Application of GIS-Coupled Modified MMF Model to Estimate Sediment Yield on a Watershed Scale

Abstract

In this study, the Morgan and Duzant version of the modified Morgan-Morgan-Finney (MMF) model coupled with geographical information system (GIS) is used for sediment yield estimation from the Gamber watershed, Satluj basin, Himachal Pradesh, India. The model incorporates particle size selectivity in the process of erosion, transport, and deposition, i.e., it simulates these processes for clay, silt, and sand separately. This modified MMF model also allows for surface runoff and sediment routing, which improves sediment yield estimation accuracy. It also determines the watershed contributions to the total sediment yield at the basin outlet. The present research fetches the MMF model in a geospatial environment and develops a system that can be used to estimate the actual sediment yield. Generally, it has been observed that the detachment of soil is greatly affected by raindrop impact. Therefore, the estimation of kinetic energy of erosive rainfall is a very important factor. Moreover, it has been noticed that the major contribution to kinetic energy of rainfall comes from direct throughfall, as compared to leaf drainage. Therefore, the relationship to estimate kinetic energy of direct throughfall developed for Indian conditions has been used rather than the traditional relationship developed for the United Kingdom. The model parameters were calibrated for the years 1998 and 2002. The results were validated for the years 1995 and 1999. The efficiency coefficient the model could achieve was 0.91. It was concluded that the model can estimate sediment yield from a catchment with reasonable accuracy.