9600 SHARON DR EXPLORER MIDDLE SCHOOL 2022-03-11

BMP and Infeasibility description applicable lists Infeasibility criteria and rationale for each BMP not selected T5.15 The following criteria can be cited as reasons for infeasibility without Permeable further justification (though some require professional services to Pavement make the observation): (continued) ❑ 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 an area designated as an erosion hazard, or landslide hazard. ❑ Within 50 feet from the top of slopes that are greater than 20 percent where the setbacks listed in DCSS Section 4-4.1 (3) cannot be achieved. El For properties with known soil or groundwater contamination (typically federal Superfund sites or state cleanup sites under 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. ❑ Within 100 feet of a closed or active landfill. ❑ Within 100 feet of a drinking water well, or a spring used for drinking water supply, if the pavement is a pollution -generating surface. 1-1 Within 10 feet of a small on -site sewage disposal drainfield, including reserve areas, and grey water reuse systems. For setbacks from a "large on -site sewage disposal system," see Chapter 246-272B WAC. ❑ Within 10 feet of any underground storage tank and connecting underground pipes, regardless of tank size. 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. ❑ At multi -level parking garages, and over culverts and bridges. ❑ Where the site design cannot avoid putting pavement in areas likely to have long-term excessive sediment deposition after construction (e.g., construction and landscaping material yards). City of Everett Public Works Small Project Stormwater Site Plan Report -Dec 2019 31