HR: 1340h
AN: H43C-1513    [Abstracts]
TI: Determination Of Baseflow Inputs In A The San Miguel River Basin, A Riparian Area In The North American Monsoon Region
AU: * De La Cruz-Ortega, L
EM: lissette@hwr.arizona.edu
AF: University of Arizona Department of Hydrology and Water Resources, 1133 E James E. Rogers Way Tucson, Tucson, Az 85719, United States
AU: Meixner, T
EM: tmeixner@hwr.arizona.edu
AF: University of Arizona Department of Hydrology and Water Resources, 1133 E James E. Rogers Way Tucson, Tucson, Az 85719, United States
AB: The North American Monsoon is a critical climatalogical phenomenon in Northwest Mexico and Southwest United States. Little is known however of how important this climate phenomenon is to long term ground water resources in this region and such information would be useful for water management. One of the better-studied systems in this region is the San Pedro, in the United States. Using geochemical and isotopic mixing techniques the waters sources of the San Pedro have been shown to include a significant fraction of summer floodwater. For this study we are looking to extend this understanding to other basins in the area; moving to basins with more and less Monsoonal influence. The more Monsoon dominated basin we are investigating is the Rio San Miguel, Mexico, a Rio Sonora tributary. We chose this river due to its several perennial reaches. At this time we have samples from two years during pre-monsoon (May) and monsoon season (July), and winter (February). The isotopic data gives a clear pattern of seasonal variability of recharge source composition. The chemical data helps us differentiate what processes are occurring along the 80 km river reach of our study. The river has 5 separate perennial reaches; the reaches group in two different groups of water source. In the lower part of the basin the data show more evaporated water than in the upper basin. The isotopic data clearly show a differentiation processes in precipitation, with more depleted water at high altitude. Surface and ground water average isotopic values are close to each other, with surface water closer in composition to summer precipitation than groundwater.
DE: 0454 Isotopic composition and chemistry (1041, 4870)
DE: 1800 HYDROLOGY
DE: 1860 Streamflow
DE: 1871 Surface water quality
DE: 4870 Stable isotopes (0454, 1041)
SC: Hydrology [H]
MN: 2007 Fall Meeting