도농복합지역 지하수 함양과 배출에 대한 연구

Abstract

This study was conducted to identify groundwater recharge and discharge amounts of a representative urban-rural composite area located in Yongin city, Kyounggi-do, Korea. Groundwater recharge would be affected by mainly two processes in the study area: rainfall and leakage from public water pipelines including water-supply and sewage system. Groundwater recharge rate was estimated to be 13.5% by applying annual groundwater level data from two National Groundwater Monitoring Stations to the master regression curve method. Subseguently, the recharge amounts were determined to be 13,253 × 10^3㎥/yr. Leakage amounts from water-supply and sewage system were estimated to be 3,218 × 10^3 and 5,696 × 10^3㎥/yr, respectively. On the whole, a total of the recharge amounts was 22,167 × 10^3㎥/yr, of which 60% covers rainfall recharge and 40% pipeline leakage. Groundwater discharge occurred through three processes in the composite area: baseflow, well pumping, and discharge from urban infrastructure including groundwater infiltration into sewage pipeline and artificial extraction of groundwater to protect underground facilities from submergence. Discharge amounts by baseflow flowing to the Kiheung agricultural reservoir and well pumping were estimated to be 382 × 10^3 and 1,323 × 10^3㎥/yr, respectively. Occurrence of groundwater infiitration into sewage pipeline was rarely identified. Groundwater extraction amounts from the Bundang subway line as an underground facility were identified as 714 × 10^3㎥/yr. Overall, a total of the discharge amounts was determined to be 2,419 × 10^3㎥/yr, which was contributed by 29% of artificial discharge. Even though groundwater budget of the composite area was identified to be a surplus, it should be managed for a sound groundwater environment by changing deteriorated pipelines and controlling artificial discharge amounts.