河流环境流量计算方法及其应用

Calculation methods of river environmental flow and their applications

研究了河流环境流量计算的Desktop Reserve Model方法与流量历时曲线转换法及其应用．Desktop Reserve Model方法将环境流量过程分为基流量、高流量两部分，将它们进行计算值叠加即可得到环境流量．流量历时曲线转换法考虑不同的河流环境管理等级，根据河流流量历时曲线，推求相应的环境流量过程．以三峡水库下游宜昌站为例，利用两种方法进行了计算．计算结果表明：Desktop Reserve Model方法应用在长江流域具有一定的适用性，该方法计算得到的环境流量占多年平均径流量的41．2％；而流量历时曲线转换法计算的环境流量过程可以较好地保持天然流量的情势，维持A～B等级环境管理目标需要60％～80％的年平均径流量，维持C～D等级需要40％～50％的年平均径流量，维持E～F等级需要20％～40％的年平均径流量．Desktop Reserve Model方法计算的环境流量与流量历时曲线转换法相比，相当于维持C～D等级以上标准所需的环境流量．

The desktop reserve model（DRM） method and flow duration curve shifting method for river environmental flow calculation are studied. In the DRM method, the process of environmental flow consists of two parts： base flow and high flow, the sum of which makes up the river environmental flow. While, considering different river environmental management levels, flow duration curve shifting method derives the environmental flow process based on the river flow duration curve. In the case studies, the aforementioned two methods are used to calculate the river environmental flow of Yichang Station, which is downstream of the Three Gorges Reservoir. The results indicate that the DRM method is suitable for the Yangtze River. The environmental flow calculated by DRM method needs 41.2% of the annual average runoff. The environmental flow process calculated by flow duration curve shifting method is relatively closer to the natural flow process. Maintaining A-B environmental management class needs 60% to 80% of the annual average runoff; and C-D class needs 40% to 50%, close to the calculation results of DRM method; and E- F class needs 20% to 40% of the annual average runoff.