Variability of discharge response from tile drains in a small agricultural catchment

作者：Borbála Széles, Ladislav Holko, Juraj Párajka, Christine Stumpp, Michael Stockinger, Peter Strauß, Carmen Krammer, Thomas Weninger, Elmar Schmaltz, Matthias Konzett, Reinhard Höllerer, Patrick Hogan, Stefan Wyhlidal, Katharina Schott, Christin Müller, Kay Knöeller, Günter Blöschl · 发表于：Journal of Hydrology · 年份：2026 · DOI：10.1016/j.jhydrol.2026.135859 · 研究领域：Soil and Water Nutrient Dynamics、Hydrology and Watershed Management Studies、Soil erosion and sediment transport

Understanding the discharge response of tile drains is essential to better manage water resources in agricultural areas. The aim of this study was to compare two tile-drainage systems in an agricultural catchment, the Hydrological Open Air Laboratory in Austria in May-October, using six years of high-frequency hydrometric and isotopic observations, to determine whether new or old water contributes more to their discharge and whether new-water contributions correlate with hydrograph flashiness or time to peak flow. The results showed clear differences between the discharge responses and new water fractions of the two tile drainage systems. Sys4 inlet represented a perennial system with larger drainage area, larger pipes and simpler topology, that responded rapidly to even small amounts of rainfall. The response was mainly independent from the soil moisture state and the groundwater level. The second drainage system, Frau2 was an ephemeral system with smaller drainage area, smaller pipes and complex topology that exhibited the flashiest behavior. Larger discharge peaks at Frau2 occurred above a certain soil moisture (0.35 m 3 /m 3 ) and groundwater level threshold (0.3 m below ground surface). Sys4 had the largest average peak flow new water fractions (0.54 with δ 18 O), higher than Frau2 (0.47) and the catchment outlet (0.41). The differences in the hydrometric and isotopic characteristics of the drains could be explained by differences in their construction properties. Discha...