Buffalo Bayou, a major stream in Houston, Texas, was the subject of a detailed water quality study. The stream is heavily stressed by domestic waste loads and has shown significant degradation in water quality since 1970. Currently, the stream reaches critically low DO values through much of its length during low flow, high temperature periods. The QUAL‐IITX model was calibrated, verified, and applied to simulate worst case conditions and to test a series of stream protection alternatives. A combined program of sewage plant regionalization, stream aeration, and flow augmentation was found to be the most cost‐effective solution.

Stream Dissolved Oxygen Analysis and Control

While an ambitious point source control program has yielded measurable improvements in water quality of the Upper Potomac River Estuary, the degree to which additionally strict point source controls are needed is the subject of current investigations by Washington, D.C. metropolitan area local jurisdictions. Indications are strong that eutrophication trends and periodic events of low dissolved oxygen will continue in the Estuary despite public expenditures for advanced wastewater treatment. Contributing to poor water quality conditions are significant uncontrolled loadings of oxygen demanding material and nutrients estimated to come from natural sources, unregulated agricultural activities, urban stormwater and other nonpoint pollution sources generated locally and upstream of the Washington region. Area jurisdictions are beginning to reappraise the region’s water quality control program with the intent of developing a more comprehensive program that considers pollutant loadings from all sources. Investigations will involve an assessment of the costs of achieving desired water quality levels, and a study of possible mixes of point source, nonpoint source and combined sewer overflow controls. Studies will involve use of refined prediction models of the Estuary which employ new information on the magnitude and fluctuation of pollution loadings.

Austan S. Librach

Papers

Managing Potomac Water Quality: Evolving Approaches