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<br />Table 5, Generalized water budget for the Upper Colorado River Basin study unit
<br />o
<br />-..1
<br />r..!:J
<br />
<br />CO Precipitation
<br />Surface-water inflow
<br />lnrerbasin water transfers (negligible)
<br />GroW1d~waler inflow (negligible)
<br />
<br />Inputs
<br />(.c.....feel par y..r)
<br />
<br />Oulput.
<br />(acre-feet per year)
<br />
<br />Evapolrdnsriration from Donirrigalcd land (residual)
<br />Surface-water outflow
<br />
<br />20,980,000
<br />o
<br />o
<br />o
<br />
<br />\4,9\ 0,000
<br />4.49\,000
<br />871.000
<br />585,000'
<br />123.000
<br />o
<br />o
<br />20.980,000
<br />
<br />Consumptive water use
<br />Interbasin water transfers
<br />
<br />Reservoir evaporation
<br />Grouod-wa[er outflow (negligible)
<br />Change in ground. wafer sloroge (negJigjble)
<br />
<br />Tolal (munded)
<br />
<br />20,980,000
<br />
<br />I Dala fmm U.S. Geological Survey National Water InfomulIion System and Upper Colorado River Commission. 1993.
<br />
<br />promote efficient runoff; annual precipitation is suffi-
<br />cient to fully recharge the aquifers in most years,
<br />thereby maintaining base flow year round, Low-
<br />altitude streams are at altitudes below 7.500 ft and
<br />receive less than 20 in, of precipitation annually,
<br />mostly from thunderslOnns, The basins for low-
<br />altitude streams have flat slopes and thick deposits of
<br />soils and alluvium that attenuate runoff, Annual
<br />precipitation is insufficient to recharge aquifers to
<br />produce a continuous base flow, Mixed-type streams
<br />have headwaters in the mountains or high mesas but
<br />flow through the low,altitude regions,
<br />
<br />Three stations have been selected to illustrate the
<br />differing fl()w characteristics of these stream types
<br />(table 6), The Colorado River below Baker Gulch
<br />(station 090 I 0500, fig, I) is on a high-altitude type
<br />stream having a drainage area of 53.4 mi2 and a mean
<br />
<br />annual streamflow of62,3 fi'ls, West Salt Creek near
<br />Mack (station 09153400. fig, I) is on a low-altitude
<br />type stream and has a drainage area of 168 mP and a
<br />mean annual streamflow of 0,88 ft3/s, This station only
<br />has 10 years of record and, therefore, flow characteris-
<br />tics at this station are not well defined, However, this
<br />record is among the longest for low-altitude streams in
<br />the basin that are not greatly affected by return flows or
<br />interbasin water transfers, The Colorado River near
<br />Cameo (station 09095500, fig, I) is on a mixed-type
<br />stream and has a drainage area of8,050 mj2 and amean
<br />annual streamflow of3,870 ft'/s, This station is
<br />affected by interbasin water transfers, storage reser-
<br />voirs. power development, and diversions for irrigation
<br />of about 160,000 acres,
<br />
<br />Table 6. Hydrologic characterislics of selected sunace,water stations in the Upper Colorado River Basin study unit
<br />
<br />[mil. square miles: f~/s. cubic feel p~r second; in., inches; Q_7_ 10, 7-day IO-year low flow: -. approximate]
<br />
<br />Hydrologic characteristic:
<br />
<br />Period of record (water year)
<br />Drainage area (mi2)
<br />Mean annual streamflow (ftJ/s)
<br />Coefficiem of variation oCannual mean srreamflow
<br />Mean annual rtUlolT (in.)
<br />10-year flood \ft'I,)
<br />Q_7,IO(fi3/,)
<br />
<br />Stadon
<br />09010500
<br />Colorado River
<br />befow Baker
<br />Gulch,
<br />Colorado
<br />
<br />Station
<br />09153400
<br />Wost S.lt Crook
<br />near Mack.
<br />Colorado
<br />
<br />StaUon
<br />09095500
<br />Colorado River
<br />near Cameo.
<br />Colorado
<br />
<br />1954-1993
<br />53.4
<br />62,3
<br />0,33
<br />] 5,8
<br />SOO
<br />3,9
<br />
<br />1974-,1983
<br />168
<br />0,88
<br />\.03
<br />0.07
<br />-140
<br />o
<br />
<br />\934-1993
<br />8,050
<br />3.870
<br />0.30
<br />6,53
<br />28.000
<br />1,050
<br />
<br />ENVIRONMENTAL SETTING 19
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