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United States Department of Agriculture

Agricultural Research Service

Title: SEASONAL ESTIMATES OF RIPARIAN EVAPOTRANSPIRATION (CONSUMPTIVE WATER USE) USING REMOTE AND IN-SITU MEASUREMENTS 1197

Authors
item Goodrich, David
item Moran, S.
item Scott, R. - 5342-45-00 (U. OF ARIZ.)
item Qi, J.
item Williams, D. - UNIV. OF ARIZ.
item Unkrich, Carl
item Marsett, R.
item Ni, W.
item Goff, B. - 5342-45-00 (U. OF ARIZ.)
item Toth, J. - 5342-45-00 (EPRI)

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

Interpretive Summary: In many semi-arid basins, groundwater from aquifers is the primary water source that sustains human habitation, agriculture and riparian systems. To most efficiently utilize groundwater it is important to know both its source from rainfall infiltrating into the aquifer and how the groundwater is used both by pumping for human and agricultural use and by naturally occurring vegetation. The largest use of groundwater by vegetation occurs in riparian areas. However, it is very difficult to estimate the amount of groundwater that riparian vegetation uses over a large area. To develop better methods to estimate this quantity, a number of multidisciplinary experiments were conducted in the U.S. portion of the Upper San Pedro Basin riparian system in southeastern Arizona during the 1997 growing season. During these experiments intensive measurements were made on the ground of surface and groundwater inflows and outflows and water use by the riparian vegetation over a small study site. At the same time, remote sensing data of the temperature of the vegetation was gathered by airplanes and satellites over the small study site and the overall riparian area which is about 30 miles long. Preliminary findings indicate that the remote sensing data and additional weather data may be used to provide annual water use estimates by the riparian vegetation over the large riparian area.

Technical Abstract: In many semi-arid basins, groundwater resources constitute the primary water source that sustains human habitation, agriculture and riparian systems. To utilize regional groundwater models to aid in management of these water resources requires accurate estimates of the basin boundary conditions. A critical groundwater boundary condition that is closely coupled to atmospheric processes and is rarely known is seasonal riparian evapotranspiration (ET). This quantity can often be a significant factor in the basin water balance in semi-arid regions, yet is very difficult to estimate over a large area. Better understanding and quantification of annual, large-area riparian ET is one of the primary 1997 objectives of the SALSA Program. A number of multidisciplinary experimental field campaigns were conducted in the U.S. portion of the Upper San Pedro Basin (USPB) riparian system to address this objective during the 1997 growing season. Preliminary data and possible simple approaches to temporally extend the "snapshot" riparian-corridor ET estimates based on remote sensing data to obtain seasonal and annual estimates of consumptive riparian water use are presented.

Last Modified: 7/22/2014
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