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Analysis of water quality changes in the mainstream and major tributaries of the Youngsan River by AR6 climate change scenario with SWAT

SWAT을 이용한 AR6 기후변화 시나리오에 의한 영산강 및 주요 지천 수질 변화 분석

  • Lee, Seungmoon (Department of Environmental and IT Convergence, Chungnam National University) ;
  • Lee, Eojin (Department of Environmental and IT Convergence, Chungnam National University) ;
  • Lee, Jihyung (Department of Environmental and IT Convergence, Chungnam National University) ;
  • Seo, Dongil (Department of Environmental and IT Convergence, Chungnam National University)
  • 이승문 (충남대학교 환경IT융합공학과) ;
  • 이어진 (충남대학교 환경IT융합공학과) ;
  • 이지형 (충남대학교 환경IT융합공학과) ;
  • 서동일 (충남대학교 환경IT융합공학과)
  • Received : 2024.09.02
  • Accepted : 2024.10.04
  • Published : 2024.10.31

Abstract

This study was conducted to predict and analyze water quality changes due to climate change using the SWAT (Soil and Water Assessment Tool) model for the main stream and major tributaries of the Yeongsan River Basin. To enhance the reliability of the model, input data was constructed using weather and flow data provided by the government from 2007 to 2021, and the model was calibrated. The mid-emission scenario (SSP2-4.5) and extreme emission scenario (SSP5-8.5), derived using the WRF climate change model from the 6th IPCC report, were applied to SWAT to predict flow and nutrient loads. The water quality changes under future climate change scenarios were analyzed by categorizing them into short-term (2021-2040), mid-term (2041-2060), and long-term (2081-2100) periods. Water quality assessments were conducted based on the Living Environment Standards and the Real-Time Water Quality Index (RTWQI). As a result, in most areas of the Yeongsan River Basin, the concentration of TN was found to be at or above the "Poor" level, with the "Very Poor" level being predominant, especially in the main stream and downstream areas. While the concentration of TP showed some variation depending on the scenario, it exhibited a trend of improvement over the long term. The RTWQI assessment generally showed higher water quality levels compared to the evaluation based on living environment standards, with a trend of water quality improvement over time. This suggests that the concentration of TN can act as a major problem as agricultural regions are the main areas in water quality management in the Yeongsan River basin. Therefore, in order to improve water quality according to future climate change, it is expected that it is necessary to further reduce point and non-point sources such as agricultural non-point source reduction management such as fertilizer management and conservation agriculture, and improvement of roof greening and sewage treatment plants in urban areas.

본 연구는 영산강 유역의 본류와 주요 지천을 대상으로, SWAT (Soil and Water Assessment Tool) 모델을 이용하여 기후변화에 따른 수질 변화를 예측하고 분석하는 것을 목적으로 수행되었다. 모델의 신뢰성을 높이기 위해 2007년부터 2021년까지 정부가 제공하는 기상 및 유량 자료를 이용해 입력자료를 구축하고 모델 보정을 실시하였다. 제6차 IPCC 보고서에 대해 WRF 기후변화 모델을 이용하여 산정된 중간 배출 시나리오(SSP2-4.5)와 극한 배출 시나리오(SSP5-8.5)를 SWAT에 적용하여 유량, TN 및 TP 부하량을 예측하였다. 미래 기후변화 시나리오에 따른 수질 변화는 단기(2021~2040년), 중기(2041~2060년), 장기(2081~2100년)로 구분하여 분석하였으며, 수질 평가는 환경부의 하천 및 호소 생활환경기준(Living Environmental Standards)과 실시간수질지수(RTWQI)를 기준으로 수행하였다. 결과적으로, 영산강 유역 대부분의 지역에서 TN 농도는 "나쁨" 이상으로 나타났으며, 특히 본류 및 하류 지역에서 "매우 나쁨" 등급이 우세하였다. TP 농도는 시나리오에 따라 다소 차이를 보였으나, 장기적으로는 수질이 개선되는 경향을 보였다. RTWQI 평가에서는 생활환경기준에 따른 평가보다 전반적으로 더 높은 수질 등급이 나타났으며, 시간이 지남에 따라 수질이 개선되는 경향을 보였다. 이는 영산강 유역의 수질 관리에 있어 농업 지역이 주를 이루어 TN 농도가 주요 문제점으로 작용할 수 있음을 시사하는 것을 알 수 있다. 따라서, 미래 기후변화에 따른 수질의 개선을 위해 비료관리, 보존 농업 등과 같은 농업 비점오염원 저감 관리와 함께 도심지역을 중점으로 저영향개발, 침투 도랑, 지붕 녹화 및 하수처리장 개선 등 점·비점오염원 저감이 더욱 필요할 것으로 보인다.

Keywords

Acknowledgement

본 연구는 환경부의 재원을 지원받아 한국환경산업기술원 "신기후체제 대응 환경기술개발사업"의 연구개발을 통해 창출되었습니다. (2022003570007)

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