Comparison of heat and bromide as ground-water tracers near streams

Ground Water
By: , and 

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Abstract

Heat and bromide were compared as tracers for examining stream/ground water exchanges along the middle reaches of the Santa Clara River, California, during a 10-hour surface water sodium bromide injection test. Three cross sections that comprise six shallow (<1 m) piezometers were installed at the upper, middle, and lower sections of a 17 km long study reach, to monitor temperatures and bromide concentrations in the shallow ground water beneath the stream. A heat and ground water transport simulation model and a closely related solute and ground water transport simulation model were matched up for comparison of simulated and observed temperatures and bromide concentrations in the streambed. Vertical, one-dimensional simulations of sediment temperature were fitted to observed temperature results, to yield apparent streambed hydraulic conductivities in each cross section. The temperature-based hydraulic conductivities were assigned to a solute and ground water transport model to predict sediment bromide concentrations, during the sodium bromide injection test. Vertical, one-dimensional simulations of bromide concentrations in the sediments yielded a good match to the observed bromide concentrations, without adjustment of any model parameters except solute dispersivities. This indicates that, for the spatial and temporal scales examined on the Santa Clara River, the use of heat and bromide as tracers provide comparable information with respect to apparent hydraulic conductivities and fluxes for sediments near streams. In other settings, caution should be used due to differences in the nature of conservative (bromide) versus nonconservative (heat) tracers, particularly when preferential flowpaths are present.
Publication type Article
Publication Subtype Journal Article
Title Comparison of heat and bromide as ground-water tracers near streams
Series title Ground Water
DOI 10.1111/j.1745-6584.2003.tb02403.x
Volume 41
Issue 5
Year Published 2003
Language English
Publisher Wiley
Contributing office(s) Toxic Substances Hydrology Program
Description 10 p.
First page 647
Last page 656
Country United States
State California
Other Geospatial Santa Clara River
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