平原河网生态流量计算方法及其适宜性研究

Ecological Flow Calculation Method and Its Suitability Study in the Plain River Network

摘要: 平原河网区经济社会高速发展导致的河流生态退化、环境恶化是当前生态文明建设重点关注的问题之一。本文针对长江中游江汉平原中小型河流全年不同时期的水文及生态特点，基于现有的生态流量计算方法，研究建立一套考虑长江中游平原河道形态、河网水力特征及主要水生生物适宜流速全年分时段生态流量的综合确定方法。该方法推荐在主要鱼类重要生长阶段采用生态水力半径法，在枯水期采用逐月Tennant法、逐月频率法计算适宜生态流量，并采用多目标湿周法和Tennant法确定全年最低流量，在长江中游平原河网区的典型河流汉北河下游得到验证与应用。适宜性分析表明，该方法计算的生态流量既考虑了区域的特征，又考虑了重点生态保护对象的需求，可为长江中游平原中小型河流水资源高效利用提供参考依据。

Abstract: As a result of the rapid economic and social development of plain river network area, river ecological degradation and environmental deterioration have become the focus of ecological civilization construction. Considering the hydrological and ecological traits of small and medium-sized rivers at different periods throughout the year in the Jianghan Plain located in the middle reach of Yangtze River, this study establishes a set of comprehensive calculation method for determining the ecological flow in different periods based on existing calculation methods, which takes the river morphology, hydraulic traits and appropriate velocity for main aquatic organisms into account. This method adopts ecological hydraulic radius method in spawning period, monthly Tennant method and monthly frequency method in dry season to determine the suitable ecological flow process, and uses Tennant method and multi-objective wet perimeter method to determine the minimum ecological flow process. The method is applied in the downstream of Hanbei River basin, a typical river in the plain network area of the middle reaches of the Yangtze River. The suitability analysis of ecological flow showed that the ecological discharge calculated by this method considered not only the characteristics of the region, but also the needs of key ecological protection objects, which could provide a reference for the efficient utilization of water resources in small and medium-sized rivers in the middle reach plain of Yangtze River.