A novel approximate solution to slope rainfall infiltration

• Published in: Journal of hydrology (Amsterdam) 2023-10, Vol.625, p.130039, Article 130039
• Main Authors: Wu, SiCong, Ma, DongHao, Liu, ZhiPeng, Chen, LiangHong, Chen, Lin, Zhang, JiaBao
• Format: Article
• Language: English
• Subjects: Analytical solution; Brooks-Corey model; Green-Ampt equation; Green-Ampt model; infiltration rate; Initial soil water content; model validation; rain; rain intensity; Slope infiltration; soil water content
• ISSN: 0022-1694; 1879-2707
• DOI: 10.1016/j.jhydrol.2023.130039

•MASCP considers the effect of ponding by introducing a developing saturated zone.•MASCP reveals scaling relations of infiltration for sloping and horizontal surfaces.•New numerical algorithm can model slope infiltration with non-uniform initial SWC. Slope rainfall infiltration is a critical component of the Earth's hydrologic processes. Although various infiltration models have been proposed to simulate rainfall infiltration, simple and accurate ones are still scarce. This work developed a non-integral infiltration model for sloping surfaces, called modified approximate solutions under constant pressure conditions (MASCP). New expressions were proposed to improve slope infiltration simulation by introducing a developing saturated zone in soil water content (SWC) profile to quantify the role of ponding water during infiltration. The MASCP was then extended to simulate the infiltration with uniform and non-uniform initial SWC distributions under complex rainfall patterns. The model performance was evaluated by comparing with Hydrus-1D and the sloping Green-Ampt model for four distinct textured soils. The results demonstrated that the ponding time and infiltration rate simulated by the MASCP agreed well with those by Hydrus-1D at all given conditions. Besides, the MASCP yielded higher simulation accuracy than the sloping Green-Ampt model, especially for coarse-textured soils, low rainfall intensity, and long rainfall hiatus. In conclusion, the MASCP is a simple and accurate computation tool for slope rainfall infiltration modeling.