Evaluating the impact of interbasin water transfer on water quality in the recipient river basin with SWAT

So-Young Woo; Seong-Joon Kim; Ji-Wan Lee; Se-Hoon Kim; Yong-Won Kim

doi:10.1016/j.scitotenv.2021.145984

Evaluating the impact of interbasin water transfer on water quality in the recipient river basin with SWAT

Sci Total Environ. 2021 Jul 1:776:145984. doi: 10.1016/j.scitotenv.2021.145984. Epub 2021 Feb 20.

Authors

So-Young Woo¹, Seong-Joon Kim², Ji-Wan Lee¹, Se-Hoon Kim¹, Yong-Won Kim¹

Affiliations

¹ Department of of Civil, Environmental and Plant Engineering, Graduate School, Konkuk University, Seoul 05029, Republic of Korea.
² Division of Civil and Environmental Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea. Electronic address: kimsj@konkuk.ac.kr.

PMID: 33647644
DOI: 10.1016/j.scitotenv.2021.145984

Abstract

During the second half of the 20th century in South Korea, interbasin water transfers (IBWTs) have been used to supply the water demands of basins with insufficient water using water from reservoirs in neighboring basins with ample water. However, since 2000, frequent droughts have resulted in water resource imbalances in donor basins, and basin residents have begun to claim their water rights. Recipient basins have also experienced water shortages and water quality deterioration due to gradual urban growth, agricultural activities, and climate change impacts. In this study, the Mangyeong River basin (1602 km²) was investigated. This basin has received 380 million m³/year of water since 2002 from the Yongdam multipurpose dam (YDD), which is located in another basin. For IBWT modeling, the Soil and Water Assessment Tool (SWAT) model and an inlet function were applied to model the recipient and donor water quality. Eight scenarios related to water transfer quantity and quality were applied with SWAT to analyze the effects of IBWT on the water quality in the recipient basin. The results showed that an increase in the IBWT amount helped to reduce the nutrient and suspended solids concentrations in the recipient basin when the donor's nutrient and suspended solids concentrations were lower than those in the recipient basin. The IBWT quantity scenarios had a greater impact on the water quality of the recipient basin than the IBWT quality scenarios. These results could provide basic information for use in deciding on the quantity and quality of IBWT between basins that are in conflict.

Keywords: IBWT amount; IBWT scenario analysis; Interbasin water transfer; SWAT; Water quality.