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Geologic history and hydrogeologic units of intermontane basins of the northern Rocky Mountains, Montana and Idaho

Hydrologic Atlas 738-A

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Abstract

The Regional Aquifer-System Analysis (RASA) program is a series of studies by the U.S. Geological Survey (USGS) to analyze regional ground-water systems that compose a major portion of the Nation’s water supply (Sun, 1986). The Northern Rocky Mountains Intermontane Basins is one of the study regions in this national program. The main objectives of the RASA studies are to: (1) describe the ground-water systems as they exist today, (2) analyze the known changes that have led to the system's present condition, (3) combine results of previous studies in a regional analysis, where possible, and (4) provide means by which effects of future ground-water development can be estimated.
The purpose of this study, which began in 1990, was to increase understanding of the hydrogeology of the intermontane basins of the Northern Rocky Mountains area. This report is Chapter Cofa three-part series and describes the quality of ground-water and surface water in the study area. Chapter A (Tück and others, 1996) describes the geologic history and generalized hydrogeologic units. Chapter B (Briar and others, 1996) describes the general distribution of ground-watcrlcwels in basin-fill deposits,
Water-quality data illustrated in this report represent the distribution of concentrations and composition of dissolved solids in ground-water and surface water in the intermontane areas. The chemistry of ground and surface water in the intermontane areas is influenced by the chemical and physical nature of the rocks in the basin deposits of the valleys and surrounding bedrock in the mountains.

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Additional publication details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Geologic history and hydrogeologic units of intermontane basins of the northern Rocky Mountains, Montana and Idaho
Series title:
Hydrologic Atlas
Series number:
738
Chapter:
A
ISBN:
0607861428
Edition:
-
Year Published:
1996
Language:
ENGLISH
Description:
1 map :col. ;86 x 64 cm., on sheet 109 x 94 cm., folded in envelope 30 x 24 cm. +1 data sheet (76 x 101 cm.)
Scale:
750000
Online Only (Y/N):
N
Additional Online Files (Y/N):
N