The physico-chemical limnology of a stretch of the Guadalupe river, Texas, with five main-stream impoundments

Physico-chemical studies on a stretch of the Guadalupe river, Tex., having five shallow, unstratified, main-stream reservoirs, were carried out at monthly intervals on a diel basis at 16 stations between New Braunfels and lake Wood; flow through the study area is controlled by releases from the five reservoirs and from Canyon reservoir, a deep storage reservoir 30 n upstream. Graphical results show that seasonal and diel changes in limnological conditions were greater in impoundments than in lotic areas and longitudinal variations in physico-chemical conditions were influenced by the impoundment of water, discharges of sewage effluents, re-aeration through turbulence, and seasonal periods of drought and flooding. High dissolved oxygen, chlorophyll a, pH value, and low bicarbonate alkalinity indicate the importance of bicarbonate ions as a carbon source for phytoplankton in this system. A bibliography of 33 references is appended.