8710 EVERGREEN WAY FRED MEYER FUELING STATION 2018-01-02 MF Import

1.0 PROJECT OVERVIEW Tliis report accompanies the constn�ction plans for ttie proposed gas station plam�ed for an existing lot located to the south of the existing Fred Meyer store at 8530 Evergreen Wey in Everett, Washington. The sitc is describcd as: Lot B of City of Everett BSP recorded April 25, 2986 undec Recarding No. 8604255001 and reviscd R�rorded Pebruary 6, 1987 under Rewrding Nos. 8?02065006 and 8702065Q07, in Snohomish County, Washington. The purpose of this report is to veril'y t!�at the existing stormwater pond located west of lhe site provides sufficient primary water quality treatment for stomiwacer runoff, and to size the proposed water quality pre-treatment vault for the planncd re-dcvclopment. The existing pond was modificd according to thc conditions determined by a prcviously written report titled: "Storm Drainagc Report for Pred Mcycr- Gverett dated March 1999, p:epared by A1iDL. That �� report sized the pond using three drainage basins named [3asin A, Basin B, and Basic C. The proposed gas station lot is part oP Basin A, which includes a total basin area of 23.22 acres, and 90 peroent impervious area. At the time the reporl was prepared, the proposed gas station site was an asphalt paved parking lot with no buildings on site. The proposed gas station site has a total area of 0.73 acre,of which 85 percent is impervious. The r�development of the site witl havc very little impact on the site hydrologically. Existing asphalt pnvement will bc removed mid replaced witli new asphalt pavement, cement concrete pads, and a canopy over thc fueling area. Approximately 700 squar: feet of existing landscape area will be removed and replaced with asphalt pavement. This area can be considered insignificant as it amounts to just owr 2 percent of the site nrea,and less than 0.05 percent of the basin arcas draining to the existing pond. The existing ponJ has sufficient capaciry to provide primnry water quality treatment for the re-dcvclopment of the site. Pre-treatment of srormwater runoff will be required for the site. Thc attached pages include calculations of runoff volume for the 6-month/24-hour stomi, and the calculations for sizing thc pre-treahnent vault based on 30 percent of the 6-month storm volume. �: ;k Y':. r% �. 106P 1.OD4x.doc 1 �