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Show GREAT SALT LAIZE AMD TFK PROPOSED DIKE by TOM LYON I have been asked to tell you something of the physical factors which are applicable to Great Salt Lake and the proposed dike. The area of the Lake at the meander line, below which the ground is owned by the State of Utah, is approximately 2200 square miles, or 1,408,000 acres. The elevation of the meander line is 4,205 feet. The present area covered by water at an elevation of approximately 4,198.4 feet west of the proposed line of dikes, is but 75 per cent of the total area below the meander line, being 1,275 square miles, or 816,000 acres. The area east of the proposed dike at the meander line is approximately 500 square miles, or 320,000 acres* The area covered by water at present has an elevation of practically 4,198* 4 feet and is but % per cent of the area below the meander line, being 280 square miles or 179,200 acres. The reason for the difference of 75 per cent and 56 per cent is due to the fact that the greater amount of water enters the lake east of the dikes, and consequently more solids are deposited. This has caused large areas of shallow water adjacent to the mouth of the Bear River and other drainage systems. The average yearly discharge for the past ten years of the Bear, Weber and Jordan Rivers is 2,334,440 acre feet, according to the data obtained from gaging stations on the Bear River, the Weber River, and the Jordan River and surplus canals. It will be noted that the gaging station on the Bear River is at Collinston a considerable distance above the mouth of the river and below a point where the gross amount of water for irrigation has been diverted, and also that the Malad River, which drains a considerable area, has not entered into the calculations. This is also true regarding the average run- off as calculated for the Weber River. The gaging station being at Plain City and some distance below the point where most of the water is diverted, is too far above the mouth of the river to include the return water from irrigation. The Jordan River and surplus canals are more nearly correct, although they do not include all of the water which ultimately reaches the lake in other channels. It is estimated that 1,500,000 feet of water reaches this lake from the unevaporated portions of that used in irrigation diverted above the gaging station plus run- off of the Malad River and other unmeasured streams. The precipitation on the lake east of the dikes as calculated from the various observation points is 1.01 feet. The total amount of water reaching the lake east of the dikes, is found by this method to be 4,154,440 acre feet. The area of the lake below the meander line east of the line of dikes, as before stated, is 320,000 acres. There is enough new water coming in each year, according to the above figures, to cover this area to a depth of 12 « 9 feet. Applying the evaporation factor of 5* 7 feet, there would be left sufficient water to cover the area 7* 2 feet; which means that 2,304,000 acre feet would be available for use each year. The estimated million and a half feet which finds its way to the lake, after being used for irrigation, will undoubtedly lag considerably behind the run- off and assist in maintaining a constant level for the lake during periods of intense use and evaporation. It is quite fortunate that this condition exists. - 21 - |