Stream Depletion Potential Index (SDPI) Structurized by Coupled Water Cycle System using Structural Equation Model (SEM)

Abstract

Land use change and poor management of water resources along with change in precipitation patterns have resulted in depleted supplies, falling water tables, shrinking stream flow to the extent of ecologically unsustainable levels. In this regard, the procedure of calculating stream depletion potential index (SDPI) is introduced to evaluate the degree of stream depletion and applied for sub-basins in South Korea. We defined stream depletion as the decline in the water level of a stream mainly by perturbation in water tables. By considering various influence variables in a coupled human and natural system (CHANS), eight indicators - precipitation, dry days, effective basin area, impervious area, environmental flow supplied by dams, stream water usage, groundwater usage and return flow - were selected. Furthermore, since effects and structures of the influence variables are altered by regional characteristics, the weights of the indicators were calculated by using three different structural equation models (SEM). As a result, some areas are vulnerable to stream depletion especially in sub-basins of western Han river, central and southern Nak-Dong river and western Yeong-San river. The index would contribute to prioritization in policy related to stream management not only for conservation of water resources but also for stream ecosystem including aquatic plant and life. (C) 2016 The Authors. Published by Elsevier Ltd.