Nabin Bhattarai

Channel Shifting Pattern of Highly Sinuous Meandering River: a Case Study of Manahara River from Pepsicola to Shankhu Nabin Bhattarai

The Manahara River flows over Kathmandu and Bhaktapur districts (topo sheets: 2785 06A, 2785 06B, 2785 02D, 2785 03 C, 2785 07A; latitude from 27°40'00"N to 27°47'3"N and longitude 85°20'00"E to 85°32'30"E). The total length of the river is 31km, which extends from northeast towards southeast and confluences with the Bagmati River. The style and degree of meandering depends on a number of geological factors, including tectonics. The general objective of the study is to find out the meandering pattern of the river. For this four years river patterns (1989, 1995, 2001 and 2007) were gathered with help of Topo-sheet and Google earth. The pattern was compared and analyzed by using GIS software (Arc View GIS 3.3), AutoCAD and Microsoft Excel. Study gave the river has been mostly shifted to NNW direction. The maximum shifting distance was found to be approximately 330m which is meandered to eastward direction in account of river trail of 1989. Bank caving is one of the main causes of river instability and therefore degrades the agricultural land resulting decreases in crop yield and huge economic crisis to the local farmers. Dominance of coarse sand was observed in the site.