Pipeflow response in loess-derived soils to precipitation and groundwater table fluctuations in a temperate humid climate

Piping is a widespread phenomenon in the world and can significantly contribute to the downward movement of water, sediments, and nutrients. This study examines the hydrological functioning of soil pipes in a loess-derived soil under pasture using hydrometric and hydrochemical analyses. It aims to investigate the relation between pipeflow, rainfall, and groundwater table fluctuations and to determine the dominant source of the water flowing through the soil pipes using both hydrometric and hydrochemical approaches. A rapid pipeflow response is observed when a threshold rainfall depth is exceeded. This threshold depth is larger in the summer (9mm) compared with that in the winter (4mm) which is related to the prestorm wetness of the soil. Hydrochemical analyses indicate that both groundwater and rainfall contribute to the pipeflow with a dominance of groundwater. This study shows that pipeflow can be an important hydrological pathway in loess-derived soils with a clear seasonal pattern in pipeflow responses to rainfall events.