Geology topics

L.K. Wenzel

Publications and source records attributed to L.K. Wenzel.

11 recordsLinked to original sources

USGS2014

Recent investigations of Thiem's method for determining permeability of water‐bearing materials

This paper presents results obtained in an investigation of the ground-water resources of the Platte River Valley that is being conducted in cooperation between the Conservation and Survey Department of the University of Nebraska and the United States Geological Survey. Most quantitative ground-water studies are concerned with the amount of water that percolates into the discharge-area of an investigated region from the recharge-area in order to determine the amount of water that can be safely withdrawn from the discharge-area without an excessive lowering of the ground-water level. D'Arcy found that the quantity of water discharged through a column of water-bearing material was proportional t o the hydraulic gradient, the cross-sectional area, and a constant which depends upon the material. If these three factors are known, the discharge through any cross section of a water-bearing formation may be computed.

Eos, Transactions, American Geophysical Union↗

USGS2014

Specific yield determined from a Thiem's Pumping‐Test

The specific yield of a water-bearing formation is defined as the ratio of (1) the volume of water, which after being saturated, it will yield by gravity to (2) its own volume (O. E. Meinzer, Outline of ground-water hydrology, U.S. Geol. Sur. Water-Supply Paper 494, p. 28, 1923). It is a measure of the quantity of water that a formation will yield when it is drained by lowering of the water-table. The determination of the specific yield is essential in many quantitative ground-water investigations. In 1931 a pumping-test was made in the Platte River Valley, in Nebraska, to determine by Thiem's method the permeability of the water-bearing sand and gravel that underlie the Valley. This test, which constitutes a part of a cooperative investigation by the Conservation and Survey Department of the University of Nebraska and the United States Geological Survey, was briefly described in the 1932 Transactions of the American Geophysical Union (p. 393). The well was pumped continuously for 48 hours, and measurements of the discharge were made every 30 minutes. During the period of pumping and after pumping stopped about 5,000 measurements were made of the depths to the water-surfaces in 80 observation-wells, which were located on lines radiating from the pumped well to distances up to 1,200 feet. Instrumental levels were run to the measuring points on each of the wells so that the altitudes of the water-surfaces could be determined for any time. From the data obtained in this test the average coefficient of permeability was computed to be about 700. In the present paper a method is presented for determining the specific yield of the water-bearing material from the data collected in this test, and the results of the computations are given. This method for determining specific yield was suggested by Meinzer (O. E. Meinzer, Outline of methods for estimating ground-water supplies, U.S. Geol. Sur. water-Supply Paper 638-c, p. 136, 1932).

Eos, Transactions, American Geophysical Union↗

USGS2014

A state‐wide program of periodic measurements of ground‐water level In Nebraska

The precipitation in Nebraska has been considerably less than normal in the last four years, and in consequence the ground ‐ water level in many parts of the State has declined to a marked extent. Moreover, in some parts of Nebraska the ground ‐ water level has declined as the result of land‐drainage, and in other parts it has risen as the result of irrigation with water diverted from streams. These changes in ground ‐ water level produced by drainage, irrigation, and decreased precipitation have caused wells to fail, streams to cease flowing, lakes to become dry, and land to become water ‐logged. Consequently, interest in fluctuations of ground ‐ water level has greatly increased, and the need of a systematic collection of base‐data for the future study of ground ‐ water problems has been recognized.

Nebraska↗

USGS1946