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<br />Uinta Basin Water Supply
<br />
<br />The main source of water for the Uinta Basin is runoff from the Uinta
<br />Mountains. The mountain streams above the irrigated lands produce high
<br />quality water with TDS ranging from 30 to 350 mg/L. Water quality in the
<br />basin deteriorates as river flows are diverted for agricultural use and
<br />return flow from irrigated areas enters the Duchesne River and its trib-
<br />utaries. Total dissolved solid concentrations in the Duchesne River below
<br />most irrigated land range from 200 to 4,000 mg/L with an average of 680 mg/L.
<br />
<br />The Uinta Basin Unit area contributes about 500,000 tons of salt
<br />annually to the Colorado River, a significant part of it from irrigated
<br />areas. Irrigation return flows from the area contribute an estimated
<br />240,000 tons annually, which results in an increase in salinity of about
<br />24 mg/L at Imperial Dam. About half of the return flow salt loading
<br />(120,000 tons), and one fourth of the total salts loading for the Uinta Basin
<br />Unit, is attributable to canal seepage.
<br />
<br />The first canal systems in the area were not designed for seepage
<br />prevention, but were relatively small projects constructed with horse-
<br />drawn plows and scrapers. Larger and longer canals, which sometimes
<br />parallel each other for long distances and often cross over other canals,
<br />were installed as the demand for land and water grew. Most canals do not
<br />have modern diversion structures, measuring devices, or control structures.
<br />
<br />The following table shows the total canal losses and salt contri-
<br />butions from all sources for each evaluation unit. This information was
<br />used in determining those canal sections considered for rehabilitation.
<br />
<br />Tab le 1
<br />Present canal losses and total salt contribution
<br />Canal loss Salt contribution
<br />(acre-feet/year) (tons/year)
<br />930 1,440
<br />715 8,280
<br />4,670 40,100
<br />13,565 33,265
<br />1,460 5,650
<br />2,745 10,085
<br />2,980 3,930
<br />845 1,170
<br />1,800 6,050
<br />1,780 2,760
<br />4,200 20,560
<br />800 590
<br />7,820 1,000
<br />2,935 1,960
<br />1,170 3,640
<br />8,900 33,830
<br />1,445 3,385
<br />3,880 10,480
<br />2,000 6,140
<br />64,640 194,315
<br />unit may include more than one canal.
<br />O'JCL1CJ
<br />
<br />Evaluation unitl/
<br />Pahcease
<br />Zimmerman Wash
<br />Pleasant Valley
<br />Grey Mountain
<br />Purdy-Midview
<br />South Fork Dry Gulch
<br />Duchesne Feeder
<br />Henry Jim
<br />North My ton Bench
<br />Dry-Gulch-Riverdale
<br />My ton Townsite
<br />Ouray School
<br />Whiterocks-East Uinta
<br />Bench
<br />Hancock Cove
<br />High line
<br />Rock Point
<br />Sand Wash
<br />Pelican Lake
<br />Totals
<br />!! An evaluation
<br />
<br />12
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