Performance of the rangeland hydrology and erosion model for runoff and erosion assessment on a semiarid reclaimed construction site

Authors: Weltz, Mark; NOUWAKPO, SAYJRO - University Of Nevada; MCGWIRE, KEN - Desert Research Institute

Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2015
Publication Date: 5/1/2016
Citation: Weltz, M.A., Nouwakpo, S.K., Mcgwire, K. 2016. Performance of the rangeland hydrology and erosion model for runoff and erosion assessment on a semiarid reclaimed construction site. Journal of Soil and Water Conservation. 71:220-236.

Interpretive Summary: The ability to assess the impact of management actions on soil and water resources is crucial to sustainable land management. The Rangeland Hydrology and Erosion Model (RHEM) was developed as an assessment and decision support tool for land managers and has been used to estimate soil erosion at national, regional and locale scales for both disturbed and undisturbed rangeland soil and vegetation conditions. In this paper, runoff and sediment data were collected during a series of rainfall simulation experiments aimed at evaluating the effectiveness of revegetation on a shrub-dominated post-construction hillslope where the soil has had time to reconsolidate. RHEM inputs are simple to collect and consist of soil texture, slope configuration, and canopy and ground cover. Experimental results showed that a mix of the shrub species rabbitbrush (Chrysothamnus nauseosus) and the invasive annual grass, cheatgrass (Bromus tectorum) were more effective at reducing runoff and soil loss than rabbitbrush alone. Detailed analysis of RHEM’s predictions showed that this model accurately predicted the beneficial effect of cheatgrass on soil loss and on runoff although further research are necessary to improve infiltration sensitivity to rock fragments and ground cover. This study demonstrates that RHEM can be effectively used by land managers and project managers to estimate soil erosion as a function of precipitation event on construction sites that have been revegetated to rangeland plant communities.

Technical Abstract: The ability to assess the impact of management actions on soil and water resources is crucial to sustainable land management. The Rangeland Hydrology and Erosion Model (RHEM) was developed as an assessment and decision support tool for resource management agencies and has been used to estimate soil erosion at national, regional and locale scales for both disturbed and undisturbed rangeland soil and vegetation conditions. In this paper, runoff and sediment data were collected during a series of rainfall simulation experiments aimed at evaluating the effectiveness of revegetation on a shrub-dominated post-construction hillslope where the soil has had time to reconsolidate. RHEM inputs are simple to collect and consist of soil texture, slope configuration, and canopy and ground cover. Experimental results showed that a mix of the shrub species rabbitbrush (Chrysothamnus nauseosus) and the invasive annual grass, cheatgrass (Bromus tectorum) were more effective at reducing runoff and soil loss than rabbitbrush alone. RHEM’s performance as expressed by the coefficient of determination r2 and the Nash-Stucliffe Efficiency NSE was r2 = 0.84 and NSE = 0.27 for runoff and r2 = 0.81 and NSE = 0.26 for sediments. Detailed analysis of RHEM’s predictions showed that this model accurately predicted the beneficial effect of cheatgrass on soil loss and on runoff although further research are necessary to improve infiltration sensitivity to ground cover. This study demonstrates that RHEM can be effectively used by land managers and project managers to estimate soil erosion as a function of precipitation event on construction sites that have been revegetated to rangeland plant communities.