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Show 72 junction of the Colorado and Gila Rivers 6,249 cubic feet per second, with a velocity of 3 feet per second. The estimated evaporation at Gamp Mohave as given by Lieutenant Bergland. deduced from observations extending over a small interval, is a little less than 8 feet; this would be increased at Yuma, while at Stone's Ferry it would be similar in amount A lake required to contain the influx of all the wtom of the river at the stage mentioned near Fort Yuma, the only point near whieh it can be diverted, would be somewhat less than one thousand square miles. The area of depressed region ( approximately) to which, a channel can be cut from the river is 1,600 square miles. Hence, it appears that during the low- water stage this lake would act as a reservoir without outlet, while at a high stage the overflow at its maximum would cause a regular channel to be cut, making its own outlet to the gulf and forming along its route a series of lagoons during seasons of no flood, or the greater part of each year; but should it be possible to introduce waters from the gulf to the lake thus to be formed in the depressed acea, the same would be transferred into a tidal lake with a current setting in toward the gulf by way of the conduit thus formed, receiving fresh waters from the river and affected by the changes of the high and low-waters from the sea. No change of climate can be expected to ensue from the formation of a lake or number of lakes, aggregating the above area. The amount of evaporation from the surface would be insufficient to change noticeably the relative humidity of the surrounding atmosphere, while the prevalent winds, both from local and far- distant sources, would diffuse and disseminate the amount of moisture thus received with great rapidity. The soils along portions of the route, as shown by Dr. Loew's report, ( see Appendix H 6,) are, many of them, of an arable nature, needing moisture only to be made productive. In the lower parts of the valley of the Colorado, cotton, coffee, sugar, tea, and flax could undoubtedly be grown with success, while a small change for the better in the relative humidity at local points could most likely be brought about by planting the eucalyptus, and trees of like strength of foliage, along the narrow valleys bordering the river. The mulberry could also doubtless be made to flourish. The unfortunate climate to which this portion of the Southwest is at present treated by the hand of nature is likely to retard its rapid settlement, even if water was plentifully availablej still at some future time in the settlement of through section = 14,244 cubic feet per second. Here the velocity throughout the section would be increased at time of high water, and a large quantity would flow outside of the section. Stone's Ferry, Nevada, Avgust 12, 1875.- Area of section = 5,723 square feet " Width = 480 feet. H ydraulic radius, or mean depth = 11.89 feet. Mean velocity = 3.217 feet per second. Discharge = 18,410.38 cubic feet. High- water mark of 1871 is 17.01 feet above surface of water at time of observations. Increase of area at high water 9,773.1. The whole discharge at high water takes place through the section. Supposing the mean velocity to remain the same as August 12,1875, the increase in discharge would be 31,439.7 cubic feet per second: but as m reality there would also be an increase in the velocity, the increase in discharge would be somewhat greater than this, but how much greater cannot be determined without direct experiments. Camp Mohave, A. T., September 2,1875.- Area of section = 4,628 square feet. Width 1,116 feet. Mean depth ( hydraulic radius) = 4.144 feet Mean velocity = 2£ 08 feet per second. Discharge = 11.610.93 cubic feet per second. High- water mark of 1874 above surface of river = 8 feet. Increase of area of section at high water 13,655.89 feet, ( excluding overflow on flats.) Increase in discharge through the section would be 34,274 cubic feet, but as a considerable quantity of the bottom beyond the section is then covered with water, this will not represent the total increase. Here there would be but. slight increase in the velocity, as the water has a chance to spread over the bottom- lauds, ( see plot of section.) |
