The thesis entitled Aquifer Vulnerability Assessment In Modjo River Catchment is arnstudy of the hydrogeological factors pertaining to the DRASTIC system and covers anrnarea of 1527sq km in the Upper Awash River Basin, particularly Modjo RiverrnCatchment, northwestern shoulder of the Central Main Ethiopian Rift system boundedrnin the Zone 37 UTM grids of 930000meter N to 1005000meter N and 490000meter E torn535000meter E. With increasing demand and reliance on groundwater from a growing rnpopulation and agricultural activity comes the need to increase efforts to protect and manage thernresources. Urban, and Industrial development, as well as agricultural activities, are potentialrnsources of groundwater contamination in the study area. The general objective of thernresearch work is to identify and produce aquifer vulnerability map to pollution in ModjornRiver catchment and to assess the risk for groundwater pollution by adoptingrnGeographic Information System (GIS) based DRASTIC system through producingrnthematic maps of pertinent hydrogeological factors within the catchment and finally tornprepare both Intrinsic and Pesticide Vulnerability Maps and determine aquiferrnVulnerability Classes based on DRASTIC Index values. Accordingly, high and very highrnvulnerable areas are found to occupy most of the gentle and plain terrains in the centralrnand southern parts of the study area whereas low and very low vulnerable area occupyrnthe elevated lands in the eastern, northeastern and northwestern parts of therncatchment. Unfortunately the high and very high vulnerable areas occupy also the highrnand moderate groundwater potential zones identified by Sisay, 2007. This givesrnadditional stimulus to the need to protect the groundwater in the study area.rnThe final use of such a study is to help planners and regulators make environmentallyrnsound decisions regarding land use and groundwater protection.rnrnKeywords: DRASTIC Model; Aquifer, Vulnerability; Intrinsic Vulnerability; PesticidernVulnerability, Modjo River Catchment ;Central Main Ethiopian Rift