Earth Sciences Commons^™

Geomorphic History Of The Grand Staircase Region Of The Colorado Plateau: Understanding Arroyo Cut-Fill Dynamics, Erosion Rates, And Wildfire, Kerry E. Riley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Most streams in the southwestern United States do not flow all year, and given their delicate balance of sediment and water flow, they are sensitive to climate change. At the turn of the 20th century, many streams in the Southwest rapidly incised into their floodplains, forming arroyos with a channel entrenched into near-vertical channel banks mostly composed of sand and mud. This dissertation investigates past changes in watersheds draining the Grand Staircase region in southern Utah with the goal of understanding how changes in climate and sediment influence these types of streams. Results show sediment supply is highly variable across …

Mechanisms Of Vegetation-Induced Channel Narrowing On An Unregulated Canyon-Bound River, Rebecca Blanche Manners

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The accurate prediction of river channel width remains a fundamental area of investigation in the field of geomorphology. River managers and scientists are interested in understanding how a channel will respond to environmental perturbations such as altered runoff patterns from climate change, a new dam, or a pulse of sediment from a landslide. Increasingly, studies that focus on this question acknowledge the importance of accounting for the vegetation that lines the river banks. For this dissertation, I strove to identify some of the primary ways by which vegetation affects channel width.

At a fundamental level, vegetation influences the size of …

Formation, Deformation, And Incision Of Colorado River Terraces Upstream Of Moab, Utah, Andrew P. Jochems

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The history of rivers is laid down as sediment in all landscapes, typically as a function of climate, geologic structures, and/or changes in sea level. When a river abandons its floodplain, this sediment collectively constitutes a landform called a fluvial terrace. Terraces are used to unlock prior characteristics of a river flowing through a given area at both local and regional scales. Dating terrace sediment allows comparison to known changes in climate and geologic deformation, two significant controls on the hydraulics of rivers and the deposition of their sediment loads.

The importance of terraces lies in their utility as markers …

Applications Of Bayesian Statistics In Fluvial Bed Load Transport, Mark L. Schmelter

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The science of fluvial sediment transport studies the processes involved in the movement of river sediments. It is commonly understood that when rivers flood they have a great capacity to move sand, gravel, and even larger cobbles and boulders. This process is not only limited to the big floods that usually attract so much attention, but also the more common river flows play a very important role in forming a river. As engineers and scientists, we like to be able to develop equations and relationships that describe some natural phenomenon—in this case, fluvial sediment transport. While we are able to …

Comparison Of Topographic Surveying Techniques In Streams, Sara G. Bangen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Bonneville Power Administration (BPA) Fish and Wildlife Program (FWP) mitigates impacts, including mortality, from hydroelectric dams in the Columbia River Basin for ESA-listed salmon and steelhead populations and other species of special concern. Given the extensive economic resources invested in mitigation and the incredible diversity of in-stream habitat across the Columbia River basin, questions have arisen about which sampling strategies are most tractable across the entire Columbia River Watershed, but also produce datasets that allow researchers to answer meaningful questions about salmonid populations and trends in habitat. In response to these issues, the NOAA Integrated Status and Effectiveness Monitoring …

Evaluation Of Lake Fertilization As A Tool To Assist In The Recovery Of The Snake River Sockeye Salmon (Oncorhynchus Nerka), Howard P. Gross

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

I analyzed lake fertilization (with nitrogen and phosphorus) as a tool to assist in the recovery of the Snake River sockeye salmon (Oncorhynchus nerka) in the oligotrophic Sawtooth Valley Lakes in southcentral Idaho. These analyses involved monitoring, manipulating, and modelling several aspects of the lakes' primary producer, nutrient, and light parameters.

In Pettit Lake, I evaluated the effects of metalimnetic and epilimnetic fertilization in 330-m³ mesocosms. The metalimnetic treatment was equal to or more effective than the epilimnetic treatment in increasing chlorophyll a, phytoplankton biovolume, and primary productivity, yet caused smaller changes in periphyton growth and …