1913 HOYT AVE WHOLE SITE 2022-05-23

• • Proposed Site Information: 1. How will your project change the existing conditions? The project will add impervious surface. 2. Please provide the following quantities of proposed hard surfaces in square feet: Proposed Roof Area: 3,495 SF Proposed Other Hard Surfaces(pavement,gravel,etc.): 873 SF 3. How will you manage rooftop runoff after the project is completed? Roof runoff will be discharged to a vegetated flow path along the southern property line 4. How will you manage stormwater runoff from hard surfaces(driveways,paved pathways, patios,etc.)?Evaluate each type of hard surface separately. The driveway area will sheet flow to the alley way. The paved pathways will sheet flow to the vegetated areas. Plan for Permanent On-Site Stormwater Management: You are required to "infiltrate, retain, and disperse stormwater"on your site to the maximum extent you can without causing erosion or flooding.The goal is to get stormwater runoff in contact with vegetated surfaces as much as possible before discharging to downstream conveyance systems. See Volume III, Chapter 12 of the 2010 Storm water Management Manual for stormwater facility requirements: https://everettwa.gov/DocumentCenter/Home/View/1214 1. Determine which options you must use for managing stormwater from rooftops via downspout disconnect by considering the following Best Management Practices (BMPs) in order: • BMP 12.30 On-site Infiltration Areas • BMP 12.40 Raingardens • BMP 12.50 Downspout Dispersion Notes: a. If location criteria can be met, but sizing criteria cannot,you must implement the BM Ps to the maximum extent you can without causing erosion or flooding. Pre-sized facilities have been designed to meet 100%mitigation. Facilities may be able to be installed to achieve some stormwater mitigation. b. Other innovative downspout control BMPs such as rain barrels,ornamental ponds, downspout cisterns,dry wells, or other downspout water storage devices may also be used with prior approval by the City of Everett.These are options to consider after the above listed BMPs are evaluated. 2. Determine which options you must use for managing stormwater from hard surfaces (driveways, paved pathways,etc.) by considering the following for each type of hard surface proposed: • BMP 12.60 Concentrated Flow Dispersion • BMP 12.70 Sheet Flow Dispersion Note: Propose an alternative stormwater management plan if none of the above BMPs can feasibly be installed. (Examples:Shallow vegetated swale,perforated pipe stub-out, etc.) Provide your Evaluation below and Show where these will take place on a site map: BMPs 12.30 (On-site infiltration)and 12.40 (Rain Gardens)were deemed infeasible as the required setback areas could not be met do to the sites small size. BMP 12.50 downspout dispersion will be used. The roof downspouts and vegetated flow path will be located along the southern property line. Other hard surfaces will use BMP 12.70 (Sheet Flow Dispersion)to disperse runoff onto nearby vegetated areas. The dfixteway_will._ sheet flow to the alley. C.Page 3 of 6 CITY OF EVERETT 13200 Cedar Street ( Everett, WA 98201 1425-257-8810 I everettwa.gov