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Show It is proposed to use a suction type dredge such as is used in many of the harbors and rivers of this country for the purpose of maintaining channels. The material dredged in most cases has been used to build new land. By this method the material for the dike would then be of the same specific gravity as that of the bottom, consequently there would be no likelihood of trouble due to the material sinking in the bottom. If an attempt were made to construct the dike of large rocks which would sink down in the ooze due to their greater weight per cubic yard, experience similar to that which occurred during the building of the Lucin Cutoff would be expected. In asking for prices of dredging this material, I specified that no borrow pits would be closer than 600 feet from the center of the line of the dike, so that the bottom would not be weakened close to the point supporting the greatest weight. Regarding spillways, I believe that the best plan would be to construct these near the ends of the islands in solid rock which would eliminate any further expense for maintenance. The time necessary to freshen the water east of the dikes depends largely upon the fact that the fresh water does not mix with the salt water immediately, but remains on the surface for a considerable time. This would tend to force heavier salt water through vents placed at the bottom of the dikes so that a large portion of the salt water would be eliminated before any mixing took place. If we assume an average depth of 5 feet for the water now occupying the eastern area, there are 8^ 6,000 acre feet of salt water present* This water would be both forced out and be diluted by 4,154,440 acre feet of fresh water before much evaporation took place. There would then be 4.6 times as much fresh water coming in as there was salt water present the first year, so that a large portion of the job would be done the first year, provided the dikes were completed during the time the lake is at its present level. Just how long it would take to freshen the water sufficiently for industrial use is hard to state definitely, but I anticipate that the water will be fit for many purposes within three or four years. - 23 - |