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Transferable Research Capabilities and Interests
Unsaturated-Zone Research Techniques Applied in the High Plains Ground-Water Study
- Incremental drilling, core and sediment recovery and processing, water and chemical extraction
- Unsaturated-zone chemical profiling, mass balance, and flux estimation
- Unsaturated-zone water flux estimation and modeling
- Recharge estimation
- Understanding natural climate variability and long-term climate change effects and aquifer response.
- Soil-water analysis and chemical transformations, denitrification microcosms
- Real-time monitoring of weather, evapotranspiration, and unsaturated-zone wetting-front migration
- For detailed information about these efforts, please see McMahon and others, 2003,
McMahon and others, 2006, and
Gurdak and others, 2007.
Research on Vertical Gradients in Water Chemistry and Age in the High Plains Aquifer
- Provide information on differences in ground-water quality and ground-water age relative to
depth within the aquifer and the underlying bedrock.
- Assesses potential for changes in the quality of produced water as the aquifer declines and
the influence of the underlying bedrock becomes more important.
- Ground-water age data helps to define the stratification and residence time of water in the
aquifer.
- Age data can be used as an independent calibration for predictive ground-water flow models.
- Age data can be used to estimate biogeochemical reaction rates.
- Chemical and age data can be used to reconstruct paleorecharge conditions.
- For detailed information about these efforts, please see McMahon, 2001,
McMahon and Böhlke, 2006,
and McMahon and others, 2004.
Ground-Water Vulnerability Research
- Ground-water vulnerability model and map development for the prediction of nonpoint-source
contamination, which aid ground-water resource management decisions.
- Delineatation of well-contributing areas and determination of well-screen depths that intercept
recently recharged ground water for vulnerability prediction.
- Estimation of uncertainty associated with propagation of inherent errors introduced into
ground-water vulnerability models and maps, for improved confidence using vulnerability assessments
during resource management decisions.
- For more detailed information about this effort, please see
Gurdak and Qi, 2006,
Qi and Gurdak, 2006, and
Gurdak and others, 2007.
Research on Climate Change within the High Plains Region
- HPGW's findings regarding recharge variability and climatic controls on chemical and water
movement represent a novel investigation of the impact of climate variability and climate change
on ground-water resources and aquifer sustainability.
- Agricultural community and local and federal agencies (water conservation districts, USDA, BOR,
etc.) that manage the ground-water resource are most interested in sustainability issues related to
water-level declines and water-quality impacts across the High Plains aquifer (HPA).
- At a recent UNESCO sponsored meeting (International Symposium on GRAPHIC -Groundwater Resource
Assessment under the Pressures of Humanity and Climate Change, April 4-6 2006, Kyoto Japan) HPGW
researchers presented preliminary findings on climate controls impacting aquifer recharge and
chemical quality.
- The goals of the United Nations sponsored GRAPHIC program: i.) identify major ground-water
resources on each continent that are highly stressed by human activities climate variability/change;
and ii.) coordinate future global research efforts to understand future climate impacts and
management options to enhance global ground-water sustainability.
Remote Sensing Research
- Classification of irrigated land from Landsat imagery using supervised classification and
band-ratio techniques.
- Change analysis in amount of irrigated agriculture from 1980 to 1992
- For detailed information about these efforts, please see Qi and others, 2002.
Future Research Possibilities
- Understanding and predicting the effect of climate change on ground-water resources is a
relatively new area of climate research and the HPA system provides an ideal field laboratory
for these investigations.
- The substantial body of existing geologic, hydrologic, climatologic, and geographic
information for the High Plains provides the necessary foundation for expanding research
into natural climate variability, climate change, human impacts, and aquifer recharge and
sustainability.
- Gradients in temperature (north-south) and precipitation (east-west) in the High Plains
allow for studies of the influence of natural climate variability under current conditions
on the HPA, in addition to studies of future climate change.
- A High Plains ground-water modeling effort to revise the current "pre-MODFLOW" model.
If you would like to discuss any part of the results, activities, or international contacts
related to High Plains ground-water (HPGW) research, please contact:
Peter B. McMahon
Project Manager - High Plains Regional Ground-Water Study
USGS Colorado Water Science Center
Denver Federal Center
P.O. Box 25046, MS-415
Denver, CO 80225
pmcmahonusgs.gov
Ph: (303) 236-4882
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