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High-resolution seismic reflection profiling and modeling of hydrogeologic system, Goddard2 Well, northwest Boise, Idaho. Technical Report BSDU CGISS 05-17; IWRRI Grant 684-K102 Item Info

The western Snake River Plain is filled, in its upper part, with sediments deposited in a variety of lacustrine and associated subaerial environments. This study examines the usefulness of high-resolution seismic reflection profiling for identifying sedimentary environments and geologic structures in the western Snake River Plain at depths that have significance for hydrologic behavior at individual wells and for the ground-water flow system in general. In addition, this study applies a discretization scheme in MODFLOW developed to accurately model single-well pumping tests which are common, by design or default, in the lower Boise River valley. A study area was chosen in northwest Boise where only the pumping well (Goddard2 well) responded during an 8-hr. test and the well exhibited negative boundary effects, and where available subsurface data from wells were not sufficient to develop a conceptual model for analysis of the Goddard2 well. [...] Engineering analysis of pumping test data by Mills (1991) identified negative boundary effects and provides a first approximation for hydraulic conductivity of the aquifer pumped by the Goddard2 well. However, a non-leaky aquifer model does not closely match observed behavior. A conceptual model for the pumping test that is consistent with well and seismic data is partially penetrating well in a sand stringer aquifer (in a floodplain environment) receiving leakage from fine-grained surrounding sediments and truncated by a fault (no-flow boundary). This conceptual model was used to simulate the Goddard2 pumping test with a discretization scheme in MODFLOW which accurately reproduces drawdown behavior at a pumping (or injection) well under non-radially symmetric flow scenarios. Results are not unique but provide a framework for evaluating elements that are significant in local and regional ground-water flow, and provide a conceptual model to be tested and iteratively improved with new data and with future aquifer testing opportunities in the area.

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Title:
High-resolution seismic reflection profiling and modeling of hydrogeologic system, Goddard2 Well, northwest Boise, Idaho. Technical Report BSDU CGISS 05-17; IWRRI Grant 684-K102
Authors:
Barrash, Warren; Dougherty, Martin E.
Date Created (ISO Standard):
1995-12
Description:
The western Snake River Plain is filled, in its upper part, with sediments deposited in a variety of lacustrine and associated subaerial environments. This study examines the usefulness of high-resolution seismic reflection profiling for identifying sedimentary environments and geologic structures in the western Snake River Plain at depths that have significance for hydrologic behavior at individual wells and for the ground-water flow system in general. In addition, this study applies a discretization scheme in MODFLOW developed to accurately model single-well pumping tests which are common, by design or default, in the lower Boise River valley. A study area was chosen in northwest Boise where only the pumping well (Goddard2 well) responded during an 8-hr. test and the well exhibited negative boundary effects, and where available subsurface data from wells were not sufficient to develop a conceptual model for analysis of the Goddard2 well. [...] Engineering analysis of pumping test data by Mills (1991) identified negative boundary effects and provides a first approximation for hydraulic conductivity of the aquifer pumped by the Goddard2 well. However, a non-leaky aquifer model does not closely match observed behavior. A conceptual model for the pumping test that is consistent with well and seismic data is partially penetrating well in a sand stringer aquifer (in a floodplain environment) receiving leakage from fine-grained surrounding sediments and truncated by a fault (no-flow boundary). This conceptual model was used to simulate the Goddard2 pumping test with a discretization scheme in MODFLOW which accurately reproduces drawdown behavior at a pumping (or injection) well under non-radially symmetric flow scenarios. Results are not unique but provide a framework for evaluating elements that are significant in local and regional ground-water flow, and provide a conceptual model to be tested and iteratively improved with new data and with future aquifer testing opportunities in the area.
Subjects:
Pump wells Pumping tests Groundwater Recharge Computer models
Location:
Snake River Basin; Southern Idaho
Collection:
Boise Basin
IWRRI number:
199501
Rights:
Rights to the digital resource are held by the University of Idaho. http://www.uidaho.edu/
Publisher:
Idaho Water Resources Research Institute; University of Idaho
Contributing Institution:
University of Idaho
Type:
Text
Format:
application/pdf
Cataloger:
KIT
Date Digitized:
2017-09-22

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Preferred Citation:
"High-resolution seismic reflection profiling and modeling of hydrogeologic system, Goddard2 Well, northwest Boise, Idaho. Technical Report BSDU CGISS 05-17; IWRRI Grant 684-K102", Idaho Waters Digital Library, University of Idaho Library Digital Collections, https://www.lib.uidaho.edu/digital/iwdl/items/iwdl-199501.html
Rights
Rights:
Rights to the digital resource are held by the University of Idaho. http://www.uidaho.edu/
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