Multi-scale Entropy Analysis to Assess Impacts of Dam Construction on Aquifer, Case Study: SAVEH Plain

According to the nonlinear relationship between the components of the aquifer, these systems are called as a complex system. In these systems due to natural and artificial changes, the estimating the degree of complexity for quality and quantity groundwater assessment is very important. In this study, in order to ascertain impacts of SAVEH dam on the complexity of the SAVEH aquifer plain, which is located downstream of the dam, multi-scale entropy (MSE) theory was applied to analyze long-term variation piezometers (1985-2014). In this approach, unlike the sample entropy that only the amount of entropy for a single scale factor measured, the MSE used to assess the possible changes in the complexity of the aquifer in multi scale factor. The results show that the complexity of the aquifer after SAVEH dam construction precipitously decreased from the beginning to the middle of the aquifer plain and an average 31 percent increase can be seen in the difference between the sample entropy (complexity) in two periods (before and after the dam construction). The complexity properties alterations of the aquifer caused the destruction of natural systems aquifer and decrease the complexity of it. The comparison between proposed approach and Mann-Kendall method is indicated that the efficiency of MSE in evaluating the complexity of aquifer systems and detection of abnormal events in the groundwater table level time series. This study could provide references for conservation of the aquifer natural environment and the assessment of impacts induced by big hydraulic structures construction on the groundwater system.