Howard, EJ & Roddy, BP 2012, 'Evaluation of the water erosion prediction project model – validation data from sites in Western Australia', in AB Fourie & M Tibbett (eds), Mine Closure 2012: Proceedings of the Seventh International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 81-92, https://doi.org/10.36487/ACG_rep/1208_09_Howard (https://papers.acg.uwa.edu.au/p/1208_09_Howard/) Abstract: Computer simulations of runoff and erosion are a key element in the design of stable waste dump outer batter profiles. The Water Erosion Prediction Project (WEPP) model is used to develop erosionally stable landform batter surfaces. Although the WEPP model has been widely validated elsewhere, there is a perceived need to similarly validate the model for mine site conditions. Erosion monitoring data collected on landforms for which model parameters are known can be used for two primary purposes: a) to demonstrate that erosion rates are consistent with site targets; and b) to validate and more precisely calibrate the erosion model used in landform design, enabling continuous improvement in the design process. Model validation techniques are discussed and validation data for several landforms are presented. In general, cumulative erosion rates measured since completion of construction show good agreement with predicted erosion rates. The data have provided validation of the landform design process used; confidence in the surface stability of existing landforms that have been constructed; refinement and improvement in the design process; and a means for continual improvement in landform rehabilitation methods.