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GJJ196 25 TurquoIse lake, TwIn lakes, and Clear Creek Reservolr. Th~s water was stored from trIbutaries of the Arkansas RIver, under storage decrees, or from trans- mountaln diversIons. In general, water Is transported down the main stem of the Arkansas River between AprIl and September when demand Is hIghest. At a specifIed time, the gate keeper at one of the three reservoIrs opens the gates to a specifIed release rate -- a trial and error procedure re- quIring posslhle one-half an hour. A large release rate for the past few years would be about 400 cfs. Of course, thIs large of a release creates changes In the stream from Its natural condItIons. The stage or water surface elevation of the RIver must Increase to accommodate the Increased dIscharge, the amount of Increase dependIng maInly on the wIdth, slope, and roughness of any parlcular cross- sectlon. SInce the dIscharge has Increased rather quickly, the effects of thIs release will pass down the River lIke a wave. At any station along the RIver channel, there wIll be an InItIal change of stage when the trans- latory wave reaches It. The stage wIll contInue to Increase untIl It reaches a maxImum, somewhat constant, value. The tIme from the InItial ef- " fects to maximum value wIll vary depending on the partIcular reach of the River. ThIs tIme might be expected to be shorter for the upper basIn sInce diffusIon mechanisms have not had tIme to operate. This Initial wave travels at a dIfferent rate than the average stream velocity. Confusion as to exact travel tImes for particular reaches may exist If local rainstorms enter the River durIng a release. As thIs water travels along the natural channel, It Is subject to cer- tain losses due to the Increased stage. At headgates to diversion ditches, , gate settIngs are often bas.d on natural rIver flow. By lncreaSlng the rIver stage, more water will usually be diverted Into these ditches. Just the opposite will happen when the stage decreases. The amount of water lost or gained wIll depend on how regularly the gate settings are checked and reset. Increased stage causes bank. storage losses.i.hich' need to bll:con<stilllred 'even though, the:;.". clef:; n; t ion.. a Imos t'. def'ies, quan,t; tati,ve',ana:1 ys j s;'" Increased stage causes a wIdenIng of the natural stream and wIll ex- pose more area to evaporatIon. SInce exact evaporation, fIgures for a speci- fic release are dependent on many varlahles, losses attributed to evapora- tion can be considered estimates only. Many of the varlables cannot be determIned ahead of time, and they can be expected to change during the reservo I r run. DetermInatIon of exact losses occurlng In the rIver due to a reservoIr release Is complIcated by a multItude of additIonal varIables. The physIcal topography, geology, and clImate of the River are constantly changIng so that different losses become more Important for dIfferent reaches of the RIver. Travel tImes for short reaches exhIbIt a wIde range of values. I ' A river, from the viewpoInt of the hydrologist, Is a non-exact thing of Nature because It effects, and Is effected by, many envorlnmental fac- tors too numerous and complex to measure and extrapolate accurately. The