Date of Award:

12-2023

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Civil and Environmental Engineering

Committee Chair(s)

David G. Tarboton

Committee

David G. Tarboton

Committee

Robert Gillies

Committee

Jeffery S. Horsburgh

Committee

Sarah Null

Committee

David Stevens

Abstract

The Great Salt Lake (GSL) and its tributaries are ecologically and economically important resources for Utah. It is a highly saline lake, with salinity that is several times saltier than the ocean. Lake uses are heavily influenced by its salinity and lake level and, similarly, river uses by its streamflow quantity. Currently, the GSL Basin is experiencing changes that affect tributary inflows, lake level, and salinity. For my dissertation and in support of better lake management, I addressed important gaps in our understanding of the lake and the changes it is undergoing.

Chapter 2 is an examination of the distribution of salinity and salt mass within the lake. Existing measurements from multiple agencies were aggregated to quantify the variability in salinity and the intermittent presence of a deep brine layer, which occurs only with causeway flow from the north to the south arms. I found that the overall mass of salt in the lake is declining and quantified this in terms of mineral extraction records and historical density measurements.

Chapter 3 estimates the historical magnitude of human consumptive water use within the basin. Lake volume changes and evaporation estimates were used to quantify inflows to the lake corresponding to changes in lake level. The trends in these inflow estimates were used to quantify basin wide human consumptive water use to be upwards of 2.3 km3 /yr and the current lake level decline associated with this estimate to be as much as 4.5 meters.

Chapter 4 presents a learning module targeting undergraduate hydrology students that was developed to advance innovative approaches in hydrologic education. While this project does not directly relate to the GSL, it enhances student learning of hydrologic processes within the GSL Basin. The newly developed content is centered on case-based, data- and simulation-driven learning of the fundamentals of hydrology, rainfall-runoff processes, and engineering design for an online module focused on a detention basin at the mouth of a canyon in the GSL Basin.

Overall, this dissertation has contributed knowledge on the salinity, deep brine layer and declining salt mass in GSL due to mineral extraction. It has also provided a lake volume based water balance estimate of consumptive water use extending back prior to the period when streamflow was measured. These contributions provide important scientific information about the lake that can inform decision making on water management and efforts to restore the lake to healthy levels.

Checksum

8ddd995ce49b16e3de33a1d4a8162dbd

Download

Share

COinS

Copyright for this work is retained by the student. If you have any questions regarding the inclusion of this work in the Digital Commons, please email us at .