섬진강 수계 수질-수생태계를 고려한 하천유지유량 평가 및 재산정

Evaluation and Re-estimation of Instream Flow Considering the Water Quality and Aquatic Ecosystem of the Seomjingang River Watershed

본 연구에서는 현재 고시, 운영되고 있는 섬진강 수계의 하천유지유량을 수량과 수질, 수생태계의 상태를 근거로 평가하여 그 적정성을 살펴보았다. 유량평가는 주요 댐 건설전 유량자료가 남아있으며, 섬진강 본류 최 하류에 위치하여 섬진강 유량관리의 핵심이 되는 구례군(송정리) 지점의 유량을 바탕으로 평가하였다. 수질과 수생태계 상황은 최근 20년간 측정된 자료를 바탕으로 확인하고 하천유지유량 달성정도는 다른 수계 주요 지점의 하천유지유량 달성도와 비교하였다. 평가자료를 기반으로 새롭게 산정이 필요한 세 개 하천과 11개 지점에 대해 하천유지유량을 재산정하였다. 현재 허가된 하천수 사용량을 기반으로 갈수기 하천유지유량 부족량 공급을 위한 필요수량을 예측해 물관리 업무에 참고가 가능하도록 제시하였다.

In this study, the appropriateness of the current publicly announced and managed instream flow in the Seomjingang River watershed was evaluated based on the water quantity, water quality, and state of the aquatic ecosystem. The stream flow was evaluated based on the observed water flow rate at the Gurye-gun (Songjeong-ri) station that is the main point of the Seomjingang River flow management and located at the lowest downstream of the main stream of the Seomjingang River. Another important reason for choosing this station was that observational data from before the construction of the major dam to the present day were available. The water quality and aquatic ecosystem conditions were reviewed based on the data measured over the past 20 years, and the achievement ratio of instream flow was compared with that of stations in the other major river systems. Based on the evaluation result, the instream flow was re-estimated for the 11 important stations of the Seomjingang River and its two branches. Based on the currently permitted water use of the Seomjingang River, the amount of water required to supply for the instream flow deficit during dry seasons was predicted and presented as a reference for water management work.