HR: 17:30h
AN: H14E-07    [Abstracts]
TI: Evaluating the effects of a +3C climate change with a regional recharge model
AU: * Flint, A L
EM: aflint@usgs.gov
AF: U.S. Geological Survey, Placer Hall 6000 J Street, Sacramento, CA 95819, United States
AU: Flint, L E
EM: lflint@usgs.gov
AF: U.S. Geological Survey, Placer Hall 6000 J Street, Sacramento, CA 95819, United States
AU: Dettinger, M D
EM: mddettin@usgs.gov
AF: U.S. Geological Survey, Scripps Institute of Oceanography, La Jolla, CA 92093,
AB: A +3C change in air temperature, a conservative average increase suggested by ongoing climate change studies, was evaluated using a monthly regional-scale water-balance model to estimate changes in snow accumulation and melt, recharge, runoff, and evapotranspiration for 5 southwestern U.S. states. Model calibrations to current conditions include potential evapotranspiration, radiation, and snow cover data, and recharge estimates using various methods. Steady-state and transient 30-yr conditions were modeled to investigate changes in timing, volume, and the spatial distribution of the parameters at a 270-m spatial resolution using a 30-yr precipitation record. Overall, average annual snow accumulation was decreased by approximately 46 percent throughout the study area, with maximum reductions in California and minimum reductions in the southern desert regions. Average reductions over the entire study area of 4 percent of in-place recharge and 8 percent of runoff were accompanied by a 20-percent increase in evapotranspiration, illustrating how the timing of snow presence and melt results in increased opportunity for evapotranspiration processes to occur. Even with a simplistic, across- the-board increase in air temperature throughout the west, the magnitude of the effects in areas that develop winter snowpacks are most notable in the Sierra Nevada and the Trinity Mountains of the Klamath River Basin, and less so in the Colorado Rockies, a result that emphasizes the potentially significant consequences of climate change on water resources in California. Regional-scale approaches to modeling the influences of climate change can be readily and expeditiously used to investigate the relative changes in hydrologic processes among large regions for prioritizing management of water resources in the western U.S.
DE: 1807 Climate impacts
DE: 1829 Groundwater hydrology
DE: 1836 Hydrological cycles and budgets (1218, 1655)
DE: 1847 Modeling
DE: 1863 Snow and ice (0736, 0738, 0776, 1827)
SC: Hydrology [H]
MN: 2007 Fall Meeting