Geospatial Variation of Rainfall Erosivity factor in Muvattupuzha River Basin

Soil erosion is a critical issue in India where 58% of the population depends on agriculture and allied sectors for their livelihoods. Rainfall erosivity is one of the main factors affecting soil erosion. The erosive power of rainfall is quantified by rainfall erosivity factor. It is the product of kinetic energy of rainfall and rainfall intensity. Continuous rainfall data is a prerequisite to obtain rainfall erosivity factor accurately. High temporal resolution data is required for the determination of these parameters. At places where high temporal resolution data is not available, rainfall erosivity index can be obtained using various relations connecting erosivity index and average annual precipitation. Such available relations are used to obtain the erosivity index of Muvattupuzha river basin. The average sediment discharge of Muvatupuzha River is 167408 MT with an erosion rate of 0.042 mm/year. The results of these equations show a percentage variation of 85% in the results. Region specific equations show better average results. The effect of latitude, longitude and elevation on the index is also analysed. Key Words: precipitation, rainfall erosivity index, erosion, sediment, storm intensity.