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Hydrogeologic sub-basins in the Palouse area of Idaho and Washington Item Info

The study referred to as 'the Palouse area' encompasses approximately 408 square miles, and includes portions of northern Idaho and eastern Washington. The Palouse area relies almost entirely on ground water for its supply of municipal, domestic and institutional water. The majority of the ground water comes from two aquifers in the Miocene basalts of the Columbia River Basalt Group (CRBG) with associated interbedded gravel, sand, silt and clay. The upper aquifer is in the Priest Rapids Member of the Wanapum Formation and deeper aquifer is the Grande Ronde Formation. Decline in water levels in both aquifers has been the focus of considerable research into the hydrogeology of the system since the early 1970's. Ground water research has added tot eh general overall understanding of the region but no geologic or hydrogeologic model has adequately predicted or explained the system. Little geologic research has been conducted at scales less than 1:250,000. Previous investigations of rare outcrops along with sporadic detailed lithologic well data suggested that the basalt units are undeformed and nearly horizontal. Several isopach and structural contour maps were constructed for the basalt and sedimentary units. These maps indicate that the rock units are not horizontal and undeformed. A review of old and new geologic data supports the conclusion that the basalts are not horizontal, and that in places they are folded into narrow anticlinal ridges separated by wide sinclinal troughs. These structural features divide the Palouse area into at least two different sub-basins. Drainage pattern difference sin the Palouse area also suggest different sub-basins. In places, stream patterns can be related to structures identified on sub-surface maps and/or existing geologic maps. Selective hydrogeological data were re-interpreted, and can be related to these sub-basins. These data consist of: ground water pump tests, static ground water levels and hydrographs. The combination of the structural contour and isopach maps, geological trends, drainage patterns, and re-interpreted hydrogeological data strongly indicate that the Palouse area is subdivided into at least two ground water sub-basins with identifiable subsurface structural features.

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Title:
Hydrogeologic sub-basins in the Palouse area of Idaho and Washington
Authors:
Teasdale, Eddy W.
Date Created (ISO Standard):
2002-05
Description:
The study referred to as 'the Palouse area' encompasses approximately 408 square miles, and includes portions of northern Idaho and eastern Washington. The Palouse area relies almost entirely on ground water for its supply of municipal, domestic and institutional water. The majority of the ground water comes from two aquifers in the Miocene basalts of the Columbia River Basalt Group (CRBG) with associated interbedded gravel, sand, silt and clay. The upper aquifer is in the Priest Rapids Member of the Wanapum Formation and deeper aquifer is the Grande Ronde Formation. Decline in water levels in both aquifers has been the focus of considerable research into the hydrogeology of the system since the early 1970's. Ground water research has added tot eh general overall understanding of the region but no geologic or hydrogeologic model has adequately predicted or explained the system. Little geologic research has been conducted at scales less than 1:250,000. Previous investigations of rare outcrops along with sporadic detailed lithologic well data suggested that the basalt units are undeformed and nearly horizontal. Several isopach and structural contour maps were constructed for the basalt and sedimentary units. These maps indicate that the rock units are not horizontal and undeformed. A review of old and new geologic data supports the conclusion that the basalts are not horizontal, and that in places they are folded into narrow anticlinal ridges separated by wide sinclinal troughs. These structural features divide the Palouse area into at least two different sub-basins. Drainage pattern difference sin the Palouse area also suggest different sub-basins. In places, stream patterns can be related to structures identified on sub-surface maps and/or existing geologic maps. Selective hydrogeological data were re-interpreted, and can be related to these sub-basins. These data consist of: ground water pump tests, static ground water levels and hydrographs. The combination of the structural contour and isopach maps, geological trends, drainage patterns, and re-interpreted hydrogeological data strongly indicate that the Palouse area is subdivided into at least two ground water sub-basins with identifiable subsurface structural features.
Subjects:
groundwater aquifers hydrogeology
Location:
Palouse
Latitude:
46.88
Longitude:
-117.17
Collection:
Palouse Basin
Rights:
Rights to the digital resource are held by the University of Idaho. http://www.uidaho.edu/
Publisher:
University of Idaho
Contributing Institution:
University of Idaho
Type:
Text
Format:
application/pdf
Cataloger:
wbv
Date Digitized:
2012

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Source
Preferred Citation:
"Hydrogeologic sub-basins in the Palouse area of Idaho and Washington", Idaho Waters Digital Library, University of Idaho Library Digital Collections, https://www.lib.uidaho.edu/digital/iwdl/items/iwdl-2002_teasdale_hydrogeologic_subdivisions.html
Rights
Rights:
Rights to the digital resource are held by the University of Idaho. http://www.uidaho.edu/
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