Evaluation of ecological flow of Lorestan Herrud river using hydrological methods

In order to preserve the existing ecosystems in catchments and also due to lack of water resources and inappropriate temporal and spatial distribution of rainfall in the country, it is necessary to consider the environmental needs of rivers. In the present study, the environmental needs of the Herrud River catchment area located in Lorestan province in two hydrometric stations of Kakarza and Dehno during a long-term statistical period of 40 years using hydrological methods of tenant, tesman, aquatic basin flow, flow continuity curve analysis, change The flow continuity curve using GEFC software and smokhtin was investigated. The analysis of the trend of discharge changes in Kakarza and Dehno basins was investigated using Monkendal graphic test and the results showed that it is not possible to imagine a trend for Herrud river in the location of Kakarza and Dehno hydrometric stations. Among the mentioned hydrological methods, the method of changing the flow continuity curve due to considering ecological management classes, paying attention to the natural fluctuations of river flow and trying to maintain these fluctuations in its proposed environmental flow compared to other methods. These are more efficient. The results showed that in order to maintain the environmental needs of the Herrud River, in class C (lowest acceptable ecological status) in Kakarza and Dehno stations, 49.47% and 56.34% of the average annual flow (5.63%, respectively) And 1.42 cubic meters per second) is required.