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SOUNDVIEW TECHNOLOGY CENTER EVERETT, WA <br /> Basin C <br /> The stormwater runoff from Basin C flows in a northeasterly direction.The majority of the basin flows exit <br /> the site in a steep ravine that intersects the northern property line in the northeast region of the site.This <br /> ravine has signs of surface flow at the low point of the swale, see photo 7. The swale travels north onto <br /> private property and is paralleled by a residential concrete driveway. The residential driveway has a <br /> drainage ditch on the uphill side, which drains any run-on flows, see photo 8. Approximately 150'from <br /> the intersection of the ravine and the concrete driveway, the ditch is rock lined, see photo 9.Also, there is <br /> a catch basin which has a 12" PVC pipe entering and exiting. Neither the inlet nor the outlet of these pipes <br /> could be located, but it can be assumed that they convey surface water flows back to the ravine. <br /> Downstream of the driveway, there exists a stormwater vault outlet and stacked gabion rock outfall within <br /> the drainage, see photo 10. The vault and outfall was constructed as part of a residential plat approved <br /> by the City of Mukilteo in 2013. The installation of this outfall appears to have significantly compromised <br /> the adjacent bank stabilization, see photo 12. <br /> Conversations with the City of Mukilteo on 3/7/17 indicate that they are aware of the conditions at the <br /> vault outfall and have provided notice of the de-stabilized condition to the owner. <br /> Downstream of the existing stormwater vault, the ravine continues in a general northerly direction where <br /> it intersects with another ravine with surface flow in the swale area, see photo 11. This is the confluence <br /> location of Basin D (described below). The ravine continues north to a point where it meets up with a <br /> ravine identified as the end of Basin A. This was the end of the field reconnaissance. This location is <br /> approximately'/a mile downstream from the site. <br /> Since this project will detain the release rates to the predeveloped release rates in excess of the release <br /> rates required for the project, no additional measures are proposed and the release flows will be <br /> dispersed on-site at the low point of the Swale. <br /> # Basin C - Photo Description <br /> C <br /> 7 Swale located in bottom of <br /> ravine channel area. <br /> SEPTEMBER 23, 2022 STORMWATER DRAINAGE REPORT PAGE 15 <br />