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• the subgrade soils. The project site surface drainage should be designed by a qualified engineer. <br />If after construction, areas of poor surface drainage are noticed the poor surface drainage should <br />be corrected. <br />POND CONSTRUCTION <br />Several sedimentation and water supply ponds will be a part of the project. Provided <br />they will not be drawn down rapidly, interior slopes can be designed at a maximum inclination <br />of 3:1, and native soils can be used to line the bottom and sides. Boring 1, made at Pond C, <br />encountered predominantly clay soils without many cobbles and may not require lining other <br />than compaction of the materials at excavation grade. Boring 2, made at the location of Pond <br />B, encountered more granular materials, and therefore the owner should plan on the importation <br />• of clay materials from other parts of the project for placement of a liner to minimize leakage. <br />Even if leakage is acceptable from a water loss standpoint, it is good engineering practice to <br />limit the amount of fugitive water available to wet large areas of clay subgrade, which will help <br />to prevent instability of downhill areas and seepage from slopes. Effective pond liner material <br />exists in quantity on the project. We recommend clays with at least 70 percent fines and liquid <br />limits of 40 or more for liner material. Where clay liners will be placed, we recommend that <br />they be 16 to 18 inches thick, placed in two lifts. <br />CONTINUING SERVICES <br />Two additional elements of geotechnical engineering service are important to the <br />,• <br />successful completion of this project. <br />33 <br />