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United States Department of Agriculture

Agricultural Research Service

Title: The Overview of Atmospheric and Surface Water Coupling to Regional Groundwater Models in Semi-Arid Basins 1200

Authors
item Maddock Iii, T. - UNIV. OF ARIZ.
item Macnish, R. - UNIV. OF ARIZ.
item Goodrich, David
item Williams, D. - UNIV. OF ARIZ.
item Shuttleworth, W. - UNIV. OF ARIZ.
item Goff, B. - 5342-45-00 (U. OF ARIZ.)
item Moran, M.
item Cooper, D. - LOS ALAMOS NAT. LAB.
item Hipps, L. - UTAH STATE UNIV.
item Chehbouni, A. - ORSTOM/IMADES

Submitted to: American Meteorological Society
Publication Type: Proceedings
Publication Acceptance Date: January 21, 1998
Publication Date: N/A

Interpretive Summary: This paper discusses issues related to coupling evapotranspiration (ET) and streamflow to groundwater models in semi-arid regions. In the present state of groundwater modeling, groundwater, streamflow, and ET components are inadequately coupled, leading to excessive streamflow loss predictions. A better understanding of how these processes interact would improve the predictive capabilities of such models. To address this problem, an experiment was conducted on a reach of the San Pedro River near Lewis Springs, in SE Arizona. The experiment was part of the Semi-Arid Land-Surfa Agricultural Research Service. Coordinated measurements of soil moisture, groundwater and surface water levels, and ET from riparian trees were made during 5, 48-hour intensive measurement periods conducted at different times of 1997 growing season. It is anticipated that the results of these coordinated studies will provide better estimates of the streamflow, groundwater and ET terms used in groundwater models developed for semi-ari basins.

Technical Abstract: In arid and semi-arid regions, groundwater and surface water interactions may be intricately coupled with evapotranspiration (ET) processes in riparian corridors. In the present state of groundwater modeling, however, streamflow and ET terms are introduced into the groundwater flow model as separate modules with no explicit coupling between them. The coupling problem is compounded by the differences in time scales of the streamflow and groundwater flow processes. In order to better understand the interrelationships among streamflow, groundwater flow, and ET, a multidisciplinary study was initiated along a reach of the San Pedro River in SE Arizona, USA. Groundwater, streamflow, and ET fluxes were monitored concurrently during 5, 48-hour intensive measurement periods conducted over the 1997 growing season. It is anticipated that the results of these coordinated studies will provide better estimates of streambed conductance, ,a more accurate curve configuration for surface and groundwater interactions, seasonal parameter estimates for each term, a better understanding of the dichotomy between the vadoze zone and the water table, and seasonal evapotranspiration curves.

Last Modified: 8/22/2014
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