Rangeland Hydrology and Erosion Model Web Tool
The RHEM core engine development was initiated in 2003. The current version of RHEM is a single storm, hillslope scale model that requires user input information (Figure 1) on:
- Soil and Cover
- Infiltration/runoff/erosion parameters
Figure 1. A flow chart of the RHEM erosion prediction procedure
RHEM is currently a single storm runoff and erosion computer model. Parameter estimation equations have been developed based on the measured rangeland erosion plot data for the two primary erodibility and infiltration parameters (Kss and Ke). Parameter estimation for other input parameters, including concentrated flow detachment, are currently under development. The parameter estimation procedures for Kss and Ke are grouped according to dominant plant forms of sod-grass, bunch-grass, shrubs, and forbs with a different set of estimation equations for each grouping. Hence currently, the model may be parameterized and executed for undisturbed rangeland conditions.
Capabilities In Progress
- Parameter estimation procedures for the remaining infiltration, runoff, and erosion parameters, which include concentrated flow erodibilities and hydraulic friction factors are underway. Once these procedures are in place, the model will be capable of representing infiltration, runoff, and erosion on both undisturbed and disturbed rangeland hillslopes.
- Procedures will be developed to specifically execute model predictions for NRI data, such that a user may estimate runoff and erosion rates for single storms at NRI sites.
- A risk assessment methodology will be developed that calculates the risk of various sized erosion events occurring at a site of interest in its current or assumed condition.
- The risk assessment methodology using return frequency storm values will be further refined to calculate the risk of various sized erosion events occurring at a site of interest in its current or assumed condition.