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1101523 The above measu rements are typical of most areas and it ca,n be expected that the seepage loss rates at any stock pond will fall within the limits shown. As with evaporation, the total seepage los s from a pond will depend on the area covered by the water, and the design of the stock pond can therefore have an important bearing on both kinds of losses with the minimum to be expected with a low ratio of water area to pond con- ten ts. Reducing seepage 10.8 se.8 Methods of reducing stock pond seepage are" in general, similar, to those which might be used in land treatment to increase runoff. Essen- tially, the objective in each case is the same. Both are to reduce preme- ability of the surface soils. Use of impermeable blankets to reduce seepage around the dam is a common practice. These are generally placed around the abutments and the upstream base of the dam. The blankets maybe formed by compaction of selected earth layers or by,paving with'80il cement or asphalt mixes. Bentonite clay- sand mixtures generally have proved effective for this purpose and are commonly used where available at reasonable cost. Commercially sacked bentonite generally' i,s too expen- sive for stock pond treatment but local supplles of impure grade can be substituted where available. As the bentonite may lose its effectiveness if stored water contains calcium, the possible chemical content of the water to be stored should be cons ide red in deciding on the method of pond treatment. The use of salt of SSc13 (soil sealer) has been employed some to decrease percolation from ponds. However, its practical usefulness has yet to be proven for the wide range of soils, climates and water qualities encountered. Direct leakage through the dam is the result of inferior construc- tion methods and usually special procedures are needed for correction. Stock pond seepage losses commonly decrease with age as a result of deposition of fine sediment and trampling'by livestock. Treatment with, salt or other dispersing agents in the early life of the pond is often used to reduce seepage. The simple inexpensive salt treatment is usually carried out by raking rock salt into the stock pond floor.' Dispers ion of the soil particle,s occurs as the pond is iilledand is most effective where the treated soils contain a minimum of 20 percent clay. Reservoirs with a bed rock floor are not amenable to treatment by dispersion methods. Use of bentonite for this purpose has given good results in the Parker Mountain area of Utah, south of Fish Lake and is cited as an example. This area is underlain by fractured and pervious 33 ;~;~ .~,~~!. ;'~;.::(;;':': . .1[..;'(/;: I ~~ !'\;~i:~~~~: ~