The area within 10 km radius of the Bongaigaon Refinery and Petrochemicals Ltd. covers an area between new Bongaigaon and Aie river. The area is generally is a flat terrain traversed by some meandering rivers such as Tangainadi, ghorbandha and Ekanjani all of which are major tributaries of river Brahamputra. The smalller tributriea draining the area are Tunia and Kujia.

The existing landuse pattern is predominantly agriculture, largely dependent on agroclimatic conditions prevalent in the area and well adapted to topographic, edaphic and hydrological patterns of this geographical area. The conspicuous features of built up land within the study area includes the BRPL complex, the new Bongaingaon railway yard and a national highway with settlements located close to valleys and along the road network. The forest area in the study is represented by conspicuous hillocks that stand out as off shoots of Assam ranges above the alluvium.

The area under forest within the study area comprise of less than 15% of the total land area. Aie is the only major river that occupies most of the northern part of the study area. Changes in its course and deposits of silt and sand in its bed create temporary island habitat in several places within the actual banks of river course. There are several large and small bodies locally known as 'beels' that are created by impoundment of flood waters and are subjected to recurring annual water logging during monsoon.

For the purpose of presenting information on the ecological baseline of the project area, the wildlife habitats within the study area have been broadly categorized into terrestrial and aquatic habitats.