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Communication at the NABS Annual meeting, Keystone, 2000
(502) CHARACTERIZATION OF DIEL WATER TABLE FLUCTUATIONS IN THE RIO GRANDE
RIPARIAN ZONE, NEW MEXICO, USA.
D.J. Gilroy, J.R. Thibault, J.R. Cleverly, and C.N. Dahm. Department of Biology, University of New Mexico, Albuquerque, New Mexico, 87131-1091
In the middle Rio Grande basin of New Mexico, returning to a more natural flow regime could help restore the cottonwood-dominated riparian ecosystem. However, in this semi-arid region, loss of water to evapotranspiration (ET) must be carefully assessed. ET can be estimated by measuring soil parameters and monitoring water table elevation, a method that requires reliable diel water table fluctuations. In 1999, piezometric data were collected at eight riparian sites, including actively flooding and non-flooding locations. Diel fluctuations occurred at the centimeter scale at seven sites. Sites subject to flooding had a clear diel signal approximately 70 percent of the time, while non-flooding sites had a clear signal over 90 percent of the time. Rapid change in the water table following heavy rainfall or upstream dam manipulations dampened or eliminated diel fluctuations, particularly at flooding sites. This method looks promising for providing reasonable, low-cost, good-accuracy ET estimates for most riparian zones along the Rio Grande.
Presented at 1:00 PM on Wednesday, May 31, 2000 in Stream / Floodplain Management
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