Geology topics

L. W. Lenfest

Publications and source records attributed to L. W. Lenfest.

3 recordsLinked to original sources

USGS1987

Evapotranspiration rates at selected sites in the Powder River basin, Wyoming and Montana

Twelve sites were chosen for a study of evapotranspiration in the Powder River basin based on variations in topography and plant communities, geographic location, and the availability of groundwater data at the sites. Evapotranspiration rates were estimated from groundwater, meteorological, and vegetation data using the Blaney-Criddle method. Five of the sites were equipped with digital recorders that provided continuous groundwater level data at the sites for the 1978 growing season. Evapotranspiration was estimated monthly during the growing season and ranged from 0 to 3.7 inches per month. Total evapotranspiration rates for the growing season ranged from 8.3 to 14.9 inches. Discharge per mile of stream reach was estimated for three of the sites and ranged from 0.03 to 0.31 cubic foot per second. The well records for the remaining seven sites consisted of monthly, or less frequent, water-level measurements. Evapotranspiration rates estimated for those months for which water-level data were available ranged from 0 to 3.8 inches per month. Only one of these sites had monthly water-level measurements for the entire growing season; a total of 9.7 inches of evapotranspiration was estimated for the growing season at this site. (USGS)

Water-Resources Investigations Report↗

USGS1987

Recharge of shallow aquifers through two ephemeral-stream channels in northeastern Wyoming, 1982-83

Quantifying the recharge from ephemeral streams to alluvial and bedrock aquifers will help evaluate the effects of surface mining on alluvial valley floors in Wyoming. Two stream reaches were chosen for study in the Powder River basin. One reach was located along the North Fork Dry Fork Cheyenne River near Glenrock, Wyoming, and the other reach was located along Black Thunder Creek near Hampshire, Wyoming. The reach along the North Fork Dry Fork Cheyenne River was instrumented with 3 gaging stations to measure streamflow and with 6 observation wells to measure groundwater level fluctuations in alluvial and bedrock aquifers in response to streamflow. The 3 streamflow gaging stations were located within the 2.5-mi study reach to measure the approximate gain or loss of discharge along the reach. Computed streamflow losses ranged from 0.43 acre-ft/mi on July 9 , 1982, to 1.44 acre-ft/mi on August 9, 1982. The observation wells completed only in the alluvial aquifer were dry during flow in the North Fork Dry Fork Cheyenne River, whereas water levels in half of the observation wells completed in the bedrock aquifers or the alluvial and bedrock aquifers rose in response to flow in the North Fork Dry Fork Cheyenne River. Groundwater recharge on August 9, 1982, was calculated using a convolution technique using groundwater levels at the upstream site and was estimated to be 26.5 acre-ft/mi. The reach along Black Thunder Creek was instrumented with one gaging station to measure streamflow and with 4 observation wells to measure water level response in alluvial and bedrock aquifers to streamflow. Recharge to the alluvial aquifer from flow in Black Thunder Creek ranged from 3.56 to 12.4 acre-ft/mi. The recharge was estimated using the convolution technique using water level measurements in the observation wells completed in the alluvial aquifer. Water level measurements in the observation wells indicated water level rises in the alluvial and bedrock aquifers in response to flow in Black Thunder Creek.

Wyoming↗

USGS1986

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)

Water-Resources Investigations Report↗