Utah Water Science Center
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Modeling Se Mixing in South Shore of Great Salt Lake
The south shore area of Great Salt Lake (GSL) has been under increasing scrutiny by concerned citizens and State and Federal regulators, because of current and future selenium inputs to this part of the lake ecosystem. Recent investigations indicate that this part of GSL consistently receives discharge with elevated concentrations of selenium from natural and anthropogenic inflows. Water with elevated concentrations of selenium has been observed at surface seeps along the south shore of GSL and immediately offshore. In addition to the present inputs, an additional anthropogenic selenium input for the south shore area is in the final permitting phase. To date (2011), no information exists on how selenium concentrations may or may not persist in the south shore mixing zone as a function of varying lake conditions or on how the concurrent input of maximum daily selenium concentrations from new anthropogenic sources could influence the selenium concentration in the open-water areas of GSL within the south shore mixing zone.
The objective of the proposed study phase is to assess the movement, mixing, and extent of the KUCC discharge plume in the GSL south shore mixing zone and Se concentrations within the plume.
RELEVANCE AND BENEFITS
The proposed study supports the goals of the U.S. Geological Survey Cooperative Water Program to support local, State, and Tribal science needs and management decisions. The study will provide the Utah Department of Forestry Fire and Lands and other resource managers with important information on the water chemistry of the south shore of Great Salt Lake toward meeting that agency’s charge to manage the lakes resource for multiple use and sustained yield.
The study will (1) utilize dye tracing techniques to map the vertical and horizontal movement of an elevated selenium discharge stream as it enters and mixes along the south shore of GSL, and (2) utilize results from objective 1 to calibrate a three-dimensional hydrodynamic model to simulate the vertical and horizontal movement of this plume as it enters and mixes along the south shore of GSL.An autonomous underwater vehicle equipped with an onboard fluorometer and other water-quality sensors will be used to map, in three dimensions, the progress and relative concentration of the plume into the open water of GSL.
Project products include: