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BMP and Infeasibility description applicable lists Infeasibility criteria and rationale for each BMP not selected T5.15 The following orhmia can be cited as reasons for infeasibility without No existing hard Permeable funherjustlfication(thoughsume require professional services to surfaces are Pavement make the observation): (continued) ❑ At sites defined as`high usesHes'(refertothe Glossary in the proposed to be SWMMWW volume I), impacted and infiltration BMPs ❑ In areas with 'industrial activity" as identified in 40 CFR are not 122.26(b)(14), recommended, ❑ Where the risk of concentrated pollutant spills is more likely such as gas stations, truck stops, and industrial chemical storage sites. see previous comments. ❑ Where routine, heavy applications of sand occur in frequent snow zones to maintain traction during weeks of snow and ice accumulation. ❑ Where the seasonal high groundwater or an underlying impermeable/ low permeable layer would create saturated conditions within 1 foot of the bottom of the lowest gravel base course. T5.14A Note: Criteria with setback distances are as measured from the bottom Infiltration BMPs Bioretention edge of the biorelention soil mix. or Rain Gardens are not recommended, Citation of any of the following infeasibility criteria must be based on see previous an evaluation of site specific conditions and a written recommendation from an appropriate licensed professional (e.g., comments. engineer, geologist, hydroge)logisd: ❑ Where professional gertechnical evaluation recommends infiltration not be used due to reasonable concerns about erosion, slope failure, or down gradient flooding. ❑ Within an area whose ground water drains into an erosion hazard, or landslide hazard area. ❑ Where the only area available forsiting would threaten the safety or reliability of preexisting underground airlines, pre-existing underground storage tanks, preexisting structures, or preexisting road or parking lot surfaces. ❑ Where the only area available for siting does not allow for a safe overflow pathway to nationalist drainage system or private storm sewer system. ❑ Where there is a lack of usable space for bimetention areas at redevelopment sites, or where there Is insufficient space within the existing public righiuf-way on public road projects. ❑ Where infiltrating water would threaten existing below grade basements. ❑ Where infiltrating water would threaten shoreline structures such as bulkheads. City of Everett Public Works Small Project Starmwater Sm Plan Report Dec 2019