9600 SHARON DR EXPLORER MIDDLE SCHOOL 2022-03-11

E, 0 BMP and Infeasibility description applicable lists Infeasibility criteria and rationale for each BMP not selected T5.14A The following criteria can be cited as reasons for infeasibility without Bioretention further justification (though some require professional services to or Rain Gardens make the observation): (continued) ❑ Where evaluation of infiltration is not required per the Infiltration Infeasibility Map due to steep slopes, erosion hazards, or landslide hazards (See City infiltration and infeasibility map). ❑ Within setback provided for BMP T7.30 (DCSS, Section 4-4.1(3.) C1 Where they are not compatible with surrounding drainage system as determined by the city (e.g., project drains to an existing stormwater collection system whose elevation or location precludes connection to a properly functioning bioretention area). I Where land for bioretention is within an erosion hazard, or landslide hazard area. Where the site cannot be reasonably designed to locate bioretention areas on slopes less than 8 percent. ❑ Within 50 feet from the top of slopes that are greater than 20 percent and over 10 feet of vertical relief. ❑ For properties with known soil or groundwater contamination (typically federal Superfund sites or state cleanup sites under the Model Toxics Control Act [MTCA]): • Within 100 feet of an area known to have deep soil contamination. • Where groundwater modeling indicates infiltration will likely increase or change the direction of the migration of pollutants in the groundwater. ■ Wherever surface soils have been found to be contaminated unless those soils are removed within 10 horizontal feet from the infiltration area. ■ Any area where these facilities are prohibited by an approved cleanup plan under the state MTCA or Federal Superfund Law, or an environmental covenant under Chapter 64.70 RCW. i l Within 100 feet of a closed or active landfill. ❑ Within 10 feet of an underground storage tank and connecting underground pipes when the capacity of the tank and pipe system is 1,100 gallons or less. As used in these criteria, an underground storage tank means any tank used to store petroleum products, chemicals, or liquid hazardous wastes of which 10 percent or more of the storage volume (including volume in the connecting piping system) is beneath the ground surface. City of Everett Public Works Small Project Stormwater Site Plan Report -Dec 2019 34