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Since only 1.0 acre feet of storage is needed and the pond contains 1.65 acres x 3.0' height = 4.95 acre <br />feet available, the pond is more than adequate to contain the runoff from the 100 year storm for the <br />drainage area designated. Willits Ponds 4, 5 and 6 as well as the lower mining area with berm will also <br />handle the runoff from the sand and gravel mining operation. The large pond area combined with the <br />porous pond bottom will ensure that the water seeps into the ground to replenish the water from the pit <br />pumping and to ensure that no discharge occurs from the site. <br />The design parameters for each of the South ponds are given below: <br />Pond <br />Name <br />Sideslope <br />Depth <br />Surface area <br />at top <br />Volume in <br />ac -ft <br />Pond <br />Purpose <br />#1 <br />2H:1 V <br />3.25 <br />0.25 ac <br />0.8 <br />runoff sediment detention <br />#2 <br />2H:1 V <br />4.25 <br />1.0 ac <br />4.0 <br />runoff storage and seepage <br />#3 <br />2H:1 V <br />3.25 <br />0.25 ac <br />0.8 <br />pit pumping detention <br />#4 <br />2H:1 V <br />3.5 <br />1.2 <br />4.0 <br />Pit pumping seepage/recycle <br />All of these ponds are shown on Maps C-2 and C-4. <br />Alma Place Mine 01/15 21 <br />