Relief Well Rehabilitation Options in Chief Joseph Dam Right Abutment Drainage Tunnel

This report summarizes the data, observations, methods, assumptions, and decisions for the design of the Relief Well Rehabilitation Project in the Right Abutment Drainage Tunnel at Chief Joseph Dam. Chief Joseph Dam (CJD) is a dam on the Columbia River and is owned and operated by the U.S. Army Corps of Engineers (USACE). It is the second only to Grand Coulee dam as the largest producer of hydropower in the United States. The right abutment drainage tunnel contains wooden stave relief wells. Water flows from these wells which reduces the hydrostatic pressure in the right abutment of the dam. The 22 wells in the floor of the tunnel are 60 years old and are in need of rehabilitation. The objective of this project is to control the groundwater gradient, prevent the movement of sediment, stop total screen collapse, and prevent initiation of backwards erosion and piping in the abutment. The rehabilitation solution is to install new stainless steel screens into the existing wells, backfill the annular space between the old wooden screen and the new stainless steel screens with a 3/8-inch pea gravel filter pack, and install a new top cap to hold the new screen in place. This report documents the data, observations, and methods used to complete the final design. During tunnel inspections USACE geologists observed dislodged end plugs and evidence of sediment movement out of the formation. The relief wells have historically high flows between 6,000 gallons per minute (gpm) to 9,000 gpm. New screens are designed based on as-built data and historic tunnel flow. The new screens are 8-in diameter, 100 slot (0.10-inch) screens. We found that screen diameter and slot size would provide adequate transmitting capacity for most of the relief wells. The filter pack gradation is based on descriptions from foundation construction reports. I found that 3/8-inch pea gravel is appropriate for the abutment material. During design, I also considered an option to install the screens into the relief wells without filter pack. I eliminated this option because it did not meet our rehabilitation objective to prevent total failure of the wooden screens.

Water chemistry controls on minor elemental concentrations and strontium isotopic compositions of freshwater biogenic carbonate in northeastern Washington streams

Tracking the movement of migratory freshwater fish is essential to those invested in rebuilding declining fish populations. Using strontium isotopic signatures to match calcified fish tissues to streams where fish spawn is a useful method of tracking migratory fish where physical tracking methods such as radio, acoustic, or external tags, have proven unsuccessful. In this study, we develop tools to practice this method of tracking fish in Lake Roosevelt and its upstream tributaries in Washington State by analyzing the elemental concentrations and 87Sr/86Sr ratios of water samples, and mussel shell samples. This study evaluates whether mussel shells act as an appropriate proxy for water chemistry by comparing the 87Sr/86Sr isotope ratios of water samples to the 87Sr/86Sr isotope ratios of mussel shells sampled from the same, or nearby, locations. We compare concentrations of Ba, Ca, Cd, Cu, Fe, Mg, Pb, Sr, and U in the water and mussel shell samples to determine the feasibility of using mussel shells as a proxy for water chemistry. If it is determined that the concentrations of these elements in mussel shells reflect that of the surrounding water composition, the elemental composition of mussel shells can be compared to that of calcified tissues in fish, such as otoliths, to infer the location of the natal stream. We report analyses of water and mussel shell samples collected from Lake Roosevelt, Sanpoil River, Spokane River, Colville River, Kettle River, Pend Oreille River, Kootenay River, and Columbia River in Washington State. Each of these rivers is a tributary to Lake Roosevelt, and each flows through different geologic units. We hypothesize that the differences in the rock units of each stream’s watershed are reflected in the elemental concentrations and strontium isotopic ratios of water in each stream and in the lake. We also hypothesize that the composition of the mussel shells will match the composition of the water samples, therefore allowing us to use the mussel shells as a proxy for local water chemistry. Additionally, we hypothesize that the composition of the mussel shells will vary by location, and that we will be able to then infer where a fish is from by matching the composition of the fish in question to the mussels we have analyzed. We found that 87Sr/86Sr values for water and mussel hinge samples collected from tributaries east of Lake Roosevelt are significantly higher than the 87Sr/86Sr values for samples collected from tributaries west of Lake Roosevelt with averages of 0.7235 and 0.7089, respectively. The average 87Sr/86Sr ratios for water and mussel hinge samples collected within Lake Roosevelt is 0.7158, which is between the averages for samples collected east and west of the lake. Generally, older rocks are exposed on the east side of the lake, and younger rocks on the west side of the lake, so our 87Sr/86Sr values support the hypothesis that geologic units are a primary control on water chemistry, and that tributary compositions mix to form an average weighed by flow in Lake Roosevelt. The 87Sr/86Sr values for water and mussel shell samples collected from the same locations have a strong, positive linear correlation, suggesting that mussel shell 87Sr/86Sr ratios reflect the 87Sr/86Sr ratios of the ambient water. With these data, we can distinguish between different streams and the lake, but cannot distinguish between samples from within the same stream or within Lake Roosevelt. The Sr:Ca and Fe:Ca ratios of water samples show positive correlations with mussel shell compositions, with R2 values of 0.82 and 0.52, respectively. Ratios of Mg, Ba, Cu, Cd, Pb, and U to Ca showed little or no positive correlation between water and mussel shell samples. The elemental concentration data collected for this study do not demonstrate whether a correlation between elemental ratios in water samples and elemental ratios in mussel shell samples collected from the same location exists. Positive Sr:Ca and Fe:Ca correlations for water versus mussel shell samples indicate that perhaps for some elements, the composition of mussel shells are representative of the composition of ambient water. Using elemental concentration ratios to complement 87Sr/86Sr isotopic data may enhance our ability to identify correlations between water and mussel shell samples, and ultimately between mussel shell and otolith samples. The hinge part of a mussel shell may be used as a proxy for local water composition because the mussel shell composition reflects that of the local ambient water. The hinge of the mussel has the same composition as the whole mussel shell. We measured variation of 87Sr/86Sr ratios in the water among different streams and Lake Roosevelt. The 87Sr/86Sr values for samples collected in tributaries east of Lake Roosevelt, which erode older rocks, are higher for mussel shell and water samples than the average 87Sr/86Sr values for mussel shell and water samples collected in tributaries west of Lake Roosevelt, which flow through younger rocks.

Cost-Efficient Spatial Placement of Water Retention Sites (WRS) to Reduce Sediment in Le Sueur River Watershed,MN

Thesis (Master's)--University of Washington, 2016-06