The purpose of this study is to describe and explain tributary changes within the lower Trinity River basin, Texas, downstream of Livingston Dam. Within southeastern Texas, an opportunistic geomorphic experiment arose when the Trinity River was impounded. The dam represents a marked moment and place of a system perturbation. Geomorphological effects of the lower Trinity River tributaries were investigated through five different types of data: analysis of published discharge and sediment load data, examination of alluvium, planform change as measured from aerial photographs, resurveys of bridge cross-sections, and field mapping of geomorphic indicators of change. Since closure, Lake Livingston has reduced sediment supply while minimally affecting the discharge regime. Channel scour is evident for about 60 km downstream. All the tributaries studied are located within this reach. Currently, there is no model that directly addresses the morphological response of a tributary streams confluence downstream of a dam. Therefore, the Confluence Effects Model is developed to predict the resulting geomorphological impacts within a tributary streams mouth with varying changes in trunk stream discharge and channel morphology. When applied to two confluences of the lower Trinity River, the Confluence Effects Model successfully predicts the resulting geomorphological changes. Within the lower Trinity River basin, the tributaries are reacting in a nonlinear and complex manner. Delayed or lagged responses are illustrated through sediment budgets for two tributaries which suggest a large amount of sediment is in storage within the tributary basins. Applying the unstable hydraulic geometry model, thirteen qualitatively different modes of adjustment with respect to increases, decreases or lack of change in width, depth, slope and roughness were observed within the tributary systems. The nonlinear and complex reactions of the tributary systems mask the effects of the impoundment beyond the confluences with the Trinity. The geomorphic characteristics of the tributaries are largely dominated by Holocene sea level change and the response to extreme events, such that dam effects become relatively localized. While this study considered a coastal plain fluvial system perturbed by human modifications, other earth surface systems may draw comparisons between emergent responses, response times and landscape sensitivity to a disturbance within a system.

Taxonomic composition and spatio-temporal variability of macroinvertebrates inhabiting snags were examined from an 8-km segment of the Elm Fork of the Trinity River. Seventy-seven macroinvertebrate taxa were collected from submerged wood during the study. Assemblages were highly variable spatially and temporally, especially among seasons. An ordination of species and environment did not find snag taxa to have striking correlations with many of the selected environmental variables, although there were some trends in flow-mediated species distributions. There were significant seasonal differences in the abundances of some taxa, particularly among the Chironomidae (Diptera). The Tribe Orthocladiini was numerically abundant during the winter, while the Tribes Chironomini and Tanytarsini dominated the summer and autumn. Additionally, this study included a secondary production and microdistribution analysis of a population of the caddisfly Cyrnellus fraternus. Distributions of C. fraternus were restricted to snags, the most stable substratum for retreat building and for resisting periodic high waters. Larvae were not found in the soft sand and mud benthic habitats near submerged wood. The insects were multivoltine with a minimum of three generations per year. Pupae were collected July through September and adults emerged from May through October. The population overwintered as larvae. Estimated annual production was 1,015.4 mg/m2/yr. Mean standing stock biomass was 61.24 mg/m2, the cohort production/biomass ratio was 4.59, and the annual production/biomass rate was 16.58/yr for this population. Standing stock biomass ranged from 1.6 to 349.1 mg/m2 during the year and was significantly higher in autumn and summer than winter. Larvae were more abundant in the lower portions of the study area where flow was reduced for much of the year, than in the upper reaches, characterized by higher current velocities. C. fraternus larvae were found in their highest numbers on snags with dense deposits of silt and sand.

From 1930 to 1955, Amon Carter, publisher of the Fort Worth Star-Telegram, exerted his power to create modern Fort Worth. Carter used his stature as the publisher of the city's major newspaper to build a modern city out of this livestock center. Between 1930 and 1955, Carter lobbied successfully for New Deal funds for Fort Worth, persuaded Consolidated Aircraft to build an airplane plant in the city, and convinced Burlington Railways to stay in the city. He also labored unsuccessfully to have the Trinity River Canal built and to secure a General Motors plant for Fort Worth. These efforts demonstrate that Carter was indeed the founder of modern Fort Worth.

"The Tennessee Valley Authority is a world example of the full development of a river basin in soil conservation, flood control, navigation, electric power, afforestation, and recreation... Many river basin areas in the United States have created planning commissions to further develop the advancement of their own watershed problems. The Trinity Improvement Association is the planning commission for the Trinity River watershed area... In Chapter II a factual resume of the Tennessee Valley Authority will be given, and this chapter will be used as a basis of comparison for the development of the Trinity River Basin. Chapter III covers the problem of soil conservation and flood control within the watershed area; Chapter IV deals with the industrial and municipal use of water and the resources of the tributary area; Chapter V contains a brief history of the canal movement on the Trinity, the feasibility of such a canal, and miscellaneous developments; and Chapter VI contains the conclusions that it seems appropriate to draw. " -- leaf 1.

To better understand abiotic dynamics in Southern reservoirs receiving heated effluents, water was analyzed before and after impoundment in 330 ha North Lake. Macronutrients, metals, and chlorinated hydrocarbons were measured. Concentrations of nutrients and metals in sediments were quantified in this 2 yr study. River water prior to impoundment contained 16 times more total phosphorus, and supported 23 times more Selenastrum capricornutum cells in an algal assay than reservoir water. The reservoir has essentially no drainage and since evaporation is high, the concentrations of many dissolved solids have increased since the reservoir was filled in 1958. North Lake is now phosphorus limited. Apparently altered chemical equilibria have caused precipitation or adsorption of phosphorus with calcium and iron.