Sources of Surface Water in Space and Time: Identification of Delivery Processes and Geographical Sources With Hydraulic Mixing-Cell Modeling
Barbara Glaser, Luisa Hopp, Daniel Partington, Philip Brunner, René Therrien & Julian Klaus
| Abstract |
Knowledge of the sources of surface water in riparian zones and
floodplains is critical to understanding its role in runoff
generation and impact on biogeochemical and ecological processes.
In this study, we demonstrate the potential of integrated
surface-subsurface hydrologic modeling (HydroGeoSphere) in
combination with a hydraulic mixing-cell approach to decipher
different sources of surface water and their mixing in space and
time. We present a novel approach to processing the model data that
allowed us to compare which mechanisms ultimately transferred water
to the surface (delivery processes) and from where the surface
water originated (geographical sources) for varying wetness states
and phases of wetting or drying across 36 test locations within the
riparian-stream continuum of an intensively-studied,
humid-temperate, forested headwater catchment (45 ha). Consistent
with current process understanding for the study site, water
exfiltrating from the subsurface was simulated as the dominant
source for riparian surface water and intermittent streamflow. The
model further helped to specify the relevance of different
subsurface stores, revealing a wetness-dependent activation of
upslope source areas. Contributions of riparian overland flow and
precipitation were minor during all investigated phases of wetting
and drying. Moreover, the spatial variability of surface water
sources proved to be smaller than expected for the heterogeneous
patterns and frequencies of the surface saturation observed and
simulated. Based on these findings, we discuss the value of
hydraulic mixing-cell modeling to complement the planning and
interpretation of field investigations and to enhance process
understanding regarding the spatio-temporal sources of surface
water. |
| Keywords |
|
| Citation | Glaser, B., Hopp, L., Partington, D., Brunner, P., Therrien, R., & Klaus, J. (2021). Sources of Surface Water in Space and Time: Identification of Delivery Processes and Geographical Sources With Hydraulic Mixing-Cell Modeling. Water Resources Research, 57, 1-24. |
| Type | Journal article (English) |
| Date of appearance | 10-2021 |
| Journal | Water Resources Research |
| Volume | 57 |
| Pages | 1-24 |
| URL | https://doi. org/10.1029/2021WR030332 |