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The Geomorphic Basis Of Colorado Squawfish Nursery Habitat In The Green River Near Ouray, Utah, Cynthia L. Rakowski

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nursery habitat availability is considered a bottleneck to successful recruitment of Colorado squawfish (Ptychocheilus Lucius). Detailed geomorphic studies were conducted in a 1.5-km reach to examine channel response to flows and the geomorphic setting of nursery habitats during a 2-year period. Videography was used to extend relationships in the 1.5-km reach to a longer 10-km reach.

Nursery habitat availability varied yearly with little persistence in location or geomorphic setting of individual habitats for the 2 years of this study. A small number of habitats provided most of the area of high-quality (i.e., deep) habitat, and most of the …

Channel Narrowing Of The Green River Near Green River, Utah: History, Rates, And Processes Of Narrowing, Tyler M. Allread

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Previous scientific research has documented channel narrowing on the Green River near Green River, Utah, but the exact timing, rates, and causal mechanisms of that narrowing have been the source of disagreement in the scientific literature. This thesis demonstrates that the Green River has narrowed in two separate periods during the last 100 years. The narrowing is driven primarily by changes in the hydrologic regime and not by the invasion of saltcedar. The channel narrowed between 1930 and 1938, when a shift from wetter than normal conditions to a period of draught led to a reduction in river discharge. Channel …

Effects Of Flow Augmentation On Channel Morphology And Riparian Vegetation In The Upper Arkansas River Basin, Colorado, Dewitt S. Dominick

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study examined historic change of riparian plant communities and fluvial geomorphic response of gravel-bedded streams and their floodplains to over 50 years of hydrologic disturbance. Four tributary basins of the Arkansas River were analyzed. Lake Creek, Clear Creek, and Cottonwood Creek are drainages similar in area, physiography, and vegetation composition. However, Lake Creek may receive an instantaneous discharge of approximately 28 m3sec^-1 from the Twin Lakes tunnel, over three times the normal flow of the stream during spring runoff. By contrast, Clear Creek and Cottonwood Creek, nonaugmented streams, were used as controls to compare the historic and present …