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<br />52. <br /> <br /> <br />001873 <br /> <br />Seepage <br /> <br />The second important reservoir los s and one that often exceeds <br /> <br />evaporation is seepage. Seepage ma y occur either as flow through or <br /> <br />around the dam, or as deep percolation in the stock pond. The former <br /> <br />is usually discernible as open flow or as wet swampy areas supporting <br /> <br />phreatophyte growth below the dam. Seepage in the pond floor is more <br /> <br />d.ifficult to identify and final disposition of the percolated water gener- <br /> <br />. ally cannot be determined. In most instances it pres!lmably becomes a <br /> <br />part of the ground-water supplies where it mayor -may not contribute <br /> <br />to the base flow of streams or be recovered throughweHs. <br /> <br />Measurements of seepage 10.sses generally have been obtained <br /> <br />indirectly by considering seepage as the difference between total re- <br /> <br />cession in the reservoir and evaporation. Langbein (1951) has described <br /> <br />a precise method of separating the evaporation and s'eepage losses in <br /> <br />the total reservoir recession. The same procedures have been used <br /> <br />. <br /> <br />. in several s.tudies by the Geological Survey, although most meaS!lre- <br /> <br />ments have been made by applying an appropriate evaporation rate to <br /> <br />the recession graph of the res'ervoir, the difference being regarded as <br /> <br />seepage. In most calculations, precipitation on the reservoir surface <br /> <br />during the period of measurement is considered although it has been <br /> <br />disregarded by some in calculating losses onthe assumption that <br />