Study on watershed analysis and sediment regime in the swalik region of Nepal

Wide spread damage due to floods is one of the very common water induced natural disasters in Nepal that account for heavy losses during the monsoon period every year. Perennial rivers that flow through Siwalik area transport heavy sediments loads than rivers located in other areas during rainy season due to very fragile geology of the Siwaliks. Investigating the sediment production and transportation regime in the Siwalik regions of Nepal, drainage analysis was conducted. Satellite data was used in identifying the changes of land coverage, floodplain and river channels. Reasons for these changes were examined with field observation and aerial photograph interpretation. These series of studies evidently showed the crucial causes of the massive sediment production were due to intense erosion that led by the fragile geology, intense rainfall, lack of vegetative coverage, exploitation of lands due to human activities and root morphologies of the indigenous vegetation.