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Evaluation of sediment transport formulae and detachment parameters in eroding rills using PSEM_2D and the Water Erosion Prediction Project (WEPP) database
Author(s) -
Nord Guillaume,
Esteves Michel
Publication year - 2007
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2006wr005444
Subject(s) - rill , wepp , soil water , erosion , hydrology (agriculture) , stream power , sediment , infiltration (hvac) , soil science , sediment transport , water flow , surface runoff , geotechnical engineering , geology , environmental science , geomorphology , soil conservation , physics , ecology , biology , agriculture , thermodynamics
The numerical model PSEM_2D is applied to reproduce the rill experiments described by Elliot et al. (1989) for five different textured soils. PSEM_2D is a two‐dimensional water flow and erosion model incorporating the first‐order detachment‐transport coupling model. The infiltration parameters and the friction factor are calibrated to reproduce both the flow discharges and the flow velocities measured by Elliot et al. (1989). Values of the determined friction factors are higher for the cohesive soils compared to the noncohesive soils. Four sediment transport capacity formulae for rills are tested: the Yalin, the Low, the unit stream power (Govers USP), and the effective stream power (Govers ESP) equations. These equations do not require any calibration. The erosion parameters for the first‐order detachment‐transport coupling model come from the Water Erosion Prediction Project (WEPP) database. They were calibrated by Elliot et al. (1989) using observed data and the rill component of WEPP. The Govers USP formula gives the best results for the cohesive soils. Nevertheless, none of the equations performs well for the noncohesive soils. The study also focuses on the results obtained for the Barnes_ND, the Bonifay, and the Collamer soils to explore the implication of the detachment‐transport coupling model on the spatial erosion patterns along the rills. A detachment‐limiting regime is produced over the whole rill for the Barnes_ND soil, a transport‐limiting regime is reached over a very short flow distance for the Bonifay soil, and a detachment‐limiting regime in the upper part along with a transport‐limiting regime in the lower part of the rills is experienced for the Collamer soil.