在评价河流水文情势变化特征时，传统水文改变指标法(indicators of hydrologic alteration，IHA)存在的指标间相关性高和数据冗余问题会造成整体评价偏差。对汉江下游流域的河流水文情势评价时，考虑到汉江流域干支流日均流量及取水调水工程等的影响，分别选择汉江干流上的3个水文站及支流流域的3个水文站点，采用主成分分析法对6个水文站IHA指标进行优选，再利用相关性分析结果进一步筛选，优选出适用于评价汉江下游流域水文情势的13个代表性指标，分别为2月流量、4月流量、7月流量、10月流量、12月流量、基流指数、最低流量出现日期、最高流量出现日期、低流量脉冲次数、高流量持续时间、日均流量增加率、日平均流量减少率和日均流量反转数。结果表明:6个水文站的代表性指标间相关性均大幅降低，13个代表性指标间的相关系数不超过0。3的占比约70％;经变化范围评价法(range of variability approach，RVA)验证，IHA指标与优选出的代表性指标对汉江下游流域整体水文改变度评价结果的差值均小于7。5个百分点，表明其能够对汉江下游流域提供较为全面合理的水文情势变化评价。。
Optimization of regional characteristic indicators for ecological flow in the lower reaches of Hanjiang River
People's development and utilization of the river are increasing because of power generation,navigation,and irrigation,at the same time,the hydrological regime of the river and the ecological environment has also caused a certain impact.When evaluating the changing characteristics of river hydrological alterations,utilizing the ecohydrological index system is often necessary to quantify the degree of river hydrological changes.Due to the large differences in climatic conditions,geomorphological features,and hydrological-ecological response relationships in different study areas,problems of correlation between indicators and data redundancy in the traditional hydrological alteration index method(IHA)may cause the overall evaluation bias.The evaluation of the hydrological regime of the river in the lower reaches of the Hanjiang River was carried out considering the influence of the average daily flow,the shape of the river cross-section,and water intake and diversion projects of the main and tributary streams in the Hanjiang River basin.For this purpose,three hydrological stations on the main river basin of the Hanjiang River and three hydrological stations in its tributary basins were selected,and the IHA indexes of the six hydrological stations in the basin were optimized by the principal component analysis method,and then further screened based on the results of the correlation test method.The results showed that:Thirteen representative indicators were February flow,April flow,July flow,October flow,December flow,base flow index,lowest flow occurrence date,highest flow occurrence date,number of low-flow pulses,high flow duration,average daily flow increase rate,average daily flow reduction rate and reversal numbers.The correlation test analysis showed that the correlation of the thirteen representative indicators of the six hydrological stations was greatly reduced,and the correlation coefficients between 70％of representative indicators did not exceed 0.3.The difference between IHA indicators and the representative indicators on the overall hydrological alteration degree of the lower Hanjiang River basin was less than 7.5 percentage points verified by the RVA method.Considering the different hydrological situations of the rivers in the mainstream and tributary basins of the lower reaches of Hanjiang River basin,different hydrological stations are optimized for representative indicators,which can evaluate the hydrological situation of the entire lower reaches of Hanjiang River basin.The representative indicators can provide a more comprehensive and reasonable evaluation of the hydrological regime of the entire lower reaches of Hanjiang River basin,which is convenient for evaluating the degree of impacts of human activities on the river promptly.
lower reaches of Hanjiang Riverregional characteristicsecological flowindicator selectiondegree of hydrological alteration
国家科技期刊平台
NSTL
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