In this work, the delay time for groundwater recharge was estimated by comparing simulated recharges by means of SWAT(Soil and Water Assessment Tool) model and WTF(Water Table Fluctuation) method. The delay time for groundwater recharge means that the time when the water from rainfall travelled through vadose zone just after getting out of soil zone bottom. As measuring this delay time is almost impossible, we used to compare the estimated values from modeling(SWAT) and analytic method(WTF). The test site is Hancheon watershed which has 8 groundwater measurement stations. The results show that the altitude has a linear relationship with the estimated delay time values. To validate these results, we conducted corelation analysis between transformed groundwater levels and observed ones. The results showed that computed groundwater levels have good corelation(R2=0.97, 0.87, respectively). The estimated delay time would be used for the groundwater behaviour characteristics in vadose zone. As recharge rates vary according to the height, the delay time is thought to be an import variable for the proper groundwater recharge estimation.

Abstract
 1. 서 론
 2. 연구 방법
  2.1. 이론적 배경
  2.2. 대상유역
 3. 결과 및 고찰
  3.1. 한천유역의 지체시간 산정
  3.2. 지체시간의 검증
 4. 결 론
 참 고 문 헌

• 김남원(한국건설기술연구원 수자원연구실) | Nam-Won Kim (Water Resources Research Dept., Korea Institute of Construction Technology)
• 나한나(한국건설기술연구원 수자원연구실) | Hanna Na (Water Resources Research Dept., Korea Institute of Construction Technology) Corresponding author
• 정일문(한국건설기술연구원 수자원연구실) | Il-Moon Chung (Water Resources Research Dept., Korea Institute of Construction Technology)