水利枢纽下游水体溶解气体饱和度预测方法研究

泄水建筑物过流水体剧烈掺气,水气两相间气体质量交换迅速而充分时,可以假定下游水体溶解气体饱和度达到最大值.在此基础上,考虑电站和泄水建筑物过流水体均匀混合后的溶解气体超饱和特性,建立水利枢纽下游水体溶解气体饱和度的预测方法.对哥伦比亚河流域4座水利枢纽和三峡工程溶解氧实测资料进行的验证计算表明,该方法的计算结果均与实测资料相近,且应用方便,可在实际工程中推广.对三峡工程典型库水位下大坝下游水体的溶解氧饱和度的预测计算表明,发生百年一遇以下洪水时,黄陵庙断面的溶解氧饱和度不超过140%;发生百年一遇以上大洪水时,需要在防洪调度的同时进行生态调度,以减免超饱和对水生生物造成的影响.

Prediction Method of Dissolved Gas Saturation in the Water Downstream of Hydro-project

A simple and easy prediction method for dissolved gas saturation in the water downstream of hydro-project is proposed in this paper. The saturation in the water downstream of sluice structure is calculated by assuming that the gas transfer between water and air is rapid enough to saturate the water in bubble swarm area, as is reasonable when sluicing water from sluice structure is intensively re-aerated. Then the saturation is further averaged by mixing flows from sluice structure and power house. Several cases including four different hydro-projects along Columbia River and Three Gorges Project are predicted for validation, and the calculated dissolved oxygen saturation is close to the original monitoring data. The results demonstrate that the presented method is easy to be applied and suitable for different projects. The method is also used to predict the dissolved oxygen saturation in the water downstream of Three Gorges Dam at different typical reservoir water levels, which shows that the dissolved oxygen saturation at the Huanglingmiao section is as much as 140% under the condition of 100-year flood. In order to mitigate and avoid the effect on aquatic of super-saturation, eco-operation is required beside the flood control when the flood exceeds 100-year point.