Laserfiche WebLink
<br />, . <br /> <br />. <br /> <br />Dist.ribution'Systems' losses include canal seepage, s.urface evaporation, <br /> <br />. <br /> <br />"non-beneficial (phreatophyte) evapotranspiration, and operational w:;.ste. <br /> <br />Canal seepage is the major component of distribution system losses. There- <br /> <br />fore, careful consideration will. be made in its determination. <br /> <br />2.8.1 Factors Affecting Seepage <br />Many interrelated factors affect seepage losses in canals. These factors <br /> <br />include the following: <br /> <br />1. The type of surface of the canal--i. e., the material of which the <br /> <br />banks are made, its permeability and nature of the lining, if any, <br />applied to its wetted perimeter. <br /> <br />2. The type of soil surrounding the canal--more particularly, <br /> <br />p~eability of adjoinin~.soil. <br />". <br /> <br />. <br />3~ The surrounding vegetation of the canal--trees: bushes and other <br /> <br />vegetation bordering the canal, as they tend to increase the rate <br /> <br />of seepage. <br /> <br />4. The wetted area of the canal bed and banks--the larger the wetted <br />.rea, the greater the seepage. <br /> <br />S. The age and shape of the canal and the frequency of its use--the <br /> <br /> <br />'more often the canal is used, the less is the rate of seepage, for <br /> <br />the soil pores tend to become saturated and then with time become <br /> <br />. ' <br />paTtially sealed. On the other hand, in a canal which is not <br /> <br />used often. the dry surface has to tDldergo the cycle of saturation <br /> <br />over again. <br /> <br />6. The weather conditions under which the canal operates--the <br /> <br />temperature of flowing water and of the soil affects the rate of <br /> <br />seepage. In dry months the rate of seepage should be more because <br /> <br />t.he moisture in the surrounding soil evaporates easily and the rate <br />