HR: 1340h
AN: GC33A-0961    [Abstracts]
TI: Hydrology and Ecology of the Colorado River Delta in the Face of Changing Climate and Land Use Practices: the Next Fifty Years
AU: * Nagler, P L
EM: pnagler@usgs.gov
AF: U.S.G.S., Southwest Biological Science Center, Sonoran Desert Research Station UA School of Natural Resources, 125 Biological Sciences East, Tucson, AZ 85721, United States
AU: Glenn, E P
EM: eglenn@ag.arizona.edu
AF: University of Arizona, Environmental Research Lab, 2601 E. Airport Drive, Tucson, AZ 85706, United States
AB: The Lower Colorado River Delta in the U.S. and Mexico is an internationally important aquatic biome, supporting fresh water and estuarine wetlands and a riparian corridor rich in avian and other wildlife. These rich ecosystems could be severely harmed by invasive species interacting with projected climate change and land use practices over the next 50 years. It is critical to measure land cover and monitor ecosystem and land use changes because these ecosystems are supported by fresh and brackish water flows originating from flood control releases and agricultural return flows in the U.S. and Mexico. Most climate models project a drying trend in the Colorado River watershed due to global warming, decreasing the frequency of flood releases to the Delta. Total basin water storage in the reservoir system is expected to be reduced by 32-40 percent, and flow volume is expected to meet demands in only 59-75 percent of years in 50 years. The frequency of spills (years in which water is released from the reservoirs to the Delta) will decrease under a global warming scenario. However, the Pacific Decadal Oscillation and ENSO events will continue to introduce variability into river flows, and there will still be years in which water is spilled to the Delta. Agricultural return flows will decrease as more water is diverted from agriculture to metropolitan use in both countries. The salinity of the ground water in Mexico, which currently supports cottonwood and willow trees in the riparian corridor, is increasing at a rate of about 20 ppm per year, and in 50 years it might be too saline for cottonwoods and willows. The riparian zone may become dominated by saltcedar and other salt-tolerant shrubs, degrading the habitat for birds and other wildlife. As flows to the Delta diminish, monitoring and active restoration projects to maintain trees and wetlands will be needed to preserve habitat value.
DE: 1812 Drought
DE: 1813 Eco-hydrology
DE: 1818 Evapotranspiration
DE: 1855 Remote sensing (1640)
DE: 1880 Water management (6334)
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting