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.