Exploring Biochar as Stable Carbon Material for Suppressing Erosion in Green Infrastructure

Many biomaterials (fibers) have been proposed for minimizing soil erosion. However, those biomaterials are prone to degradation under microbial activity. In contrast, biochar, a relatively stable carbon material (half-life period >100 years) has been explored recently for minimizing soil erosion. Life period of such material is well beyond the design period of any geo-environmental infrastructure. This study evaluates individual and coupling effects as well as the relative importance of four important factors, biochar content, slope gradient, slope length, and rainfall intensity using flume tests. Bare soil (BS) and soil-biochar composites (SBCs) were subjected to flume testing under factorial experiment design. The experimental results indicate that biochar addition significantly increased water retention capacity and decreased soil loss. It lowered the sensitivity of green infrastructure to rainfall events and enhanced the resistance of green infrastructure to water-related hazards. Biochar content is the most significant effect in reducing total erosion sediment, while slope length and slope gradient are the least important factors. Based on the performance of SBCs, biochar is suggested as a promising stable carbon material for the green infrastructure.