Integrated modeling of climate change and urbanization impacts on water management

This study analyzed the effectiveness of two alternatives for water management under urbanization and climate change scenarios. Climate change and urbanization scenarios were obtained using a statistical downscaling method (SDSM) model and an impervious cover model (ICM), respectively. Alternatives considered for the Anyangcheon watershed were the redevelopment of the existing reservoir and the reuse of wastewater treatment plant effluent. The flow and biochemical oxygen demand (BOD) concentration duration curves were derived, and the number of days required satisfying the environmental requirement flow and the target BOD concentration was counted using the Hydrological Simulation Program-Fortran (HSPF) model. Results of this study showed that low flows and BOD concentrations were very sensitive to climate change and urbanization as compared to high flows. Climate change reduced the effectiveness of the alternatives in terms of low flow and water quality, while urbanization caused an increase in effectiveness in general. Also climate change affected the effectiveness on water quality more but urbanization caused that on low flow more. Climate change scenario A2 showed a larger impact than A1B. The alternative having large improvements of hydrological cycles shows the larger decrease of effectiveness due to climate change and urbanization. Although urbanization distorts the hydrological cycle, effective alternatives can reduce its damage. When climate change and urbanization occur at the same time, the effectiveness of the alternatives usually decreases. The number of days required satisfying the target water quantity and quality is more sensitive to urbanization than low flow and BOD concentration. These results showed that climate change and urbanization should be considered in water resource/watershed and environmental planning.