405 RIVERSIDE RD 2023-01-30 - Laserfiche WebLink

I 2.1.4 Element 4: Install Sediment Controls All stormwater runoff from disturbed areas shall pass through appropriate sediment removal BMPs before leaving the construction site. BMPs will be constructed as one of the first steps of Igrading and will be functional before other land disturbing activities take place. In addition, sediment will be removed from paved areas in and adjacent to construction work I areas manually or using mechanical sweepers, as needed, to minimize tracking of sediments on vehicle tires away from the site and to minimize washoff of sediments from adjacent streets in runoff. IWhen permanent stormwater BMPs will be used to control sediment discharge during construction, the structure will be protected from excessive sedimentation with adequate erosion l and sediment control BMPs. Any accumulated sediment shall be removed after construction is complete and the permanent stormwater BMP will be restabilized with vegetation per applicable design requirements once the remainder of the site has been stabilized. IApplicable BMPs: • BMP C200: Interceptor Dikes and Swales • BMP C207: Check Dams • BMP C220: Storm Drain Inlet Protection I • BMP C233: Silt Fence • BMP C241: Sediment Pond 1 A single sediment pond will be utilized for the onsite disturbed area. The surface area for the sediment pond is determined by calculating the runoff rate of the 10-year return period developed storm event using the city of Everett design guidelines (WWHM2012 Modeling ISoftware). The area tributary to pond A is 4.70 acres and will be composed of an estimated 85% Iimpervious coverage. The required sediment pond area was determined using the City of Everett drainage Manual along with WWHM2012 stormwater modeling software (model printout I included in Appendix H). Sediment ponds and risers are designed to accommodate the 10 yr recurrence interval flow. See Appendix B for TESC details. I I I IPage 19