OCR Text |
Show outlet will continue to discharge into Great Salt Lake, outside of the diking project, at a point 2 miles south of the proposed south dike. From this agricultural project northerly to the diking project it is a distance of 2 or 3 miles through shad- scale land of irregular topography, the swales being much higher in elevation than 4205, and the bi- passing of water from the diking project through these swales Into the lake proper is impossible except at 1870- 1880 elevations of the lake, and in that event short dikes across the swales will remedy the condition. It is, therefore, concluded that for normal elevations of G- reat Salt Lake from the flooding point of view, no patented lands will be affected, and for extremely high stages of the lake, the lands bordering the meander line may receive shallow flooding or sub- irrigation with fresh water, which is preferable to a like treatment with salt water. In other words there is a reservoir site available which will hold the water, and around which the conditions will be materially improved by the proposed work. From figures given above it is seen that for 80 years Great Salt Lake has been maintained at more or less uniform state, by the inflow of fresh water, the only known outflow being in the nature of evaporation. The mean area of Great Salt Lake is approximately 1.2 million acres. Applying the evaporation rate from salt water surface, the less of water from the lake, ( equivalent to inflow all sources) is 3 » 8 million acre- feet which at present is being wasted into the brine. This total inflow includes measured inflow, precipitation on the lake, and unmeasured inflow such as unmeasured streams, springs, seeps, etc. By far the larger portion of inflow enters the lake along its eastern side. With this quantity of water available it is concluded that proper sized units may be selected and that sufficient water is available to more than fill them yearly. Great Salt Lake being the sump or catch- basin of all fresh water within the Great Basin will continue to receive this water through surface- flow or underground seepage regardless of future development higher en the tributary streams. The area East of Antelope Island has been considered as one unit. Stream flow records show that the inflow into this area together with a 1200 second foot canal from Weber River will produce enough water to change its entire volume yearly after deducting for evaporation from fresh water- surface. If instead of a canal, a dike were built about 1/ 2 mile out from the meander line and extending from this project northerly across the mouth of Weber River an additional supply of water would reach this project amounting in all to 1- 1/ 2 times its volume. Such a plan would produce valuable hunting grounds through northern Davis County and at the mouth of Weber River. Consider next the freshening of the water confined within the unit east of Antelope Island, which would be typical of other units so selected. At present within this unit there is 112,000 acre- feet of salt water, while the capacity when filled to elevation 4203 is 437,000 acre- feet and when filled to 4205 is 620,000 acre- feet. ( For comparison, Echo Reservoir holds 72,000 ac. ft., Mountain Dell 35CO ac ft.) At comparatively small cost, the salt water may be pumped cut and filling started with an empty reservoir. If not pumped out, and the salt water through agitation, becomes mixed with the inflowing fresh waters then tne mixture of the first year would be less than 3% salt, and in the fourth year this salt content would be less than 1%, - 18 - |