Laserfiche WebLink
� The Watershed Co an <br /> � � C� �� b � <br /> n <br /> JUN 2 2 1998 `-" <br /> June 16, 19�8 CITY OF EVERETT <br /> :.npinaednp/Pubiic S�rvice6 <br /> Liz Greenhapen <br /> Planninp and Community Development <br /> City of Everett <br /> 2930 Wetymore Avenue, Suite 800 <br /> Everett, Wa. 98201-4044 <br /> Re: Water supply to planned wetlands at Narbeck Wetland Sanctuary <br /> Liz: <br /> The present outlet of Narbeck Swamp is a ditched chennel, Narbeck Creek. <br /> No appreciable quan!ity of water seturates the outlet flank of Narbeck <br /> Swarra. <br /> The wetland design calls for utilizinp the base outlet flows of Narbeck <br /> Swamp to create some eight additional acres of wetland. Outlet waters <br /> from tdarbeck Swamp wiil first fill an approximate one acre pool of open <br /> water. Fiows will then be dispersed across a broad front of some 540 <br /> feet of leaky berm. Flood flows will be directed down the existing <br /> drainage pathway. (See attached detail.) <br /> Base flows will first "leak" through the berm, then follow a sinuous <br /> pathway of sheetflows and shallow depressions, then congregrate in <br /> various broad swales, and finally drain into the existing Narbeck Creek <br /> channel. <br /> The City of E��erett has done soms flood flow modelling of tne Narbeck <br /> system. If my memory is correct, existing Narbeck Swan�p was calculated <br /> to knock the 25•year storm event down from 25 c.f.s. to 12 c.f.s. <br /> Unlik� �cnowledge gained from flood flow modelling, however, knawladpe <br /> gained to determine potential water supply in to-be-created wetlands is <br /> 1411'Market Street • P.O.6oz 1180 • Kirklan� •WA 98033-0918•Phone(42S)822-5242•Fax(425)827-8136 <br />