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Communication at the NABS Annual meeting, Keystone, 2000
(506) MONITORING DIEL WATER TABLE FLUCTUATIONS TO ESTIMATE RATES OF
RIPARIAN EVAPOTRANSPIRATION ALONG THE RIO GRANDE, NEW MEXICO, USA.
J.R. Thibault, D.J. Gilroy, J.R. Cleverly, and C.N. Dahm. Department of Biology, University of New Mexico, Albuquerque, NM 87131-1091
Allocation of water to restore riparian ecosystem functioning in the semi-arid middle Rio Grande basin of New Mexico requires reliable inter-annual estimates of water loss to evapotranspiration (ET). In 1999, we quantified riparian ET using a flux tower equipped with a 3-dimensional eddy covariance system. Sonic anemometry is state-of-the-art methodology, but it is expensive and requires frequent maintenance. We also monitored the water table using automated groundwater piezometers. Daily rates of ET and water table fluctuation during 155 days of the growing season were significantly correlated (r2 = 0.62, P < 0.001). Flux tower ET rates and diel piezometric head fluctuations will be compared at three additional sites during the 2000 and 2001 growing seasons. ET can sometimes be estimated using diel head fluctuations and local soil characteristics. If strong correlations are consistently found at the sites, the use of automated piezometers could provide a relatively inexpensive, low maintenance method for estimating annual ET.
Presented at 1:00 PM on Wednesday, May 31, 2000 in Stream / Floodplain Management
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