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<br />TABLE X <br /> <br />Dilution Water Required Below Montrose, Colorado <br /> <br />Time Flow Required, cfs <br />Present 7 <br />1976 14 <br />1985 17 <br />2010 26 <br />2060 37 <br /> <br />Based upon historical streamflow records (1912-1962), minimum <br />daily and average monthly flows in the Uncompahgre River near Colona <br />have exceeded 37 cfs about 99 percent of the time. Under project <br />operation minimum flows are expected to average 50 cfs during the <br />winter months. <br /> <br />As previously noted, the water in the Uncompahgre River is <br />seriously degraded between Colona and Delta. Protecting and improv- <br />ing the water quality of the Uncompahgre River is necessary if the <br />area's potential for economic growth is to be realized. <br /> <br />Flow regulation is necessary to maintain water.quality in the <br />lower Uncompahgre River. If flows are maintained at Delta for water <br />quality control, points upstream will be taken care of as well. With <br />streamflow regulation the lower Uncompahgre River would have lower <br />concentrations of dissolved solids, hardness,biochemical oxygen demand, <br />bacteriological density,and temperature. <br /> <br />To reduce the high levels of total dissolved solids in the <br />Uncompahgre River at Delta by using water from Ridgway Reservoir <br />(approximately 300 mg/l total dissolved solids), or other water <br />of equivalent quality, 74,000 acre-feet of dilution water would <br />be required annually to maintain existing water quality with project <br />operation. To reduce concentrations of total dissolved solids,to <br />l,OOO mg/l at Delta would require 197,000 acre-feet without the <br />project, and 234,000 acre-feet with the project. Table XI shows the <br />computed dilution water requirements at Delta, by months, based upon <br />the Bureau of Reclamation's project operation study,* historical <br />period (l947-6l). <br /> <br />*September 6, 1963 <br /> <br />30 <br />