Summary--Lower Colorado River Basin Project

Document: Summary--Lower Colorado River Basic Project, May 26, 1965, page 3The same circumstances relate to Grand Canyon National Monument. The Bridge Canyon Reservoir would back water into the inner gorge through the entire length of the river in the Monument. Construction of the Marble Canyon Dam and Reservoir would have no effect on the National Park since the dam and reservoir would be upstream from the park boundary. An explanatory map showing the relationship of the dams and reservoirs to Grand Canyon National Park and Monument is attached. The existing and proposed Colorado River hydroelectric power resource will be fully integrated with power and energy from other sources, primarily thermal plants using fossil fuel and atomic energy. These atomic and fossil fuel powered generating units also have been proposed as alternatives to the Marble and Bridge Canyon hydroplants. However, thermal generation facilities are best adapted to baseload energy and are most efficient when producing at a nearly constant rate. The demand for electrical energy does not follow a pattern of constant use. The peak demands that occur during short periods of each day must be met from a source easily adapted to an on-and-off operation. This so-called peaking-type energy can be produced most economically by hydroelectric generation since these units may be put into operation by a simple turn of a valve, permitting water to pass through turbines and thus producing energy almost instantaneously. This is the major role visualized for the potential hydro units at Marble and (if studies prove it desirable) at Bridge powerplants. However, a standard minimum flow will be maintained below Marble Canyon Dam at all times no different from that which has been in effect since filling started at Glen Canyon Dam. Thus, the integration of these two kinds of power generation, hydro and thermal, is most feasible to produce a total electrical energy product at maximim efficiency and minimum cost. It is significant to add that there is extreme competition among utilities desiring licenses to construct single-purpose hydroplants at most presently undeveloped river sites. This would seem to contradict assertions that the proposed Federal hydropower developments are uneconomical and would soon be outmoded. The desalting of sea water, using a combination desalting-steam electric generating plant, offers an exciting and attractive potential of supplying additional water and power for the water-short areas but does not appear to be a substitute at this time for development of water supplies by existing means. 3Epson Perfection 4870 Photo, 400 dpi, 8 bit, 2,101,230 byte