Award Date

8-1996

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Geoscience

Number of Pages

212

Abstract

This investigation was conducted to determine the location, nature, and boundaries of the most permeable unit within the alluvial aquifer material in Las Vegas Valley. It was prompted by declines in specific capacity of about 90% at the Las Vegas Valley Water District's West Central Well Field. It was hypothesized that the decline in specific capacity resulted from dewatering of the most permeable interval of the alluvium. Lithologic descriptions from wells and aquifer test information were analyzed for geologic and hydrogeologic variability. New information, in the form of detailed unpublished lithologic and hydrologic information, was available from twenty water wells drilled between 1989 and 1994.

The geology was defined using allostratigraphic units.

Aquifer test and lithologic information was used to define the boundaries of units of differing permeability within the subsurface. These units of differing permeability are the six (6) hydrostratigraphic units introduced in this investigation. The most permeable hydrostratigraphic unit is a distinct 20 to 90 m thick horizon, lying generally above 230 m below land surface. When the production wells were first installed at the West Central Well Field in the 1960's, most of the permeable unit was saturated. In 1993 the potentiometric surface was at or below the bottom of this hydrostratigraphic unit.

Keywords

Alluvium; Aquifers; Nevada – Las Vegas Valley; Sediments (Geology) — Permeability

Disciplines

Geology | Hydrology | Sedimentology | Stratigraphy

Language

English

Comments

Incomplete paper data.


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