Abstract. This paper quantifies the transformed effectiveness of alternatives for watershed management caused by climate change and urbanization and prioritizes five options using multi-criteria decision making techniques. The climate change scenarios (A1B and A2) were obtained by using a statistical downscaling model (SDSM), and the urbanization scenario by surveying the existing urban planning. The flow and biochemical oxygen demand (BOD) concentration duration curves were derived, and the numbers of days required to satisfy the environmental flow requirement and the target BOD concentration were counted using the Hydrological Simulation Program-Fortran (HSPF) model. In addition, five feasible alternatives were prioritized by using multi-criteria decision making techniques, based on the driving force-pressure-state-impact-response (DPSIR) framework and cost component. Finally, a sensitivity analysis approach for MCDM methods was conducted to reduce the uncertainty of weights. The result indicates that the most sensitive decision criterion is cost, followed by criteria response, driving force, impact, state and pressure in that order. As it is certain that the importance of cost component is over 0.127, construction of a small wastewater treatment plant will be the most preferred alternative in this application.

This study provides a systematic three-step approach to prioritizing feasible locations for permeable pavement, taking into account environmental, economic, and social aspects.Step 1 is the identification of potential locations on the basis of spatial and economic feasibility, and on the receptiveness of the local government and residents.Step 2 involves the use of Visual MODFLOW software to simulate groundwater levels with and without permeable pavement.Step 3 is the prioritization of all feasible locations using three multi-criteria decision making methods: the weighted sum method, composite programming and TOPSIS. Weighting values were derived from iterative feedback surveys completed by 22 regional experts. This framework was applied to the Mokgamcheon watershed, central Korea, which suffers from instream flow deficit during the dry season. The results show that by considering anthropogenic factors and hydrological effectiveness, this approach effectively prioritizes feasible alternatives that can be implemented into comprehensive hydrological cycle rehabilitation plans.

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Coastal areas are being increasingly damaged by the expansion of seawater‐intrusion areas. This study suggested a three‐step method to prioritize the countermeasures adopted to reduce the areas affected by seawater intrusion. First, the most vulnerable area to damage from seawater intrusion was selected among 25 areas on the western coast of the Republic of Korea using three multicriteria decision‐making (MCDM) methods. As a result, Taean‐gun was selected as the most vulnerable area for seawater intrusion. Second, a numerical model called SEAWAT was configured to predict the areas where seawater intrusion could potentially occur. For future scenarios, Representative Concentration Pathways (RCPs) 4.5 and 8.5 were used as the sea‐level rise scenarios. To predict the future use of groundwater, the future groundwater extraction rate was predicted using a linear regression of the groundwater‐use data over the past 10 years. As a result, it was predicted that 68.5% of the total Taean‐gun area would be affected by seawater intrusion for RCP 8.5 and current trends in groundwater use. Third, the effectiveness of the measures adopted for the reduction of seawater‐intrusion areas were analysed by considering the projected future scenario and the local characteristics (including the total population, population density, groundwater‐level distribution, salinity distribution, groundwater‐use characteristics, and ground‐elevation distribution) of the Taean‐gun district. After considering the effects of the countermeasures adopted for the different locations in Taean‐gun and the data related to seawater intrusion, the priority areas for applying countermeasures against seawater intrusion were determined using three MCDM methods. It was concluded that the Taean‐myeon is a priority area for applying countermeasures.

This paper quantifies the transformed effectiveness of alternatives for watershed management caused by climate change and urbanization and prioritizes five options using multi-criteria decision making techniques. The climate change scenarios (A1B and A2) were obtained by using a statistical downscaling model (SDSM), and the urbanization scenario by surveying the existing urban planning. The flow and biochemical oxygen demand (BOD) concentration duration curves were derived, and the numbers of days required to satisfy the environmental flow requirement and the target BOD concentration were counted using the Hydrological Simulation Program-Fortran (HSPF) model. In addition, five feasible alternatives were prioritized by using multi-criteria decision making techniques, based on the driving force-pressure-state-impact-response (DPSIR) framework and cost component. Finally, a sensitivity analysis approach for MCDM methods was conducted to reduce the uncertainty of weights. The result indicates that the most sensitive decision criterion is cost, followed by criteria response, driving force, impact, state and pressure in that order. Since it is certain that the importance of cost component is over 0.127, use of the groundwater collected by subway stations will be the most preferred alternative in this application