3618 SHORE AVE 2023-10-24 - Laserfiche WebLink

'Hayward September 08, 2021 Executive Summary This site has an address of 3618 Shore Ave Everett, Wa 98203 and has a parcel number of 00433600002700. The property is 0.4 Acres in size (17,424 sf) in the City of Everett, zoned; R- S. The existing condition of the site is developed with two houses and several outbuilding/garages and driveway areas.All existing impervious surface is proposed to be removed under this permit application. This project is part of a proposed 2 lot short plat. Proposed lot lines are shown on the civil plans. At this stage of the project the proposed development is limited to proposed lot 2. However, at the request of the city of Everett, the impervious calculations for both lots 1 and 2 are included in this report in order to demonstrate stormwater management feasibility for the whole site once the 2 lot short plat is approved. Even though lot 2 is not proposed to be developed at this time. The proposalis inclusive of a new single-family home with a rooftop area totaling 2,337 sf and a new 1,918sf access driveway for lot 1 which is to be constructed after this permit approval. The proposed development for future lot 2 is also inclusive of a single family home with a rooftop area of 2,734 sf and a 1,145 sf driveway but is NOT proposed to be built at this time. The total proposed impervious surface for both lots 1 and 2 is 8,134sf. Frontage improvements including paved driveway access to both lots 1 and 2 and widening of Shore Ave have a total offsite pollution generating impervious area of 768 sf. Flows from frontage improvements are expected to flow into a catch basin in Shore Ave and reach the stormdrain utility in Shore Ave. This application is under the jurisdiction of the City of Everett and the 2019 Department of Ecology Stormwater Management Manual for Western Washington. Per the DOE SWMMWW this project triggers the evaluation of Minimum Requirements#1-9. This project does not trigger Minimum Requirement#7 for Flow Control and therefor,this project has chosen LID bmps in the hierarchal order of List#3 for Flow Control Exempt Projects. Additionally, a Memorandum has been prepared by Nelson Geotechnical Associates. In said memorandum, it is stated that within 200 ft of the subject property lies a steep north-facing bluff slope. The subject property is located above said slope and thus, it is the professional opinion of the geotech engineer, " Infiltrated stormwater within the site has the potential to flow along relatively impermeable soil contacts that may underlies the site and ultimately daylight on the steep slope as groundwater seepage. This could result in increased shallow surficial sliding events along the face of the steep north-facing bluff slope."In order to avoid erosion and destabilizing of the downstream slope; infiltration is not feasible on site and will not be considered for stormwater management purposes. Downspout dispersion has been chosen as the only feasible bmp for stormwater management of all proposed surfaces on Lot 1. Said dispersed flows will be tightlined via a stormdrain pipe down to an existing stormdrain infrastructure in Shore Ave. For the purpose of full site drainage feasibility after the proposed 2-lot short plat is complete; it is demonstrated that downspout dispersion for the future proposed rooftop on lot 2 is feasible and will be tightlined to the existing storm infrasture in Shore Ave just like flows from lot 1. The future proposed driveway for lot 2 will utilize sheet flow dispersion where flows will reach a catch basin and be routed into the stormdrain in Shore Ave. The 13 Elements of Stormwater Pollution Prevention Plan(SWPPP) are addressed on the