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E.H. Walker

Publications and source records attributed to E.H. Walker.

5 recordsLinked to original sources
USGS1976

Fresh ground water found deep beneath Nantucket Island, Masachusetts

In a deep water-resources and stratigraphic test well near the center of Nantucket Island, about 30 miles (48 kilometres) off the New England coast, freshwater has been found at greater depths than predicted by the Ghyben-Herzberg principle. An uppermost lens of freshwater, which occupies relatively permeable glacial-outwash sand and gravel to a depth of 520 feet (158 metres), is believed to be in hydrodynamic equilibrium with the present level of the sea and the height of the water table. However, two zones of freshwater at 730 to 820 ft (222-249 m) and 900 to 930 ft (274-283 m) are anomalously deep. Although several explanations are possible, the most likely is that the entire surface of the Continental Shelf was exposed to recharge by precipitation during long periods of low sea level in Pleistocene time. After the last retreat of glacial ice, seawater rapidly drowned the shelf around Nantucket Island. Since then, about 8,000 years ago, the deep freshwater zones which underlie dense clay layers have not had time to adjust to a new equilibrium. Under similar circumstances, freshwater may remain trapped under extensive areas of the Continental Shelf wherever clay confining beds have not permitted saltwater to intrude rapidly to new hydrodynamic equilibria positions. The implications are far reaching because all continental shelves worldwide were exposed to similar hydrologic influences during Pleistocene time.

Massachusetts↗
USGS1970

The Raft River Basin, Idaho-Utah as of 1966: A reappraisal of the water resources and effects of ground-water development

The Raft River basin, mostly in south-central Idaho and partly in Utah, is a drainage basin of approximately 1,510 square miles. Much arable land in the basin lacks water for irrigation, and the potentially irrigable acreage far exceeds the amount that could be irrigated with the 140,000 acre-feet estimated annual water yield. Therefore, the amount of uncommitted water that could be intercepted and used within the basin is the limiting factor in further development of agriculture irrigated with water derived from within the basin; Water for additional irrigation might be obtained by pumping more ground water, but only if large additional ground-water storage depletion can be tolerated. Alternatively, supplemental water might be imported.

Idaho, Utah↗
USGS1967

Ground-water aspects of the lower Henrys Fork region, Idaho

The lower Henrys Fork region includes the plains and low benches between Ashton and the junction of Henrys Fork and Snake River in eastern Idaho. The northwestern and western parts of the area are part of the Snake River lava plain. The central part of the area is occupied by alluvial plains of the Snake, Teton, and Falls Rivers, and Henrys Fork. The southeastern part of the area is a bench (Rexburg Bench), chiefly on silicic and basaltic volcanic rocks, which rises gradually to mountain peaks southeast of the area. The basalt, and the sand and gravel under the alluvial plains are good aquifers and yield large amounts of water with small drawdowns. The silicic volcanic rocks and the interbedded ash, pyroclastics, and sedimentary deposits generally yield much less water than the basalt and alluvium. The regional water table slopes southward beneath the basalt and alluvial plains. Seepage from stream channels and irrigated tracts has resulted in an extensive body of ground water perched above the regional water table. The perched water in part moves vertically down to the regional water table and in part laterally to the streams. Ground water beneath the Rexburg Bench moves generally northwestward to join the regional ground-water body beneath the alluvial plain. The regional water table is below the level of the streams in the area and ground water in the main aquifer, therefore is not tributary to the streams. Recharge to the regional water table is estimated to average 725,000 acre-feet annually. Pumping from the regional ground-water reservoir for irrigation or other uses would have no effect on streamflow or surface-water rights within the study area. However, depletion of the underflow would eventually reduce the inflow to American Falls Reservoir unless the depletion was offset by additional recharge. Total withdrawals of ground water for irrigation in 1962 were estimated to be 25,000 acre-feet and caused no significant decline in the water table. In the Ashton area surface-water irrigation has cause water to be perched in basalt above the silicic volcanic rocks and much of this perched water contributed to streamflow. The flow of Henrys Fork would be decreased by the amount of pumped ground water consumed by crops. Ground-water prospects for irrigation in the Falls River area are not encouraging.

Idaho↗