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Worksheet 2 Infeasibility Criteria MINIMUM REQUIREMENT #5 On -Site Stormwater Management The following tables summarize infeasibility criteria that can be used to justify not using various on -site stormwater management best management practices (BMPs) for consideration for Minimum Requirement IS. This information is also included under the detailed descriptions of each BMP in the 2019 SWMM but is provided here in this worksheet for additional clarity and efficiency. Where any inconsistencies or lack of clarity exists, the requirements in the main text of the Stormwater Manual shall be applied. Evaluate the feasibility of the BMPs in priority order based on List #1 or #3. Select the first BMP that is considered feasible for each surface type. Document the infeasibility (narrative description and rationale) for each BMP that was not selected. Only one infeasibility criterion needs to be selected for a BMP before evaluating the nett BMP on the list. Attach additional pages for supporting information if necessary. Lawn and Landscaped Areas BMP and Infeasibility description applicable ltsh Infeasibility criteria and rationale for each BMP not selected T5.13 ❑ Siting and design criteria provided in BMP T5.13 Posiconstruction (Mormwater Manual Volume V, Section SS) cannot be achieved. Soil Quality and p Lawn and landscape area is on till slopes greater than 33 percent. D th di BMP and Infeasibility description applicable lMts Infeasibility criteria and rationale for each BMP not selected T5,30 ❑ Site setbacks and design criteria provided In BMP 1`330 NO ROOFS Full Dispersion (Starmwater Manual Volume V, Section 5.3) cannot be achieved. ❑ A 65 to 10 ratio of forested or native vegetation area to Impervious area cannot he achieved. ❑ A minimum forested or native vegetation flowpath length of 100 feel(25 feet for sheet flow from a non native Pervnone") cannot be achieved. T5.10A ❑ Evaluation of infiltration is not required per the Infiltration Downspout Infeasibility Map due to steep slopes, erosion hazards, or Full Infiltration landslide hazards. ❑ Site setbacks and design criteria provided in BMP TS.l OA (Stormuater Manual Volume ill, Section 3.1.1) cannot be achieved. ❑ The lots) or site does not have out -wash or loam soils. ❑ There is not at least 3 feet or more of Permeable soil from the proposed final grade to the seasonal high groundwater table, hardpan layer, or other impermeable layer. ❑ There is not at least 1 foot or more of Permeable soil from the proposed bottom of the infiltration system to the seasonal high groundwater table, hardpan layer, or other impermeable layer. City of Everett Public Works Small Project Stormwater Site Plan Report Dec 2019