The water resources system of Jeju-do Island entirely depends on groundwater. This study is making a precision observation of baseflow, surface water, water shortage that might be vulnerable to climate change and drought in future. The field observation of baseflow discharges in Akgeuncheon stream has regularly been made with ADCP and ADC and Flowmate every two weeks for twenty-two (22) months (July 8, 2011 to April 27, 2013). This paper represent the results of calculating discharge of a number of hydraulic structures (broad-crested weirs) with comparing and has been calculated more accurate discharges with suitability of different observation methods. The average discharge has been observed 0.851 m3/s, whereas the average ADC and Flowmate is 0.709 m3/s. Meanwhile, stream discharge has been calculated 0.709 m3/s through the broad-crested weir equation. The discharge has calculated with the weir equation greatly changed according to even a small change in the water level. However, it showed a similar trend to one of the observed discharge. Although, in past there were generating errors caused by observers’ strides, vertical and horizontal flow velocity distribution when the average flow velocity had been measured, non-prismatic flow, turbulent flow and others in ADC. This study comes up with the weir equation is more suitable for the characteristics of Jeju-do could be presented through an observations of baseflow discharge.

Abstract
 1. 서 론
 2. 재료 및 방법
  2.1. 유량측정방식
  2.2. 연구대상 유역
  2.3. 유량관측 방법
 3. 결과 및 고찰
 4. 결 론
 참 고 문 헌

• 이준호(제주대학교 토목공학과) | Jun-Ho Lee (Department of Civil Engineering, Jeju National University)
• 양성기(제주대학교 토목공학과) | Sung-Kee Yang (Department of Civil Engineering, Jeju National University) Corresponding author
• 정우열(제주대학교 토목공학과) | Woo-Yul Jung (Department of Civil Engineering, Jeju National University)