8525 EVERGREEN WAY BURGER KING 2021-05-10

2014 SWMMWW MINIMUM REQUIREMENTS SUMMARY MR : MINIMUM REQUIREMENT SSP : STORMWATER SITE PLAN MR#1 PREPARATION OF STORMWATER SITE PLAN: Stormwater site plan follows 2014 Stormwater Management Manual for Western Washington. MR #2 CONSTRUCTION OF STORMWATER POLLUTION PREVENTION PLAN (SWPPP): A SWPPP is provided under Section IV. MR#3 SOURCE CONTROL OF POLLUTION: Per S427 BMP's for s for Storage of Liquid, Food Waste, or Dangerous Waste Containers. Store containers in impervious containment under a roof, or other appropriate cover, or in a building. When collection trucks directly pick up roll containers, ensure a filet is on both sides of the curb to facilitate moving the dumpster. For storage areas on-site for less than 30 days, consider using a portable temporary secondary system like that shown in Figure IV-2.2.8 Secondary Containment System (p.669) in lieu of a permanent system as described above. MR #4 PRESERVATION OF NATURAL DRAINAGE SYSTEMS AND OUTFALLS: The developed site drainage will be discharged towards an existing drainage system for each basin. Basin A will drain into the existing onsite system in the northern portion of the site to connecting to the system along Evergreen Way. Basin B will continue to drain into the existing onsite system connecting to the system along Holly Drive. Both basins will be connected to follow their natural drainage path through a closed pipe system. MR#5 ONSITE STORMWATER MANAGEMENT: For onsite stormwater management (MR#5) list # 2 was used for both basins per Vol 1 section 2.5.5 of the SWMMWW. Full dispersion was considered first however it was deemed infeasible due to the lack of native vegetation. Downspout full infiltration was deemed infeasible as the site lacks the necessary area to accommodate full infiltration facilities within the required setbacks. Bioretention was deemed feasible. Onsite stormwater management for roof areas will be provided by two bioretention facilities, one for each basin, per BMP T5.14B. The overflow from the bioretention will be connected to the existing drainage system onsite that drains to Evergreen Way for Basin A and South to Holly Drive for Basin B within a closed pipe system. For other new and replaced hard surfaces, full dispersion was considered infeasible due to the lack of vegetation, permeable pavement was deemed feasible and will be used. Most of the parking lot will receive a 2" overlay and follow the existing grade to sheet flow to onsite catch basins. BMP T5.13 Post Construction Soil Quality will be used for all pervious areas. Insight Engineering Co. -Stormwater Site Plan 12/20/2018 -7-