Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
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Water-Resources Investigations Report↗
Geology topics
David W. Briar
Publications and source records attributed to David W. Briar.
Geologic history and hydrogeologic units of intermontane basins of the northern Rocky Mountains, Montana and Idaho
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.
Hydrologic Atlas↗
Ground-water levels in intermontane basins of the northern Rocky Mountains, Montana and Idaho
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 groundwater systems as they exist today, (2) analyze the known changes that have led to the systems 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 B of a three-part series and shows the general distribution of ground-water levels in basin-fill deposits in the study area. Chapter A (Tuck and others, 1996) describes the geologic history and generalized hydrogeologic units. Chapter C (Clark and Dutton, 1996) describes the quality of ground and surface waters in the study area. Ground-water levels shown in this report were measured primarily during summer 1991 and summer 1992; however, historical water levels were used for areas where more recent data could not be obtained. The information provided allows for the evaluation of general directions of ground-water flow, identification of recharge and discharge areas, and determination of hydraulic gradients within basin-fill deposits.
Hydrologic Atlas↗