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5. SOURCE CONTROL (MR #3) <br />This project proposes to construct future residential development. Per Volume 1 of the <br />2019 DOE manual, residential development does not require source control, however <br />basic water quality is proposed on this site. <br />6. PRESERVATION OF NATURAL DRAINAGE SYSTEM (MR #4) <br />Any runoff leaving the site will be directed to the right-of-way as in the existing <br />conditions. By not grading or compacting the majority of the pervious surfaces to <br />remain after construction in the area of disturbance a maximum amount of site runoff <br />from the developed project will be absorbed and infiltrated into the existing on -site <br />soils. This will mimic the existing conditions by maintaining the existing direction and <br />condition of flow from this site. <br />7. ON -SITE STORMWATER MANAGEMENT (MR #5) <br />As documented in Section 1 of this report this project is required to meet Minimum <br />Requirements 1-9. As a result, this project is required to use the On -Site Stormwater <br />Management BMP's from the 2019 DOE SVVMMVVW. <br />Per the DOE SVVMMVVW the BMP's must be evaluated in the order they are listed. <br />Lawn and Landscaped Areas: <br />1. Post -Construction Soil Quality and Depth: Required <br />Roofs: <br />BMP T5.30 - Full Dispersion: Not feasible due to not having 65% preserved <br />vegetation. <br />Downspout Infiltration: <br />With a design infiltration rate of 0.3 inches per hour, infiltration trenches are infeasible <br />because at 2-feet wide, lots 1, 2, 4, 5 and 6 would require approximately 250 linear <br />feet of trench. Required to be spaced 6 feet apart on center, there is not enough room <br />on each lot to fit these systems. Based on the on -site soils and recommendations <br />provided by the geotechnical engineer, shallow infiltration was found to be feasible by <br />the use of rain gardens (bioretention cells). Therefore, bioretention, where feasible, is <br />the selected BMP for this project. <br />This project proposes to utilize Bioretention Areas (BMP T7.30) to mitigate roof runoff <br />on lot 3, where ample open space exists on these lots down -gradient of the proposed <br />duplex. The bioretention cell was sized using the recommended infiltration rate from <br />the project Geotech and the VVWHM2012 software. Using the provided design <br />infiltration rate of 0.3 inches per hour, each bioretention cell is shown to infiltrate 100 <br />percent of the roof runoff it receives (see Appendix A for VVWHM printout). Therefore, <br />roof runoff from lot 3 will be fully infiltrated. <br />Perez SP <br />March 2022 <br />Revised: June%4ugust2022 Page11 <br />