1500 INDUSTRY ST 2018-01-01 MF Import

��^� �S� CIVIL ENGINEERMG.IAN�PLANNING,SIIPVEYING.EIIVIRONMENiAI SERVICES � Z o< , � �= August 29. 2002 as - �. py. ``T�NG ENG\HE6 .iane Zimmerman City of Everett �ngineering&Public Works City Service Center 3200 Cedar Street Everett,WA 98201 RE: Drainage Basin Analysis for Seaway Business Park—Lot 8 SEC Merrill Creek Parkway and Hardeson Road,Everett,Washington Our Job No. ]0470 Dearlane: This letter is a response to the City's comment and concern regarding the discharge location for the proposed Seaway Business Park. We understand the Ciry's position focuses on the issue of maintaining the natural discharge location for the pre-developed site. Project Background: This project when fully developed is an �pproximately 37-acre site located on the southeast corner of Merrill Creek Parkway and Hardeson Road within the City of Everett, Washingron. The projec[proposes to construct approximately seven warehouse buildings with dock high loading, drive aisles, parking, and associated storm drainage collection and conveyance facilities. At this time, only one of the buildings will be constructed, which is Building H. Drainagc Analysis and Runoff Control: Pre-developed Basin Through discussions tvith the City, it was indicated that this project contains 2 separate drainage sub-basins for die site, totaling 37.1 acres. The majority of the site, namely 25.7 acres, drains to the northwest and discharges ro the Merrill and Ring Creek IIasir,. However, a significant portion, namely I L4 acres drains to the northeast and discharges to the Glemvood Creek drainage basin. Please refer to the Pre-Developed B�sin Map attached. Developed Basin: The intent of diis project will be ta maintain the drainage areas ot the two separate pre- developed sub-basins. Due to several site constraints including lat layout and construction timing, this project proposes ro divert an approximately "equivalent area" to the Glemvood Creek basin. The equivalent area will compose of the "clean" storm runoff from the roofs ef all buildings with the e.�ception of 13uilding H. The equivalen[area when fully developed tolals approximately 1 L4 acres. Proposed Drainage System: The proposed area draining to the Merrill and Ring Creek IIasin consists of pavement, sidewalk and landscape improvements ro the entire site and will be collected and routed to Aie new combined deten[ion and water quality treatment pond located at the northwest comer of the site. This pond has bcen sized in accordance with the City of Everett requirements. � 1821572NDAVENUESOI�TH KENT,WA9B032 (425�251�6222 (425�251-BiB2FAT www.barghausen.com