Quality Control
Intention:
- Limit the disruption of natural hydrology
- Increase on-site filtration
- Manage storm water runoff
- Eliminate sources of contaminants
- Reduce impervious cover
- Reduce/eliminate pollution
- Remove pollutants from storm water runoff
- Stormwater Design (for reduction of impervious surface)
- alternative surfaces: rain gardens, vegetated swales, rainwater recycling
- non-structural surfaces: vegetated roofs, pervious pavement, grid pavers
Implementation:
- treat and capture 90% storm water runoff
- remove 80% TSS (total suspended solids)
- use acceptable BMPs (Best Management Practices) considering the following:
- sustainable design strategies: low impact, environmentally sensitive design)
- alternative surfaces: vegetated roofs, swales
- natural and mechanical treatment: constructed wetlands, vegetated filters and open channels
Codes/Standards Applied:
- Guidance Specifying Management Measure for Sources of Non-Point Pollution in Coastal Waters, Jan. 1993. (I just call this Coastal Waters – 1993 for memorization sake)
- BMP (Best Management Practices)
- EPA
Extra Credit:
- none
Submittal Phase:
- Design
Links from Reference Guide:
Other Sustainable Sites Credits
- SS P1 – Construction Activity Pollution Prevention (prerequisite)
- SS 1 – Site Selection
- SS 2 – Development Density & Community Connectivity
- SS 3 – Brownfield Redevelopment
- SS 4.1 – Alternative Transportation – Public Transportation Access
- SS 4.2 – Alternative Transportation -Bicycle Storage & Changing Rooms
- SS 4.3 – Alternative Transportation – Low Emission & Fuel Efficient Vehicles
- SS 4.4 – Alternative Transportation – Parking Capacity
- SS 5.1 – Site Development – Protect or Restore Habitat
- SS 5.2 – Site Development – Maximize Open Space
- SS 6.1 – Stormwater Design – Quantity Control
- SS 6.2 – Stormwater Design – Quality Control
- SS 7.1 – Heat Island Effect – Non-Roof
- SS 7.2 – Heat Island Effect – Roof
- SS 8 – Light Pollution Reduction
11 Comments On This Post
Pat, great site, very helpful! However, if I’m reading this correctly, under implementation, you have alternative surfaces and non-structural surfaces listed backwards (at least according to the 3rd edition).
The ref. guide gives you equivilent amounts of of water treatment required for the different watershed types. But i am confused. If you are supposed to treat 90% of runoff in a Humid Watershed site (which receives at least 40 inches per year) how is that equivalent to treating just 1 inch of run off. 90% of 40 inches of rainfall is not 1 inch. Can someone please explain this to me.
The wording should be to treat the first inch of runoff. This means that the first inch of runoff per storm is treated which over the entire year (storm every 3 days or so) equates to treating 90% of the annual rainfall. This occurs since most storms (i.e. 90%)are smaller than 1 inch in size.
It appears you used the same intention criteria from 6.1. The intention for 6.2 worded slightly different…the main difference having focus on elimintating sources of contaminants, and removing polltants from stormwater:
Reduce or eliminate water pollution by reducing impervious cover, incresing onsight infiltration, eliminating sources of contaniminants, and removing pollutants from stormwater runoff
I second the question posted by John regarding how 90% of 40 is 1. Are they considering runoff as something different than the annual rainfall?
My feeling on this – without digging – is that the 1″ might be expected during a typical “rain-event” in the types of climates listed, respectively. I live in a humid climate (OK) and 1″ of rain is a fairly common event. Yes, it rains more on occasion. We need to consider also if this is a function of time (24Hr?).
this site seems to elucidate things better.
http://www.stormwatercenter.net/Manual_Builder/Sizing_Criteria/Water%20quality/Options%20for%20Water%20Quality%20Volumes.htm
Though it perplexes me that the LEED manual would be so unclear.
very helpful but you have Alt surfaces and non-structural elements BACKWARD.
Yes it is backwards, careful those not referencing the LEED manual: “Use alternative surfaces (e.g., vegetated roofs, pervious pavement or grid pavers) and nonstructural techniques (e.g., rain gardens, vegetated swales, disconnection of imperviousness, rainwater recycling) to reduce imperviousness and promote infiltration, thereby reducing pollutant loading.
The natural/mech treatment systems are correct.
Hi,
wonder if you could explain the following from the ref guide-
Under SS6.2 Stormwater Design Quality Control
what is ‘Disconnection of imperviousness’
what is a ‘manhole treatment device’
Thanks
Gail
Gail,
An example of “disconnection of imperviousness” would be to have roof downspouts discharge onto to green surfaces where the runoff will naturally filter into the soil and vegetation. Inhis manner the downspouts are disconnected from the site storm sewer system.
My undersanding of a manhole treatment device would be something like a sand filter system.
Hope that helps. If not let me know and I will try to clarify.