Geology topics

E. A. Zimmerman

Publications and source records attributed to E. A. Zimmerman.

3 recordsLinked to original sources

USGS1982

A plan for hydrologic investigations of in situ, oil-shale retorting near Rock Springs, Wyoming

The recovery of shale oil by the in-situ retort process may cause hydrologic impacts, the most significant being ground-water contamination and possible transport of contaminants into surrounding areas. Although these impacts are site-specific, many of the techniques used to investigate each retort operation commonly will be the same. The U.S. Geological Survey has begun a study of hydrologic impacts in the area of an in-situ retort near Rock Springs, Wyoming, as a means of refining and demonstrating these techniques. Geological investigations include determining the areal extent and thickness of aquifers. Emphasis will be placed on determining lithologic variations from geophysical logging. Hydrologic investigations include mapping of potentiometric surfaces, determining rates of ground-water discharge, and estimating aquifer properties by analytical techniques. Water-quality investigations include monitoring solute migration from the retort site and evaluating sampling techniques by standard statistical procedures. A ground-water-flow and solute-transport model will be developed to predict future movement of the water plume away from the retort. (USGS)

Open-File Report↗

USGS1982

Hydrology of Salt Wells Creek — A plains stream in southwestern Wyoming

Development of energy minerals in plains areas of Wyoming is expanding rapidly. Such development may affect water resources and hydrologic relations of the plains; however, little information exists concerning hydrologic processes for these areas. This report summarizes results of a hydrologic study made during 1975-78 of Salt Wells creek, a drainage area of about 500 square miles located southeast of Rock Springs, Wyoming. The area is typical of arid and semiarid plains areas in southwestern Wyoming where mineral development is occurring. Salt Wells Creek is predominately an intermittent stream. Numerous springs in the headwaters cause small perennial flows in some upstream tributaries, but evaporation, freezeup, and seepage deplete these flows so that the middle and lower reaches of the main channel have only intermittent flows. The intermittent nature of streamflow affects water quality. It was observed that a flushing of dissolved solids and suspended sediment occurs during the first flows of a runoff event. A striking feature of the stream is its deeply incised channel. The downcutting is attributed to the cummulative effects of: (1) a change in the relative climate, amounts of annual precipitation occurring as rain and snow, (2) change in base level due to downstream channelization, and (3) changes in land use. Because of the incision, erosion is now expanding to include intervening tributaries.

Wyoming↗

USGS1977

Ground-water resources and geology of Colquitt County, Georgia

Limestone beds of Eocene, Oligocene, and lower Miocene age, called the principal artesian aquifer, are the chief source of ground water for Colquitt County. Because streams are small, undependable and relatively inaccessible to most users, ground water is the most important source for increased industrial and agricultural water use. Southeast of Moultrie the principal artesian aquifer is very productive, and has transmissivity in excess of 145,000 feet squared per day (13,500 meters squared per day). A structural or paleogeographic feature called the Suwannee strait traverses the county from near the southwest corner to the northeast corner. In this strait, limestone in the principal artesian aquifer is partly replaced by fine-grained clastic sediment, impairing transmissivity and making wells hard to construct. Transmissivity is much lower northwest of the strait than it is southeast, probably because of facies changes in the aquifer. In the belt of the hypothesized Ochlockonee fault, water containing greater-than-usual concentrations of dissolved solids is produced. This anomaly could be the result of the fault having acted as a conduit when the vertical hydraulic gradient was upward from a deeper aquifer, or be the result of the movement of ground water from a sulfate-rich source in the sediments of the Suwannee strait. In south-central Colquitt County, clay-capped permeable beds extending above potentiometric surfaces create conditions favorable for breathing wells. Predominantly clastic beds of Miocene age overlie the Suwannee Limestone. These beds have a transmissivity of about 2,280 feet squared per day (215 meters squared per day), but they are of comparatively little importance because larger yields can be obtained from the underlying principal artesian aquifer. Moreover, wells are difficult to construct in the poorly consolidated clastic sediments, and water from these shallow beds is likely to be depleted during droughts. The ground water is generally hard, but is otherwise of good quality. One exception is near the hypothesized Ochlockonee fault where water contains higher-than-usual concentrations of various ions, especially sulfate. Another exception occurs along the axis of the Suwannee strait where clay minerals in the channel facies may soften the water by ion exchange.

Georgia↗