3323 HOYT AVE WHOLE SITE 2020-06-17

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: Onsite infiltration areas will not be used as the underlying infiltrative capacity of Till soils is minimal. Additionally,the design criteria cannot be met to provide 250sf per 1,000sf of rooftop. Raingardens will also not be able to be used as the low permeability of Till soils will likely create stagnate water. Downspout Dispersion will not be able to be used as there is not a 25ft flow path on the site while still complying with the GMA and City of Everett Code. Downspout perforated pipe stub outs/infiltration trench will be proposed.An infiltration trench is shown to the maximum extent feasible. The trench is connected through the center with a perforated pipe to release un-infiltrated stormwater. This trench measures 26.3 sf and is maximized amongst the setbacks between homes and property lines. The perforated stub out connection/Infiltration trench is located in the center of the site,in between the two proposed structures. Pa e4of7 s 5.,... c,.t" _.,. __,.E� . 3200 Cedar Street Everett, VIA e y�.afi..2 ._�. 425-257-8R10 ,c..v e T..t#,iaJ r