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` Terra Vista NW,LLC Stormwater Management Report <br /> List #1: On-site Stormwater Management BMPs for Projects Triggering <br /> Minimum Requirements #1 through #5 <br /> Lawn and Landscape Areas: <br /> 1. Post-Construction Soil Quality and Depth in accordance with BMP T5.13: Post-Construction Soil <br /> Quality and Depth. <br /> Project does not disturb existing landscape areas whereby existing soils can be retained for <br /> reuse. New planting area will import topsoil material to meet soil quality and depth <br /> standards of BMP T5.13. <br /> Roofs: <br /> 1. Full Dispersion in accordance with BMP T5.30: Full Dispersion, or Downspout Full Infiltration <br /> Systems in accordance with BMP T5.10A: Downspout Full Infiltration <br /> Infeasible—Flow path is not over native vegetation and 65%of the site has not been retained <br /> as native vegetation; infiltration is not feasible per the geotechnical report. <br /> 2. Rain Gardens in accordance with BMP T5.14: Rain Gardens, or Bioretention in accordance <br /> with BMP T7.30: Bioretention Cells, Swales, and Planter Boxes. The rain garden or bioretention <br /> facility must have a minimum horizontal projected surface area below the overflow which is at <br /> least 5% of the area draining to it. <br /> Infeasible—Per the Geotech report, infiltration is not feasible. <br /> 3. Downspout Dispersion Systems in accordance with BMP T5.10B: Downspout Dispersion <br /> Systems <br /> A downspout diversion system will be used. The roof area is 3,555 sf. Per BMP T5.10B, the <br /> length of the dispersion trench shall be 10 ft per 700 sf of roof area. Therefore the length of <br /> the trench shall be 50-ft. Since the roof area is more than 700 sf, a notched dispursion trench <br /> per Figure 111-3.1.6 of the SWMMWW will be used. <br /> 4. Perforated Stub-out Connections in accordance with BMP T5.10C: Perforated Stub-out <br /> Connections <br /> Infeasible—Per the Geotech report, infiltration is not feasible. <br /> Other Hard Surfaces: <br /> 1. Full Dispersion in accordance with BMP T5.30: Full Dispersion <br /> Infeasible—Flow path is not over native vegetation and 65%of the site is not forested. <br /> 2. Permeable pavement in accordance with BMP T5.15: Permeable Pavements <br /> Infeasible—Per the Geotech report, infiltration is not feasible. <br /> 3. Rain Gardens in accordance with BMP T5.14: Rain Gardens, or Bioretention in accordance <br /> with BMP T7.30: Bioretention Cells, Swales, and Planter Boxes. The rain garden or bioretention <br /> facility must have a minimum horizontal projected surface area below the overflow which is at <br /> least 5% of the area draining to it. <br /> Infeasible—Per the Geotech report, infiltration is not feasible. <br /> 4. Sheet Flow Dispersion in accordance with BMP T5.12: Sheet Flow Dispersion, or Concentrated <br /> Flow Dispersion in accordance with BMP T5.11: Concentrated Flow Dispersion <br /> (180303)Aikins Residence Page 7 March 6,2020 <br />