7200 HARDESON RD 2016-01-01 MF Import

r �� P A i t The primary sveam chan�l and overflow channzl created by the resroration project would convey stormwater from the proposed development to the regional detention pond. � The City of Everett approved the following design flows for the dowastream end of the project reach: w �r w �r 2 year = 50 cfs 25 year = 133 cfs 100 year = 200 cfs During final design, the Flows will be further refined. Water quality is fair to good in Merrill and i'ung Creek except during storm events. � Limited daW show elevated metals concentrations and high levels of suspended solids and silicon during major storm events. The elevated suspended solids are most likely related to runoFf from the existing gravel mine. [arge volumes of silt from the gravPl mining operation have dzgraded downstream reaches of the creek Moreover, peak storm Ilows have increased erosion of the channel downstream of the site. The proposed development project wuuld reduce the runoff from the exposed area of the gravel pit and reduce sedimentation downstream. Runoff from the development's parking lots would be treated in grassed biofiltration swales to minimize the impact of polluUnts on the creek. The proposed stream restoration project would improve water quality in the stream by further setd[ng solids from suspension and providing shade for the stmam. Overall, the development project, in conjunchion with the restoration project, would improve waler quality in the drainage ba�in. If the development and restoration projects do not proceed, existing adcerse impacts to water quality would continue. PROJECT GOALS AND OBJECTIVES The goal of the proposed project is to restore 625 feet of the stream channel and stream corridor near Hardeson Road and enhance and protect downstream water quality in Merrill and Ring Creek. The specific environmental objectives of the project are to: • establish a 60-foot cor.^' �- of nat;ve vegetation that contains the stream; � �