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East Multnomah County Groundwater Flow Model
SSP&A
developed, calibrated, and applied a regional three-dimensional
groundwater flow model for a complex multi-aquifer system in the
southern Portland basin near Portland, Oregon. SSP&A
used the model to aid the City of Portland in the operation of emergency
public water-supply wells which were threatened by local contamination
by volatile organic compounds, and to aid in development of remedial
alternatives for remediation of nearby sites. The model software and
documentation were submitted by SSP&A
to the City of Portland and other parties to serve as an ongoing tool
for addressing groundwater contamination and water supply in the
Portland area. SSP&A
continues to provide expert technical advice on groundwater issues to
the Oregon Department of Environmental Quality.
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Kansas versus
Colorado
SSP&A
serves as a technical assistant to the State of Kansas in a legal
dispute involving the availability of waters from the Arkansas River.
The major case issue involves the effect of extensive groundwater
pumping from alluvial aquifers in Colorado on the availability of
surface-water flow in Kansas. The State of Kansas has claimed that the
State of Colorado is pumping to an extent which reduces stream flow
sufficiently to be in violation of the Arkansas River Compact. SSP&A
conducted analyses supporting this claim, and Mr. Larson, Executive Vice
President of SSP&A,
testified on behalf of the State of Kansas before a Special Master of
the U.S. Supreme Court. Recently, the Court found in favor of the State
of Kansas when they declared the State of Colorado to be in violation of
the Arkansas River Compact.
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Navajo Aquifer
Study, Arizona
SSP&A
was retained to compile and review an extensive collection of
hydrogeologic data and existing reports on groundwater conditions in the
Black Mesa area of Arizona to evaluate the potential hydrologic impacts
of large-scale industrial pumping on the Navajo sandstone aquifer. SSP&A
evaluated the adequacy of existing data and groundwater models and
developed recommendations for further studies.
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Coal Slurry
Pipeline Study
A coal slurry pipeline proposed for operation in the Powder River basin
of Wyoming required pumping a large volume of water from the Madison
limestone aquifer. SSP&A
evaluated existing studies and developed groundwater flow and
water-quality models to evaluate the impact of pumping 20,500 acre-feet
per year from the aquifer. The groundwater flow model was a numerical
simulation model of the aquifer which used the Monte Carlo method to
assess the range of possible impacts given the statistical uncertainty
in the hydraulic parameters. Water-level declines, stream-flow and
spring-flow reductions, and water-quality impacts were calculated. The
results of the modeling efforts were incorporated into the Environmental
Impact Statement for the project.
Madison Limestone
Aquifer Study
SSP&A
developed mathematical models of the Madison limestone and the
underlying Bighorn dolomite in Wyoming to evaluate the potential for
long-term groundwater development. SSP&A
used a multi-layer, finite-difference model to simulate
three-dimensional groundwater flow. The model allowed SSP&A
to represent many of the specific features of the aquifers, including
the boundary conditions, the unconfined conditions near rock outcrop
areas, the hydraulic connection between aquifers, and the aquifer-stream
interaction. Through the results of this modeling effort, SSP&A
was able to determine the water-supply potential of the formations, and
to outline an efficient strategy for the development of a well field
that would provide the projected water supply.
Gallup Basin Study
SSP&A
evaluated hydrogeologic data and reviewed existing groundwater flow
models to assess the impacts of proposed groundwater withdrawals from
the San Andres-Glorieta Aquifer in the Gallup Basin, New Mexico, on
water levels, spring flow, and stream-base flow. SSP&A
also directed additional modeling activities and provided expert
testimony in water-rights litigation.
Bluewater Basin
Model
A three-dimensional groundwater flow model for a regional groundwater
basin in northwestern New Mexico was developed by SSP&A
and was calibrated using an extensive database of historical pumping for
municipal, industrial and agriculture use. The model has been used in
conjunction with evaluations of surface-water conditions to assess the
historical and future water levels and spring flow. The evaluations have
been used to determine the impacts of water-rights transfers.
Mesilla Bolson
Study
The impact of large-scale pumping on water quality and water levels in
the Mesilla Bolson and Lower Rio Grande Valley of New Mexico were
evaluated. An extensive database of water levels, water quality and
pumpage was compiled. Numerical models were developed to calculate
water-quality impacts and water-level declines.
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Hueco Bolson Study
Hydrologic and water-quality impacts of proposed development of
municipal well fields with 264 million gallons per day capacity were
evaluated. An extensive database containing records for over 1000 wells
and over 60 years of water level and pumping data was compiled.
Numerical flow and transport models were developed for the Hueco Bolson
in New Mexico and Texas to assess the impacts and to determine the
long-range capacity of the aquifer under various use scenarios. The
results of the assessments were used by the New Mexico Attorney General
in water-rights hearings on the proposed development and on the
interstate transfer of groundwater from New Mexico to Texas. Expert
testimony was presented by Mr. Larson, Dr. Andrews and Ms. Hathaway.
Washoe County
Study and Models
SSP&A
conducted a reconnaissance investigation to evaluate the availability of
groundwater in northern and central Washoe County, Nevada, for export to
southern Washoe County. The investigation included the preparation of an
inventory of available groundwater for approximately 30 groundwater
basins, the conceptual design of development schemes, the identification
of hydrologic and environmental constraints on development, and the
numerical evaluation of groundwater storage in selected basins as a
means for terminal storage.
Las Vegas
Ground-Water Basin Analysis
The Las Vegas Valley Water District, Nevada, has been developing a
numerical regional groundwater flow model and approximately 25 sub-basin
models to support the District's applications for water rights in these
sub-basins. SSP&A
is critically reviewing the development of these models and their use in
the water-rights application process, and will be providing expert
testimony at hearings associated with the adjudication of these water
rights. |
