黄河中下游河道生态需水研究

 根据黄河流域生态需水的特点，将研究重点放在中下游河道，选择黄河中下游及部分支流的主要控制断面研究黄河流域河道内生态需水。以河流水体存在（不断流或干涸）、水生生物完整性以及河流系统的水沙平衡为保护目标，分别计算河道最小生态流量、适宜生态流量和洪水期生态流量，将不同生态流量耦合时间特征计算了全过程生态需水。研究结果表明，黄河中下游河道适宜生态流量、洪水期生态流量和最小生态流量的相对值分别为18%～29%、156%～187%、9%～15%，对应于汛前期（4-6月）、汛期（7-8月）和汛后枯水期（9-3月）的河道生态需水，据此算得黄河中下游流域年生态需水总量占多年平均径流量的35%～43%。从河流生态需水时间特征出发提出的全过程生态需水计算成果，将为黄河流域的水资源合理调度和管理，生态系统保护和恢复提供科学依据。

Ecological Flow Regime in Middle and Lower Reaches of the Yellow River

Maintaining the natural hydrologic variability of river flows is critical for protecting river ecosystems. Minimum ecological flow， appropriate ecological flow and ecological flow during flood period and the ecological flow regime in the middle and lower reaches of the Yellow River are calculated and studied respectively for maintaining river scale (avoid flow-breaking or drying-up)， sustaining the basic integrality of aquatic species and preventing the river sediment accumulation. Based on temporal characteristics of three kinds of ecological flows，ecological flow regime in the middle and lower reaches of the Yellow River is set up. The calculation results indicate that the appropriate ecological flow (April to June) is between 18% and 29% of mean annual flow， the ecological flow of flood period (July to August) is 156%~187%， and the minimum ecological flow (September to March) is 9%~15%. Mean annual ecological water requirement is 43%~71% of multi year average discharge. The results can provide scientific supports for water resources management and water ecosystem protection in that region.