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The Timing And Magnitude Of Channel Adjustments In The Upper Green River Below Flaming Gorge Dam In Browns Park And Lodore Canyon, Colorado: An Analysis Of The Pre- And Post-Dam River Using High-Resolution Dendrogeomorphology And Repeat Topographic Surveys, Jason S. Alexander

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Channel narrowing on the Green River in Utah and Colorado has been well documented by several authors and has been attributed to reductions in flow after 1930, the construction of Flaming Gorge Dam (FGD), and the invasion of the woody riparian plant Tamarisk (tamarix ramosissima). Narrowing has occurred through the deposition of inset floodplains, which have vertically accreted within a previously larger active channel. Prior to closure of FGD, lower magnitude floods aggraded surfaces in the areas of the channel that had the highest divergence in the velocity flow field (i.e. bars and banks). These surfaces later became …

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 …

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 …