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SPILL WAYS, , 12.1 NECESSITY OF SPILL WAYS, , The spill ways are openings provided at the body of the dam to disc, the excess water or flood water when the water level rises above the norma, level (Fig. 12.1). tl, , The spill ways are provided on the, dam for the following reasons,, , (a) The height of the dam is always, fixed according to the maximum, reservoir capacity. The normal, pool level indicates the, , maximum capacity of the, , reservoir. The water is never, stored in the reservoir above this level. The dam may fail by over turning, , so, for the safety of the dam the spill ways are essential., , (b) The top of the dam is generally utilised by making road. The surplus water, in not be allowed to over top the dam, so to stop the over topping by the, surplus water, the spill ways become extremely essential., , (c) To protect the downstream base and floor of the dam from the effect of, scouring and erosion, the spillways are provided so that the excess water, flows smoothly., , harge safely, | pool, , Maximum pool level, ormal pool level, , , , , sDam, , , , , » Spill way, Fig. 12.1 Spill way, , , , , 12.2 LOCATION OF SPILL WAY, , Generally, the spill ways are provided at the following places, (a) Spill ways may be provided within the body of the dam (Fig. 12.1)., (b) Spill ways may sometimes be provided at one side or both sides of the dam, (Fig. 12.2)., (c) Sometimes by-pass pill way is provided which i, ieee oe is completely separate from, , Scanned with CamScanner
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Fig., , , , , , , , Side spill way, , 12.2 Side spill way, , , , , , 1, Top of dah, , By-pass “), spill way, , Fig. 12.3 By-pass spill way, , Scanned with CamScanner
