11000 16TH AVE SE 2016-01-01 MF Import

� t�1 t�7 y Qy � tx-� t" i-3 f/� ', H � � fC C� H �1 "il H hd N H � O� OHh , �, � g other paved areas) and streets. The stormwater from streets and , �� driveways o-iill be collected in a network of catch basins and z H � underground pipework and co�nbined with stormwater from roofs and � y � oth?r impermeable sur�a�es, treated with .;il and grease H y separation and conducted to the individual stormwater detention , g �' H facilities as outlined in the Preliminary Storm Draina9e Plan. C� t7 V� � t� � As indicated in the Drainage Plan, stormwater runoff collected z y �, within the northern portion of the multi-family development �aill y o �' be conducted to the existing receiving facilities in 16th Avenue S.E. for ultimate tra iission northerly to the proposed City of Everett regional •.: :� quality facility. A portion of the runoff will be combin�d with stormwater from the adjacent Interstate 5 corridor and conducted to a Z�0 foot grass-lined biofiltration/recharge swale. Water not subject to infiltration will be coll;cted for ultimate discharge into existin9 storm- water facilities, including an oil/water separation vault, in 16th Avenue S.E. A small se9ment of the aite's runoff will be conducted directly to the exisiing stormwater facilities in 16th Avenue S.E. These latter flows will be conducted to Silver Lake. 2) Could waste materials enter ground or surface waters? If so, �`„��, generall;; describe. I "`"�� Typical components of stormwater from roads a�d parking areas � are petrochemicals and the products of internal comb�stion engines. Stormwater runoff from the instant proposal 's ! 1�'�` ' impervious surfaces will be collect�.d and treated with oil/grease separation prior to outfall into the proposed wet � ponds and/or grass-lined s�aales. Biofiltration in the 9rass- lined sw.le and the downstream oil\water separator in the l6th i �`�"� Avenue S.E. right-of-way are effective means of treating and � �� reducing particulate loads and associated pollutar,ts in such drainage waters and providing final polishing prior to discharge ' into sensitive water bodies such as Silver Lake. I ��o d. Proposed measures to reduce or control surface, ground, and ' ' runoff water impacts, if any: During construction, temporary measures will be employed to , �� s control runoff and water quality, including use of silt fences, straw bales across draina9eways, placement of rip-rap and construction of temporary siltation/holding ponds. `..1�,� � Oil/9rease separation and biofiltration in the grass-lined swale in the completed project and in the proposed city wet pond will control impacts of runoff from impervious surfaces, including those subject to vehicle use. In keeping with the results of the Phase 1 water quality study , performed for the City of Everet* by the University of 10