Ground-water levels and use of water for irrigation in the Saratoga Valley, south-central Wyoming, 1980-81

Although surface water is the principal source of irrigation water in the Saratoga Valley, Wyoming, development of groundwater for irrigation is increasing. Most of the 30 irrigation wells in the valley are capable of producing more than 200 gallons per minute. Approximately 2,700 acre-feet of groundwater for irrigation were pumped from the shallow aquifer during 1980 and 4,200 acre-feet during 1981. The shallow aquifer , the subject of this study, consists of the North Park Formation and a lower sandstone unit of late Tertiary (Miocene) age and deposits of Quaternary age along the North Platte River. During 1980, water levels were measured in about 140 wells, 41 of which had been measured prior to 1969. The 1980 water levels were within 5 feet of the pre-1969 water levels. During 1980-81, 21 of the wells were used as observation wells. A water-level contour map of the study area was prepared by the Kriging statistical procedure water surface altitudes for 235 groundwater and stream locations. The map indicates that the direction of groundwater flow is from the borders of the study area toward the North Platte River and north-westerly (downstream) parallel to the river. (USGS)