Colorado River Ecology and Dam Management Proceedings of a Symposium May 24-25, 1990 Santa Fe, New Mexico (1991) / Chapter Skim
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Hydrology of Glen Canyon and the Grand Canyon
Hydrology of Glen Canyon and the Grand Canyon
Pages 40-53
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From page 40... ...
This paper will not look at all facets of hydrology but rather will highlight what is needed in terms of data and analysis in order to better understand the hydrology of the Grand Canyon. EARLY UNDERSTANDING OF COLORADO RIVER FLOWS The Colorado River basin both above and below the Grand Canyon has been influenced by diversions from the early days of settlement of the West.
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From page 41... ...
C Grover, then head of the Water Resources Division, wrote in the foreword to La Rue's second major work on the Colorado, "The need for further agricultural development in the Colorado River basin will increase gradually, while the demand for electric energy in the basin and in regions outside the basin, but within economic transmitting distance will increase more rapidly.
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From page 42... ...
214-215~. Thus, Glen Canyon and nearby sites were under consideration for development from the earliest assessments of the Colorado River basin.
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From page 43... ...
Uncertainty concerning hydrology determines the reliability of estimates of water and sediment throughput of the Colorado River and the resultant impact on growth and erosion of beaches in the Grand Canyon. The capability of Lake Powell and Lake Mead to store sufficient water to deliver the 75 million acre-feet every 10 years to the lower states plus l.5 million acrefeet per year to Mexico depends on the reliability of the estimates of streamflow.
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From page 44... ...
Leopold demonstrated that an increase in total reservoir capacity in the Colorado River basin would achieve practically no additional water regulation if evaporation loss is subtracted from annual
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From page 45... ...
Therefore, bank storage must be a derived figure or at any rate seems not to be derived from a physically based model of the surrounding aquifer. The USBR should develop a physically based groundwater model for the determination of bank storage, such as is used in reservoirs in the Columbia River basin (Thompson, 1973, 1974~.
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From page 46... ...
The gravel bars immediately below Glen Canyon Dam should affect the different turbine ratings differently. A study should be undertaken to determine whether, in fact, some turbines are more efficient and what can be done to improve the performance of the less effective ones.
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From page 47... ...
Therefore, the release rules from Hoover Dam should be considered a part of the hydrology of the Grand Canyon. The resulting hydrology of the Grand Canyon depends on water availability.
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From page 48... ...
RELATIONSHIP OF SEDIMENT TRANSPORT TO STREAM FLOW IN THE CANYON Fluctuations of flow, not mean flow for the day, control sediment transport and stability of the ecosystem in the Grand Canyon. Pulses of flow released at Glen Canyon Dam will be attenuated as the flow travels downstream through the canyon.
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From page 49... ...
EFFECT OF OPERATION OF UPPER BASIN STATE RESERVOIRS ON GLEN CANYON AND THE GRAND CANYON Present upstream use of waters in the Colorado River basin are on the order of a little over 4 million acre-feet, based on the difference between the USER figures on water availability and inflows to Lake Powell. For 1968-1974 upstream depletions varied from 3.6 million acre-feet in 1969 to 4.96 million acre-feet in 1971, with an average of 4.28 million acre-feet for the 7 years.
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From page 50... ...
Therefore, the possibility of wide variations in the elevation of Lake Powell is fairly large because that possibility depends on the assumed average natural inflow. TRAVEL TIMES THROUGH THE GRAND CANYON The storage behind Glen Canyon Dam attenuates the fluctuation in discharges while power production reintroduces them and controls the hydrology of released flows; then travel down the canyon attenuates the pulses.
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From page 51... ...
LEE'S FERRY DISCHARGE (in cfs) 0 To Little Colorado River · To Bright Angel Creek 16 18 20 FIGURE 3-4 Relationship of Ravel time to stream discharge through the Grand Canyon from Lee's Ferry to Little Colorado River and Bright Angel Creek.
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From page 52... ...
Any tracing of flows through the canyon should be based on streamflow records at the Leers Ferry gage, not on turbine computations of streamflow. Travel times for the venous reaches of the Grand Canyon should be determined and used to calibrate flow and sediment routing models.
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From page 53... ...
1965-1990. Status of Reservoirs, Colorado River Storage Project, Lake Powell Reservoir Behind Glen Canyon Dam.
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