https://doi.org/10.1029/2020WR027514

McDonnell, J. J., Spence, C, Karran, D. J., van Meerveld, H. J., and Harman, C.: Fill-and-spill: A process description of runoff generation at the scale of the beholder, Water Resources Research, 57, e2020WR027514, https://doi.org/10.1029/2020WR027514, 2021

Descriptions of runoff generation processes continue to grow, helping to reveal complexities and hydrologic behavior across a wide range of environments and scales. But to date, there has been little grouping of these process facts. Here, we discuss how the “fill-and-spill” concept can provide a framework to group event-based runoff generation processes. The fill-and-spill concept describes where vertical and lateral additions of water to a landscape unit are placed into storage (the fill)—and only when this storage reaches a critical level (the spill), and other storages are filled and become connected, does a previously infeasible (but subsequently important) outflow pathway become activated. We show that fill-and-spill can be observed at a range of scales and propose that future fieldwork should first define the scale of interest and then evaluate what is filling-and-spilling at that scale. Such an approach may be helpful for those instrumenting and modeling new hillslopes or catchments because it provides a structured way to develop perceptual models for runoff generation and to group behaviors at different sites and scales.

Northern-Water-Futures, Refereed Publications

https://doi.org/10.1029/2020WR027514