Groundwater-Stream Water Interaction Induced by Water Curtain Cultivation Activity in Sangdae-ri Area of Cheongju, Korea

Koo

et al. 2021

Water

The Juksan weir, installed in the Yeongsan river in South Korea from 2010 to 2012, has secured sustainable water resources and helped control flooding. However, low river flow velocities due to the weir have deteriorated the quality of the river water. For natural river restoration, the water gate was opened in 2017. In this study, the three-dimensional finite difference model Visual MODFLOW was used to analyze the effects of gate opening on stream–aquifer interactions. A conceptual model was developed to simulate the stream–aquifer dynamics caused by the operation of the water gate at the Juksan weir. Groundwater data were also analyzed to determine the impacts of weir operations on groundwater quality. Our results indicate that a lower river level due to the weir opening changed the groundwater flow, which then affected the water balance. The change in groundwater flow increased the variability of the groundwater quality which had homogenized because of induced recharge after the construction of the weir. This could affect groundwater use in agricultural areas near the weir. Therefore, further groundwater monitoring and hydrodynamic analyses are required to anticipate and address any potential issues.

Section: Introductionmentioning

confidence: 99%

Changes in Stream–Aquifer Interactions Due to Gate Opening of the Juksan Weir in Korea

Koo

et al. 2021

Water

“…Moreover, the stream‐aquifer interaction could affect groundwater temperature and quality, which could adversely affect greenhouse heating as well as crop irrigation. The groundwater temperature could decrease due to the intrusion of cold stream water during the pumping season (Moon et al ). The groundwater quality could be deteriorated by the polluted stream water (Ray et al ), while saline groundwater could be diluted by induced recharge (Lee et al ).…”

Section: Introductionmentioning

confidence: 99%

Modeling Stream‐Aquifer Interactions Under Seasonal Groundwater Pumping and Managed Aquifer Recharge

Koo²,

2018

Groundwater

In South Korea, a significant amount of groundwater is used for the heating of water-curtain insulated greenhouses during the winter dry season, which had led to problems of groundwater depletion. A managed aquifer recharge (MAR) project is currently underway with the goal of preventing such groundwater depletion in a typical cultivation area, located on an alluvial aquifer near the Nam River. In the present study, FEFLOW, a three-dimensional finite element model, was used to evaluate different strategies for MAR of the cultivation areas. A conceptual model was developed to simulate the stream-aquifer dynamics under the influence of seasonal groundwater pumping and MAR. The optimal rates and duration of MAR were assessed by analyzing the recovery of the groundwater levels and the change in the groundwater temperature. The simulation results indicate that a MAR rate of 8000 m /d effectively restores the groundwater level when the injection wells are located inside the groundwater depletion area. It is also demonstrated that starting the MAR before the beginning of the seasonal pumping is more effective. Riverbank filtration is preferable for securing the injection water owing to plentiful source of induced recharge from the river. Locating the pumping wells adjacent to the river where there are thick permeable layers could be a good strategy for minimizing decreases in the groundwater level and temperature.

“…Induced groundwater recharge by seasonal pumping in winter appears to have a large impact on the groundwater temperature near the corresponding stream (Kim et al ). A recent study in an area of water‐curtain cultivation showed temporal variations of groundwater temperature and a strong influence of stream water on the stable isotopic composition of groundwater (Moon et al ). The chemical characteristics of groundwater can also be changed by induced recharge (Hiscock and Grischek ; Ray et al ).…”

Section: Introductionmentioning

confidence: 99%

Impacts of Seasonal Pumping on Stream‐Aquifer Interactions in Miryang, Korea

Koo²,

Kim

2017

Groundwater

Self Cite

Large agricultural fields in South Korea are located mostly on alluvial plains, where a significant amount of groundwater is used for heating of water-curtain insulated greenhouses. Such greenhouses are commonly used for crop cultivation during the winter dry season from November to March. After use the groundwater is discharged directly into streams, causing groundwater depletion. A hydrogeological study was carried out in a typical agricultural area of this type, located on an alluvial aquifer near the Nakdong River. Groundwater levels, chemical characteristics, and temperatures from 68 observation wells were analyzed to determine the impacts of seasonal groundwater pumping on the groundwater system and stream-aquifer interactions. Our results show that the groundwater system has not yet reached a state of dynamic equilibrium. Decades of excessive seasonal pumping have caused a gradual decline of groundwater levels, leading to groundwater depletion, especially in areas further from the river. Seasonal pumping has also significantly affected groundwater quality in the aquifer near the river. Groundwater temperature is decreasing (in this case a disadvantage), and saline groundwater is being diluted by induced recharge. The results of this study provide a basic outline for effective integrated water management that is widely applicable in South Korea.