동절기 시설재배단지의 수막용수 사용후 배출수의 유량 및 수질 부하 특성 평가

Abstract

In Korea, large greenhouse complexes are commonly established near rivers to ensure stable access to groundwater, which is intensively used during winter water-curtain cultivation to protect crops from low nighttime temperatures. However, most of the pumped groundwater is discharged directly into adjacent streams, raising concerns regarding both groundwater depletion and water-quality deterioration. This study investigated these issues in a major greenhouse cluster located in Sangnam-myeon, Miryang-si, Gyeongsangnam-do, by quantifying return flows and evaluating associated pollutant loads. From November 2024 to March 2025, four monitoring sites were equipped with water-level loggers, velocity sensors, time-lapse cameras, and automatic sampling instruments to capture hydrological and water-quality dynamics. Stage-discharge relationships were developed for each site and applied to construct continuous return-flow time series. The average return flow per greenhouse unit was 15.72 m3/day (range: 9.33-20.97), with peak discharges observed in December and January when heating demand was highest. Water-quality analysis revealed substantial pollutant loads originating from return flows, including SS (110.36 kg/km2 ⋅day), COD (29.16), TN (18.83), and NO3-N (6.38), whereas TP remained consistently low. These findings demonstrate that water-curtain return flows exert strong influences on both stream hydrology and non-point source pollution, underscoring the need for integrated management strategies that jointly consider groundwater use, winter agricultural practices, and downstream water-quality protection.