Professor Jonghun Kam and Kwang-Hun Lee from POSTECH analyzed water quantity and quality data from agricultural reservoirs in South Korea to understand the hydrological impacts of severe drought on water quality. The study, published in Water Research, aimed to investigate the effects of extreme weather events on the water and carbon cycles using observational data.
In South Korea, over 3,000 agricultural reservoirs are used for water resource management during rice planting season. The researchers monitored water levels and collected seasonal water quality data from these reservoirs since 2020. This national-level dataset provided a unique opportunity to study the coupled dynamics of the water and carbon cycle, shedding light on the impact of extreme drought on water quality.
Utilizing rotated principal component analysis, researchers extracted key modes from extensive datasets of water levels and water quality from over 2,200 agricultural reservoirs in Korea from 2020 to 2022. They found that as water temperatures rose and reservoir levels decreased due to drought, there was an increase in total organic carbon (TOC) concentrations. Additionally, fluctuations in reservoir levels in different regions were correlated with shifts in TOC concentrations, particularly in areas with a larger areal fraction of rice paddy fields surrounding reservoirs.
The study revealed that during a severe drought in 2022, there was a potential shift in the role of agricultural reservoirs from carbon storage to carbon source, emitting carbon into the atmosphere. This highlights the importance of understanding how extreme weather events like droughts can impact water quality and the carbon cycle in agricultural reservoirs. The findings emphasize the need for integrative environmental and water policies to prioritize water quantity and quality, especially as we move towards a carbon-neutral era.
Professor Jonghun Kam emphasized the significance of utilizing water big data and advanced statistical methodologies to quantitatively demonstrate the alterations in the water and carbon cycles caused by extreme drought. He stressed the importance of developing comprehensive environmental and water policies to address both quantity and quality as we navigate towards a carbon-neutral future. The research received support from the Ocean, Land, and Atmosphere Carbon Cycle System Research Program of the National Research Foundation of Korea.
Overall, the study by Professor Jonghun Kam and Kwang-Hun Lee provides valuable insights into the hydrological impacts of severe drought on water quality in agricultural reservoirs. By analyzing water quantity and quality data from over 2,200 reservoirs in Korea, the researchers were able to demonstrate the shifts in the water and carbon cycles during extreme weather events. Their findings underscore the importance of developing integrated environmental and water policies to prioritize both quantity and quality as we transition to a carbon-neutral era.