Development of integrated watershed management schemes for an intensively urbanized region in Korea

A systematic, seven-step approach to integrated watershed management for sustainability was proposed and applied to upstream watershed of the Anyangcheon in Korea, which experiences streamflow depletion, frequent flood damages, and poor water quality due to rapid urbanization. To understand watershed components and processes, static and dynamic data were collected and synthetic hydrologic cycles generated by HSPF (Hydrologic Simulation Program - FORTRAN) were simulated (STEP 1). To identify and quantify problems within the watershed, three indices (following the pressure-state-response model) were employed: Potential Flood Damage (PFD), Potential Streamflow Depletion (PSD), and Potential Water Quality Deterioration (PWQD). Composite programming, a method of multi-criteria decision-making, was employed to estimate all indices and analytic hierarchy process are introduced to quantify the weighting values of all indicators (STEP 2). The primary goal of managers is to maintain certain minimum levels of water for instreamflow requirement and total maximum daily load (TMDL). Therefore target water quality and, instreamflow requirements (including low flow and fish flow) were specifically set (STEP 3). All possible management alternatives were listed (STEP 4) and a few specific management options which are technically, economically, and environmentally feasible, were selected (STEP 5). The ability of each feasible option to achieve the desired water quantity and quality criteria was analyzed and quantified using the HSPF (STEP 6). Finally, an evaluation index was calculated using each of the proposed alternatives in order to rank the sustainability and priority of alternatives (STEP 7).