905 80TH ST SW MTORRES AMERICA 2018-09-18

February 22,2016 Project No. T-7364 If fill berms will be constructed, the berm locations should be stripped of topsoil, duff, existing fill soils, and soils containing organic material prior to the placement of fill. The fill berms should be constructed by placing structural fill in layers no more than 12 inches thick,compacting each layer to a minimum of 95 percent relative compaction, as determined by ASTM Test Designation D-1557 (Modified Proctor). Material used to construct pond berms should consist predominately of granular soils with a maximum size of 3 inches and a minimum of 20 percent fines. The results of laboratory testing indicate that soils meeting this gradational requirement exist on-site. Terra Associates, Inc. should examine and test all on-site or imported materials proposed for use as berm fill prior to their use. Because of exposure to fluctuating stored water levels, soils exposed on the interior pond slopes may be subject to some risk of periodic shallow instability or sloughing. Establishing interior slopes at a gradient of 3:1 (Horizontal:Vertical) will significantly reduce or eliminate this potential. Exterior berm slopes and interior slopes above the maximum water surface should be graded to a finished inclination no steeper than 2:1 (Horizontal:Vertical). Finished slope faces should be thoroughly compacted and vegetated to guard against erosion. 4.10 Drainage Surface Final exterior grades should promote free and positive drainage away from the building at all times. Water must not be allowed to,pond or collect adjacent to foundations, or within the immediate building area. If a positive drainage gradient cannot be provided, surface water should be collected adjacent to the structure for discharge into the site stormwater system. Final grades at the top of site slopes must promote surface drainage away from the slope crest. Water must not be allowed to flow uncontrolled over the slope face. If surface runoff must be directed towards the top of a slope, it may be necessary to route collected water to an appropriate point of discharge beyond the toe in a closed system. Subsurface We recommend installing a continuous drain along the outside lower edge of the perimeter building foundation. The drains can consist of 4-inch diameter perforated PVC pipe that is enveloped in washed'/z-to 3 -inch gravel sized drainage aggregate that extends six inches above and to the sides of the pipe. The pipe can be laid to grade at an invert elevation equivalent to the bottom of footing grade. The foundation drains and roof downspouts should be tightlined separately to an approved point of controlled discharge. All drains should be provided with cleanouts at easily accessible locations. These cleanouts should be serviced at least once each year. Page No. 11