1001 N BROADWAY EVCC 2025-10-03 - Laserfiche WebLink

METHODOLOGY Drainage design for the project is based on City of Everett Municipal Code (EMC) 14.28, Sul face and Stoi•rn Drainage. EMC 14.28 refers to the 2019 version of the Washington State Department of Ecology's (DOE) Stormwater Management Manual for Western Washington (Stormwater Manual) for the city's stormwater technical manual. This project is located within a Combined Sewer Collection Area and subject to different stormwater requirements, detailed in Section 6-10, Combined Sewer System, of the 2020 City of Everett Design and Construction Standards and Specifrcations (DOSS). The project is categorized as a redevelopment project generating less impervious surfacing as compared to the existing condition. This net loss of impervious surfacing does not exceed the threshold for Flow Control BMP requirements. On-site stormwater management design requirements will be used for this project. The following sections address the requirements from Section 6-10 of the DCSS. STORMWATER NARRATIVE Existing Conditions The project site is currently occupied by an existing retail building, a paved parking lot, and landscape islands. The site is bounded to the north by WSU Extension development, to the west by the North Broadway Avenue right-of-way, and to the south and east by commercial and residential properties. Access to the project site is from two existing intersections along N. Broadway Avenue, at 10"' Street to the south and Tower Street to the north. The site generally slopes to the east, with areas along the southern and eastern property lines sloping north and west toward the existing building. The site is composed mostly of asphalt pavement, with landscape islands spaced throughout. The site is separated into two subbasins, with the parking lot area discharging stormwater to the north and the building area discharging to the east. All stormwater discharges to the City's combined sewer system that extends to the southeast. Stormwater from the existing building roof area is routed through the internal roof drain system, which discharges to the existing combined sewer main extending along the south and east property lines. Stormwater from the parking area is collected and conveyed by a series of catch basins and underground storm pipes to the existing storm system of the recently constructed WSU Building project that conveys stormwater north to a separate combined sewer system that eventually merges with the combined sewer system from the south subbasin. There are no existing detention or water quality facilities that serve the project area. Stormwater Site Plan 2 E• , , Learning Resource Center