Physically based soil erosion and sediment yield models revisited

- 50 physically based soil erosion and sediment yield models are reviewed.
- Models shortcomings, strengths, equations and future research are presented.
- Study compiled past, present and future state of soil erosion modelling processes.
- Extensively used promising models are SWAT, WEPP, AGNPS, ANSWERS and SHETRAN.
- Improvement in the evaluation capability of physically based models is suggested.

A plenty of models exist for study of the soil erosion and sediment yield processes. However, these models vary significantly in terms of their capability and complexity, input requirements, representation of processes, spatial and temporal scale accountability, practical applicability, and types of output they provide. The present study reviews 50 physically based soil erosion and sediment yield models with respect to these factors including shortcomings and strengths. The literature generally suggests the use of models like SWAT, WEPP, AGNPS, ANSWERS and SHETRAN for soil erosion and sediment studies. Most of the developed soil erosion and sediment yield models are capable of simulating soil detachment and sediment delivery processes at hillslope scale; a limited development was found in the field of reservoir siltation and channel erosion processes. The study proposes a guideline for selection of an appropriate model to the reader for a given application or case study. The future research suggested to improve the simulation and prediction capability of physically based soil erosion and sediment yield models, and should focus on incorporation of improved global web based weather database, inclusion of sediment associated water quality and gully erosion simulation module, and improvement in reservoir siltation and channel erosion simulation processes.