No description available.

published_or_final_version / Civil Engineering / Master / Master of Philosophy

The addition of dams into a riverine system causes a wide range of changes (i.e., sedimentation, erosion, thermal) to the river as well as to the fish assemblages of that river. Although there have been many studies documenting the changes that occur to the fish assemblages in the impounded river, there have been fewer studies examining the effects of a reservoir on the fish inhabiting the tributaries upstream of the impoundment. One possible impact of a reservoir could be to act as a barrier to fish migration between streams. To determine if reservoirs restrict migration, the genetic diversity of two species of darter, the rainbow darter Etheostoma caeruleum Storer and the Highland Rim darter Etheostoma kantuckeense Ceas and Page, was determined from populations inhabiting the Barren River Lake drainage basin. Between ten and twenty-six individuals of each species were collected from each of 6 sites. Three streams were directly connected to Barren River Lake and three streams were directly connected to Barren River upstream of the reservoir. Allelic variation at 3 microsatellite loci was analyzed to determine the degree to which each population is isolated. If the reservoir is restricting gene flow between populations, the populations in streams adjacent to Barren River Lake would be predicted to have lower allele diversity and heterozygosity than those adjacent to the Barren River. Consistently high levels of allelic diversity (total number of alleles, N), observed heterozygosity (Ho), and effective number of alleles (Ae) across both reservoir and river study sites led to the rejection of the hypothesis that the reservoir is acting as a genetic barrier to darters. M-ratios differed between species, with Etheostoma caeruleum exhibiting consistently higher M--ratios than Etheostoma kantuckeense. The low M- seen in E. kantuckeense could be due to small sample sizes (largest sample for this species showed the highest M-), and could also be due to small natural populations. With the exception of Salt Lick Creek, high allelic diversity was observed at most sites for E. kantuckeense. A low M- coupled with high allelic diversity in most E. kantuckeense populations, may indicate that all of the study populations are recovering from a bottleneck event. These results indicate Etheostoma kantuckeense is sensitive to changes in the environment. When conservation agencies assess fish populations in South Central Kentucky, it is advantageous to know which species are currently at risk, which species are sensitive to environmental changes, and which species or populations are recovering from events that were detrimental to their genetic diversity.

The objective of this study was to determine the relationship between fish assemblage structure and habitat in streams dominated by an agricultural landscape. Fishes from 20 natural and 20 channelized streams were sampled using electrofishing gear in East Central Indiana. Streams that had been channelized had a lower quality fish assemblage when compared to natural streams as measured by the Indiana V. Eastern Corn Belt Plain Index of Biotic Integrity (IBI). Stream habitat was evaluated using the Qualitative Habitat Evaluation Index (QHEI), which indicated that channelized streams had lower quality primarily due to a loss of heterogeneous habitat. Pearson correlation analysis relating ECB IBI and QHEI was positive and significant, and demonstrated that a reduction in riffle and pool areas associated with channelization was the most significant factor influencing the fish community. Furthermore, species lost when streams are channelized were predictable, and often represented environmentally sensitive species. The results of this study suggested that stream channel alterations have a negative and lasting influence on the fish assemblage which should be recognized prior to any stream development. / Department of Biology

Thesis (M.S.)--University of Tennessee, Knoxville, 2008. / Title from title page screen (viewed on Mar. 12, 2009). Thesis advisor: Carol Harden. Vita. Includes bibliographical references.

Thesis (M.S.)--Texas A&M University, 2003 / "August 2003." Includes bibliographical references (p. 70-82). Also available via the Internet.

This study sets out to evaluate the use of geophysical methods for delineating buried stream channels, which can act as zones of preferential flow within a less hydraulically conductive aquifer. This information is important for gaining an understanding of flow dynamics of alluvial systems. The most reliable method of delineating the dimensions of aquifers is by drilling, which is an expensive proposition and is best preceded by a preliminary geophysical study to help define target zones for a drilling program. The study area is located adjacent to the Coerney River in the Sundays River Valley. Geologically it consists of approximately 5 metres of alluvial fines, covering 3 metres of coarse cobbles and boulders, all underlain by alternating siltstone and sandstone beds of indeterminate thickness. Throughout the area the water is very shallow at approximately 2 metres depth and the groundwater tends to be very saline. An air photo study revealed an old oxbow channel that had been covered over by subsequent agricultural land use. The geophysical methods available for the study were portable seismic refraction, electrical resistivity and electromagnetics. Preliminary field tests clearly showed that seismics did not produce valid results. The methods of electrical resistivity and electromagnetics produced good data and were subjected to further assessment. A grid was surveyed over the study area and both geophysical methods were applied at regularly spaced stations. Soil samples were taken over the same survey grid and analyzed for electrical conductivity in a soils laboratory. The results were compared to the geophysical data in an attempt to quantify the relationship between geophysical response and soil salinity. The data from the electromagnetic survey showed areas of low electrical conductivity which was a possible indication of zones of preferential groundwater flow. A transect of boreholes was drilled over selected electrical conductivity lows and successfully intersected the buried stream channel. A comparison of the borehole logs with the layered earth models from the Vertical Electrical Soundings indicated that the electrical resistivity method was not responding to the features of the buried stream channel and the cobblestone layer. This proved the electromagnetic method to be more valuable for this particular study

No description available.

No description available.

Stream channelization is a common form of anthropogenic disturbance, whose impacts on cold water salmonid communities have received little attention in comparison to the body of work demonstrating its negative effects on low land, warm water systems. Here, I compared the effects of stream channelization on fish and invertebrate communities and their habitats in disturbed and undisturbed cold-water mountain streams in southern Alberta. I demonstrate that stream channelization has imposed significant alterations to stream habitat, most notably a loss of deep habitat, and that these alterations have led to a statistically significant decline in abundance and biomass of Rainbow Trout and Mountain Whitefish, as well as a significant decline aquatic invertebrate biomass. Because of the importance of monitoring fish abundance in deep pools, I used snorkel surveys instead of electrofishing. In shallow, disturbed streams, however, snorkel surveys may be less effective and should be used with caution. / ix, 104 leaves : col. ill., col. maps ; 29 cm