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3. Basic downspout dispersion was considered next for the new roof surfaces. Due <br /> to the limited vegetated/pervious surfaces available around the church a minimum <br /> flow path of 25-50 feet could not be obtained. As a result, basic dispersion was <br /> found to be infeasible. <br /> 4. Perforated Stub-Out Connections were there for selected for the new roof <br /> surfaces. <br /> Other Hard Surfaces: <br /> 1. Full dispersion was found to be infeasible for this project site, as previously <br /> mentioned. <br /> 2. Permeable pavement was considered next. Based on the previous grading and <br /> disturbances around the existing church, permeable pavement was found to be <br /> infeasible. In addition, permeable pavement can only replace existing pavement in <br /> outwash soil types. <br /> 3. Bioretention was considered next. As noted above the existing <br /> grading/disturbances around the church result in no existing soil that has not been <br /> compacted, graded or filled and the minimum soil depth of 36"to hard pan or water <br /> table could not be provided. Therefore, bioretention/rain gardens are found to be <br /> infeasible. <br /> 4. Sheet flow dispersion was considered for the sidewalk surfaces. Runoff from the <br /> new/replaced sidewalk surfaces will utilize sheet flow dispersion by allowing runoff <br /> to sheet flow off the edge of the new concrete surfaces and drain over the adjacent <br /> landscaping prior to collection by the drainage system. <br /> Finally, per List#1 lawn and landscaped areas must implement post-construction soil <br /> quality and depth in accordance with BMP T5.13 in Volume 5, Chapter 5. Therefore, BMP <br /> T5.13 will be applied to all areas of lawn/landscaping on this site to further provide filtration <br /> and absorption of site pervious runoff. <br /> It should be noted that for the replaced asphalt access along the west side of the <br /> new/remodeled church it was not feasible to apply any of the LID BMPs due to the existing <br /> site conditions. Since permeable pavement was not feasible along with other types of <br /> infiltration sheet flow dispersion could not be used based on the existing site <br /> improvements. <br /> Zillah 2-Lot SFR's 18-0605 <br /> June 2018 Page 11 <br />