HECGeoRAS interface in co-ordination with ArcView3.3 was applied. The results of flood frequency analyzed by WECS/DHM method showed instantaneous discharges of 84,141,185, 232, 298, 352 and 411m3/s for 2, 5, 10, 20, 50,100 and 200-years return period floods. Flood depth area showed that the Basti was submerged at water depth greater than 2m. Risk was evaluated by connecting societal attributes of Basti to flooding events. Societal attributes included general poverty analysis, environment and health, flood hazard, institutional involvement etc. As the Basti was unmanaged and populated with 34 percent child and old age group, no warning system adapted, frequent flood experiences, less cultural flood adapted, relatively poor people, lower environmental condition and at last but not the least that Basti located at flood plain, the flood hazard risk levels were considered to be consequently high. As 58.4 percent population of Basti are poor and barely living at a sustenance level, a flood disaster could be completely devastating for them. A landless, illiterate, poor (family) with no savings and no other means of income and shelter if hit by a flood, faces a much deplorable situation.