This study analyzed the velocimetry of runoff and measured the flood discharge by applying the SIV (Surface Image Velocimetrer) to the daytime and nighttime flow image data with special reference to Seong-eup Bridge at Cheonmi stream of Jeju during the flow by the severe rainstorm on May 27, 2013.
A 1000W lighting apparatus with more than 150 lux was installed in order to collect proper nighttime flow image applied to the SIV. Its value was compared and analyzed with the velocity value of the fixed electromagnetic wave surface velocimetry (Kalesto) at the same point to check the accuracy and applicability of the measured velocity of flow.
As a result, determination coefficient R2 values were 0.891 and 0.848 respectively in line with the velocity distribution of the daytime and nighttime image and the flow volume measured with Kalesto was approximately 18.2% larger than the value measured with the SIV.

Abstract
 1. 서 론
 2. 연구대상 하천
 3. 연구방법
  3.1. 관측자료
  3.2. 천미천 유역의 강우량 분석
 4. 결과 및 고찰
  4.1. 유출수문곡선과 유출특성
  4.2. 주ㆍ야간 유출영상의 정확도 비교
 5. 결 론
 REFERENCE

• 김용석(제주대학교 토목공학과) | Yong-Seok Kim (Department of Civil Engineering, Jeju National University)
• 양성기(제주대학교 토목공학과) | Sung-Kee Yang (Department of Civil Engineering, Jeju National University) Corresponding author
• 류권규(동의대학교 토목공학과) | Kwonkyu Yu (Department of Civil Engineering, Dong-eui University)
• 김동수(단국대학교 토목환경공학과) | Dong-su Kim (Department of Civil & Env. Engineering, Dankook University)