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• <br />• <br />• <br />Table 4.t3-7a Speciticatlons for Embankment Constructlon <br />1. Stri in <br />All construction areas will be stripped of vegetation and debris. All topsoil in the construction area <br />will be removed and stockpiled. <br />2. Embankment Material <br />The material will be clay-siR with little sand and medium placticiry. The material will be used at each <br />impoundment site. <br />3. Moisture and Comoaction <br />The distribution of materials shall be such that the compacted material will be homogeneous and free <br />from lenses, pockets, streaks, or other imperfections. The material shall be deposited in hor¢ontat <br />layers six to twelve inches thick. The excavating and placing operations shall be such that the mate- <br />rial when compacted will be blended sufficienty to secure the best practicable degree of com- <br />paction, impermeability, and stability. Compaction and moisture contern shall be adequate for use <br />as an earthen till dam. <br />4. Principal Spillwav <br />The conveyance may be a corrugated metal semicircular flume. The flume shall be set in a concrete <br />base in excavated material centered in the emergency spilhvay. ARernate spillways have con- <br />veyance through a v-notched or flat bottom concrete spillway design. <br />5. Emerqency Spillwav <br />The emergency spillway will be a single spillway on the side of the impoundment. The entry will be <br />smooth and flat with walls on 3:1 slopes. <br />6. Core Trench <br />The core trench will be 5 feet in depth with a 10-foot wide floor. The walls will have 1:1 slopes. The <br />core trench will be backfilled with the same material to be used in the embankmern and placed in <br />accordance with Article 3. <br />7. Reqradinq <br />Borrow areas at each site will be regraded as needed to prevent erosion or ponding of water. The <br />regrading will blend wRh the natural topography at each site. <br />8. Size of Embankment <br />Total height of embankment will include a 5% allowance for settling. Wid[h a[ the top of the <br />embankment will be 15 feet with side slopes of 3H:1V on [he downstream side and 2H:1V on the <br />upstream side. <br />PR-3 <br />a-1st ` 1?FVIS(ON A 'R Ep <br />i <br />i DATE <br />