Expected Graduation Year
College of Engineering
Civil and Environmental Engineering Department
Groundwater and surface water are increasingly thought of as a single source with groundwater and surface waters being exchanged at highly variable spatial and temporal scales. Karst geology results in shorter groundwater travel times which alter the dynamics between groundwater and surface water. Within the groundwater dominated Logan River watershed in northern Utah, a portion of a karst spring entering the river is used as a drinking water source for Logan City, and a large fraction of the river is used as a secondary water source for northern Cache Valley. Currently, there is limited information on groundwater contributions over space and time in this watershed and methods for quantifying them are lacking. Using streamflow data collected at 16 gauging sites, including seven main-stem sites and nine tributaries and diversions, a flow balance was completed to provide estimates of net groundwater discharge or recharge. The watershed was divided into five sub-reaches, three mountainous and two urban. All mountainous and one urban sub-reach experienced consistent groundwater discharge while the other urban sub-reach was an area of groundwater recharge. The influence of groundwater discharge on surface water quantity in the majority of these reaches highlights the need to further differentiate influences of shallow groundwater from deep groundwater because the availability of shallow groundwater will vary with changes in annual precipitation, while deeper groundwater influences could prove more resilient during droughts.
Tennant, Hyrum, "Groundwater Influences on the Logan River Watershed" (2017). Research on Capitol Hill. Paper 62.