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6. PRESERVATION OF NATURAL DRAINAGE SYSTEM <br />The runoff from the NPGIS improvements will be partially infiltrated on -site and conveyed <br />off -site via a perforated stub -out connection. By not grading or compacting the majority of <br />the pervious surfaces to remain after construction in the area of disturbance a maximum <br />amount of site runoff from the developed project will be absorbed and infiltrated into the <br />existing on -site soils. This will mimic the existing conditions by maintaining the existing <br />direction and condition of flow from this site. <br />7. ON -SITE STORMWATER MANAGEMENT <br />Per Section 2.5.5 of the 2014 DOE manual projects must incorporate On -Site Stormwater <br />Management BMPs based on lists provided in that section. The applicable list for this <br />project is List #1 since this project only triggers MR #1-5. <br />When using List #1 each BMP must be considered in the order provided in the list. The <br />first BMP determined feasible for each type of surface must be used. <br />Lawn and Landscaped Areas: <br />Post Construction Soil Quality (BMP T5.13) - Selected/Feasible <br />Roofs: <br />Full Dispersion or Downspout Full Infiltration - Not Feasible <br />This project is not able to protect 65% of the site area as forest or native conditions <br />and still have a viable project.. Therefore, BMP T5.30 — Full Dispersion is Not <br />Feasible. This project is,located within the City's "Infiltration in -feasible" red zone <br />so all infiltration type BMPs are therefore deemed Not Feasible. <br />Rain Gardens or Bioretention - <br />Not Feasible <br />This project is located within the City's "Infiltration in -feasible" red zone so all <br />infiltration -type BMPs are therefore deemed Not Feasible. . <br />Downspout Dispersion Systems - <br />Not Feasible <br />BMP T5.10B requires that dispersed flows pass over vegetated areas with slopes <br />less than 15%. The slopes on this project exceed 15% is the areas available for <br />dispersion, therefore, Downspout Dispersion is Not Feasible. <br />Perforated Stub -out Connections - Selected/Feasible <br />Other Hard Surfaces: <br />Full Dispersion.- Not Feasible <br />Reid SP 15-0714 <br />July 2017 Page 10 <br />