Geology topics

Research about Trinity River basin

Source-linked reports with geographic coverage including Trinity River basin.

3 recordsLinked to original sources

USGS2020

The utility of zooarchaeological data to guide listing efforts for an imperiled mussel species (Bivalvia: Unionidae: Pleurobema riddellii)

The status of species in freshwater systems shift over time due to natural and anthropogenic causes. Determining the magnitude and cause of these shifts requires a long-term perspective. This process is complicated when there are also questions about the taxonomic validity of a species. Addressing these issues is important because both can undermine conservation and management efforts if incorrect. Pleurobema riddellii , Louisiana Pigtoe, is under review for protection under the U.S. Endangered Species Act, but its status in the Trinity River basin, where the taxon was described, remains in doubt due to questions about its taxonomy and occurrence within this basin. To address these questions, we compared shell morphometrics of P. riddellii dating to the late Holocene with modern P. riddellii , late Holocene Fusconaia sp., and modern Fusconaia sp. using multivariate analyses to test associations between the putative morphotypes. Based on these analyses, we demonstrate that P. riddellii was likely present in the Trinity during the late Holocene, which indicates questions about its taxonomic validity or presence in this basin are unfounded. Our study further highlights the role zooarchaeological studies can play in status assessments and their utility in better understanding biogeographic patterns for rare species.

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USGS2003

Applying indicators of hydrologic alteration to Texas streams: overview of methods with examples from the Trinity River basin

Streamflow is a component of aquatic ecosystem health, and long-term alteration of streamflow characteristics can produce large changes in aquatic ecosystem structure and function. The physical, chemical, and biological properties of aquatic ecosystems are all affected by the magnitude and frequency of streamflow. For example, the physical structure (hydrogeomorphology) of aquatic habitats is a property of the interaction between streamflow magnitude and frequency and the physical landscape (Leopold and others, 1992). Chemical processes are affected by changes in water residence time, which is a function of streamflow. Similarly, the structure and function of biological communities associated with stream ecosystems depend in large part on the hydrologic regime (Poff and Ward, 1989, 1990; Sparks, 1992). Within-year variation in streamflow is essential to the survival, growth, and reproduction of aquatic species. Altering streamflow magnitude and frequency and within-year variability has the potential to modify critical aspects of the physical habitat (Bain and others, 1988). Documenting the degree to which streamflow has been modified by the cumulative effects of water development is critical to assessing aquatic ecosystem health. The U.S. Geological Survey (USGS), in cooperation with the Texas Commission on Environmental Quality, conducted a study of the application of the Indicators of Hydrologic Alteration (IHA) methods developed by Richter and others (1996, 1997) to identify streams at risk for biological impairment from the loss of streamflow-dependent habitat. This report provides a brief overview of selected IHA methods for assessing hydrologic alteration; presents examples that illustrate the application of the methods using streamflow data from a subset of USGS stations in the Trinity River Basin, Texas, analyzed in the study; and addresses applicability of the methods statewide.

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USGS1999

Water quality in the Trinity River basin, Texas, 1992-95

Water quality in the Trinity River basin was studied during 1992-95 as part of the USGS National Water-Quality Assessment (NAWQA) Program. Studies included chemical sampling of streams, streambed sediments, biota, and ground water; measuring distributions of biological communities in streams; and measuring physical characteristics of streams that affect biological habitat. The sampling design, in general, relates water-quality conditions to causative human and natural environmental factors. The occurrence of pesticides, for example, is related to land use. Trends are mixed, with a substantial improvement in the diversity of fish species downstream from Dallas and large decreases in regulated contaminants such as DDT; but increases in unregulated contaminants such as polychlorinated biphenyls.

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