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i ~ ~ ~»caca 3 • 5.0 CONCLUSIO;]S ~1VD R£CO?E~?EVDaTIO:<S During the period 23-31 August 1973, a section of the Yampa River near Craig, Colorado caas losing 10 to 17 cubic feet per second or four to eight percent of the upstream flow to ground-water recharge. The loss section was an 800 foot stretch beginning 1.0 miles upstream of the confluence of the Yampa River and tdilliams Fork. Losses across the entire 4.6 mile reach from S.H. 13 to the confluence with [~,'illiams Fork were 10 to 11 cfs, or four to five percent of the flow at S.H. 13. This included an estimated evapotranspirative loss of about two cfs, yielding net losses of eight to nine cfs. Whereas the net losses Caere less than the probable recharge losses, it is possible that tcao to eight cfs were being discharged from ground water to the river. It was determined that, if present, this discharge was occurring over a one mile stretch beginning two miles below S.H. 13. This • cannot be conclusively stated for three reasons: (1) there Caere n0 %vil5i5i:c:,it f~21d data ~u inLLi~citt ~hdC ground-cater d15Charge was occurring at any point, (2) the amounts involved are so small as to be near the confidence limits of the field techniques, 4:id (3) changes in channel storage, if present, could not be fully evaluated. Although the above results were observed during Che period of this study, it is likely that results would be differ- ent during another oeriod under different antcedent conditions. The winter of 1977-78 was unusually wet, and snowmelC in the mountains provided significant base flora into the late summer. On the other hand, the summer was normally dry. This helped achieve steady-state conditions. Hocaever, during weC times, it is likely that there would be some ground-water discharge to the river. Unfortunately, a study during a wet period would be ex- tremely difficult to perform accurately. However, if ground- water discharge were occurring during a wet period, the higher • river floras would provide significantly increased dilution ca- pacity for any dissolved substances present in the ground water. 5-1