I-90 West of George Paving - Warm Mix Asphalt
The Washington State Department of Transportation (WSDOT) paved about 5,000 tons of warm mix asphalt (WMA) as part of their I-90 West of George Pav...
Greenroads Manual
EW-2: Runoff Flow Control
1-3 point
Goal
Mimic predevelopment hydrological conditions in the right of way (ROW).
Requirements
- Implement a stormwater management plan for the site using stormwater best management practices (BMPs) for stormwater flow control. Use low impact development (LID) BMPs to the maximum extent feasible as determined in Project Requirement PR-8 or by a licensed professional. Do not use detention ponds procured outside of the ROW.
- Demonstrate that these BMPs meet minimum critical erosive flow criteria for waters receiving runoff from the ROW.
- Compute the 90th percentile average annual rainfall event runoff volumes and flow rates for the project ROW area, including any tributary area outside the ROW that may generate additional runoff volumes which flow otherwise uncontrolled into the ROW BMPs (i.e. “run-on”). Note that BMPs should be sized appropriately if considering any runoff volumes generated from outside the ROW.
- Compare the computed flow rates and runoff volumes from post-construction to computed predevelopment values and express as a percentage. See Table EW-2.1
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