The overall goal was to delineate the significant water quality changes which would occur upon transformation of Texas river systems into a contiguous series of slackwater pools. Bacterial data available from one impoundment since 1925 showed decreases following upstream impoundment construction and recent increases due to urban runoff. A simplified procedure for temperature prediction in a stratified southwestern impoundment was developed using a combined net energy transfer-diffusion approach. Primary emphasis was placed on the obtainment of valid data on the hypolimnetic dissolved oxygen sources and sinks for development and validation of a prediction model. The major sink was microbial respiration on the sinking epilimnetic phytoplankton debris. Different nutrients were found to limit phytoplankton growth in various seasons. (Author)