6.-Hydrological modelling of an urban watershed Guwahati city drainage- A case study

Abstract

The Guwahati City, the capital of Assam state is the biggest city in entire North-Eastern region. The city is not only the political and commercial capital of Assam but also gateway to the North-Eastern region comprising of seven states. The greater Guwahati area is iocated at latitude 26°-10' N and longitude 92°-49' E. The river Brahmaputra flows along the north of Guwahati city in the westerly direction. The city extends upto 24 km. along the river and at an average width of 9.60 km. along North-South. The city covers an area of 217.60 sq. km. in the south of the river Brahmaputra. The average ground level of the city near the Brahmaputra river is 51.30m, except the hilly areas in the eastern zone of the city. The Western range has an average ground water level of 45.00 m. The central area includes Fatasil Ambari hill zone with pockets of low lying areas with ground water level of 49.00 m on an average. The average annual rainfall in greater Guwahati area is 1864 mm. The climate of the city is moderate with temperature variation between summer and winter. As per the provisional estimates of the 1991 census, the city has a population of 5,77,591.