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-4 - <br />on the construction and operation of the pond should be further evaluated by Resource <br />Engineering. <br />DESIGN RECOMMENDATIONS <br />The following design recommendations are provided assuming the excavation is kept above the <br />groundwater level adequate distance to avoid dewatering and soft subgrade conditions. <br />POND EMBANKMENTS <br />We assume that the pond will be lined with a 50 to 60 mil membrane depending on pond use and <br />liner bedding requirements. It is possible that deer and elk will be in the pond and standing on <br />the liner which may require a thicker liner and a soil cover over the synthetic liner. <br />The currently proposed downstream embankment of the pond and cut above the pond are at 5 <br />Horizontal to 1 Vertical slope which should be suitable regarding slope stability and seepage. <br />The interior pond cut and fill embankments should be sloped no steeper than 3 Horizontal to 1 <br />Vertical due to the potential for slope failure during rapid drawdown. The liner manufacturer <br />may require flatter slopes. Soil cover on the liner may be needed for UV and wildlife protection. <br />The grading of the foundation and embankment should be performed as presented below in the <br />"Earthwork" section. The unlined graded slopes should be vegetated and riprap or erosion mat <br />should be provided as needed to prevent erosion in concentrated surface runoff areas. <br />EARTHWORK <br />The on-site clay soils will need to be moisture conditioned to within about 2% of optimum <br />moisture content when used as embankment fill. We expect the upper, lower moisture content <br />soils will need around 5 to 8% increased moisture to achieve near optimum moisture content. <br />Imported embankment fill (if any) should consist of similar clay soils, devoid of topsoil, <br />vegetation, debris and rock larger than about 5 inches and be evaluated for suitability by the <br />geotechnical engineer. Prior to fill placement, the embankment foundation should be prepared <br />by removing vegetation, stripping topsoil, scarifying to a depth of at least 8 inches and <br />compacting to at least 95% of standard Proctor density. The embankment fill should be spread <br />in relatively thin lifts and compacted to at least 95% of standard Proctor density at a moisture <br />content within 2 percentage points of optimum. In-place moisture and density testing should be <br />H-P%Ki1MAR Project No. 18-7-599 <br />