Abstract
Stratified flows and the resulting density-driven currents occur in the natural environment and commonly in saline lakes. In the Great Salt Lake, Utah, USA, the northern and southern portions of the lake are divided by an east-to-west railroad causeway that disrupts natural lake currents and significantly increases salt concentrations in the northern section. To support management efforts focused on addressing rising environmental and economic concerns associated with varied saltwater densities throughout the lake, the causeway was recently modified to include a new breach. The purpose of this new breach is to enhance salt exchange between the northern and southern sections of the lake. Since construction, it typically exhibits a strong density-driven bidirectional flow pattern, but estimating flows and salt exchange has proven to be difficult. To obtain much needed insights into the ability of this hydraulic structure to exchange water and salt between the two sections of the lake, a field campaign coupled with CFD modeling was undertaken. Results from this study indicate that the vertical velocity profile in the breach is sensitive to density differences between flow layers along with breach geometry and water surface elevations. The CFD model was able to accurately represent the bidirectional flows through the breach and provides for improved estimates of water and salt exchanges between the north and south sections of the lake.
Highlights
Due to uncertainty in the specific location of the acoustic doppler velocimeter meter (ADVM) relative to the pier in the transverse direction, the computational fluid dynamics (CFD) portion of this study considered vertical profiles at 10 distances from the respective piers selected based upon information gathered from the U.S Geologic Survey (USGS) (Figure 4b)
USGS has multiple buoys in the GSL where grab samples are analyzed for total dissolved solids (TDS) along with corresponding σ
The at the Great Salt Lake causeway was simulated with an large eddy simulation (LES) CFD model to support results of this study indicate that the model can be used to simulate other lake levels management efforts that include environmental and economic concerns
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Some of the major saline lakes are the Caspian Sea (coastline shared by Azerbaijan, Iran, Kazakhstan, Russia, and Turkmenistan), the Great Salt Lake (GSL) (Unites States), and Lake Urmia (Iran). As the saline lake levels drop due to climate change and over consumption, there is a clear need to understand changes in water and salt transport throughout these lakes. In the GSL a railroad causeway divides the lake into northern and southern sections and limited connectivity is provided at causeway breaches In these settings, the water and salt exchanges through these hydraulic structures are difficult to quantify, but critical for management efforts related to long-term ecosystem health and related industries via the evolution of the GSL’s density profile [10,11]. The modeling effort provides a better understanding of the bidirectional buoyancy-driven flow through the WC breach that provides GSL management and stakeholders with insights into how the openings in the causeway could be used for effective brine management in the future [12,13]
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