Improving the Representation of Hydrological Processes by the
Multi-dimensional Modeling Approach
Abstract
Watershed hydrological processes controlled by subsurface structures
that have hierarchical organization across scales, but there is a lack
in multiscale model validation. In this study, using a comprehensive
dataset collected in the forested Shale Hills catchment, we tested the
series HYDRUS codes (i.e., HYDRUS-1D at the pedon scale, HYDRUS-2D at
the hillslope scale, and HYDRUS-3D at the catchment scale) that included
a hierarchical multi-dimensional modeling approach for water flow
simulation in the vadose zone. There is good agreement between 1D
simulations and measurements of soil moisture profiles controlled by
soil hydraulic parameters and precipitation characteristics; however,
short-term fluctuations in preferential flow were poorly captured.
Notably, 2D and 3D simulations (Nash–Sutcliffe efficiency, ), which
accounting subsurface preferential flow controlled by slope positions
and shallow fractured bedrock, provided better results than 1D
simulations (). Our modeling approach also illustrated that the studied
watershed was characterized by weathered and un-weathered fracture
bedrocks, which routed water through a network of subsurface
preferential flow pathways to the first-order stream. Furthermore, a
dual-porosity or anisotropy model produced more accurate predictions
than a single-porosity or isotropy model due to a more realistic
representation of local soil characteristics and layered structure. Our
multi-dimensional modeling approaches credited with diagnosing and
presenting the dominant hydrological processes and the interactions
within soil-landscape features across one sloped catchment.