Physical Sciences and Mathematics Commons^™

Multi-Objective Water Management In Idaho's Henrys Fork Watershed: Leveraging Reservoir Operation And Groundwater Pathways To Benefit Aquatic Habitat, Christina N. Morrisett

All Graduate Theses and Dissertations, Fall 2023 to Present

Multi-user water management is a challenging arena further complicated by climate change. This research is based in the Henrys Fork, Snake River, Idaho—an agricultural watershed that exemplifies those throughout the semi-arid American West. This dissertation uses an integrated approach that considers groundwater-river relationships, farm-scale decisions and basin-scale outcomes, upstream reservoir operation for downstream aquatic habitat, water rights, and collaborative stakeholder management to identify drought adaptation strategies accordingly.

Chapter 2 uses an interdisciplinary approach to quantify how improvements to irrigation efficiency at the farm-scale (i.e., converting from flood to sprinkler irrigation) can add up to affect hydrology at the landscape-scale and …

Movement Patterns Of A Federally Endangered Minnow In A Fragmented Desert River, Martinique J. Chavez

All Graduate Theses and Dissertations, Fall 2023 to Present

Fishes are unified in their need to move within the systems they occupy, and their movement patterns can be fundamental to their ecology and survival. Many large rivers in North America are fragmented by dams that modify natural flow regimes, compromise connectivity, and imperil freshwater fishes dependent on unrestricted movement in order to complete their life history. Coincident with widespread river fragmentation, are the declines of numerous endemic desert fishes in the American southwest. The Rio Grande Silvery Minnow (Hybognathus amarus, RGSM), has experienced a 95% reduction in its historical range and is now restricted to a highly …

Controls On Sediment Connectivity In Fluvial Networks Impacted By Wildfire Across Utah, Alec Arditti

All Graduate Theses and Dissertations, Fall 2023 to Present

Flooding and sedimentation caused by wildfire are among the greatest threats to watersheds, fish populations and reservoirs in the western US. Burned landscapes are at risk for increased runoff and erosion and have the potential to transport sediment that may put downstream resources at risk. The ability of the channel to transport sediment downstream, known as the connectivity, is important for determining where impacts may occur. Sediment bottlenecks are locations within the watershed where local conditions produce a persistent decrease in downstream connectivity of sediment, resulting in increased sediment deposition and potentially a substantial modification of the local channel and …

Ecology And Management Of Dyer's Woad (Isatis Tinctoria) In Northern Utah, Erin Marie Hettinger

All Graduate Theses and Dissertations, Fall 2023 to Present

Dyer’s woad (Isatis tinctoria L.) is a non-native forb that continues to threaten natural areas throughout Northern Utah and much of the Intermountain West. Once introduced, dyer’s woad can become extremely invasive, decreasing forage quality, and displacing native species. While dyer’s woad is found throughout much of Northern Utah, its range in other states remains limited. If promptly managed, control success in these areas will be much higher and populations may be kept at bay before ecological damage becomes severe.

This project tested the ability of dyer’s woad seedlings to compete with common rangeland grasslands at varied densities as …

Analyzing The Impacts Of Beaver Dam And Beaver Dam Analog Complexes To Stream Ecology Within The Intermountain West, J. Marshall Wolf

All Graduate Theses and Dissertations, Fall 2023 to Present

Streams, rivers, and their floodplains throughout the world are impaired due to human modifications. Recent research has demonstrated that restoration projects prioritizing the proper functioning of ecosystems have better restoration outcomes than projects which focus on restoring form alone. Throughout North America, beaver-mediated restoration is becoming a leading method for improving the functioning of stream ecosystems that are in a degraded state. In areas where beaver are absent or the habitat is too degraded to currently permit their dam building, man-made beaver dam analogs (BDAs) are being used to restore stream habitat with an eye to future beaver recolonization. However, …

Inundated Vegetation Response To Ongoing Restoration And Its Impacts On Fish Community Structure, Emmanuel J. May

All Graduate Theses and Dissertations, Fall 2023 to Present

Shallow lake ecosystems and their associated wetland habitats globally are subject to non-native species introductions, nutrient loading, and water level fluctuations, each of which can decrease vegetated habitat availability, exposing vulnerable native aquatic species to predation. Managers are frequently tasked with mitigating native species declines by restoring vegetation considered crucial for their survival. However, restoring vegetation can be challenging in the presence of multiple stressors, requiring managers to assess the relative importance of the different stressors limiting vegetation recovery.

Utah Lake is a large shallow lake subject to multiple stressors and has shifted from a mesotrophic lake with abundant aquatic …

Fire And Flow: Assessing The Long-Term Effects Of Wildfires And Impact Of High Flow Events On Phosphorus Concentrations In Mountain Streams, Rachel Watts

All Graduate Theses and Dissertations, Fall 2023 to Present

Climate change has led to significant shifts in the Earth’s weather patterns, often leading to longer, more intense droughts, irregular but extreme storms, and more severe wildfires with longer burn durations. These weather pattern changes have frequently led to shifts in ecosystem dynamics, impacting aspects such as nutrient flux, species diversity, and overall habitat health. Regarding nutrient flux specifically, changes in phosphorus (P) concentrations can negatively impact stream systems as elevated levels can lead to toxic algal blooms, which can cause habitat degradation, loss of usable recreational areas, and large fish kills. A common trigger of these P spikes is …