논산 장성천의 유량 산정 방법별 비교 및 기저유출량 평가 연구 = Evaluation of Streamflow Methods and Baseflow in the Jangseong Stream

다국어 초록 (Multilingual Abstract)

This study aimed to estimate streamflow at two upstream and downstream points of the Jangseong Stream, a small tributary located in Seokseo-ri, Yangchon-myeon, Nonsan-si, Chungcheongnam-do, and to evaluate baseflow ratios using the measured discharge. The study further sought to identify the factors contributing to the high baseflow ratio observed in the area.
Streamflow measurements were conducted under both non-rainfall and rainfall conditions using the weir method, the velocity–area method, and the float method. The discharge values varied by method depending on the physical assumptions and field conditions involved. These discrepancies appear to result from factors characteristic of small streams, such as aquatic vegetation, bed irregularities, and approach flow conditions, highlighting the limitations of accurate flow estimation in upstream reaches. To address these limitations, this study finally applied multiple techniques in parallel (weir and velocity–area methods).
Using the streamflow measurements at both locations and the external inflows between the two points (including irrigation canal inflow and groundwater pumping), the baseflow ratio was calculated. The baseflow ratio during non-rainfall periods exceeded 81%, falling within the typical range, whereas during rainfall events it ranged from 15% to 88%, higher than the general range. This result is attributed not merely to measurement error but to inherent watershed characteristics—including a gravel-dominated sediments, meandering channel, and lateral groundwater inflow—reflecting the unique geomorphic, geologic, and sedimentary environment of this basin. These conditions indicate strong hydraulic connectivity between the stream and the aquifer and explain that the Jangseong Stream functions as a “groundwater-dominated stream,” with substantial groundwater contribution not only during low-flow periods but also during normal-flow conditions.
Future research should include repeated flow measurements across various hydrologic seasons to quantify temporal variability. Integrated analyses of stream–groundwater exchange incorporating alluvial thickness, grain size, hydraulic conductivity, EC, T, and isotopic data are also recommended. This study provides fundamental data to improve the accuracy of discharge and baseflow analysis in small watersheds and underscores the importance of incorporating site-specific characteristics in hydrologic assessments of stream–groundwater interactions.

목차 (Table of Contents)

• 목 차 ⅰ
• List of Tables ⅲ
• List of Figures ⅳ
• Ⅰ. 서 론 1
• 1. 연구 배경 1
• 2. 연구 목적 2
• Ⅱ. 연구 지역 3
• 1. 지형 및 지질 3
• 2. 기상 현황 4
• 3. 유역 및 수계 6
• Ⅲ. 연구 방법 7
• 1. 현장 조사 개요 7
• 2. 하천 유량 산정 방법 9
• 1) Weir법 9
• 2) 유속-면적법 10
• 3) 부표법(부자법) 10
• Ⅳ. 하천 유량 산정 12
• 1. 하천 유량 산정 결과 12
• 1) Weir법 12
• 2) 유속계법 13
• 3) 부표법 14
• 2. 유량 산정 결과 비교 17
• Ⅴ. 유량 차이를 활용한 기저유출율 평가 19
• 1. 강우 조건 구분 19
• 1) 무강우 조건(Dry condition) 19
• 2) 강우 조건( Wet condition) 19
• 2. 기저유출율 산정 20
• 1) 수지 분석을 통한 기저유출량 산정 방법 20
• 2) 입력 자료 구축 22
• 3) 기저유출량 산정 23
• 4) 기저유출량과 기저유출율 평가 24
• Ⅵ. 토 의 27
• Ⅶ. 결 언 29
• 참 고 문 헌 30
• 영 문 초 록 33