HR: 0800h
AN: H21B-1002    [Abstracts]
TI: Water Quality Parameters as Environmental Tracers of Stream Exchanges with Ground Water
AU: * Cox, M H
EM: mhcox@usgs.gov
AF: U.S.Geological Survey, 345 Middlefield Rd, Menlo Park, Ca 94025
AU: Constantz, J
EM: jconstan@usgs.gov
AF: U.S.Geological Survey, 345 Middlefield Rd, Menlo Park, Ca 94025
AU: Michel, R L
EM: rlmichel@usgs.gov
AF: U.S.Geological Survey, 345 Middlefield Rd, Menlo Park, Ca 94025
AB: Water quality data is collected on a routine basis in both surface water and ground water. This paper evaluated the potential use of water quality parameters as environmental tracers of near stream ground water along a 130 km reach of the Russian River in Northern California. For a water quality parameter to be useful as an environmental tracer it must show temporal variability at a boundary (typically the upper boundary) as well as spatial variability in ground water. Three water quality parameters (temperature, specific conductance, and chloride) were sampled quarterly in conjunction with traditional environmental tracers (deuterium and 18-oxygen isotopes) in the river and nearby ground-water wells. For the Russian River, surface water was characterized by an increase in daily mean temperature, specific conductance, and chloride concentration progressing from the upper reach to the lower reach of the study area, with a strong seasonal variation throughout the entire reach. Deuterium showed a strong seasonal variation, whereas 18-oxygen had only a minor seasonal variation in the surface water. A high degree of hydrologic connectivity between the surface water and ground water was indicated at four sites, where hydrochemical changes indicate surface water was infiltrating into the alluvial aquifer. The chemistry of the ground water at these sites was characterized by seasonal trends and dampened and delayed tracer signals relative to the river. At other locations, hydrologic connectivity was less evident and there was no strong correlation in hydrochemical changes between the surface water and ground water. The preliminary results of the study indicated that water quality parameters used as environmental tracers have clear potential to characterize the spatial and temporal variability of the Russian River.
DE: 1806 Chemistry of fresh water
DE: 1829 Groundwater hydrology
DE: 1831 Groundwater quality
DE: 1871 Surface water quality
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting