Previous investigations-________________________________________ 2 Methods of investigation.______________________________________ 4 Personnel arid acknowledgments_____-___________-__-__-_-_-___-5 System used in numbering wells and test holes____________________ 6 Geography______________________________________________________ 6 Climate._____________________________________________________ 6 Soils-______________________________________ 7 Natural vegation______________________________________________ 9 Geology._________________________________________________________ 9 Physical and hydrologic properties of the rock materials._______________ Laboratory methods of analysis____________-_____________-___-_-Permeability _ _______________________________________________ Characteristics of the surficial sediments________________________ Characteristics of the water-bearing materials _________________________ Transmissibility _ _ _____________________________________________ Specific yield________________________________________________ Ground water _____________________________________________________ Principles of occurrence________________________________________ Fluctuations of the water table________________________________ Fluctuations caused by precipitation_________________________ Fluctuations caused by evapotranspiration__________________ Fluctuations caused by the Platte River_____-_____-_-_-_ Relation of fluctuations to recharge and discharge.____________ Rate and direction of movement of ground water ________________ Depth to water_____________________________________________ Groundwater discharge___-_________________-_-_____-_-_-_-_-Wells. ____________________________________ Domestic supplies.____________________________________ Irrigation supplies-____________________________________ Transpiration and evaporation_____________________-_-___-Chemical quality of the water, by P. G. Rosene___________-__-Chemical composition of the water____________________________ 28 Water quality in relation to use_________________________________ 33 Conclusions______________________________________________________ Selected references_________________________________________________ 55 ni Page TABLE 1. Coefficient of permeability of water-bearing materials from test hole 12-8-27dd, Merrick County.___________________ E16 2. Coefficient of permeability of water-bearing materials from test hole 11-8-ldd, Hamilton County_________________ 17 3. Chemical analyses of ground water._______________________ 4. Chemical analyses of surface waters-______________________ 5. Chemical and physical data for Wood River near Chapman. _ 6. Periodic water-level measurements in selected wells in the Chapman area, Nebraska.______________________________ 7. Logs of test holes_-_-___________________________________ 8. Logs of auger holes__-____-______________________________ 9. Coefficient of permeability of water-bearing materials from auger holes in the Chapman area______________________ 10.

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Hamilton County includes an area of about 538 square miles and in 1960 had a population of 8,665. The general physiography of the county is that of an almost level eastward-sloping depositional plain, the original surface of which has been slightly modified by stream erosion and wind action. The West Fork of the Big Blue River is the only perennial stream in the county. Ephemeral streams, which flow only during and after heavy rains, are the Big Blue River, Lincoln Creek, and Beaver Creek. The Platte River, which forms the northwest boundary of the county, flows during the winter months but usually is dry during the summer. The climate is subhumid, the normal annual precipitation being about 24 inches. Agriculture is the principal industry in the county; corn is the most important crop. More than 113,000 acres was irrigated with water pumped from 1,196 wells in 1957. Hamilton County is in the southeastern part of the loess-plains region of Nebraska, just west of the glaciated region. Sand and gravel, and associated silt and clay deposits of Quaternary age, mantle the area. The parts of these deposits that are below the water table are saturated and yield large quantities of water to wells. The deposits of Quaternary age rest on an eroded bedrock surface of rocks of Cretaceous age, except in one small area in the southwestern part of the county where they rest on a remnant of deposits of Tertiary age. The deposits of Tertiary age are partly consolidated fine-textured sand, silt, and clay. These deposits are saturated and may yield water to some wells. The rocks of Cretaceous age have little significance as potential source of ground water in Hamilton County. The water that is available to wells in the county is derived principally from precipitation; the recharge through the soil is believed to average about 40,000 acre-feet per year. Some recharge is also obtained from the Platte River when it is in flood stage, but the amount thus received is relatively small compared to that received from precipitation. The use of ground water for irrigation has increased greatly since 1952, and analyses of the hydrologic data indicate that the groundwater discharge exceeds the recharge. The natural recharge is about equal to the amount of water required to irrigate one-ninth of the land. Development in 1957 had reached the point where almost one-third of the land in the county was being irrigated with ground water. N-l N-2 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES The ground water is generally of relatively low mineralization and in most of the county is of the calcium bicarbonate type. Near the north and west borders of the county, the relatively high mineralization and high concentrations of sulfate in the ground water probably are due in part to recharge from the Platte River. The continued lowering of the water table may cause the more mineralized water in the western part of the county to move into the areas where the water is now the least mineralized. The water is suitable for irrigation, domestic, and many in...

The Cedar Rapids Division of the lower Platte Kiver basin, an area proposed for irrigation development by the U.S. Bureau of Keclamation, is largely in the drainage basin of the Cedar Kiver, a tributary of the Loup Kiver, but also includes a part of the drainage basin on the north side of the Loup River between the mouths of Cedar River and Beaver Creek. The area includes, in downstream order, parts of Wheeler, Greeley, Boone, and Nance Counties. The investigation covered an area that was formerly a nearly level to rolling plain but in which minor relief has been produced by stream erosion and wind action. The upper fifth of the area is in the Sand Hills region of Nebraska, and the lower four-fifths is in the Loess Plains region. Semiconsolidated deposits of Pleistocene age underlie the dune sand and loess. These deposits range from fine-textured sand, silt, and clay to coarse-textured sand and gravel. The parts of the semiconsolidated deposits that are below the water table yield water to wells. Ground water in these deposits is discharged naturally along the courses of the principal streams. In three localities the upper part of the Cedar Rapids Division, the vicinity of the north boundary of Nance County, and the lower part of the Division only small amounts of water can be obtained from wells. At other places, wells will yield as much as 200 gallons per minute; and in a few localities as much as 1,800 gallons per minute. Irrigation wells have been installed in those areas where yields of 200 gallons per minute or more can be obtained. Ninety-four irrigation wells irrigated about 8,000 acres in 1960. The ground water is generally of low mineralization and is of the calcium bicarbonate type. It is suitable for irrigation, domestic use, and many industrial uses.