MITIGATION OF COLD WATER POLLUTION DOWNSTREAM OF A MAJOR DAM

摘要

In recent years, cold water pollution has arisen conceived as a major issue to the downstream environment of most Australian dams. Many Australian dams currently lack selective withdrawal capabilities and most release water mainly from the bottom of the reservoir. Reports have been published (Lugg, 1999) of the impact of cold water releases on the downstream environment for many kilometres. There have been many solutions proposed, however the effectiveness of these solutions are yet to be established. The intake tower of Brogo Dam had a similar problem of water withdrawn from the bottom of the reservoir. In 1995, the tower was converted into a multi-level intake system by introducing a sliding plate mechanism in the existing concrete arrangement. This paper presents the concept and strategies adopted in transforming the existing tower into a multi-level intake tower. The safety mechanisms and design aspects of various components are briefly discussed. Finally, the water quality data before and after installing the system is presented to establish the effectiveness of the system in controlling the thermal pollution of the down-stream water releases. The data provided would be beneficial to dam designers, owners, operators and users.