9227 4TH AVE W 2024-08-12 - Laserfiche WebLink

b. In planting beds, will place three inches of compost and till in to an eight-inch depth. c. In turf areas, will place two inches of compost and till in to an eight-inch depth. d. Apply two to four inches of arborist wood chip, coarse bark mulch, or compost mulch to planting beds after final planting. Undisturbed soils will be protected from compaction during construction. Preserve native soils by stockpiling site duff and topsoil and reapply after grading and construction. See FIGURE 2 EXISTING AND DEVELOPED DRAINAGE & SWPPP PLAN. Roofs: 1. Full Dispersion per BMP T5.30 or Downspout Full Infiltration per BMP T5.1 OA Full Dispersion is infeasible due to insufficient flow path length and lack of native forest vegetation. Full infiltration is infeasible due to site constrains, soils conditions and infiltration is not recommended on this project site. 2. Bioretention per BMP T7.30 Bioretention is not feasible due to site constrains, soils conditions and infiltration is not recommended on this project site. 1. Downspout Dispersion Systems in accordance with BMP T5.10B This BMP is feasible and will be implemented on site. 2. Perforated Stub-out Connections in accordance with BMP T5.10C Although this BMP is feasible but the project is implementing Downspout Dispersion BMP T5.1 OB. The location and types of BMPs selected are shown in the project site/drainage plans —See FIGURE 2 EXISTING AND DEVELOPED DRAINAGE & SWPPP PLAN. Other Hard Surfaces: 1. Full Dispersion in accordance with BMP T5.30 Full Dispersion is infeasible due to insufficient flow path length and lack of native forest vegetation. 2. Permeable Pavement in accordance with BMP T5.15 Permeable Pavement System is considered infeasible for the new driveway and landings due to the following: The underlying impermeable/low permeable layer that would create saturated conditions within 1 foot of the bottom of the lowest gravel base course. Drainage Report—9227 4t"Ave W Everett,WA 98204 Nov. 10,2022 Page 15