Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 148-163).

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

Master of Landscape Architecture / Department of Landscape Architecture/Regional and Community Planning / Timothy D. Keane / The purpose of the investigation was to inventory and analyze riparian corridor vegetation changes throughout the Black Vermillion watershed from approximately 1857 through 2007. Three sub-watersheds were studied; North Fork, Irish Creek and Black Vermillion Main Stem. Research questions investigated were: 1) What changes in riparian corridor width have taken place since the original territory surveys done in 1857 and why? 2) How has land cover adjacent to riparian corridors changed since the original territory surveys? 3) Has woody species composition in the riparian corridors changed? The research questions were addressed using a variety of techniques and tools including aerial photography, basic GIS, and vegetation survey techniques. Territory of Kansas survey maps and notes that were completed in 1857 were used as baseline reference conditions concerning corridor width and woody species present in the riparian corridors. Inventory and analysis of the riparian vegetation change over time and adjacent land cover will aid in understanding the present ecology of these riparian corridors and are important to stream and riparian ecosystem rehabilitation. Woody riparian corridors increased in width throughout the watershed from 1857 until about 1956 (probably due to a decrease in prescribed burning and lack of grazing), which is the pre-channelization period for this watershed. After channelization (late 1960's & early 1970's), average corridor widths dropped significantly as the stream was shortened a total of 15.8 miles (25.4Km). Most often, the land cover changed from native, tallgrass prairie to cultivated cropland or pasture. Woody species composition has changed over time from established mature woodland to a pioneer successional stage. The findings of this study can influence beginning stages of design for natural habitat rehabilitation purposes in this watershed. Design decisions for land rehabilitation purposes should consider reference conditions (historic), and to understand reference conditions we must study the history of land use and land change. This study provides a template for studying the history of land use and land use change of riparian corridors for Midwestern, agricultural landscapes.

Published literature about six Pacific Northwest stream systems was contrasted to provide a regional perspective on channel response to disturbance. This investigation was prompted by a combination of recent environmental legislation, mounting social pressures to plan projects at a drainage basin scale, and the difficulty in defining and predicting the response and recovery of a stream channel to land-use management or storm events. Detailed studies of Redwood Creek, CA; the San Lorenzo River, CA; the South Fork Salmon River, ID; the Upper Middle Fork of the Willamette River, OR; the Alsea River System, OR; and Carnation Creek, B.C. were reviewed and contrasted. Differences in channel response to disturbance appear to be the result of the sequence of storms, the interactions between storms and land-use, the processes that deliver sediment to the channel, the available stream power, and the bank stability. Basins with low debris avalanche and earthflow potential, high stream power, and stable stream banks experience only localized and short-lived response to disturbance. On the other hand, basins with frequent debris avalanches or high earthflow potential and unstable banks experience widespread and persistent response. This study concludes that there must be realization and acceptance of the random nature of channel response and recovery following disturbance. Field evaluation, professional judgement, risk assessment, and adaptive management are the most powerful tools available in the prediction of channel response. / Graduation date: 1993

The first objective of this investigation was to derive and compare scour depth equations in a long contraction using the most widely used sediment transport equations and a variety of other equations. The second objective was to determine a procedure to find an equivalent rectangular section which would convey the same water discharge and sediment load at same slope as an irregular, natural channel in order to simplify numerical computations of scour depth and to allow appropriate application of long contraction scour theory. Some of the transport equations were manipulated algebraically to develop equations for scour depth and slope in a long contraction; others were manipulated using computer programs written especially for each equation, thus deriving scour depth equations. A computer program was written to compare characteristics of a non-rectangular section with rectangular sections of different widths in order to derive a procedure to find an equivalent rectangular transport section (a triangular section was used in this investigation) but the procedure is equally valid for any irregular, natural section. This investigation indicated that depth in the contraction is greater than in the wider approach channel. How much greater depended on which sediment-transport equation was used. Most of the derived scour equations, based on the different sediment transport equations, predicted that the y₂/y₁ ratio decreases as slope, velocity, c, and τₒ'/τ(c) or √τ/ρ)/ω increase; a few do not. Most of the analysis predicted S₂ < S₁, but a few do not. Field and experimental data provided extra evidence that the depth in the contracted section is greater than in the approach reach and how much greater. The evidence that the slope is flatter is not sufficient to be completely convincing. The equivalent rectangular transport section which can carry the same water and sediment discharge at the same slope as the natural section has a depth which is a large fraction of the deepest part of the original section, and the width is considerably narrower than the top width of the original section. Results of the investigation also indicated that the slope, velocity, sediment concentration, and sediment size have little effect on the geometry of the equivalent rectangular section.

Thesis (Ph.D.)--University of Melbourne, Dept. of Civil and Environmental Engineering, 2001. / Typescript (photocopy). Includes bibliographical references.

Thesis (M.S.)--University of Wyoming, 2007. / Title from PDF title page (viewed on Nov. 6, 2008). Includes bibliographical references (p. 104-109).

This study compared three different types of reaches at streams and how bryophyte species richness, diversity and abundance in the riparian zone differ between them. The different types of reaches are those that have been treated by two types of restoration techniques (best practise and advanced) and streams that have still not been restored (channelized). The bryophytes were gathered from 15 tributaries to Vindelälven, which is in northern Sweden. Bryophyte species richness and diversity was highest at the streams that were still not restored, and I found numerous factors that could explain why this was the case. Fourteen environmental variables were tested against the three bryophyte factors to try to explain the variation found in the study. Time since restoration and the amount of tree biomass in the area could explain the species richness found at the different river types. The study shows that short-term effects of restoration on the riparian zone is a decrease in bryophyte species richness and diversity. However, given enough time the bryophytes are expected to recover in regards to species richness and diversity.

No description available.

No description available.