Study of the dynamic evaluation model of overall hydrological alteration degree based on the rva and set pair analysis-Markov chain methods

摘要

The concept of overall hydrological alteration degree in the traditional range of variability approach is no longer suitable for the requirements of the current changing environment. First, by introducing the analytic hierarchy process and including the concept of deviation in the range of variability approach, the traditional range of variability approach is improved. Second, by using the daily flow data from the Guide gauging station in the lower reaches of Longyangxia reservoir from 1954 to 2017 and by combining the concept of connection degree in set pair analysis, a more comprehensive overall hydrological alteration degree is obtained. Finally, based on the results of overall hydrological alteration degree in each period, a dynamic evaluation model of overall hydrological alteration degree is established based on a set pair analysis-Markov chain method. The results show that the overall hydrological alteration degree of the Longyangxia reservoir in the postimpact period is at the second level; its average is -0.43, but its identity tends to increase. Furthermore, the dynamic evaluation model shows that the overall hydrological alteration degree of its stable state will be 0.1726, its impact flow changes and its stable state will be at the third level. This is a positive developing trend.