MORPHOMETRY AND ITS IMPACT ON LANDUSE IN NANOI RIVER BASIN, ASSAM, USING GEO-INFORMATICS TOOL.

Morphometric analysis of a river is an essential requirement to evaluate the nature of changes of river basin and its impact on land use pattern. Unstable nature of a river caused unprecedented changes on land and hydrology. A drainage basin being the best unit for hydro-physical studies among many (Horton, 1945, Chorley, 1969), bears a great significance in today?s hydro-environmental investigation of channel network and drainage morphology along with flood events and their relationship with land, water and man (Chorley,1969b). Hydro-geomorphic processes play key roles in creating, modifying, or destroying aquatic habitat and act as ecological disturbances. The drainage network, land, water, soil, geology and forest covers are the most effective approach in land use and land cover of a river basin area. Land use is a dynamic phenomenon. Due to increasing population growth and infrastructural activities in India people are using the lands which were earlier not suitable because of impact of the morphometric character of river basin. Geo-informatics tools are being increasingly used in resource evaluation to improve the quality and quantity of the land in a basin area. In the northern plains of Assam the river Nanoi plays a critical role by changing land use pattern and causing long and recurring floods hazard on floodplain. Records revealed that more than 100 years long history of flood problems the river basin continuously suffering through extensive flood (Gait, 1926). The surface water and ground water are the main sources of water which is mainly depending on rainfall for the proper land use pattern in the basin area. The basin gradient of Nanoi river is extremely low in the downstream part and suddenly step in the foothill region of the Arunachal Himalaya. During heavy downpour particularly lower part experienced severe flood and also changed the land use pattern in every year. Therefore, the land use is intimately related to the mechanism of river morphometry in Nanoi river basin. The researcher tried to find out the different factors of river basin area responsible for change the land use using Geo-informatics tools and toposheet of the concerned area.