Assessment of Environmental Flow Requirements by Entropy-Based Multi-Criteria Decision

Environmental flow methodologies based on hydrological indices have increasingly evolved, because they play an important role in a riverine ecosystem management. Moreover, human activities, such as dams, in many basins have altered their natural hydrologic processes and they also change habitat for aquatic and riparian species. Decision making by echo-managers considering these multi-variables has been subjective. Therefore, to provide eco-managers with guidelines, an eco-index with entropy related to the probability density function (pdf) and Ordered Weighted Averaging (OWA) operator is been suggested in this study. The index was applied to Geum River in South Korea with 33 Indicators of Hydrologic Alteration (IHA) by Richter et al. (1998) through IHA software (TNC 2009). The objective of this paper is to outline an entropy-based hydrologic alteration assessment of biologically relevant flow regimes using gauged flow data. On the Geum River, dams have affected river flow measured at four stations and the eco-index suggests that more attention needs to be paid to the tributaries between Gongju and Gyuam stations. Echo-Index with maximum entropy and OWA operator reflects the effect of every parameter and helps with determination considering multi variables. In future more temporal and spatial information needs to be examined for ecosystem alteration.