The quantitative analysis of the disaster effect on water supply systems can provide useful information for water supply system management. In this study, a total disaster index (TDI) was developed using open-source public data in 419 water treatment plants in Korea with 23 input variables. The TDI quantifies the possible effects or damage caused by three major disasters (typhoons, heavy rain, and earthquakes) on water supply systems. The four components (regional factor, risk factor, urgency factor, and response and recovery factor) were calculated using input variables to determine the disaster index (DI) of each disaster. The weight of the input variables was determined using principal component analysis (PCA), and the weights of the DI of three natural disasters and four components used to calculate the TDI were determined by the analytical hierarchy process (AHP). Specifically, two ensemble machine learning models, random forest (RF) and XGBoost (XGB), were used to develop models to predict the TDI. Both models predicted the TDI with the coefficient of determination and root-mean-square error-observations standard deviation ratio of 0.8435 and 0.3957 for the RF model and 0.8629 and 0.3703 for the XGB model, respectively. The relative importance analysis suggests that the number of input variables can be minimized, which improves the models’ practical applicability.

In Korea, the carbon emission from the agricultural, livestock, and fishery sectors were 24.7 million tCO₂-eq in 2018. Following the 2050 carbon neutral declaration, the total carbon emissions from these sectors are expected to decrease to 15.4 million tCO₂-eq by 2050, a reduction of 37.7%. Therefore, efforts are being made to reduce the use of chemical fertilizers, soil nitrogen emissions, and greenhouse gases in the agricultural sector. In this study, we analyzed the effects of irradiation charges on greenhouse gas reduction and water quality improvement after rice cultivation without the addition of any fertilizer. The greenhouse gas emission for fertilizer during irradiation cultivation was estimated to be 237 kgCO₂-eq/1,000m², 4 kgCO₂-eq/1,000m² less than that by using a crop protection agent (241 kgCO₂-eq/1,000m²). The measurement was based on the amount of nitrogen, phosphorus, and potassium (62.90, 22.83, and 19.31 kg, respectively) per 1,000 m² barley cultivation. In addition, a reduction in fertilizer use was estimated to reduce eutrophication by approximately 25.47 kgPO₄^3--eq. Thus, the eutrophication of rivers from farmland, a nonpoint pollution source, is predicted to reduce by expanding irradiation cultivation.

The aim of this study was to quantify the environmental impacts of dams, used for the control of riverine water resources, through life-cycle assessment techniques. The studied pneumatic and upright rubber dams had sizes of 500 mm (H) × 15,000 mm (L) and 2,000 mm (H) × 15,000 mm (L), respectively. The characterization values of the dams were compared in view of global warming. If the pneumatic and upright rubber dams both had sizes of 500 mm (H) × 15,000 mm (L), they would emit 5.365E + 05 kg CO 2 -eq and 5.441E + 055 kg CO 2 -eq, respectively. Meanwhile, if they both had sizes of 2,000 mm (H) × 15,000 mm (L), they would emit 2.193E + 06 kg CO 2 -eq and 2.094E + 06 kg CO 2 -eq, respectively.These results indicated that the environmental impact of dams can be strongly influenced by their size and construction method. In particular, their operating energy and the characteristics of their raw and subsidiary materials were the highest-ranked environmental impact factors in our sensitivity analysis. Therefore, in order to reduce greenhouse gas emissions, the environmental impact of river structures with a relatively long lifetime should be pre-evaluated when their construction is being planned.

Water footprint means the direct and indirect water resource amount used for the life cycle of different goods, services and industries. In this study, the direct and indirect water resource consumption in industrial sectors were calculated by using water footprint evaluation method. As a result, agriculture and marine product industry takes part of 93% of whole water resource amount, showing the greatest amount of basic unit of water coefficient (637 m 3 /won) following by petroleum and cool products industry of about 13 m 3 /won. In the agriculture and marine product industry, the direct water consumption was only 25 billion m 3 compared to the indirect water, which is 130 billion m 3 . The next highest industry was chemical product industry, which consists of 2 billion m 3 of the direct water and 4.5 billion m 3 of the indirect water consumption. In case of industries which have high direct water, it would be more effective to reduce amount of water related to the industry than to reduce water in actual process. This water footprint of each industry and evaluation method will be useful tool and method for development of national water management policy and regulation.

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