Chetta S. Owens

The Effects of Hydropower Releases from Lake Texoma on Downstream Water Quality

ABSTRACT Impacts of peaking generation on water quality in the tailwater of Lake Texoma, on the Texas and Oklahoma border, were evaluated during summer stratification in the lake. Sampling was conducted before, during, and after a daily generation cycle with measurements of temperature, dissolved oxygen, iron, manganese, and turbidity. Temperatures were near 25°C during generation, fluctuated 3–4°C during nongeneration, and increased in a downstream direction to near 28°C. Dissolved oxygen concentrations were between 4 and 6 mg L−1 during generation and increased in a downstream direction. During nongeneration, concentrations in the upstream regon of the tailwater were near 2 mg L−1 but were between 4 and 10 mg L−1 in the rest of the study area. Maximum concentrations, 6 to 10 mg L−1, were observed prior to the hydrograph peak at each station, suggesting leading edge effects of increased flow and aeration as substrate was covered during river stage increases. Concentrations of metals increased in a downst...

Evaluation of Transparency and Light Attenuation by Aquashade

ABSTRACT Aquashade™, a colorant and dye registered by the US Environmental Protection Agency (USEPA) for use in aquatic environments to manage plant growth, does not reduce the visibility of water that otherwise would meet safe swimmming standards. This product was examined for its potential impact on underwater visibility in surface waters used for recreational swimming. Aquashade™ treatments of 0, 1, and 5 mg L−1 were evaluated in 3-m deep outdoor tanks containing reservoir water. Transparency and light attenuation were examined using a Secchi disk and an underwater photo synthetically active radiation (PAR) meter. In the first experiment, filtered lake water was used, while in the second, bentonite clay was added to provide a light transparency of approximately 1 m. In filtered lake water, Aquashade™ treatments (1 mg L−1 and 5 mg L−1) reduced light transparency by approximately 10% and 30%, respectively, but the transparency (272 and 194 cm, respectively) was well above typical international (100 cm) a...