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Show PAGE TWO GEOLOGIST POINTS OUT NEED OF FRESH WATER IN S. L. VALLEY BY TOM LYON Geologist, International Smelting Company. An industrial community is limited by the water available for steam generators and all other purposes which are many. Salt Lake has reached its limit. In looking over the water supply of this state which would be available to Salt Iake City one is impressed first by the lack of reservoir sites which may be economically developed to furnish the water. There is, however, a tremendous quantity of water flowing into the Salt Lake valley each year. As a matter of fact the average fresh water discharge of the Bear, Weber and Jordan rivers and the surplus canals since 1917 amounts to 2,334,440 acre feet annually. This water flows directly into the Great Salt Lake where the evaporation factor is sufficient to keep the level of the lake within reasonable bounds. With this quantity of water available it seems then our prob lem would be to find the place where this water could be stored and put to profitable use. A glance at the map of Great Salt Lake shows that the eastern portion of the lake, which is relatively small and receives practically all of the fresh water now flowing into the valley, could be separated from the balance of the lake by supplementing the already partial barrier, which consists of Promontory Point, Fremont and Antelope Islands, by connecting these topographical features with a series of dykes, thereby impounding a runoff in an area about the size of Great Salt Lake. The dykes involved in this scheme would total 11.9 miles, there being 2.1 miles between Fremont Island and Promontory Point, 6i miles between Antelope Island and Fremont Island, and 21 miles between the mainland and the southern extremity of Ante-- : lope Island. It will be noted that Prom onitory Point, Fremont Island and Antelope Island line up in a rough way with the Oquirrh range of mountains and undonbtedly the spaces between the islands represent low passes in a buried mountain range. The proposed dikes should be built so that the top would be considerably above the level of the lake in order that they would not be destroyed by wave action during storms. The elevation of the surface of the lake on January 15, 1932 was 4,198 feet above sea level. During May, 1924, the elevation of the lake was 4,205 feet, or about eight feet above the present level. The lake was lower during 1904 1905, 1906 and 1907 than at present.. The lowest elevation of which we have altitude of the surface was 4,195.7 rxx,x x xxx x x a record occured during 1905 when the feet or 2.3 feet lower than the present level. About the only published information regarding the depth of the lake is a report of Captain Stansbury which was made in 1850. At that time the elevation of the lake was 4,201 feet above sea level, which is 3 feet higher than at present. Captain Stansbury's report states that the water from the mainland to the south end of Antelope Island varied from 1 to 8 feet in depth and that most of the way the water was very shallow. An average depth of five feet will probably be safe to use in estimating the amount of material necessary for a dike. According to the same report the depth of the lake from Antelope Island to Fremont Island was from 31 to 6 feet with a maximum of 12 feet. It would probably be safe to say the average depth of six feet for this dike. The lake from Fremont Island to Promontory Point has a maximum mile was depth of 6i feet and found to be from one to two feet deep. Five feet seems to be a safe figure to use for the average depth of this area, although I believe much deeper channels have been found, in which event they could be used very advantageously for spill ways. If we assume that a dike, the top being 17 feet above the elevation of 4,201 feet, 40 feet wide on top and a 1 slope on each side, using a safety factor of 5,459,110 cubic yards of earth and 1,349,207 yards of rip rap would be necessary. It might be well to con sider a dike somewhat higher than! this so that at least a year's supply of fresh water could be held back, allowing excessive evaporation of the western half of the lake, during which time a large supply of salt, etc., could be reclaimed in their crude state and. be refined while the excess water in the eastern half of the lake could be evaporated during the next season. Inj addition to the dikes, suitable spill, ways should be constructed at the points of extreme depth where the heavier mineral laden water could be flushed out as the fresh water seems to remain upon the top of the lake, some time before complete diffusion one-ha- lf one-fift- h 4-- 3, i j J 400,000 acre feet of lake water. The available water each year, when some additional is allowed for the flow from seepage, due to irriagtion, small springs, streams, etc., will be approximately about this same amount alBRI0H AM lowing for evaporation. It will be difficult to determine precisely the length of time that will be required to obtain fresh water due to the fact that we do not know how quickly the fresh water will be assimilated by the salt water, nor do we know what the sweeping action might be in carrying out undiluted salt water, but if we should assume that the additional water would carry of the salt, at the end of the seventh year the salt concentration should or 20 per cent, or approximatelV 0.15 per cent. The limit of ordinary chloride salts is .25 to 1 per cent, for sodium carbonate salts it will be .05 per cent The greatest concentration of alkali salt permissible under the most favorable conditions is about 0.3 to 0.4 per cent, consequently the waDIKE v ters from the proposed fresh water storage should be fresh enough for industrial, agricultural and domestic purposes within seven or eight years after the completion of the dikes. NFARMINGTON ANTELOPE The contamination of this water by sewage from the Salt Lake, Ogden and metropolitan areas can easily be prevented by one of two methods. First, septic or digesting tanks, second, by extending the pipe line containing the sewage to the western side of the dike. It is simply a matter of economy as to which method can be used. The question would be the proper way to finance a project of this kind. In as much as the revenue resulting would be problematical, a bond issue is out of the question as this would involve setting aside a certain sum each year for retiring the bonds in addition to paying the interest. There would probably be two sources of revSketch map of Great Salt Lake showing the proposed dykes. There are two proposals for dyking enuefirst, a royalty of some kind the lake. One is shown on the map as B, which would require the construction of dykes No. 3 and 4. paid for the use of the water, secondV. a 2 The other proposal provides for the construction of dykes No. 1, and 4, thereby making larger body if a road were constructed along of fresh yater. This would eliminate dyke No. 3. top of these dikes, some revenue could be collected from tourists and sighttakes place. degrees warmer than the fresh water ter reaching the lake each year from seers for the privilege of driving over the road. Antelope island would unirrigated land. Prof. Becking of the Hopkins Mar- - fan. We have found that by separating doubtedly be the site of amusement In addition to the water flowing inine Station Pacific Grove, Cal., gives In addition 4 the lake we can make available for resorts of various kinds. us some interesting information. Prof. to the lake there will be about acre feet of water due to preci- industrial purposes and irrigation of o furnishing fresh water for indusBecking states that at the mouth of Bear river, the fresh water flows out: pitation on the surface of the lake lands, lying adjacent to the lake at trial and irrigation purposes the fresh over the salt water in the lake in a east of the dike. The present water not too high an elevation, over 1,000,- water lake, which would be created, 000 water of acre feet would be the largest refuge for mi- -i annually. e shape, the fresh water layer evaporation is 4,667 feet per year, or One in of the in east gratory birds for great distances both in area the feet for acre thickness questions 1,303,230 important gradually decreasing some four miles south of the mouth of the dike. As the water becomes connection with this project is the north and south, and the federal govof the river. In November, 1928, fresh the evaporation factor will in- length of time required for the water ernment should be interested in this fresh water film was about four inch- crease until it reaches 5,653 feet, or to become fresh enough for use in the project from a biological standpoint, We have approximately 300 prison-- j es thick and flowing in a southerly an increase of nearly one foot. This area east of the dike. If we use the direction, while immediately below it, will further decrease the water avail- depths given in Stansbury's report ers in our state penitentary who have an 8 per cent brine unmixed with the able, leaving 1,034,282 acre feet avail- and assume the average depth for the nothing to do-- and whom we do not fresh water was flowing in the oppo- able for use. In addition to this there diked-of- f portion to be five feet, we site direction, the brine being a few is undoubtedly a large quantity of wa would then have impounded about 1,- (Please Turn to Page Four) lf How Engineers Would Put Great Salt Lake To Work one-ha- lf ' ffi00rr Ull) D X AyI. C 5MNDUS3))D ther i j j 279,-52- j i j fan-lik- j J I j I x xxx xx xiIax xxx xxx x isrx We Like Oui W SO WILL YOU IF YOU LET US DO YOUR PR N G WEAR WlWim VALLEY LEAMSL ? o |