Model Library

Capabilities

• It has a modular design;
• It estimates soil loss distributions spatially and temporally on daily, monthly, or annual scales (Flanagan et al., 1995);
• The model links hillslope profiles to channels and impoundments (Flanagan et al., 1995);
• It identifies sediment zones, accounts for backwater effects, and represents erosion variability due to management practices (Flanagan et al., 1995);
• It has the most process-based and finest temporal resolution hydrologic foundation (McGehee et al., 2022).

Limitations

• It is designed for hillslope profiles and small watersheds with hydrology dominated by Hortonian overland flow, requiring watershed representation for scales larger than 100 meters to avoid exaggerated erosion predictions (Flanagan et al., 1995);
• Snow drifting calculations are not included in the current WEPP version (Flanagan et al., 1995);
• It models sediment transport but provides limited data on stream hydrology, lake levels, and groundwater dynamics (Keller et al., 2023; McGehee et al., 2022);
• For single-event configurations, it does not compute percolation or lateral flow (McGehee et al., 2022);
• It does not account for spatial variability in hillslope conditions or the long-term effects of vegetation and management on soil properties (McGehee et al., 2022);
• Classical gully erosion is not addressed by its procedures (Flanagan et al., 1995);
• It restricts initial saturation to 95% (McGehee et al., 2022);
• Challenges in simulating soluble nitrogen transport, compost dynamics, and vegetative filter strip (VFS) dynamics (McGehee et al., 2022).

Inputs

Topography, LULC, Soil data, Meteorology (optional), Management data

Outputs

WEPP can simulate climate, surface hydrology, hydraulics of overland flow, water balance, plant growth, residue management and decomposition, soil disturbance by tillage, and irrigation to predict hillslope erosional processes (Flanagan et al., 2007).

References

McGehee, R. P., Flanagan, D. C., Engel, B. A., & Gilley, J. E. (2024). A validation of WEPP water quality routines in uniform and nonuniform agricultural hillslopes. International Soil and Water Conservation Research, 12(3), 487-505. https://doi.org/10.1016/j.iswcr.2023.11.005

Guidotti, V., Ferraz, S. F. de B., Pinto, L. F. G., Sparovek, G., Taniwaki, R. H., Garcia, L. G., & Brancalion, P. H. S. (2020). Changes in Brazil’s Forest Code can erode the potential of riparian buffers to supply watershed services. Land Use Policy, 94, 104511. https://doi.org/10.1016/j.landusepol.2020.104511

Objectives

This study aimed to validate the most recent version of WEPP-WQ for single-storm or non-uniform condition simulations, as there has been no validation for previous versions.

The study aims to evaluate APPs' ability to provide watershed services, examine how riparian buffer restoration and land management affect erosion, sedimentation, and freshwater supply, and answer three questions: the effect of buffer width on sediment protection, the role of best management practices versus native forests, and the effectiveness of buffer restoration in ensuring watershed services.