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<br /> <br />00'0'" <br /> <br />13 <br /> <br />Helation of Base Flow with Ground-Water Availability <br /> <br />1\ large pOl'tion of the base-flow component of streamflow comes from <br />ground water. Therefore, the areal distribution of base flO\\' should he in- <br />fluenced by geologic conditions that also influence the OCcurrence of ground <br />water. Unfortunately. the~'e is no simple factor' that adequately portrays <br />these geologic conditions. As will be discussed later, several basin fac- <br />tors, such as the areal var'iation in yields of gr'ound-water wells (fig. 4>, <br />were examined as possible indicator's of the ground-v/ater' contr-ibution to <br />ba~e flow, but none were found statistically significant. Future studies may <br />find base flow I'elated to Dthet' geologic factors which at'e presently incom- <br />pletl)' defined, such as alluvium permeability oc gt'ound-water level eleva- <br />tions ahove the stream. <br /> <br />Relation of Base Flow with Dir'ect Runoff <br /> <br />Base flO\v, as defined for this study, is equal to total streamfto\v <br />minus direct runoff, whe"e dil'ect runoff consi5t5 or" the flood-ilow or storm- <br />now pOI.tion which traveLs with little delay on aI' Just below the gnmnd sur- <br />face when the rainfall cate is mo"c intense than the infiltration and reten- <br />tion "ates. Thus dil'ect cunoff is that ponion of total flow that may be de- <br />tained and beneficially stored in farm ponds and small detention reser'voirs <br />either for reducing flood damage or for suppl:-ing supplemental releases in <br />r'cgions of insufficient base now. <br /> <br />Values of mean direct runoff, in cubic feet pcr second per square <br />mile, are shown in figure 5 for' 105 basins or' sub-basins in Kansas and <br />vicinity. The values wer'e computed fcom data in Technical I'eport 6:\ a" <br />fl'om table I, (p. 111) in the same manner as mean base flow \vas computed <br />fOI' figuJ'c 2. The values cepresent the mean long-term unit cate during <br />the standard base period, generally 1923-62. Like base flow, direct run- <br />off \'arie~ consider'ably between adjacent basins but increases from a low <br />oi 0.0056 efs pel' sq. mi. in westel-n Kansas tu a high of 0.751 cfs per sq. <br />mi. in eastern Kansas. The ratio of di"ect I'unoff to total flow may be com- <br />puted at a site by sUbtJ'acting from 1.00 the value, "ratio of base flow to <br />total flow," shown in figure 3. <br /> <br />Values of direct r'unoff ma.y be slightly le~s in recent yea"s than the <br />avccage during the base pel'iod because of the effect of water-supply and <br />recreational t'eservoirs, and of stock and farm ponds. <br />