Ground-water investigations in the lower Cache la Poudre River basin, Colorado

Content Provider	Semantic Scholar
Author	Hershey, Lloyd A. Schneider, Paul Allen
Copyright Year	1964
Abstract	Ground water is a major natural resource in the lower Cache la Poudre River basin. During periods of low precipitation and short surface-water supply, supplemental irrigation water from ground-water sources provides the needed moisture to sustain crops in this predominantly agricultural area. The lower Cache la Poudre River basin lies in northwestern Weld and northeastern Larimer Counties, Colo., and contains abdut 800 square miles of irrigated, dry-farmed, and grazing land. Alluvial deposits overlying rocks of Late Cretaceous age constitute the principal aquifers in the area. Yield from the alluvium ranges from a few gallons to 2,000 gallons per minute. Because of the availability of surface water, ground water is used principally as a supplemental irrigation supply. During periods of low surface-water supply, heavy pumping of wells substantially lowers the water table in parts of the area, but the ground-water reservoir recovers after normal precipitation has resumed. Principal sources of recharge to the aquifers are seepage from ditches and storage reservoirs, downward percolation of applied surface water, and precipitation. About 86,000 acre-feet of ground water was pumped for irrigation in the lower Cache la Poudre River basin in 1959; an average of 78 acre-feet per well was applied to irrigation during the same year. The chemical quality of ground water used for irrigation in the lower Cache la Poudre River basin has been evaluated from the analyses of 88 water samples collected during the study. Dissolved-solids content is the principal factor of evaluation for these samples. High concentrations of calcium and sulfate cause some of the water to be undesirable for irrigation use under average soil and drainage conditions. Good soil and drainage conditions and the use of surfacewater reduce the hazard of applying the locally highly mineralized water to crops. INTRODUCTION Ground water is a major natural resource and the principal source of supplementary irrigation water in the lower Cache la Poudre Eiver basin, especially during periods of low precipitation and short surXI X2 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES face-water supply. Ground water has also been developed for stock and domestic supplies from alluvial and bedrock aquifers. The principal source of ground water for irrigation is the alluvium of the flood plain and the terrace deposits of the Cache la Poudre River and its tributaries. Water supply for agriculture in the project area is largely dependent on surface water. Surface water is distributed to the area by more than 30 maj or canal systems and from about 75 storage reservoirs. The canals divert water from the Cache la Poudre Eiver northwest of Fort Collins, Colo., and from various points along the stream valley. Irrigation supplies are drawn directly from the diversion canals as needed, and some of the water is diverted to storage reservoirs. LOCATION AND EXTENT OF THE AREA The lower Cache la Poudre Eiver basin, as defined in this report, is an area of about 800 square miles and includes parts of northwestern Weld and northeastern Larimer Counties, Colo. (fig. 1). Most of the area lies north of the lower Cache la Poudre River between Laporte, Colo., and the junction of the Cache la Poudre River with the South Platte River east of Greeley, Colo. PURPOSE AND SCOPE OF THE INVESTIGATION This investigation is one of a series of studies being made by the U.S. Geological Survey for the U.S. Bureau of Reclamation as a part of the program of the Department of the Interior for the development of the Missouri River basin. Ground water has been extensively developed for irrigation in the lower Cache la Poudre River valley during the past 30 years. This study is to evaluate the present state of development and to determine hydrologic relationships within the project area. In addition, the chemical quality of the ground water is evaluated in terms of its suitability for crop irrigation. This report presents preliminary data on the relative availability of ground water, the extent of present development, the chemical quality of water, the hydrologic relationships, and the critically overdeveloped areas. Ground-water investigations in Colorado are under the direct supervision of E. A. Moulder, district engineer for Colorado. The qualityof-water investigations are under the direction of D. M. Culbertson, district engineer in charge of quality-of-water studies in the Missouri River basin. GROUND WATER, CACHE LA POUDRE RIVER BASIN, COLO.
File Format	PDF HTM / HTML
DOI	10.3133/wsp1669X
Alternate Webpage(s)	https://pubs.usgs.gov/wsp/1669x/report.pdf
Alternate Webpage(s)	https://doi.org/10.3133/wsp1669X
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article