우리나라 수질오염총량관리제도의 목표수질 평가방법에 관한 연구 = A Study on Target Water Quality Evaluation Methods in the Korean Total Pollution Load Management System

국문 초록 (Abstract)

현재 우리나라 수질오염총량관리에서는 과거 3년간의 평균수질로 목표수질 달성여부를 평가하고 있는데, 이 방법은 유량변화에 따른 수질변화를 반영하지 못하는 한계가 있으며 오염부하량 관리를 통해 목표수질을 달성하고자 하는 오염총량관리 기본 취지에도 맞지 않는다. 따라서, 본 연구에서는 오염부하량에 근거해서 유량 조건별 목표수질 달성 여부의 평가가 가능한 방법을 제시하고자 하였다. 총량측정망 운영을 통해 확보되고 있는 8일 간격의 수질 및 유량자료를 활용하여 부하지속곡선을 작성할 수 있으며, 부하지속곡선을 이용하면 부하량에 근거한 목표수질 달성여부를 평가할 수 있다. 금강수계 21개 단위유역에 대해서 부하지속곡선 방법을 적용하여 목표수질 달성여부를 유량 조건별로 평가한 결과와 현행 3년 평균수질 산정방법 및 기준유량 조건에서의 3년 평균수질 산정방법으로 평가한 결과를 비교한 결과, 2023년의 BOD 목표수질을 초과한 단위유역의 비율은 평가방법별 각각 47.6%, 23.8%, 19.0%로 나타났으며 T-P의 경우 각각 57.1%, 23.8%, 14.3%로 나타나 부하지속곡선에 방법으로 평가한 목표수질 초과 비율이 상대적으로 높게 나타났다. 이는 부하지속곡선에 의한 평가방법이 현행 평가방법 보다 목표수질 달성여부를 엄격하게 평가한다는 것을 보여준다. 부하지속곡선에 방법을 이용하면 유량변화를 고려한 목표수질 달성여부 평가가 가능할 뿐만 아니라 할당부하량 산정을 위한 수질예측에 유역모델과 같은 동적모델이 적용되어 시계열 예측이 가능한 경우의 목표수질 평가시에도 매우 유용할 것으로 생각된다.

다국어 초록 (Multilingual Abstract)

In the current Total Pollution Load Management system(TPLMs), the achievement of target water quality is evaluated using the average water quality over the past three years. However, this method has limitations as it does not reflect changes in water quality due to variations in flow rates, and it is inconsistent with the fundamental objective of TPLMs, which aims to achieve target water quality through pollutant load management. Therefore, this study proposes a method that enables the evaluation of target water quality achievement under various flow conditions based on pollutant loads. Using water quality and flow data, which are collected at eight-day intervals through the TPLM monitoring network, load duration curves (LDC) can be created. By utilizing this method, target water quality achievement can be assessed based on pollutant loads. Comparing evaluations for 21 sub-watersheds within the Geum River basin, target water quality achievement in 2023 was assessed by both the LDC method and the current three-year average method. The proportion of sub-watersheds exceeding the target BOD levels was 47.6%, 23.8%, and 19.0%, and for T-P, it was 57.1%, 23.8%, and 14.3% for each respective method. These results indicate that the LDC method yields relatively higher excess rates, showing that it provides a stricter evaluation of target water quality achievement compared to the current method The LDC method not only allows for the evaluation of target water quality achievement by considering flow variations but also is expected to be very useful when time-series predictions are required for target water quality assessments using dynamic models like watershed models, which are applied to estimate allocated loads.

참고문헌 (Reference)

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