put in these new stricter requirements, otherwise no new density for you. Luckily this time, cities were hot commodities in terms of development so developers in cities were like, yea we should do that its worth it. So DC for the past decade has actually been really successful with this stuff (outside of the issue of the combined sewer problem which is over a century old).

          Now the suburbs, they lagged a bit, they saw DC doing this stuff and other parts of Maryland which were more progressive, and they said, well… we don’t wanna force our developers to just stop working here, we’ll just keep the standards we have for now (which are stricter than the state and your neck of the woods remember). So through most of the 2000s Fairfax and Arlington made it only voluntary for developers to provide even stricter standards. Then in the late 2000s, when housing all but stopped, and commercial high rises was all that was going well, the countys said, well these guys really want to build out here so lets start making very specific districts (so that single family homes could still not have to) for these big developers to have to completely provide high end controls.

          So Tysons and Arlington got these much stricter standards to make up for other areas that they didn’t want to have to have as strict a standard, which again even those other areas are stricter than what the state is trying to implement as a whole.

          Thats the timeline. Tysons and Arlington are successfully reducing their pollutant loads and their runoff volumes to those streams but you have to understand the sprawl on the fringes don’t have these problems because they didn’t grow up during the non-regulated era. So they have some regulations already in place, however their regulations don’t go far enough yet, we learned alot since the 90s. Those outer burbs need to enact the same standards that Tysons and Arlington are putting in for their urban development.

          But those outer burbs don’t want to do that for the same reason Fairfax and Arlington didnt want to enact too quickly regulations back in the old days either, because they are scared they will shut down all the development if they make everyone play on a level playing field. They can’t require 90% TSS removal because home builders simply can’t build to that standard while still making a profit. They can’t require that new homes reduce the total runoff volume in the post developed to forested conditions because it would mean tripling the size of those ponds you see, and the value of the sales of those homes don’t add up to the cost of the additional volume they would have to provide.

          That is the definition of a subsidy. If those builders had to do that, they would have to charge 200-300k more per house than they do now and days to make up for the additional cost in order to do the same things Tysons and Arlington require.

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          1. 

             larryg

             April 6, 2014

             re: ” Larry, it is hard to be polite when this stuff isn’t sinking in online which is why I want to talk on the phone.”

             no excuses. I don’t treat you that way even if I think you are the one who is ignorant.

             “I will continue to use my time to explain how things in cities work to you.”

             you can “explain” til the cows come home. just keep it clean unless you want to get the same treatment.

             “Arlington says it “dumps to streams” because literally eventually all outfalls go to streams. It is a matter of what the volume and flow to that stream is.”

             we agree. can it continue to do that without being required to cut the flows because they are causing damaged in big storm runoffs?

             “Its not that DC is cheaping out by doing the tunnel, it is the cheaper option than the alternative which is to relocate the entire system. You can’t rip out all of the pipes in a 2 century old city. Theres too much there already. It would cost hundreds of billions.”

             agree.

             “This solution turns back the bad decisions of the past by diffusing the flow which is a form of hydrological splitting (that is more technical than I think I can explain to you) but it is the same basis for the TMDL treatment that richmond is taking up in terms of BMP nutrient treatment.”

             what would do with the runoff water that no longer goes into the sewers ? Like in Arlington, there would still be significant surface water runoff.

             “But again you are really frustrating because you are not understanding all of the timeline of this thing man. Seriously you gotta listen dude.”

             I don’t think you are listening here guy.

             “1850s people learned poop shouldn’t be on the surface, so they built pipes to take it away and combined it with road inlets and building roofs.”

             they dumped it.. in alleys, ditches and in their backyards in “cess pools” which is where that phrase came from. check it out.

             “By the turn of the century cities realized their poop was causing health problems because it was killing off fish and it was being used for water so they built waste water treatment plants near the outflows so as to treat all that collected water before releasing it.”

             sort of…

             “This worked much better 99% of the time and no one had the kinds of electronic equipment to say otherwise. For the most part, the water looked healthier (which it was better than before) and the fish were doing better.”

             In the 1950s people started actually recording information on our waterways though, and they saw, wow we have a lot of bad pollutants in this water that still come from sewage. They saw that those 1% events were causing risidual damage that wasn’t physically observable but was having long term impacts. So many jurisdictions expanded their WWTP to make them bigger so they could handle more flow.

             for your “history” – were you around the DC area and the Potomac river in the 1960’s? if you were tell me the condition of the river

             “That was a stop gap, they realized if the population ever grew then that would be just as big of a problem because the plants would keep chasing the population, but they had to do something so they did it.

             Thats sanitary up till the 50s.” DC/NoVa history?

             “Now at the same time, people were starting to see roads, and automobiles, and post industrial processes and their understanding of water quality started expanding with regard to non-point source. ”

             cities had roads, grid streets from 1850 on..

             “We had known that some industrial processes were bad for rivers (controls on coal, and steel operations) but at that time no one thought about, well what about all this tearing down trees, and fertilizer, and all the extra water that isn’t being sucked up by plants?

             In the 70s the first research on those were starting to form a much better understanding. People were seeing, oh actually its not just industry that causes stream damage, the combined presence of all this pavement and roof causes water way banks to erode, deposits all of our pollutants on those roads into the streams, etc. So some of the more liberal cities in the country started enacting requirements like cisterns and storm water sand filters for any new buildings because at a minimum they wanted to not allow any more growth without proper controls. The existing stuff was still a problem, but atleast it didn’t continue to get worse.”

             you’re kinda weaving your own history here.. it’s not bad wrong.. but it’s ignoring the fact that cities had roads and cleared land for more than a hundred years prior to the 70’s.

             “At the same time, suburbs were becoming big things, so cities were not seeing the growth the experienced before so the redevelopment wasn’t changing the horizon fast enough. Those suburbs at the time, didn’t listen to the cities, they wanted the tax money, so early on they allowed no regulations on stormwater.”

             at that point – many burbs had no sewer. Down our way municipal water and sewer were not common.. most homes were on well-septic. Only Fredericksburg and the homes near it were on water/sewer but there were roads with curb drains that went into pipes that went to outfalls thence into water courses.. many dry – until it rained.

             “They were separated systems from sanitary (because they didn’t want to fall for that mistake like early cities) but none of the parcels held onto water or treated water.”

             well no.. it was mostly because there was no water/sewer to start with.. there were subdivisions with roads, ditches, curbs and drains.. but no sewer.

             “Then 10-20 years later, these suburbs started seeing the effects of their decisions, oh crap we should have listened to cities, …”

             not entirely correct guy. in the suburbs – runoff infrastructure preceded water/sewer which came later on and usually was separate. Fredericksburg – a longtime city has CSO issues – the two counties that abut it Stafford and Spotsy do not have those issues.. their water/sewer did not get combined with the runoff infrastructure from the get go.

             “our streams are looking terrible, our fishing areas are having problems, and we need to fix this stuff. So inner suburbs (no longer on the fringes of development and in many ways established) in the 90s, like Fairfax and Arlington, started requiring that any new projects provide these kinds of controls that cities 20 years before were requiring. ”

             I think you need to check the history of CSOs and the involvement of the EPA in terms of who wrote the regs and required changes. This is why we still have many urban areas with CSO issues and the EPA is still on them about it.

             “Some of that happened as subdivisions, some happened as higher density, but the requirements were same for either in terms of whatever your impact is, you gotta mitigate for it. Now, by this time, Fairfax and Arlington was largely built out with homes, and since their land planners didn’t want to push for much more than just homes at that time, the fixes didn’t work very quickly. To date there are suburban like parts of Arlington around Four Mile Run which still need mitigation cause no one has redeveloped there for 50 years. But Rosslyn to Ballston where high rises went up, make up for many of those issues by over detaining and over treating their impacts. ”

             my perception is that nothing much happened until the EPA got in that game and to this day Fairfax is suing the EPA over runoff issues for Accotink.

             “Arlington county was able to get this concession because those developers really wanted to build there, and it was worth their time to play ball and give them better stormwater.”

             Now flash forward to the 2000s. New studies started seeing, hey, we’ve done pretty good, stuff in waterbodies is getting better but we have new measurements we never thought about before like the temperature of the water (which causes fish kills too) and other types of nutrients that can cause other kinds of problems. We should start treating that. So once again, cities started telling their new urban developments, hey if you guys wanna play ball you better put in these new stricter requirements, otherwise no new density for you. Luckily this time, cities were hot commodities in terms of development so developers in cities were like, yea we should do that its worth it. So DC for the past decade has actually been really successful with this stuff (outside of the issue of the combined sewer problem which is over a century old).”

             if you’re telling me that developers were the ones seeking changes.. it’s totally bogus.
             The EPA has been the impetus since the 1960’s when the Potomac was open acknowledge by most as a virtual open sewer and it’s not like no one knew the problem with the CSOs either.. they knew..

             “Now the suburbs, they lagged a bit, they saw DC doing this stuff and other parts of Maryland which were more progressive, and they said, well… we don’t wanna force our developers to just stop working here, we’ll just keep the standards we have for now (which are stricter than the state and your neck of the woods remember). So through most of the 2000s Fairfax and Arlington made it only voluntary for developers to provide even stricter standards. Then in the late 2000s, when housing all but stopped, and commercial high rises was all that was going well, the countys said, well these guys really want to build out here so lets start making very specific districts (so that single family homes could still not have to) for these big developers to have to completely provide high end controls.”

             the developers down our way have largely fought these things tooth and nail, locally and in the GA.

             the tightening of these regs has come almost 100% from the EPA not the localities.

             the local elected down this way are like screaming meemies over the July 1 storm regs coming up. They’re “consulting” with their lawyers to see if they can ignore the rules.

             “So Tysons and Arlington got these much stricter standards to make up for other areas that they didn’t want to have to have as strict a standard, which again even those other areas are stricter than what the state is trying to implement as a whole.”

             well I might have believed you if I didn’t know that Fairfax got Cucinelli to sue the EPA over Accotink Creek.

             “Thats the timeline. Tysons and Arlington are successfully reducing their pollutant loads and their runoff volumes to those streams but you have to understand the sprawl on the fringes don’t have these problems because they didn’t grow up during the non-regulated era. ”

             that’s just total BULL TE. Our countryside is littered with storm ponds with chain link fence around them from the local WaWa to the Public Safety building just built.

             “So they have some regulations already in place, however their regulations don’t go far enough yet, we learned alot since the 90s. Those outer burbs need to enact the same standards that Tysons and Arlington are putting in for their urban development.”

             good grief guy. the new regs are based on TMDLs – and last time I checked they are one set of regs that apply statewide.

             “But those outer burbs don’t want to do that for the same reason Fairfax and Arlington didnt want to enact too quickly regulations back in the old days either, because they are scared they will shut down all the development if they make everyone play on a level playing field. They can’t require 90% TSS removal because home builders simply can’t build to that standard while still making a profit. They can’t require that new homes reduce the total runoff volume in the post developed to forested conditions because it would mean tripling the size of those ponds you see, and the value of the sales of those homes don’t add up to the cost of the additional volume they would have to provide.”

             The TMDLs put the standard at the river. each locality has to do what it takes to keep their effluents under the TMDL thresholds.

             that’s harder in areas where there are more impervious surfaces but it’s the same rules in terms of the nitrogen and phosphorous thresholds. No locality is getting an easier deal than other localities.

             “That is the definition of a subsidy. If those builders had to do that, they would have to charge 200-300k more per house than they do now and days to make up for the additional cost in order to do the same things Tysons and Arlington require.”

             we have to meet the same storm water regs and the same TMDL standards.

             we are for sure inefficient users of land but we have a lot lower percent of impervious surfaces which means much more of the runoff infiltrates before it gets into the streams.

             even then – we have just massive storm ponds behind our commercial development built in the last 10-15 years. Massive… we have a Mall built in the 1970’s and has no ponds – none and 50 acres of parking lot and a new development five miles away with 10 acres of parking and 10 acres of storm ponds even though they are using LID in the parking lots.

             VDOT just widened some roads down our way – and there are massive storm ponds…

             you need to wander down our way and take a look guy.. it ain’t what you think. The reason I talk ponds is that we now have hundreds of them.

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             1. 

                Tysons Engineer

                April 6, 2014

                No dude, you are reading but you still aren’t listening.

                ALL WATER IN THE WORLD LEADS TO WATER BODIES

                Suburbs this same thing happens. You still dont concede that there is no retention in your suburban ponds. thats not retention dude you need to realize that. its detention.

                The water flows into the same waterbodies during a storm event just like in Arlington and Tysons and Fairfax.

                Unlike Stafford and other exurbs like your place, in urban areas, they actually reduce back to volume that was naturally going there. In your neighborhood, the volume going to the eventual stream is increased.

                Get it?

                You have a fundamental misunderstanding of stormwater and it stems from the following factual things

                1) You think your ponds are retaining volume. They dont, they only depeak.

                2) You think your ponds don’t have downstream flows, they do.

                3) You think Ponds are the only way to hold water, not true at all, disproven by over 3 million cisterns in operation in US cities.

                4) You think sanitary and storm systems are combined in modern systems. They are not.
             2. 

                larryg

                April 6, 2014

                re: ” No dude, you are reading but you still aren’t listening.

                ALL WATER IN THE WORLD LEADS TO WATER BODIES

                Suburbs this same thing happens. You still dont concede that there is no retention in your suburban ponds. thats not retention dude you need to realize that. its detention.”

                ” Detention basin – Wikipedia, the free encyclopedia
                en.wikipedia.org/wiki/Detention_basin‎
                Wikipedia
                These basins are also called “dry ponds”, “holding ponds” or “dry detention basins” if no permanent pool of water exists.”

                ”

                A stormwater management pond is an artificial pond that is designed to collect and retain urban stormwater. They are frequently built into urban areas in North America to also retain sediments and other materials.

                In urban areas, impervious surfaces (roofs, roads) reduce the time spent by rainfall before entering into the stormwater drainage system. If left unchecked, this will cause widespread flooding downstream. The function of a stormwater pond is to contain this surge and release it slowly. This slow release mitigates the size and intensity of storm-induced flooding on downstream receiving waters. Stormwater ponds also collect suspended sediments, which are often found in high concentrations in stormwater water due to upstream construction and sand applications to roadways.

                Engineering[edit]
                At its simplest, a stormwater pond can be constructed by creating a dam across a drain or stream at a convenient valley, with a restricted diameter outlet pipe through the dam. Normal flows are carried through the pipe, but heavy flows back up and the water behind the dam is choked back. Over the following few days, the level subsides. If the lake fills to capacity, then it will begin to spill over”

                “The water flows into the same waterbodies during a storm event just like in Arlington and Tysons and Fairfax.

                Unlike Stafford and other exurbs like your place, in urban areas, they actually reduce back to volume that was naturally going there. In your neighborhood, the volume going to the eventual stream is increased.

                Get it?”

                I get the total BS.. storm ponds in Fairfax don’t work like storm ponds in Stafford?

                good lord TE.

                you are so full of yourself and your BS it reeks!
             3. 

                Tysons Engineer

                April 6, 2014

                YES THAT IS CORRECt

                STORM PONDS IN STAFFORD ARE DIFFERENT THAN FAIRFAX.

                What part of that don’t you understand? The requirements in Fairfax are stricter than stafford. Do you not understand that there is sizing involved. You don’t just put the same thing for each one. There is also treatment that is required. If you make a bowl without any ability to filter, it doesn’t do as much as one which does have filtering. So yes, the ponds in Fairfax ARE BETTER THAN IN STAFFORD because they treat to higher levels.

                Just like you can size a septic system to have effluent levels at different % also. It depends where you put your overflow, what your load is, ALL OF THAT.

                Telling me I am the one BSing? When you still think stafford ponds are RETENTION PONDS?

                http://sustainablestormwater.org/2009/05/28/stormwater-101-detention-and-retention-basins/

                http://www.lccdnet.org/wp-content/uploads/2011/04/Ponds.pdf

                Staffords actual facilities
                http://www.co.stafford.va.us/DocumentCenter/View/4287

                Most of them are detention ponds. Some atleast are extended detention, thats atleast something, but none of those facilities are sized appropriately to meet LEED 6.1 and 6.2, nor would they be strict enough to be allowed in Fairfax or Arlingtons Urban zones.
             4. 

                Tysons Engineer

                April 6, 2014

                I designed 8 subdivisions and 3 commercial sites in Stafford. So while you think “ive never been down your way” no infact Im quite fricken aware of the crap standards your county put in place. It was very easy to get things approved there back in 2005.
19. 

    Tysons Engineer

    April 6, 2014

    Dude Larry,

    You need to get this understood.

    Stormwater doesn’t work like that. Seriously. You dont know what you are talking about. Do you know why sanitary sewer is collected in WWTP? because otherwise each individual property would need to do their own treatment. Otherwise it would make more sense for each property to do it.

    In the case of stormwater, EVERY SINGLE PARCEL does do it on their property.

    You are just flat our wrong on everything that you think you understand about this dude.

    Yes every parcel treats storm water in a way equivalent to how a WWTP does it for a whole sewer shed. Look up products like Filterra, Baysaver, Storm Saver, they have been around for years. Your precious Stafford hasn’t implemented these AT ALL, while Fairfax and Arlington did long long ago.

    Fairfax by the way actually has more storm ponds than Stafford just for your own information, but many of them are from an older by gone era. Your understanding of SWM regulation is about up to date through 1999.

    You are just the most frustrating person I have ever talked to about on this subject. No matter what I say you ignore it, despite the fact that I am the one with a career of this, who has actually designed not just Richmond compliant systems but systems that are far better in every measurable metric you could imagine. Yet, no lets ignore everything I am saying and keep listening to you… who thinks that the only way to reduce volume is through a detention pond WHICH DOESNT EVEN REDUCE VOLUME.

    You win. I don’t give a shit anymore.

    Love peace and soul. I’m so glad that you think somehow Stafford with its good ole boy network of folks, constant skirting of regulations from point source and non-point source pollution, and over all subsidization of an unhealthy life has got everything down pat. They are doing great in terms of stormwater, and maybe someday us idiots who have been telling them how to do it for 3 decades, who they are adopting our multi-decades old regulations, will get the chance to be as great as Stafford county Virginia.

    In closing I post the following which still holds true. THAT ALL projects must follow, none of the urban projects get to skirt.

    States without regulation
    No requirements for 2-yr and 10-yr detention

    Virginias 90s requirements, the NOVAs early Ches Bay acts (Staffords highest level to date)
    Required 2-yr and 10-yr DETENTION

    Virginias new requirements, Maryland and NOVA current standards County wide for all Fairfax projects minimum
    Required 2-yr and 10-yr DETENTION
    Required BMP to reduce pollutant loads, 50% of SOME new pollutants compared to existing conditions

    LEED Requirements, required in high density areas of NOVA, becoming closing to enaction state wide in Maryland (Required of all Tysons and Arlington urban projects)
    Requires 2-yr and 10-yr detention
    Requires 2-yr complete removal of new volume, temperature increases
    Requires net zero pollutant loads (100% treatment) compared to existing

    But you are right, evidently somehow requiring the same stuff but more means that urban areas are subsidized. Thats logical.

    Out.

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20. 

    Tysons Engineer

    April 6, 2014

    Also educate yourself

    http://www.novaregion.org/DocumentCenter/Home/View/1679

    That document has existed since 1992 as a regulation in Northern Virginia. And only now is the state, in their ground breaking fashion, adopting those same standards… which by the way the urban areas of NOVA already require even more on top of.

    Read the damn manual. Don’t listen to me, read the manual though. You need to be educated in this stuff if you want to start throwing stones and saying IM THE ONE? who is spouting BS. This is literally what i do. But you know what, I will take your offense, because ultimately when you learn the truth you will feel terrible and apologize to me.

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21. 

    Tysons Engineer

    April 6, 2014

    Read section 1.3 of your own county’s regulations. They themselves acknowledge their old standards are not enough

    http://www.co.stafford.va.us/DocumentCenter/Home/View/107

    That retainage, and reuse, is the only way. Ponds are old news Larry, no jurisdictions other than the cheap ones promote ponds as the solution anymore.

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    1. 

       larryg

       April 6, 2014

       re: ” Ponds are old news Larry, no jurisdictions other than the cheap ones promote ponds as the solution anymore.”

       it’s what they build guy. that and some LID which helps reduce the size of the pond.

       Log in to Reply
       1. 

          Tysons Engineer

          April 6, 2014

          Stop calling me guy. You don’t know what they build because you don’t work in the damn industry. And no, based on the latest requirements that Stafford finally published, they are no longer allowed to build that way.

          And you still dont freaking understand that there are DIFFERENT KINDS OF PONDS, and that PONDS ALONE are not the only way you can meet the requirements. There are much better ways to do it, in much more efficient foot prints that cost more and thats why they weren’t required before.

          But all along, like I have been saying, Tysons and Arlington have BEEN DOING IT. Yes Fairfax’s ponds WERE IN FACT BETTER THAN STAFFORDS for the past 2 decades because while you guys were just detaining, we were actually treating and holding far greater equivalent volumes per acre.

          You have no idea what the hell you are talking about, and its sad that you believe your knowledge on the subject is better than someone who literally is licensed in the field who has actually built this stuff through out his career.

          But whatevs, read below btw. Enjoy!

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          1. 

             larryg

             April 6, 2014

             “Stop calling me guy. ”
             Okay Fella.

             😉

             “You don’t know what they build because you don’t work in the damn industry. And no, based on the latest requirements that Stafford finally published, they are no longer allowed to build that way.”

             actually I pay attention. I visit the ponds and other facilities behind most commercial.. and I do it during big rain events also.

             “And you still dont freaking understand that there are DIFFERENT KINDS OF PONDS, and that PONDS ALONE are not the only way you can meet the requirements. There are much better ways to do it, in much more efficient foot prints that cost more and thats why they weren’t required before.”

             there may be but almost all of the commercial I see these days still have ponds. some have smaller ponds than before because they are using more extensive LID but I’ve yet to see one without some kind of pond and almost none down this way that have water treatment machines.

             “But all along, like I have been saying, Tysons and Arlington have BEEN DOING IT. Yes Fairfax’s ponds WERE IN FACT BETTER THAN STAFFORDS for the past 2 decades because while you guys were just detaining, we were actually treating and holding far greater equivalent volumes per acre.”

             well geeze.. did I ever say that Stafford was better or even equal?

             “You have no idea what the hell you are talking about, and its sad that you believe your knowledge on the subject is better than someone who literally is licensed in the field who has actually built this stuff through out his career.”

             people who know for real don’t have to do what you’re doing.. which is
             abusing your position by trying to play bully boy and it won’t work – fella.

             But whatevs, read below btw. Enjoy!

             Log in to Reply
       2. 

          Tysons Engineer

          April 6, 2014

          Its what they build in your cheap sprawlly subdivisions because up until now those cheap sprawlly subdivisions were never required to build more. They would not be up to code up here in Fairfax, in fact based on the link below I researched and provided for you, your very own county would no longer accept them. They are simply grandfathered in.

          Read it. Then I expect a full apology for wasting my time and not listening.

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22. 

    Tysons Engineer

    April 6, 2014

    “Traditionally, stormwater drainage systems have consisted of natural streams and swales, engineered open conveyance channels, storm sewers, and road culverts while stormwater management facilities consisted of detention ponds, infiltration facilities, and other best management practices (BMPs). These BMPs reduce peak runoff rates from a developed site to pre-development condition. They also detain runoff which allows pollutants to settle out before being released.
    These measures release cleaner runoff at rates no more likely to cause flooding downstream than before development, but they do not address the erosion potential posed by the shear increase in runoff volume from a developed site. To address this, stormwater management systems are designed to detain the volume of runoff from the most frequent storms (1-year, 24-hr) on site and release it over the entire 24-hour period of the event.
    Ultimately, however, these measures allow almost all the increased runoff caused by the development to leave the site. A relatively recent development in stormwater control systems is low-impact development (LID). Under this approach, integrated management practices (IMPs) are used to control and actually retain stormwater at the source of the runoff and more closely replicate pre-development hydrology. Typical IMPs include bioretention facilities, dry wells, filter strips, buffer strips, grassed swales, rain barrels, cisterns, and infiltration facilities.”

    Thats from your own county’s suggestions on what needs to be implemented, which literally reiterate what LEED and Urban areas of NOVA have had to do for a decade.

    Your county is WAAAAy behind the ball on this stuff which is why, despite being built later than Fairfax, there are so many detention ponds in Stafford, because the developments weren’t being told to provide anything else.

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    1. 

       larryg

       April 6, 2014

       re: ” Ultimately, however, these measures allow almost all the increased runoff caused by the development to leave the site. A relatively recent development in stormwater control systems is low-impact development (LID). Under this approach, integrated management practices (IMPs) are used to control and actually retain stormwater at the source of the runoff and more closely replicate pre-development hydrology. Typical IMPs include bioretention facilities, dry wells, filter strips, buffer strips, grassed swales, rain barrels, cisterns, and infiltration facilities.”

       we do what the state requires.. that’s what most jurisdictions do whether they are the “burbs” or just “other”.

       we do all of the above.. but I’ve yet to see a site that does not also have some kind of storm pond even when they do all of these other things.

       that’s why I asked.. originally..

       we have a River organization down this way that promotes all of these things and actually goes out and builds them in some residential but commercial is usually heavy duty and as I said.. have yet to see a commercial without at least a dry pond…

       these dry ponds are becoming more popular because they are sized to hold the initial flush – completely and then once they are filled – start metering by the size of the outflow pipe. most of these newer ponds have outflow pipes that if they get topped – have some portion of the dam in rip-rap to handle to topping.

       the point of all of that stuff is to reduce/hold back the volume.

       don’t we agree on that? again.. any fool can grab a few web pages to get the skinny on this.. it’s not like it’s some deep dark secret.

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       1. 

          Tysons Engineer

          April 6, 2014

          Larry I literally provided a whole host of links from the Tysons plans which shows all the projects that in FACT are required to do more than the state.

          Since 1992 Northern Virginia has been required to do more than the state for all projects based on the 1992 Ches Bay BMP handbook. Since 2005 all urban areas of Washington Metro have had to do more by being LEED compliant in stormwater.

          What else do you want me to say to you other than what? Also linking you to those documents? I already have.

          All sites that I referred to, if you had spent 10 seconds to look at the Tysons projects, include multi-hundred thousand cubic foot retention systems like cisterns which do the same thing as ponds. On top of that all of them have filtration systems like sand filters which do much better than your traditional ponds you see in Stafford.

          ALL OF THEM. Know why? Because if they didnt it would be the quickest county rejection ever because it is a basic requirement. They must remove added volume to the level of colonial development (ie forests) and they must also depeak just like traditional ponds, and they must treat via infiltration or sand filtration.

          All of them because that is Fairfax county’s and Arlington’s rules of the game. Don’t wanna play? Then go build in Stafford (although atleast it looks like Stafford is slowly coming along also) so now perhaps they’ll go to some further out county instead.

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          1. 

             larryg

             April 6, 2014

             “Larry I literally provided a whole host of links from the Tysons plans which shows all the projects that in FACT are required to do more than the state.

             Since 1992 Northern Virginia has been required to do more than the state for all projects based on the 1992 Ches Bay BMP handbook. Since 2005 all urban areas of Washington Metro have had to do more by being LEED compliant in stormwater.”

             by who? and why?

             “What else do you want me to say to you other than what? Also linking you to those documents? I already have.”

             maybe explain how NoVa doing “more” means the bubs are “subsidized”?

             😉

             “All sites that I referred to, if you had spent 10 seconds to look at the Tysons projects, include multi-hundred thousand cubic foot retention systems like cisterns which do the same thing as ponds. On top of that all of them have filtration systems like sand filters which do much better than your traditional ponds you see in Stafford.”

             I take your word for it… but does that mean Stafford is “subsidized”?

             “ALL OF THEM. Know why? Because if they didnt it would be the quickest county rejection ever because it is a basic requirement. They must remove added volume to the level of colonial development (ie forests) and they must also depeak just like traditional ponds, and they must treat via infiltration or sand filtration.
             ”
             wait. wait.. who is “they” and who made the regs” and who required meeting those regs?

             it’s hard to believe that Fairfax enacted tighter regs than required at the same time the EPA has a consent decree for Accotink Creek.

             that seem incongrous

             “All of them because that is Fairfax county’s and Arlington’s rules of the game. Don’t wanna play? Then go build in Stafford (although atleast it looks like Stafford is slowly coming along also) so now perhaps they’ll go to some further out county instead.”

             and Accotink? why ?

             New stormwater regs coming down our way in July and both counties are less than happy about it. Stafford is creating a new SW tax and Spotsy is considering a Tea Party inspired ” come and get me you coppers!” disobedience until the DEQ sheriff shows up to escort them to the hoosegow!

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             1. 

                Tysons Engineer

                April 6, 2014

                Again you keep confusing old developments that havent redeveloped in 50 years (like annandale and other suburban style place) with new developments in urban Tysons which exceed the EPAs own regulations.

                And at its heart, yes it is very important that fairfax is stricter than stafford because your argument all along is that ponds is the only way to do blah blah blah, and that urban areas are somehow subsidized for stormwater blah.

                No in fact, new urban areas are not at all, and it was in fact stafford which had the lighter standards even though as I have run through many times before 20,000 homes in Stafford creates far more runoff than the equivalent in an urban area.

                You are wrong Larry just admit it.

                I conceded that in the case of full sustainability that urban areas can be worse than suburban. But you need to understand that urban areas will ALWAYS be better per capita than their suburban comparisons in the fields of both storm and transportation.

                Argue on the issues of energy loss from power plants, argue on the issue of new materials having a giant carbon footprint, but when you argue on storm water you have no idea how out of whack your assertion is.
             2. 

                Tysons Engineer

                April 6, 2014

                Who created the regulations for NOVA BMP? It came out of the occuquan study, it was agreed to by the jurisdictions by their leaders, ultimately adopted by their Boards of Supervisors. Arlington, Fairfax, Prince William, and Loudoun. Some of them came on later than others, but at the core Arlington and Fairfax’s board of supervisors via the study of their engineering and public works staff, and adopted from new studies coming nationally from the EPA.

                The suburbs are subsidized because ultimately it all leads to the same watershed. So property A in farther suburbs not as strictly regulated, gets to one thing, but Property B in closer burb or urban has to do something more. Ultimately the entire watershed has goals to meet, so the more urban areas are actually over mitigating in order to get there compared to laggard areas which are fine with the status quo.

                So yes, Property A is subsidized because he doesnt have to spend ass much as Property B to put in all the other stuff that helps watersheds like filtration, nutrient removal, etc.

                The countys that don’t regulate are quite blunt about it too, they say the costs to do so would be too burdensome and would stop development. Property A would not be economically feasible if it had to do the same thing as Property B, so instead Property A gets to skirt by with lesser rules.

                How is that not subsidization?
       2. 

          Tysons Engineer

          April 6, 2014

          Well your new regulations in Stafford say dry ponds shouldn’t be used. So I dunno what to tell you. At a minimum you must provide a dry pond WITH other stuff. A dry pond is nothing, it provides almost no treatment as seen in the linked info I sent you from Stafford, its minimal it doesn’t mean treatment. That is the exact same thing as a concrete cistern. If your land values were high enough, instead of a pond you would see a cistern instead. Its the exact same volume the difference is one goes underground the other is above ground cause it can be cause its cheap.

          But they do the same thing.

          But unlike Staffords old regs, in Fairfax they went further and required actual treatment also. Have been since 1992. And again, since 2005 urban areas have been required to do even more treatment.

          “the point of all of that stuff is to reduce/hold back the volume.”

          No, because you dont understand that your sentence is a contradiction. There is a difference between your two basic premises. Reduce (actually get rid of) and hold back (slow down slightly). Detention ponds hold back, harvesting and reuse via cisterns for use in process water, in irrigation, etc actually gets rid of.

          Could a dry pond be used for this? No because in order to reuse water you have to be outside of a storm event. Dry ponds by definition are dry within 24 hours of a rain storm, the very time you wouldn’t be able to use that water. A cistern on the other hand, holds water for weeks, long after a storm, and slowly uses it for toilet flushes, for irrigation, for cooling towers. etc.

          So no, we don’t agree on that, and it goes to show you no you can’t just look up a few web pages to get the skinny because it isn’t simple. It is complicated stuff and you actually have to understand what you are reading to get the skinny.

          Thats not an insult to you, but you need to recognize that engineering isn’t simple, you can’t just as a layman understand this stuff.

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          1. 

             larryg

             April 6, 2014

             “Well your new regulations in Stafford say dry ponds shouldn’t be used. So I dunno what to tell you. At a minimum you must provide a dry pond WITH other stuff.”

             looking at what VDOT and Fredericksburg/Spotsy are doing.

             “A dry pond is nothing, it provides almost no treatment as seen in the linked info I sent you from Stafford, its minimal it doesn’t mean treatment. That is the exact same thing as a concrete cistern. If your land values were high enough, instead of a pond you would see a cistern instead. Its the exact same volume the difference is one goes underground the other is above ground cause it can be cause its cheap.”

             we use them at a parks and rec site where when it has water they use it for the ball fields. but when dry – they hold back the first flush.

             no ponds that I’ve seen down this way have treatment equipment.

             “But unlike Staffords old regs, in Fairfax they went further and required actual treatment also. Have been since 1992. And again, since 2005 urban areas have been required to do even more treatment.”

             and that’s a “subsidy” for Stafford?

             “the point of all of that stuff is to reduce/hold back the volume.”

             “No, because you dont understand that your sentence is a contradiction. There is a difference between your two basic premises. Reduce (actually get rid of) and hold back (slow down slightly). Detention ponds hold back, harvesting and reuse via cisterns for use in process water, in irrigation, etc actually gets rid of.

             Could a dry pond be used for this? No because in order to reuse water you have to be outside of a storm event. Dry ponds by definition are dry within 24 hours of a rain storm, the very time you wouldn’t be able to use that water. A cistern on the other hand, holds water for weeks, long after a storm, and slowly uses it for toilet flushes, for irrigation, for cooling towers. etc.”

             where I live – 3 VDOT ponds in a row. the bottom one always has water the top one usually dry -the middle one sometimes wet, sometimes dry. Same thing at the local park.

             mix and match?

             “So no, we don’t agree on that, and it goes to show you no you can’t just look up a few web pages to get the skinny because it isn’t simple. It is complicated stuff and you actually have to understand what you are reading to get the skinny.

             Thats not an insult to you, but you need to recognize that engineering isn’t simple, you can’t just as a layman understand this stuff.”

             oh bull feathers.. TE… I can’t tell you what the design should be but I sure as hell can read up on the concept and how it works.

             and yeah… it was an insult.. you’ve been doing them for a number of responses.. in varied ways.. so don’t pat yourself on the back too much – DUDE and see if you can get a handle on your testosterone malady while you’re at it!

             Log in to Reply
23. 

    Tysons Engineer

    April 6, 2014

    Oh page 23 of that same manual is just as great. It has the actual percentage of removal for each type of facility. Notice the one thats nearest to the worst? Filter strips, detention ponds, and smaller retention basins without water reuse. See which ones are near the top? Sand filters and infiltration. Now you caaaaan have a giant retention basin type III, but up until now Stafford hasn’t required those so I doubt any that you see were voluntarily done. The requirement was for detention basins and detention basins only up until the last couple years in Stafford (congrats to them for finally joining on board) and still remains that way for the rest of Virginia until finally they enact their new regulations.

    See how there are in fact different types of ponds? Remember when you said I was bullshitting? And I was supposed to not be angry at that?

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    1. 

       larryg

       April 6, 2014

       re: ” Now you caaaaan have a giant retention basin type III, but up until now Stafford hasn’t required those so I doubt any that you see were voluntarily done. The requirement was for detention basins and detention basins only up until the last couple years in Stafford (congrats to them for finally joining on board) and still remains that way for the rest of Virginia until finally they enact their new regulations.”

       I don’t defend Stafford. I just point out that like most jurisdictions they do what the state requires and they get voted out of office if they go too far .

       “See how there are in fact different types of ponds? Remember when you said I was bullshitting? And I was supposed to not be angry at that?”

       you WERE bullshitting guy.. I never said that there were not different types of ponds.. or that it was BS to say there were different kinds..

       geeze!

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       1. 

          Tysons Engineer

          April 6, 2014

          How was I BSing? How

          You say I am bullshitting because hey in stafford theres lots of ponds, as proof that the suburbs are able to do something that urban areas cant.

          I say, yes but in Fairfax those ponds do more because they are stricter and in fact there are even structural ponds that do more.

          You call me a bullshitter, insulting my integrity.

          I then find a document FROM stafford proving my point that in fact Fairfax and as such urban areas up here that Fairfax adopted from, have been doing it better and that Stafford is trying to be more like them….

          And then you defend calling me a BSer with what? Just saying that I was? Sorry no I wasn’t bsing this is reality. Some people think reality is bullshit, but I personally think it’s all we have.

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24. 

    Tysons Engineer

    April 6, 2014

    Gonna respond down here

    The VDOT 3 series you refer to is likely a baffled sediment forebay, the main storage pond, and then a secondary spillway.

    http://www.virginiadot.org/business/resources/LocDes/BMP_Design-Manual/Chapter_2_Dry_Extended_Detention_Basin.pdf

    VDOT by the way is no one to be citing as the leader in this field. They have longer than anyone else avoided playing by the same rules.

    You keep saying down here I dont see any…

    Yes thats obvious… the Stafford County regulations have only JUST started requiring this in 2012 per the link I already provided to their storm requirements. That was old standard, which they now admit wasn’t adequate. Which I continued to tell you, and that Fairfax and Arlington has been properly doing the right way (the new way Stafford plans to) for 20 years. On top of that Fairfax and Arlington have moved on to even stricter standards in urban areas which match with LEED 6.1 and 6.2 on top of all of that. Maybe in 20 years Stafford will wise up and do the same, and then you’ll start seeing rainwater harvesting cisterns, reuse, and infiltration/sand filter down there too.

    Until then, yes you can visit many many stafford sites and see lots of dry ponds. Perhaps instead, you should be visiting lots and lots of Fairfax and Arlington sites to see how they do the same, and more things, in structural ways inside of building garages, underneath plazas, and in a myriad of other ways because then you will understand better what new sites will have to incorporate.

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    1. 

       larryg

       April 6, 2014

       looks like this:

       http://goo.gl/maps/4nmZq

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    2. 

       larryg

       April 6, 2014

       and this:

       http://goo.gl/maps/qjk5t

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    3. 

       larryg

       April 6, 2014

       and this:

       http://goo.gl/maps/SJNXp

       can you show some up your way that treat water and do a better job than these?

       thanks.

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       1. 

          Tysons Engineer

          April 6, 2014

          And this

          From Tysons

          https://www.google.com/maps/@38.9210144,-77.2151187,334m/data=!3m1!1e3

          and This

          https://www.google.com/maps/@38.9310379,-77.2274337,174m/data=!3m1!1e3

          and this

          https://www.google.com/maps/@38.9316303,-77.2164133,282m/data=!3m1!1e3

          and this

          https://www.google.com/maps/@38.9258644,-77.2098263,277m/data=!3m1!1e3

          and this

          https://www.google.com/maps/@38.9279699,-77.2079725,281m/data=!3m1!1e3

          Whats your point? These are all either VDOT standard ponds or out-dated old standards. Tysons has versions of this too, as the above links show. Theres nothing mystical about what Stafford is doing compared to what Fairfax did. Its in fact that Fairfax wants to replace these outdated facilities that is why Tysons is mitigating with new standards, that and sites that predated the pond requirements back then.

          “can you show some up your way that treat water and do a better job than these?”

          Well there in lies the real dilemma ay? I can’t really “show you” via aerials underground facilities within buildings can I?

          Hence why I linked you with all those plans that showed what is constructed structurally that acts as a pond.

          Here I’ll do all the work for you

          http://www.fairfaxcounty.gov/tysons/development/cases/download/nvcommercial_2013_12.pdf

          Skip to page 16

          Retained volume of 21,000 cubic feet through various LID measures including green roofs with retention depth and bioretention. The roof areas are being provided with a storage media of 12″ for the full credit, or 4″ for a smaller credit adding up for a total site reduction of the 1″ storm.

          That particular location chose to provide the retention and reuse volume in a disconnected fashion using its roof prints as the storage, and providing the storage and treatment for the road portions via multiple bioretention areas.

          Heres another project that is being built currently

          Jump to page 22 and go through each parcel component

          http://www.fairfaxcounty.gov/tysons/development/cases/download/arborrow.pdf

          It shows cisterns for each block as well as some areas with vegetated swales that act on top of the cisterns.

          Thats how urban areas provide treatment and volume reduction in line with LEED on top of all the other designs necessary like the ROVA 2-yr and 10-yr peak reduction.

          Then jump to page 33 and you will see some of the additional controls like the green roof retention being provided, as well as some LID elements like expensive permeable pavement. That page also shows some good cross sections of what they look like.

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       2. 

          Tysons Engineer

          April 6, 2014

          I have two posts that do just that awaiting moderation. Hopefully soon you will see.

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25. 

    Tysons Engineer

    April 6, 2014

    Here are some examples of underground vaults, there’s dozens of types of all shape and size depending on the foot print of the drainage area.

    http://www.advanceconcreteproducts.com/1/acp/retention_chamber.asp

    This is a prepackaged filter vault

    http://www.conteches.com/portals/0/Images/CONTECH%20Product%20photos/Stormwater%20Management/Filtration/stormwater-management-stormfilter_1.jpg

    I could post hundreds of these, in NOVA they are nothing new. They are used where it makes the most sense financially. They exceed most older storm pond formats that to date VDOT still uses.

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26. 

    Tysons Engineer

    April 6, 2014

    You should really read this as well before we continue

    http://dukespace.lib.duke.edu/dspace/bitstream/handle/10161/512/MP_wdh11_a_200805.pdf?sequence=1

    Its kind of a bridging document between layman and technical folks.

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    1. 

       larryg

       April 6, 2014

       TE this is not a “bridging” document. It’s an advocacy for rainwater harvesting .

       it’s talking about a building that has a separate plumbing for toilets without as far as I can tell addressing the costs of the separate plumbing even though it goes on and on about storage tanks and fitting.

       it worries about not having ENOUGH water longer term by limiting the concept to one tank rather than as many as you’d need to maintain enough flush water over time – i.e. to capture water when there are higher than normal rainfall events – in order to carry it through the times when tank storage is low.

       this is blather.

       it has zero to do with the fundamental reason and purpose for storm water management to start with.

       it’s an advocacy piece to claim that runoff water could be used to flush toilets – but you’d still have to have municipal water for the low times and it ever addressed what you do with the excess runoff in high storm events – because it’s fundamentally not about managing storm water but instead about finding uses for SOME of it – not all of it.

       this is bogus as to the bigger issue of how to manage stormwater when it exceeds the means to store/use it.

       that’s the problem with Accotink Creek. It’s not a shortage of water.. it’s an excess of runoff which has nowhere to go but down Accotink creek… which is a severely compromised urban stream suffering from pollutants washing into it from impervious surfaces.

       this is why I say BS , TE.. it’s BS to blather on about the “potential” for rainwater “harvesting” when the real storm water problems are creeks like Accotink and 4 mile run in Arlington and other severely impacted streams in the NoVa region.

       You won’t help those streams with “rainwater harvesting”. It won’t make a dent in the problem and let me ask you – is there a single building in all of NoVa that has separate water supply plumbing for toilets that’s fed by a rainwater harvesting system?

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27. 

    Tysons Engineer

    April 6, 2014

    Larry,

    Harvesting as a general amount is almost always just a supplement to total reuse amount. Which means more often than not there is volume available. Remember also that the total storage in LEED compliant structures is for a 2-yr storm.

    2-yr storm means the likelihood it happens in 2 years. So no you are actually the one that is full of BS, because the usage of that volume happens FAR more often than a 2-yr cycle.

    Again, perhaps before you start lobbing these idiotic attacks without knowing anything behind it, you should actually fricken know something about the subject.

    What the hell do I need to do before you listen? Ive disproven everything you’ve said and you keep asking for more.

    Want me to do my own god damn case study?

    When rainwater harvesting is proposed it has to show a monthly run through of use versus refill. You can’t get acceptance of harvesting without showing that it balances the best way possible, while providing the stormwater control necessary. These are all documents one has to submit to get approval.

    But yes, its all a conspiracy you, I’m being paid off by some cistern advocacy group that has all that extensive cistern money.

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    1. 

       larryg

       April 6, 2014

       re: ” Harvesting as a general amount is almost always just a supplement to total reuse amount. Which means more often than not there is volume available. Remember also that the total storage in LEED compliant structures is for a 2-yr storm.”

       it does not solve the runoff problem.

       “2-yr storm means the likelihood it happens in 2 years. So no you are actually the one that is full of BS, because the usage of that volume happens FAR more often than a 2-yr cycle.”

       the problem with runoff is not the “usage” of it – it’s what happens to the part that is far in excess of what you can use in a single storm.

       “Again, perhaps before you start lobbing these idiotic attacks without knowing anything behind it, you should actually fricken know something about the subject.”

       bull feathers.. TE.. you’re playing the “expert” and it’s bogus.

       “What the hell do I need to do before you listen? Ive disproven everything you’ve said and you keep asking for more.”

       you’ve disprove nothing.. because I’m not asserting anything. I’m express skepticism about your claims like this one that somehow rainfall harvesting in relevant in rain events that far exceed the current ability to manage them.

       Want me to do my own god damn case study?

       no. you have to be honest and truly address the substance of the issue of what we do with storm water that exceeds our current ability to manage and gets into the waterways in volumes that do damage.

       “When rainwater harvesting is proposed it has to show a monthly run through of use versus refill. You can’t get acceptance of harvesting without showing that it balances the best way possible, while providing the stormwater control necessary. These are all documents one has to submit to get approval.”

       I ask – is the twin plumbing accounted for in the cost-benefit? I did not see it.

       “But yes, its all a conspiracy you, I’m being paid off by some cistern advocacy group that has all that extensive cistern money.”

       there is no conspiracy.. but we’re talking about rainwater harvesting in a very “iffy” scenario.

       are there buildings with twin plumbing for rainwater harvesting ?

       why would you only have one tank and then have to switch to municipal water rather than having enough tanks to provide a continuous supply without running out?

       I think you misunderstand. I totally support stormwater management . I’m a paddler. I paddle creeks and rivers and I know them well including the difference between a healthy one and a degraded on.

       I even support rainwater harvesting if it can be done cost-effectively.

       but rainwater harvesting will not fix the larger rain events that put damaging volumes into creeks.

       I’ve asked you several times about Accotink and you never answer. why?

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       1. 

          Tysons Engineer

          April 6, 2014

          Jesus what are you talking about. ITS SIZED FOR GD 2-yr STORM! YOU INSUFFERABLE blatherer

          Look

          LOOK AT THE DAMN DOCUMENTS I PROVIDED FOR THE TYSONS PROJECTS THAT ARE APPROVED.

          They have all the storage numbers you need.

          The re-use is supplemental, which means in fact that the storage is available because it is sized to store the entirety of the 2-yr increase.

          If a tank is 13,000 cubic feet thats about 98k gallons that it can fill up. For a 200,000 sf building, you have about 8,000 gallons of usage PER DAY for toilets, not to mention irrigation that its often used for also.

          Which means the tank if it were full just after a 2-yr storm, would take all of 15 days before it were emptied. Now of course, it rains after that as well, but the intensity won’t be any where near a 2-yr storm amount most of the time. It would be anywhere from 10 to 25 times as small as a 2-yr storm on average in this area. So you would not significantly fill that cistern up. So the truth is, the cistern is a decent supplement, but it almost always is low in terms of how much water is in it.

          And that is exactly how it should be, because its primary function is for stormwater management, and its SECONDARY function is to supplement potable water.

          At its core you think you are smarter than engineers who do this for a living, and whose careers actually focus on these issues. Why in hells name would someone not have to provide a balance diagram? Do you think our profession is so stupid to have forgotten something like that?

          Jesus

          I have no fricken clue what the hell you are talking about about the Accotink, it seems mostly like a bullshit path which has nothing to do with what is actually being discussed.

          WHAT THE HELL DOES THE COST have to do with anything. I’m showing you projects that are doing it, so people smarter than you evidently think it is cost effective because THEY ARE DOING IT, in multi million dollar projects that need financing and need to show they are cost effective. So now you are smarter than commercial land developers who have done financing of high rises for decades also huh?

          Jesus

          You are clueless. End of story.

          Yep all the cisterns are just always full genius, they do nothing, water comes in water goes out. Of course you don’t need to provide any proof for the stupid comments you make, you just blurt out these insane theories and then I have to actually spend all the time providing all the evidence that makes them look like stupid conspiracy theories.

          Now go ahead, tell me about god damn Accotink WHICH IS SURROUNDED BY COMMUNITIES THAT WERE BUILT BETWEEN 1950 and 1970 WHICH I ALREADY FRICKEN TOLD YOU predates any of these storm regulations in Fairfax.

          GO on, keep on talking about it as if it is germane just like the damn side bar we spent two hours on when you thought sanitary sewers and storm sewers are combined.

          Hopeless.

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28. 

    Tysons Engineer

    April 6, 2014

    By removing the 2-yr storm volume it also reduces the 10-yr storm peak the same DAMN way your precious stafford ponds do. If you actually read the links I spent my time getting for you on the Tysons projects you’d see the numebrs for your self you blathering moron.

    I’m done seriously you are a hopeless idiot. I’m tired of holding back my true feelings, you are clueless.

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29. 

    James A. Bacon

    April 6, 2014

    To preserve your mental health, I suggest that both Tysons Engineer and Larry G cease and desist. After roughly 100 comments, it is reasonably clear to any outside observer that you two will never come to agreement. The irresistible force has met the immovable object, and the immovable object won! (I’m not saying which one of you is which.)

    My advice is to leave the computer and pour yourself a stiff Scotch, then watch re-runs of “Game of Thrones” in anticipation of the new season about to begin!

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    1. 

       larryg

       April 7, 2014

       Actually, although it’s been long and tortured and TE seems to have a bit of a testosterone issue at times.. I have gotten value out of it though it’s bit like picking through manure to find edible morsels!

       😉

       The fundamental problem with CSOs is the varying and overwhelming nature of surface water, i.e. runoff. Rather than do storm ponds or the modern things now done, cities originally believe as TE as said that they could essentially kill two birds with one stone and take care of both sewer and runoff through one set of pipes to the river and I say to the river because originally there were sewer pipes that went STRAIGHT to the river with no WWTP so there really was no “problem” in the sense of no being able to hold the effluent until it was treated; there was no treatment!

       that’s the way early sewer systems “works”.

       for instance the history of Blue Plains: ” When the wastewater treatment plant at Blue Plains opened in 1938, it was a primary treatment facility only. It was designed to serve a population of 650,000 people through the year 1950. The operating cost was less than $175,000 per year. At that time, the relatively small discharge from Blue Plains to the Potomac River was less than 100 million gallons per day (MGD).”

       recall 2 things:

       1. – what did they have PRIOR to 1938 in terms of WWTP? answer not much, mostly outfall pipes from Combined Sewer systems.

       2. – what condition was the Potomac River in after the building on Blue Plains in 1938?

       recall the days in the 1960’s era when the Potomac was classified as an open sewer.

       what’s the point of the above? to provide an ACCURATE HISTORY of where the CSO problem came from to start with.

       the original solution to storm water was curbs with drains to pipes to outfalls. there was no detention or retention nor treatment.

       over the years, Blue Plains (and thousands of other WWTPs) were systematically improved to primary, then secondary and finally advanced/tertiary treatment – but when those upgrades were done – none (that I’ve ever heard of) ever intended to try to retain and store – for subsequent treatment – anything beyond the sewage. If it was going to rain, they knew it was going to overwhelm the plant and every plant built had a bypass on it just for that purpose.

       This was the case whether you lived in Richmond, Baltimore, Norfolk or DC or wherever there were grid streets, water and sewer and curb drains that took surface water and put it in the sewers.

       places that never had water/sewer to start with but still had development and streets had to provide facilities to transport storm water away and it usually consisted of things like curbs with drains that led to ditches and culverts to outfalls at existing water bodies.

       they would even do this to lakes.. and you can still see the old outfalls on lakes – some still in use, some disconnected.

       so exurbs like Stafford/Spotsy back in the 1940’s, 50’s and even 60’s had very, very little water and sewer except for downtown Fredericksburg. The counties had virtually no commercial development because of a lack of water/sewer except at the boundaries with the city where they bought connections to the city’s water/sewer.

       the residential in the county – was virtually all well and septic and there were even subdivisions (and still are) with well and septic.

       Fredericksburg had and still has CSOs like other older grid-street cities.

       what evoked my conversation with TE was – can modern approaches to handling surface water runoff during not just typical but bigger storm events be managed – purely by things like LEED LID, rainwater harvesting and re-use, etc.. or is some kind of onsite temporary storage still needed.

       the last things he posted where helpful in that context.

       if you take a look at the Tysons aerials he provided -you will see some ponds. what you will also see is a lot of older development without apparent ponds and I presume no other means of controlling the runoff either.

       why was this worth 100 comments?

       it wasn’t. it might have been worth 20-30 .. if we could have gotten past the blather, BS, .. and testosterone-laden insults.. but oh well..

       I’ve asked several times about Accotink because Fairfax is purported to be “light years ahead” of others in the area of surface runoff water but apparently not so with creeks like Accotink and 4 mile run and others which are your basic typical urban creeks – in just terrible condition and on the dirty waters lists. Most creeks in most urban areas are in similar condition.

       what I have not yet found out though I’m sure will evoke more staccato tourette responses…. but it sort of appears that Tysons might be handling most normal/typical storm water – onsite. That still leaves the question as to what happens in a really big rain event.. but as I said..getting good answers is like trying to pick through the manure to find the morsels!

       I don’t expect any/all of whatever is done at Tysons to fix the rest of Fairfax which really looks a lot of Spotsy and Stafford except a lot more of it filling up most of the landscape whereas down our way- we have a subdivision then a field or woods then a subdivision. In Fairfax, it’s subdivision after subdivision, after subdivision but in all 3 places they are SFD with 3-5 in the household.

       Our early subdivisions had no runoff management – and neither did the older subdivisions in Fairfax.

       the difference again is the sheer number of subdivisions in Fairfax verses a checkerboard type pattern in our area – more available undeveloped land which the counties are now planning to use for regional storm facilities that they’ll start with new subdivisions but size large enough to handle the older subdivisions also – and they’ll pay for it with storm water fees and taxes.

       Stafford and Spotsy, by the way do NOT like the smaller, localized storm ponds..(like you’d see behind a WaWa or strip shopping center). They hate them.. because .. and this part is truly ironic, because the storm ponds are full of trash and debris and detritus which the county commissioners find “ugly”. We no sh_t… but if it were not for the pond, that stuff would be in the river then the Bay, right?

       but as much as Stafford/Spotsy hate those ponds, they hate the more advanced LID solutions even more – because it makes development more expensive and developers complain all the time about unnecessary job-killing regulations – that govt-loving buffoons like to implement.

       what I would suggest for going forward.

       one post on one specific thing, at a time and wait for a response – and keep the face slapping to a dull roar.

       and TE – thank you for the morsels!.. I can say that anyhow!

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    2. 

       larryg

       April 7, 2014

       and folks might find this helpful:

       Detention Basin or Retention Basin? Which One Is It?

       Not Interchangeable Terms

       Some terms and phrases used in the business of flood damage reduction seem to find their way through the public-at-large either being interchanged with similar terms or referred to altogether incorrectly.

       DETENTION and RETENTION are two such terms.

       Both detention basins and retention basins are ways in which flood damage reduction can be accomplished. Although the terms are sometimes used interchangeably, there are differences between them.

       Detention Basin

       A DETENTION BASIN is an area where excess stormwater is stored or held temporarily and then slowly drains when water levels in the receiving channel recede. In essence, the water in a detention basin is temporarily detained until additional room becomes available in the receiving channel. Detention basins are used extensively in the Harris County region.

       Retention Basin

       A RETENTION BASIN also stores stormwater, but the storage of the stormwater would be on a more permanent basis. In fact, water often remains in a retention basin indefinitely, with the exception of the volume lost to evaporation and the volume absorbed into the soils. This differs greatly from a detention basin, which typically drains after the peak of the storm flow has passed, sometimes while it is still raining. Additional uses for stormwater retention are to help recharge large underground water aquifers, a use that isn’t practical in Harris County. Retention basins, for the sake of flood damage reduction, are not common in the Harris County region; they are popular in parts of the country that have soils more amenable to this type of flood damage reduction measure.

       Basically
       The short of it is this:

       DETENTION is the temporary storage of excess stormwater.

       RETENTION implies that stormwater is stored indefinitely.”

       my only quibble is water is never stored “indefinitely”.. . unless it is
       draining into an aquifer.. and while that ‘s pretty common out west,
       it’s less so in the east.. where some soils just are not porous enough.

       no mater the basin type – think about what happens when it rains.

       water flows into those basins.

       the only real difference is how much water flows into them – before it start to flow out of them.

       in a dry pond – it has to totally fill up to the outlet pipe before it starts releasing water. in the pond with water in it – it boils down to how far the outflow pipe is above the typical surface level.

       and I’ll post this aerial again of a recent large parking lot built at the courts/public safety complex at Spotsylvania Court House.

       It has a pond .. actually two – smaller ones that almost dry up if we go without rain for a few weeks but the thing I wanted to point out was the grassy areas between the parking bays…. look close.. and you’ll see no curbs on the downslope side.. it goes into an engineered grass covered gravel swale when then drains into a pipe that goes to the storm pond.

       the ponds are tiny in comparison to others with similar sized parking lots but that lacked the engineered swales.

       Now think back to Tysons and picture those two small ponds as buried vaults and voila! there is no storm pond!

       HOWEVER, there IS a FLY in the OINTMENT and that is – what happens in a very large storm event? In the Spotsy Parking lot – those two ponds have an outlet that goes to an outfall and once the rainfall exceeds the capacity of the storm facility, it just dumps the rest.

       it don’t happen very often.. once a year or so.. but when I go down to check on it – it in a big rain (like we might be getting today).. it IS dumping the excess to the outfall which is a small creek in the adjacent woods. In an urban area that small creek would be totally surrounded by development with far, far more impervious surfaces.

       here’s the map… you can zoom in on it to see the engineered swales as well as the ponds and their outfall. (the terrain slopes from the upper left to lower right and on the bottom end of the lot next to the ponds – for size scale – is a trailer (sheriff command post)):

       http://goo.gl/maps/dVr7j

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