Managing an Urban Watershed

As a result of the instances in the early 1980s of high densities of fecal coliform being detected in Lake Houston, concerns were raised about the continued use of the lake as a major drinking water supply for the city of Houston, Texas. Effluent from several wastewater treatment plants in the watershed was suspected as the primary source of indicator organisms, and public health officials implemented a management plan to ensure proper operation of the plants. A study to assess the effectiveness of the plan, which called for strict enforcement of chlorine residual requirements, showed it to be working successfully. The study also showed, however, that other point and nonpoint sources of pollution were contributing indicator organisms to the lake. Also, although the total coliform density in the forebay water at the Houston water treatment plant increased after rainstorms, no deterioration of finished drinking water quality occurred.