Abstract
Equipped with complex terrain structure, physical models provide an
alternative way in understanding and modeling how critical zone shapes
hydrologic processes in headwaters for hydrology research and education.
However, this type of physical models is limited by frustrating
rain-erosion or gully-erosion. Herein, the technique of permeable bricks
with cementation property that can help to solve the soil backfilling
problem was adopted to construct a physical model with complex terrain.
Through material tests for different aggregate-cement ratios, we found
that saturated hydraulic conductivity (Ksat) of samples is well
correlated with bulk density (BD), e.g., the correlation coefficient
(R2) is as high as 0.75 between Ksat and BD. Then, the
test material selected was applied as a soil alternative in the physical
model in which two artificial soil layers have been designed through
altering BD. Additionally, the non-uniform scaling of terrain was
applied for the convenience of teaching, and it was constructed by
reducing a steep 0.31-ha zero-order basin to 1/130 in horizontal
direction and 1/30 in vertical direction. Multiple observation items,
e.g., shallow groundwater level, soil moisture content, subsurface and
surface runoff, etc., could provide potential opportunity to explore the
role of soil and terrain in modulating streamflow. We’d like to share
this effective tool to facilitate the research works of critical zone
science and enrich experimental teaching methods.