Meanders Geometry of Alaknanda River in Srinagar Valley (Garhwal Himalaya)

Abstract

The Alaknanda River is a most significant parental river of Ganga and forms an 11.5km long and 2.5 km wide valley locally known as the Srinagar Valley. The main purpose of the present study is to examine the planimetric geometry and hydraulic properties such as depth, width gradient, shape, size, sinuosity index etc in meanders as constructed with straight reach and to examine correlation between different parameters. The entire study has been carried out by remote sensing and GIS techniques on Arc GIS 9.3 software. For the analysis of meander geometry, the Alaknanda River in Srinagar valley is divided into 8 segments of three reaches from Supana to Kirtinagar. Each segment consists of a channel meander. Plan metric geometry and hydraulic properties of each meander bend have been examined and analyzed. Sinuosity index of the Alaknanda River is 1.34 in the study area which indicates that the river is sinuous to meander. The average entrenchment ratio of the channel is 3.27 which shows slightly entrenchment channel. The average wave length of the River is 1.4km. The tectonic control clearly reflects on the pattern, shape and size of the meanders. All the meanders are controlled by transverse fault pattern along the NAT. A strong correlation ship exists between amplitude and sinuosity index (R- 0.94) and width and length ratio (R- 0.96). Finally, it may be concluded that meander amplitude has played a major role in increasing the sinuosity ratio in selected segments in Alaknanda river course.