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MR #4: Preservation of Natural Drainage Systems <br /> Natural drainage patterns shall be maintained,and discharges from the project site shall occur at the natural <br /> location. This Minimum Requirement has two main components to achieve: 1) maintain the natural on-site <br /> drainage pattern and concentrated discharge location at the downstream property boundary,and 2) prevent <br /> erosion at and downstream of the discharge locations. This requirement includes maintaining or replacing <br /> systems which convey runoff accross the site from upstream areas.All outfalls require energy dissipation. <br /> Task 1: Document existing and proposed drainage patterns and discharges <br /> Check the boxes that apply below: <br /> ❑ This site has existing drainage systems or outfalls.These items are shown on the <br /> Stormwater Site Plan provided in MR#1 and are to include:type,slope,dimensions, <br /> channel lining,direction of flow and buffer. <br /> O This project will not alter the existing drainage system in any way. If the existing <br /> outfall(s) show sign of erosion and scour,energy disipation measures will be installed <br /> or improved upon. Construction activity of any kind will not occur within at least 10 ft <br /> of the edge of the channelized flow,BMP C102: Buffer Zones will be implemented <br /> during the life of the project to include visible flagging or other demarcation technique. <br /> If this requirement is not met a Hydraulic Project Approval (HPA) may be required from <br /> the Washington Department of Fish and Wildlife. <br /> ❑ The site does not have any existing drainage systems or outfalls. <br /> Describe how stormwater will be discharged from the site without causing erosion and <br /> flooding downstream: <br /> • The existing concentrated drainage system traversing the property will be impacted as <br /> part of this project and is shown on the stormwater site plan. <br /> Describe how your project impacts or changes the existing drainage systems as a result <br /> of your project and how you will address it: <br /> Runoff will be dispersed with a vegetated flow path > than 25 FT <br /> per BMP T5.11 per figures 5.3 and 5.4 with BMP T5.12 per figure 3.7 <br /> and BMP T5.13 will provide Flow Control and preserve the onsite <br /> sheet flow @ the natural location tht discharge to the neighboring site <br /> City of Everett Public Works <br /> Small Project Stormwater Site Plan Report-Dec 2019 15 <br />