三峡水库坝身泄流超饱和复氧分析

高坝泄水时,高速掺气以及消能过程中水流的强烈碰撞,卷吸大量的气泡进入水体,在水体静压作用下释放空气溶入水中,导致水体中包括氧在内的溶解气体浓度常常超饱和,易引发鱼类气泡病,严重威胁它们的生存和繁殖.分析三峡大坝至葛洲坝水利枢纽河段的水质监测数据表明,在泄流期间溶解氧浓度基本都超饱和.本文结合三峡大坝泄流现状,分析了大坝泄流超饱和复氧的起因、导致超饱和复氧的影响因素、所带来的问题以及应采取的措施,对改善鱼类等水生动物的生存环境,实现生态水利目标,具有重要的学术意义和社会效益.

Supersaturated re-aeration analysis on the Three Gorges reservoir during discharge

High-speed entrained flow and strong collision during the process of the energy dissipation in stilling basin will cause large numbers of air bubbles entrapped into water during high-dam discharge. Under the effects of hydrostatic pressure, the air bubbles can release much air into water and becomes dissolved oxygen. Excess air entrained into water can always cause the supersaturated re-aeration. High levels of dissolved oxygen may cause gasbubble disease in fish and endanger their existence and propagation. The data of dissolved oxygen concentrations at the upstream and downstream of Three Gorges dam are analyzed. The results show that the dissolved oxygen concentrations at the downstream of dam are supersaturated during sluicing. Based on the supersaturated re-aeration state-of-the-art at the Three Gorges dam during discharge, this paper analyzes emphatically the contributing factors of the supersaturated re-aeration during sluicing and its harm for fish. It is very important to improve the living environment for fishes and maintain a healthy eco-environment for river.