ChapterIII(a) - Pollution Control Board, Assam

EIA Report Proposed INDAdept G Project – Guwahati Refinery Chapter 3Wetland near Birkuchi (Silsako beel)Wetland near Sachhal3.3.5. Geomorphology of the study areaUndulatory terrain with variable relief is the characteristic feature of the study area. Thearea is a part of Precambrian Massif with residual hills, inselberg and valleys with sedimentfills. A number of small Residual hills are found dotting the city area some of which includethe Sarania hill, Navagraha hill, Nilachal hill, Chunchali hill, Khanapara hill and Narengi hill.The Brahmaputra river flowing in east-west direction is the most spectacular geomorphicfeature. The river in the study area flows through a bed rock segment within the study areahaving a minimum width of ~1.2km towards the western most. Bars are the prominentfeatures along the reach of the river. The Brahmaputra forms the trunk drainage system.Basistha, Kalmani and Bharalu along with their tributaries drain into the Brahmaputraforming the surface drainage of the city. A unique feature of the plains is the presence ofnumerous static water bodies or beels of various areal extents. The most important of themwithin the study area is the Silsako bill which covers almost 2.5 sq km of area. Numerousstreamlets drain into these beels.The landscape is changing its profile due to the anthropogenic activities like cutting of thehill slopes and filling up of the wetlands for settlements, commercial and recreationalpurposes.36