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Geohydrology and numerical model analysis of ground-water flow in the Pullman-Moscow area, Washington and Idaho. U.S. Geological Survey Water-resources investigations report 89-4103 Item Info

The Pullman-Moscow area of southeastern Wash ton and northern Idaho depends on ground water as the principal source of water, but increasing pumpage rates and declining ground-water levels indicate a need for ground-water management. Using data from a study done by the U.S. Geological Survey in the 1970's and up-to-date data collected for this study, a three-dimensional numerical computer model of the ground-water-flow system was constructed to provide an understanding of the geohydrology of the study area. The ground-water-flow model incorporates three layers -- an overlying surficial loess layer, a Wanapum Basalt layer, and a Grande Ronde Basalt layer. A ground-water-system recharge rate was estimated using a methodology developed by the U.S. Geological Survey. Ground-water discharge was modeled as ground-water pumping, flow to rivers and streams, and flow out of seepage faces, where a layer is incised by a river valley. Three cross-sectional flow models, distributed across the domain of the three-dimensional model along estimated flow lines in the Grande Ronde Basalt, were used to obtain hydraulic coefficient input for the three-dimensional model. The three-dimensional model was calibrated using the time-averaged method for the period 1974-85, and was evaluated by simulating historical pumpage rate changes (1890-1985) and comparing simulated with observed water-level changes. Model results suggest that ground-water levels would stop declining if ground-water pumpage were to stabilize at a constant level. However, ground-water levels will continue to decline in the foreseeable future as long as ground-water pumpage continues to increase. Further study of the recharge, movement, and discharge of ground water in the area is needed to increase the accuracy of any ground-water-flow model to predict the response of the flow system to future pumping stresses.

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Title:
Geohydrology and numerical model analysis of ground-water flow in the Pullman-Moscow area, Washington and Idaho. U.S. Geological Survey Water-resources investigations report 89-4103
Authors:
Lum, W. E. II; Smoot, J. L.; Ralston, D. R.
Date Created (ISO Standard):
1990
Description:
The Pullman-Moscow area of southeastern Wash ton and northern Idaho depends on ground water as the principal source of water, but increasing pumpage rates and declining ground-water levels indicate a need for ground-water management. Using data from a study done by the U.S. Geological Survey in the 1970's and up-to-date data collected for this study, a three-dimensional numerical computer model of the ground-water-flow system was constructed to provide an understanding of the geohydrology of the study area. The ground-water-flow model incorporates three layers -- an overlying surficial loess layer, a Wanapum Basalt layer, and a Grande Ronde Basalt layer. A ground-water-system recharge rate was estimated using a methodology developed by the U.S. Geological Survey. Ground-water discharge was modeled as ground-water pumping, flow to rivers and streams, and flow out of seepage faces, where a layer is incised by a river valley. Three cross-sectional flow models, distributed across the domain of the three-dimensional model along estimated flow lines in the Grande Ronde Basalt, were used to obtain hydraulic coefficient input for the three-dimensional model. The three-dimensional model was calibrated using the time-averaged method for the period 1974-85, and was evaluated by simulating historical pumpage rate changes (1890-1985) and comparing simulated with observed water-level changes. Model results suggest that ground-water levels would stop declining if ground-water pumpage were to stabilize at a constant level. However, ground-water levels will continue to decline in the foreseeable future as long as ground-water pumpage continues to increase. Further study of the recharge, movement, and discharge of ground water in the area is needed to increase the accuracy of any ground-water-flow model to predict the response of the flow system to future pumping stresses.
Subjects:
Groundwater Groundwater development Confined aquifers Unconfined aquifers Water supply Computer models
Location:
Pullman; Moscow; Northern Idaho
Latitude:
46.74
Longitude:
-117.17
Collection:
Palouse Basin
IWRRI number:
199004
Rights:
In copyright, educational use permitted. Educational use includes non-commercial reproduction of text and images in materials for teaching and research purposes. For other contexts beyond fair use, including digital reproduction, please contact the University of Idaho Library Special Collections and Archives Department at libspec@uidaho.edu. The University of Idaho Library is not liable for any violations of the law by users.
Publisher:
Idaho Water Resources Research Institute; University of Idaho
Contributing Institution:
University of Idaho
Type:
Text
Format:
application/pdf
Cataloger:
KIT
Date Digitized:
2017-09-12

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Preferred Citation:
"Geohydrology and numerical model analysis of ground-water flow in the Pullman-Moscow area, Washington and Idaho. U.S. Geological Survey Water-resources investigations report 89-4103", Idaho Waters Digital Library, University of Idaho Library Digital Collections, https://www.lib.uidaho.edu/digital/iwdl/items/iwdl-199004.html
Rights
Rights:
In copyright, educational use permitted. Educational use includes non-commercial reproduction of text and images in materials for teaching and research purposes. For other contexts beyond fair use, including digital reproduction, please contact the University of Idaho Library Special Collections and Archives Department at libspec@uidaho.edu. The University of Idaho Library is not liable for any violations of the law by users.
Standardized Rights:
http://rightsstatements.org/vocab/InC-EDU/1.0/
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