Dhemaji district is divided into two Sub-divisions viz Dhemaji and Jonai Sub-Division. There are five Community Development blocks namely Bordoloni, Dhemaji, Machkhowa, Sissiborgaon and Jonai Murkongselek. Physiographically, the district of Dhemaji is a part of the Brahmaputra river valley. It is bounded on the north by Arunachal Paradesh and Brahmaputra river on the south (the proportional river Brahmaputra is included within the district). Physiographically the area can broadly be divided into three parts, i.e., the hilly tract, the piedmont alluvium and flood plain. Geomorphologically the area can be classified mainly into four divisions: structural hills, piedmont zone, alluvial plan and flood plain. Piedmont zone is in the northern part of the study area. Two gravelly formations are encountered and identified in the VES and in drilling. Resistivity value of the first gravel zone ranges from 267 to 7080 ῼm and perusal of litholog of Borola Miri Gaon, Tarajan Mohori Camp, Bokabil and Moridhol EW shows that the zone is dominantly gravelly AQUIFER MAPPING IN DHEMAJI DISTRICT, ASSAM 20 mixed with sand. 2D disposition of this zone in the subsurface along the strike of piedmont is lens shaped with continuously thinning and thickening.