825 N BROADWAY 2017-01-13 - Laserfiche WebLink

2. Site Assessment Big J's site consists of a vacant lot with gravel, exposed soil and unmaintained non-native vegetation. The site slopes to the south east but runoff is blocked by an existing retaining wall on the west edge of the property. The site then slopes up to meet the existing parking lot to the south. The current drainage outfall location is unknown at this time. The Index site is the cleared area from the Index Hall buildings that were recently demolished. The site is primarily comprised of patchy grass and exposed earth from permanent stabilization efforts after demolition, with some residual gravel and concrete areas including sidewalks. The site gradually slopes to the south and east. There are steeper slopes on the east edge with vegetation. Stormwater sheet flows to the existing catch basins located in the existing parking lot to the south. 3. Site Development Plan This section provides an overview of the site development plan, including threshold discharge area determination, determination of flow control and water quality requirements, and a discussion of On-Site Stormwater Best Management Practices (BMPs). FLOW CONTROL REQUIREMENTS Per the requirements of the City of Everett Public Works Policy No. 2-11, runoff from the proposed development must meet the Level 2 flow control standard to match runoff from the existing site conditions because both sites discharge to the combined sewer system. The Index Site existing condition is considered to be the building and site conditions prior to demolition. A comparison of existing and developed land cover for each site is shown in Table 3-1 and Table 3-2: Table 3-1: Existing Site Land Cover Table 3-2: Developed Site Land Cover Maps showing the existing and proposed land cover areas are located in Appendix A. Big J's Site development will include a stormwater detention pond to meet the flow control requirement. Design details are shown on the project plans and the MGSFIood model report is included in Appendix B to demonstrate compliance with the flow control standard. KPFF Consulting Engineers 2