HR: 0800h
AN: H41C-0422    [Abstracts]
TI: Modeling the Dynamics of the Great Salt Lake as an Integrator of Regional Hydrologic and Climate Processes?
AU: * Mohammed, I N
EM: nourein@cc.usu.edu
AF: Utah State University, 4110 Old Main Hill, Civil and Environmental Engineering, Logan, UT 84322-4110 United States
AU: Tarboton, D G
EM: dtarb@cc.usu.edu
AF: Utah State University, 4110 Old Main Hill, Civil and Environmental Engineering, Logan, UT 84322-4110 United States
AB: The Great Salt Lake (GSL), Utah, is the fourth largest, perennial, terminal lake in the world. The Great Salt Lake (GSL) level fluctuates due to the balance between inflows and outflows. These fluctuations are of interest whether they are high (flooding hazards) or low (economic impacts). Inflows are due to streamflow, primarily from the Bear River (54%), Weber River (18%) and Jordan/Provo River (28%) systems. Inflows also include precipitation directly on the lake and groundwater both from the East and West sides. The only outflow is evaporation that is controlled by the climate and area of the lake that changes with level. The GSL reached historic high levels above 1284 m in 1873 and 1986. A historic low at 1278 m occurred in 1963. These fluctuations represent the integrated effect of climate and hydrologic processes as well as the dynamic interaction between lake volume, area and salinity that impact evaporation from the lake. The topographic area-volume relationship in the GSL plays a role in the system dynamics because area is a control on the evaporation outflux. This paper examines the relationships between Basin climate (precipitation and temperature), Inflows to the lake (primarily streamflow) and outflows (evaporation). The role played by the topographic elevation-area-volume relationship on lake dynamics and the correspondence between modes in volume and area distributions and peaks in the area-volume derivative was examined. We derived, using a steady state approximation, the relationship between distributions of lake volume and lake area and the area-volume derivative from the topography/bathymetry. This analysis showed that both the topography/bathymetry and multimodality in the area distribution are required to explain the observed multimodality in the volume distribution. We also separated lake volume changes into increases in the spring (due to spring runoff) and declines in the fall (due to evaporation) and then related these volume changes to streamflow, precipitation, and basinwide climate inputs. The results of this study improve understanding of the sensitivity of the GSL level to the interplay between topography and fluctuations in precipitation and climate and thereby contribute to knowledge on the interactions between hydrologic processes and long-term large-scale climatic fluctuations.
DE: 1899 General or miscellaneous
SC: Hydrology [H]
MN: Fall Meeting 2005