Influence of drawing water to Baojixia irrigation area on hydrologic regularity and ecosystem of Weihe River | 宝鸡峡引水对渭河水文规律及生态系统的影响

Chinese. 研究水文变化与河流生态系统的响应关系，通过对生态系统进行诊断，为河流生态系统的研究提供新途径。对渭河44年（1960－2005年）的水文资料和宝鸡峡灌区32年（1972－2005年）的引水资料进行统计与分析，探讨引水对渭河水文规律的影响，并采用变化范围法（RVA）对32个水文改变指标（IHA）进行统计，研究引水对渭河水文情势及生态系统的影响。引水导致渭河年平均流量较天然径流明显减少，且枯水年份尤为突出，32年中有8年年平均流量低于生态基流量；输沙量较引水前减少了80%强；且对河流的枯季月流量、年最小流量平均值、年最小1日流量发生时间、年低流量发生次数及平均延时、流量平均增加率等影响较大。宝鸡峡灌区引水对渭河的水文规律及生态系统的影响较大，尤其是低流量出现的频率和时间过多，严重影响河流的功能实现，迫切需要开展维持渭河河流健康生命的相关研究，在保证河流生态系统安全的同时，支持和改善灌区建设，以确保粮食稳定和区域社会的安全发展。

English. A new approach appeared to settle the above problem, that to diagnose the river ecosystem by analyzing the response relationship between hydrological change and river ecosystem. Using 44 years’ (1960－2005) historical hydrological data and 32 years’ (1972－2005) drawing water data for Baojixia irrigation area, the influence of water diversion on hydrologic regularity of Weihe River was studied. Then with RVA method adopted for statistical analysis of 32 IHA indexes, the influence of water diversion on flow regime and ecosystem of Weihe River was also analyzed in this paper. Drawing water from Weihe River led to the decrease of its annual discharge and more strongly in dry years, causing the average discharge lower than the basic flow of Weihe River in 8 years time of the past 32 years. In addition it impacted the sediment discharge, cutting 80 percent. And an obvious change occurred on monthly water condition in the dry season, annual minimal mean runoff, julian date of each 1-day annual, number of low pulses and its median duration and rise rate after drawing water. The results indicated that water diversion to Baojixia irrigation area has a great effect on hydrologic regularity and ecosystem safety of Weihe River, especially on functions related to low flow. And related research on keeping river healthy is urgently needed to assist supporting and improving irrigation district construction to ensure river ecosystem, to guard the stable development of grain production and safety of regional development.