Concentrated flow erosion processes are distinguished from splash and sheetflow processes in their enhanced ability to mobilize and transport large amounts of soil, water and dissolved elements. On rangelands, soil, nutrients and water are scarce and only narrow margins of resource losses are tolerable before crossing the sustainability threshold. In these ecosystems, concentrated flow processes are perceived as indicators of degradation and often warrant the implementation of mitigation strategies. Nevertheless, this negative perception of concentrated flow processes may conflict with the need to improve understanding of the role of these transport vessels in redistributing water, soil and nutrients along the rangeland hillslope. Vegetation influences the development and erosion of concentrated flowpaths and has been the primary factor used to control and mitigate erosion on rangelands. At the ecohydrologic level, vegetation and concentrated flow pathways are engaged in a feedback relationship, the understanding of which might help improve rangeland management and restoration strategies. In this paper, we review published literature on experimental and conceptual research pertaining to concentrated flow processes on rangelands to: (1) present the fundamental science underpinning concentrated flow erosion modeling in these landscapes, (2) discuss the influence of vegetation on these erosion processes, (3) evaluate the contribution of concentrated flow erosion to overall sediment budget and (4) identify knowledge gaps

In this study, we present the improved Rangeland Hydrology and Erosion Model (RHEM V2.3), a process‐based erosion prediction tool specific for rangeland application. The article provides the mathematical formulation of the model and parameter estimation equations. Model performance is assessed against data collected from 23 runoff and sediment events in a shrub‐dominated semiarid watershed in Arizona, USA. To evaluate the model, two sets of primary model parameters were determined using the RHEM V2.3 and RHEM V1.0 parameter estimation equations. Testing of the parameters indicated that RHEM V2.3 parameter estimation equations provided a 76% improvement over RHEM V1.0 parameter estimation equations. Second, the RHEM V2.3 model was calibrated to measurements from the watershed. The parameters estimated by the new equations were within the lowest and highest values of the calibrated parameter set. These results suggest that the new parameter estimation equations can be applied for this environment to predict sediment yield at the hillslope scale. Furthermore, we also applied the RHEM V2.3 to demonstrate the response of the model as a function of foliar cover and ground cover for 124 data points across Arizona and New Mexico. The dependence of average sediment yield on surface ground cover was moderately stronger than that on foliar cover. These results demonstrate that RHEM V2.3 predicts runoff volume, peak runoff, and sediment yield with sufficient accuracy for broad application to assess and manage rangeland systems.