| OCR Text |
Show OCCURRENCE OF UNDERGROUND WATER. 89 nonflowing wells. As shown by PL VII, this line lies close to the Jordan in the southern part of its course, but across the river from Murray takes a westward turn, and, following the base of the upland, extends to Great Salt Lake at the northern base of the Oquirrh Mountains. This line also roughly marks the boundary between shallow and deep ground water. In the lowland area ground water is abundant and generally lies within 10 feet of the surface, while on the upland water is generally scarce and is found only at a depth of over 50 feet. UPLAND AREA WEST OF JORDAN RIVER. In general the upland has the aspect of a rolling plain which gradually rises to the base of the mountains, but in detail the plain is varied by the presence of benches and escarpments, relics of Lake Bonneville and of a few drainage ways that have incised channels across the plain. Locally, especially at the northern end of the Oquirrh Mountains and at the Narrows, where Jordan River flows through the Traverse Mountains, the shore lines of Lake Bonneville are unusually well marked. Different stages of the lake's history are recorded by a series of distinct benches, which descend one below another from the Bonneville level; at Jordan Narrows, for instance, no less than ten periods of pause in the lake level are. thus recorded. Shore phenomena in general, however, are less prominently marked on the western margin of Jordan Valley than on the eastern, adjacent to the Wasatch Mountains. Bingham Creek is the only perennially flowing stream which runs for any considerable extent across the plain, though Butterfield Creek flows for a short distance after it emerges from the mountains southwest of the town of Herriman. This area is also traversed by a number of arroyos which contain water only for a few days after storms and during the time of rapidly melting snow. The Utah and Salt Lake and the South Jordan canals, carrying water from the upper part of Jordan River, extend along the eastern border of the upland and supply irrigation water to a narrow belt. Above the upper canal the area is desert and practically uninhabited, except for the town of Herriman and a few scattering ranches which obtain local supplies of water. The Utah Lake project of the Reclamation Service plans to make available for irrigation a belt from 2 to 4 miles wide west of the Utah and Salt Lake canal, but a large part of this upland area west of Jordan River has too great an elevation to be cheaply irrigated from Jordan River. Some amelioration of the present arid conditions may be effected by constructing reservoirs at the base of the mountains, but the collecting area is small and no very extensive additions to the water supply are likely to be derived from this source. More or less dry farming is already practiced here. The land is fertile, is practically free from alkali, and because of its location would be very valuable if an adequate supply of water could be obtained. Unfortunately, so far as known, underground water conditions afford little prospect of a large supply from that source, though valuable quantities can locally be recovered. This upland area is largely underlain by gravel and sand, and along the base of the mountains coarse gravel predominates. The material was derived from the disintegration of the adjacent highlands and mostly deposited offshore in the ancient lake. The constituents have been worked over and sorted during the different stages of the lake's history, both by wave action and by subaerial influences, so that the resulting material is heterogeneous both as to its composition and arrangement. Drills have recorded only to a very limited extent the nature of the deposits that underlie the surface. Judging from the records and from conditions elsewhere, it is probable that bed rock lies not far from the surface contiguous to the base of the mountains, and that at a distance from the highland bed rock lies at a considerable, though unknown, depth. Nearer the mountains the unconsolidated valley filling is doubtless of coarser texture than farther away, and it is likely that the materials are arranged lenticularly rather than in continuous beds. That portion of the slight precipitation on the low, small watershed of the Oquirrh and Traverse mountains that is not evaporated or does not join the permanent run- off is absorbed by the porous deposits. Under the influence of gravity the water |
