5900 36TH AVE W 2025-01-06 - Laserfiche WebLink

SOUNDVIEW TECHNOLOGY CENTER EVERETT, WA PROJECT OVERVIEW PROPOSED IMPROVEMENTS The proposed development will consist of three (3) 2-story buildings totaling approximately 485,700 SF with approximately 581 parking stalls, stormwater management facilities, utilities and on-site landscaping on a 39.4-acre site at 5900 36t" Avenue W in Everett, Washington. The property is zoned M-1 (Industrial) DESIGN CRITERIA At the time of the Public Works permit approval in 2017, the City of Everett utilized the 2014 Stormwater Management Manual for Western Washington (2012 manual amended in 2014) drainage requirements. The City has not adopted the 2019 Stormwater Management Manual for Western Washington. Since the proposed buildings were not approved for permit in 2017 along with the civil plans, runoff from the new building roof areas must be modelled in accordance with the 2019 stormwater manual requirements. To simplify modelling, the entire site has been designed using current WWHM stormwater modelling data. Stormwater discharges shall match developed discharge durations to predeveloped durations for the range of predeveloped discharge rates from 50 percent of the 2-year recurrence interval peak flow up to the full 50-year peak flow.The pre-developed condition to be matched shall be a forested land cover. Jurisdictional Requirements Table 1 below summarizes the City of Everett Stormwater requirements. TABLE 1 Jurisdictional Requirements Duration Analysis: 2-year: Reduce to 50% pre-developed duration 50- ear: Match pre-developed Water Quality Flow Rate: Vault#3 (Basin B) = 0.077 CFS Vault#4 (Basin C) = 0.044 CFS Downstream Analysis: Level 1: '/a mile downstream SEPTEMBER 23, 2022 STORMWATER DRAINAGE REPORT PAGE 1