The purpose of this work is to create a sediment budget template (SBT) with Aberdeen Pool on the Tennessee-Tombigbee Waterway as the demonstration site. The first task is to define the sediment behavior for the system in question. USGS data are used for sediment concentrations and flows. The USGS data are the basis for the Power Curve Program which defines the sediment behavior in terms of a power function. The second program, Tier 1 Program, uses the power curve coefficients along with the bankfull discharge to define the sediment fluxes. Thirdly, the Tier 2 Program uses power curve coefficients with daily flows to calculate daily sediment flux which are integrated over each year to calculate the yearly fluxes. From the sediment fluxes, a mass balance equation is implemented to estimate total deposition. Lastly, the computer program SIAM is used to estimate deposition amount. Comparison among the three different methods provides a best estimate of the final depositional approximation.

More than half the North American freshwater mussel species in the family Unionidae (unionids) are imperiled or extinct. Alteration of rivers is considered a major contributor to unionid population declines. Losses could occur through disruption of the reproductive cycle. Unionid reproduction requires attachment of larva (glochidia) to host fishes; therefore, changes in the host fish community could alter the reproductive potential in unionid communities. There have been few attempts to compare reproductive success before and after alteration. I examined the pattern of glochidia use on two common host fishes, Lepomis megalotis and Cyprinella venusta, before and after alteration of the Tombigbee River. While both host species declined in the river, the number of glochidia per infested fish and proportion of infested fish increased post-impoundment in L. megalotis but not C. venusta. My results demonstrate the importance of considering reproductive changes as a driver of unionid mussel declines in North America.

Paddlefish are long-lived large river fish which are declining in many areas of their range due to habitat modifications and overfishing. A framework for management of paddlefish in Mississippi is proposed and a case study of its application to the paddlefish population of the Tennessee-Tombigbee Waterway (TTW) is presented. The framework includes four phases: (I) distribution and stock assessment; (II) determination of limiting factors; (III) design and implementation of management actions; and (IV) review and monitoring. Phase I of management in the TTW consisted of gill-net surveys in four impoundments. Paddlefish abundance was estimated at 1,581 to 8,851 in Demopolis Lake, Alabama. In Gainesville Lake, Alabama, CPUE was 16.8 times less than Demopolis Lake. No paddlefish were caught in Aliceville Lake, Mississippi/Alabama, or Columbus Lake, Mississippi. Demopolis Lake paddlefish grew faster than more northern populations, but slower than more southern populations (Lt = 971.8 [1 − e−0.2844 (t+0.6962)]) and had a high annual mortality rate (A = 0.406) comparable to other southern populations. Potential limiting factors related to spawning in Demopolis Lake and stocking programs in Columbus Lake were investigated pursuant to Phase II. Paddlefish eggs were collected in the Noxubee River and a unique flowing bendway habitat in Demopolis Lake during early April when discharge was ¡Ý2.74 m above 50% exceedance. Flow timing and magnitude in the Noxubee River was related to paddlefish year-class strength (linear regression P = 0.089; R2 = 0.830). Radio-tagged paddlefish exhibited seasonal site fidelity and 4 of 10 translocated fish returned to their area of initial capture.,Columbus Lake provides food resources and physiochemical characteristics adequate for paddlefish survival, but depth and zooplankton density are more favorable in Demopolis Lake. Emigration of stocked juvenile paddlefish was low in Columbus Lake habitats; survival (percent after one month ¡À SE) was 5 ¡À 5 in backwaters and 28 ¡À 9 in the mainstem after one month. Phase III recommendations include further investigation of early life history requirements and protection of bendway and tributary habitat in Demopolis Lake. The annual stocking of 4,000 juvenile paddlefish in the mainstem of Columbus Lake and up to 1 million larval paddlefish in a tributary is recommended.

Thesis (M.S.)--Mississippi State University. Department of Civil and Environmental Engineering. / Title from title screen. Includes bibliographical references.

Thesis (Ph.D.)--Mississippi State University. Department of Wildlife and Fisheries. / Title from title screen. Includes bibliographical references.

Regulation of the Upper Tombigbee River and its incorporation into the Tennessee-Tombigbee Waterway has resulted in main-channel flows that differ from the pre-regulation condition. Flows differ in (1) magnitude: higher base flows, damped peak flows, and (2) variability: the river rises and falls faster and the number of reversals has increased. A shift in the trophic ecology of the resident fish assemblage corresponded with the altered hydrology. Assemblage-level trophic plasticity manifested through dietary shifts in species present during both time periods are coupled with changes to the taxonomic structure observed previously. Species representing the contemporary assemblage feed on fewer taxa regardless of respective trophic ecologies and include taxa that are not characteristic of diets under pre-regulation conditions. More basal resources contributing to production resulted in a greater number of trophic pathways flowing through a decreased dietary breadth. Reduced foraging efficiency is inferred for riverine specialists, possibly resulting in lower fitnesses. Tributaries are highlighted as important in maintaining biodiversity in the regulated main-channel because flows and associated trophic ecologies of resident fishes are relatively similar to those observed under pre-regulation conditions. Materials and taxa exhibit unique interactions at “zones of confluence” where unregulated tributaries merge with the main-channel. Quantifiable characteristics of trophic ecology and ecomorphology, along with connectance to free flowing major tributaries, emerge as potential indicators of the vulnerability of fishes to hydrologic alteration.

At the time of its construction (1971-1985), the Tennessee-Tombigbee Waterway was a highly scrutinized public works project, but the years after its construction have remained largely unexplored. Research in the John C. Stennis Collection, U.S. Army Corps of Engineers and Tennessee-Tombigbee Waterway Development Authority archives, and local newspapers, revealed that despite developers’ promise the waterway’s economic impact failed to live up to expectations, while its environmental influence more than exceeded them. Though rural southerners failed to benefit economically from the waterway, they embraced the environmental changes forced upon the project by the National Environmental Policy Act. Built as a promise of economic development, the Tenn-Tom offers a model of how economics and environmental forces intersected within the rural South. The waterway’s history as an economic and environmental force demands a reconsideration of the role of public works projects in southern environmental history.