Analysis of sheet erosion component variability on four complex hillslopes and consecutive storms under laboratory conditions

Understanding of rainfall-runoff processes in arid and semi-arid regions, such as runoff discharge (Q) and sediment concentration (SC) in hillslopes with different geometries, can offer better insights into hydrological processes. Consequently, considering intra- and inter-storm dynamics of Q and SC during consecutive storms (CSs), on hillslopes of various geometric shapes, has not been accurately and scientifically studied. The current research was planned to study the response of the sheet erosion components. The experiments were performed on four complex hillslopes (CHs) including straight-parallel, straight-convergent, concave-convergent, and convex-convergent under five CSs with rainfall intensity of 45 mm/h on a sandy loam soil in a 1 × 2 m2 plot under laboratory conditions. The results showed that the individual effects of the CSs and CHs and their interactive effects on Q and SC were significant (P ≤ 0.00). However, Q was more influenced by the CSs (ηp2 = 0.65) and SC was more affected by the CHs (ηp2 = 0.77). Moreover, analysis of the hydrographs (HGs), sedigraphs (SGs), and sediment rating loops (SRLs) observed in four CHs during five CSs indicated the diversity in the behavior of the SC (from 2.32 to 68.68 g/L) in comparison with variations in Q (from 14.68 to 38.38 mL/s).