Graduate Thesis Or Dissertation
 

MetcalfBeckyElise2004.pdf

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https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/4t64gr661

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  • In an effort to restore summer flows in the Walla Walla River to provide passage and habitat for ESA (endangered species act) listed bull and steelhead trout irrigation districts left 13 cubic-feet-per-second (c.f.s) (0.37 m ³/s) in the main channel during irrigation season (May-November) for the first time in over 100 years in 2000. However, the water percolated from the surface within a short distance of the bypass area. Agreement flows for 2001 and 2002 were 18 c.f.s. (0.51 m ³/s), and 25 c.f.s. (0.71 m ³/s) respectively, with an average of 28.5 c.fs. (0.81 m ³/s) and 32.7 c.f.s (0.93 m ³/s) actually bypassed in 2001 and 2002 respectively. In 2001 the average loss was 15.1 c.f.s. (0.43 m ³/s), in 2002 the average loss was 22.3 c.f.s. (0.63 m ³/s). The ability of the mainstem to carry flow is critical to restoring fish habitat and passage. Two methods were used in conjunction to understand the interactions that occur between the Walla Walla River and the underlying alluvial aquifer. The first method was chemical signature work using naturally occurring anions in both the surface water and groundwater. Groundwater has relatively high concentrations of anions such as chloride and sulfate, compared to surface water. This allows for the use of a mixing analysis approach which estimates the relative contributions of each of the sources. Results indicate that the levied section of the river is primarily effluent in nature, contributing water to the aquifer. It is also shown that below the levied section the aquifer contributes to the river. The second method was the use of stream bed temperature profiling devices. These devices record the temperature of the stream bed material with time and depth. Stream temperatures are well described by a sine wave pattern on a diurnal basis. The amplitude of the diurnal stream temperature at depth below the streambed decreases as a result of infiltration, and the signal is shifted in time. With these data we determined the rate of infiltration from the surface water into the groundwater. Analysis of the stream bed temperature at depth was done using sine wave fitting, and numerical modeling with the software HYDRUS-2D. Infiltration estimates ranged from 6 cm/day, to 308 cm/day. Extrapolating this point measurement to the levied stretch from Nursery Bridge to Tumalum Bridge (3200 m) using the average width of the river (10 m) gives an estimate of flow loss of 0.3 m ³/s, using half the width of the levy for area of infiltration estimates (25 m) gives an estimate of flow loss of 0.76 m3/s. These values compare favorably with manually measured in-stream flow losses for 2002. The true area of infiltration (and thus in-stream flow loss) is most likely larger that the actual stream channel, and slightly smaller than half the width of the levy. In addition it was observed that the permeability of the stream bed decreases by a factor of 2 to 4 between the 19th of June and the 12th of November. The decrease in time is to be expected in high energy gravel bed rivers due to sorting, sedimentary and biological clogging during the months when the stream bed is not re-worked by high flows.
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file details MetcalfBeckyElise2004.pdf 2017-08-19 公开 下载