6133 LAKE CHAPLAIN RD 2025-08-19

On-Site Stormwater Management BMPs for MR#1-5 Projects (continued). Other Simplified infeasibility criteria Feasible/infeasible? Check box if criterion is true. Only one box needs to be checked to Provide justification if Priority BMP name indicate that the BMP is infeasible. infeasible. 1 BMP T5.30: ❑ Flow control exempt as site directly discharges to Puget Sound ❑ Not applicable since Full or Snohomish River;or in a storm drainage system that is site is flow control Dispersion entirely manmade from the site to one of these water bodies. exempt(direct ❑ <65 to 10 ratio of forested or native vegetation area to discharge) impervious area. ❑ Infeasible ❑ <100 feet(<25 feet for sheet flow from a non-native pervious 0 Feasible surface)forested or native vegetation flow path length. ❑ Dispersion area located in a critical area buffer. Justification: ❑ Dispersion area located on slope>20 percent. ❑ Dispersion area contains septic systems. ❑ Site setbacks and design criteria provided in BMP T5.30 (SWMMWW Section V-3)cannot be achieved. 2 BMP T5.15: Selection of any of the following criteria does not require input from ❑ Not applicable since Permeable a licensed professional,although some may require professional site is flow control Pavements services: exempt(direct ❑ Flow control exempt as site directly discharges to Puget Sound or discharge) Snohomish River;or in a storm drainage system that is entirely ❑ Infeasible manmade from the site to one of these water bodies. ❑ Feasible ❑ Evaluation of infiltration is not required per the Infiltration Infeasibility data available on Map Everett. Justification: ❑ Within a designated erosion hazard or landslide hazard area. ❑ Within 50 feet from the top of slopes>20 percent where the setbacks listed in DCSS Section 4-4.1(3)cannot be achieved. Attach supporting ❑ Site has known soil or groundwater contamination(typically documentation if this federal Superfund sites or state cleanup sites under MTCA).See BMP is feasible: Volume V of the SWMMWW for specific setbacks. ❑ USDA Custom Soil ❑ Within 100 feet of a closed or active landfill. Report ❑ Within 100 feet of a drinking water well,or a spring used for ❑ Small-scale Pilot drinking water supply,if the permeable pavement is(or has run- Infiltration Test on from)a pollution-generating hard surface. (PIT)results per ❑ Within 10 feet of an UST and its connecting underground pipes SWMMWW (capacity of the tank and pipe system is<_1,100 gallons). specifications ❑ Within 100 feet of an UST and its connecting underground pipes ❑ USDASoilType(s) (capacity of the tank and pipe system>1,100 gallons). ❑ Measured ❑ Within 10 feet of small on-site sewage disposal drainfield, Infiltration Rate in including reserve areas,and grey water reuse systems. in/hr(from PIT) ❑ At multi-level parking garages,and over culverts and bridges. ❑ Separation to ❑ Where site design cannot avoid pavement in areas likely to have groundwater and long-term excessive sediment deposition after construction(e.g., hardpan construction,landscaping material yards). ❑ Subgrade slope and/or wearing course slope>6 percent. ❑ Underlyingsoils are unsuitable for supporting traffic loads when saturated.Soils meeting a California Bearing Ratio of 5 percent are considered suitable for residential access roads. City of Everett Public Works Small Project Stormwater Site Plan/Report—Sept.2023 Page 25 of 40