Rainfall-driven transfer to the stream-conduit network observed through increasing spatial scales in mixed land-use paddy farming karst terrain.

Abstract in brief

• Rainfall significantly affects the movement of faecal microorganisms in karst terrains, which are vital for providing drinking water to many people, but managing water safety is challenging due to limited understanding of how rainfall influences water flow responses.
• During intense storm events, concentrations of microorganisms can increase dramatically—by up to 13 orders of magnitude—and most of the microbial export occurs within 48 hours, especially during high-intensity rainfall.
• The study found that microorganism concentration increases with discharge (water flow) at all sites, but the rate of increase varies based on location within the catchment, rainfall amount, and land use, with more rapid changes happening downstream due to the karst system's fissure networks.