Observation and Comparison of Precipitation and Water Abstraction Data in Taiwan, Japan, and South Korea

The abstraction of precipitation can be defined as the difference between precipitation and runoff. Understanding the dynamics behind water abstraction could provide new insights into hydrological processes and contributes to improved water resource management strategies. This research aims to investigate the phenomenon of water abstraction and critically examine the widely acknowledged assumption that near-surface air temperature is the primary factor influencing the magnitude of water abstraction. The study employs a simplified water balance equation to quantify water abstraction, using observed data from dam catchments in Taiwan, Japan, and South Korea, which span a range of climate types. Data mining techniques, including linear regression and related statistical analyses, are applied to explore the relationship between precipitation and water abstraction across various timescales. Preliminary results indicate that, on a monthly timescale, there is generally a positive correlation between precipitation and water abstraction during the flood season (January–May and November–December) across all catchments. However, the relationship during the dry season (June–October) remains ambiguous. Among the three regions, Japan experiences the highest water abstraction during all seasons, whereas the lowest water abstraction is observed in South Korea during the dry season and in Taiwan during the flood season. On an annual timescale, Japan shows the relative highest water abstraction, while South Korea records the lowest. Notably, our findings diverge from previous research. In Taiwan, particularly during the flood season, an increased incidence of negative water abstraction has been observed. This phenomenon suggests that runoff processes in Taiwan are more influenced by groundwater dynamics than by precipitation.