除鄱阳湖和洞庭湖外,长江中下游通江湖泊基本以涵闸形式连通江湖。由于缺乏水体的自然交换,此类湖泊经常出现水质超标的情况,特别是枯水期。以华阳河湖群为例,通过实测资料分析、现场调研、数值模拟研究了其进行生态调度的可行性及具体方案。研究结果表明:华阳河湖群TN、TP浓度随水位的升高呈下降趋势,但当湖群水位超过某值(13.5 m)后,浓度下降趋势变缓,且湖群9月下旬多年平均水位高于现行非汛期控制水位,因此,利用华阳和杨湾闸进行湖群非汛期生态调度是可行的。在考虑现行闸门调度方式、江湖关系、确保防洪安全和水环境改善4个原则的基础上,结合数值模拟结果,确定了华阳河湖群非汛期生态调度方案,即利用杨湾闸和华阳闸控制湖区10—12月份水位控制在13 m,1—2月份控制在12.5 m,3—4月份控制在11.8 m。

Except from Poyang Lake and Dongting Lake, river-communicating lakes in the middle and lower reaches of the Yangtze River connect with the Yangtze River by culverts and sluices in general. The water quality of such lakes is inferior on account of the weak water exchange capacity, especially in dry season. Taking Huayang river-lake group as an example, we studied the feasibility of ecological operation and specific plans in non-flood period via data analysis, field investigation and numerical simulation. Results reveal that the concentrations of TN and TP decrease with the rising of water level; but such tendency attenuates when water level exceeds a certain value (13.5 m). The annual mean water level of lake group in late September is higher than the current controlled water level in non-flood period, indicating that it is feasible to use Huayang and Yangwan sluices for ecological regulation in non-flood period. In line with the current dispatching mode, the relation between rivers and lakes, the flood control security and the water environment improvement as well as the simulated results, we obtained the specific plan of ecological operation for Huayang river-lake group in non-flood season: using Yangwan sluice and Huayang sluice to control the water level in the lake area at 13 m in October-December,12.5 m in January-February,and 11.8 m in March-April.