Laserfiche WebLink
3. Control Flow Rates <br /> a. Protect properties and waterways downstream of construction sites from erosion <br /> and the associated discharge of turbid waters due to increases in the velocity and <br /> peak volumetric flow rate of stormwater runoff from the project site, as required by <br /> local plan approval authority. <br /> b. Where necessary to comply with Special Condition S9.D.3.a, construct stormwater <br /> infiltration or detention BMPs as one of the first steps in grading. Assure that <br /> detention BMPs function properly before constructing site improvements (for <br /> example, impervious surfaces). <br /> c. If permanent infiltration ponds are used for flow control during construction, <br /> protect these facilities from sedimentation during the construction phase. <br /> 4. Install Sediment Controls <br /> The Permittee must design, install and maintain effective erosion controls and sediment <br /> controls to minimize the discharge of pollutants.At a minimum,the Permittee must: <br /> a. Construct sediment control BMPs(sediment ponds,traps, filters, infiltration <br /> facilities,etc.) as one of the first steps in grading.These BMPs must be functional <br /> before other land disturbing activities take place. <br /> b. Minimize sediment discharges from the site.The design, installation and <br /> maintenance of erosion and sediment controls must address factors such as the <br /> amount, frequency, intensity and duration of precipitation, the nature of resulting <br /> stormwater runoff, and soil characteristics, including the range of soil particle sizes <br /> expected to be present on the site. <br /> c. Direct stormwater runoff from disturbed areas through a sediment pond or other <br /> appropriate sediment removal BMP, before the runoff leaves a construction site or <br /> before discharge to an infiltration facility. Runoff from fully stabilized areas may be <br /> discharged without a sediment removal BMP, but must meet the flow control <br /> performance standard of Special Condition S9.D.3.a. <br /> d. Locate BMPs intended to trap sediment on site in a manner to avoid interference <br /> with the movement of juvenile salmonids attempting to enter off-channel areas or <br /> drainages. <br /> e. Provide and maintain natural buffers around surface waters, direct stormwater to <br /> vegetated areas to increase sediment removal and maximize stormwater <br /> infiltration, unless infeasible. <br /> f. Where feasible,design outlet structures that withdraw impounded stormwater <br /> from the surface to avoid discharging sediment that is still suspended lower in the <br /> water column. <br /> 5. Stabilize Soils <br /> a. The Permittee must stabilize exposed and unworked soils by application of effective <br /> BMPs that prevent erosion.Applicable BMPs include, but are not limited to: <br /> temporary and permanent seeding, sodding, mulching, plastic covering, erosion <br /> Construction Stormwater General Permit Page 26 <br />