A sizable number of macrophytes growing luxuriantly in Kawar lake, the largest one of its kind in Bihar, are utilized by the native folk for food (Euryale ferox, Ipomoea aquatica, Nelumbo nucifera, Nymphaea nouchali, Nymphaea sp. - a probable hybrid, Cyperus rotundus), fodder (Commelina benghalensis, Cynodon dactylon, Cyperus iria, C. rotundus, Echinochloa colonum, E.

Flood hazard in a basin depends upon the hydrological response of the upstream basin area. The upstream basin area may produce different amounts of run-off for a given rainfall based on its hydrologic response. The present communication shows the importance of drainage network characteristics in understanding the hydrologic response of a basin. The study is carried out through Geomorphic Instantaneous Unit Hydrograph analysis, wherein Horton's morphometric ratios were used to define the drainage network. A floodprone river basin in north Bihar plains has been selected as a study area.

Flood hazard is one of the most severe problems in the Himalayan river basins. Although floods are essentially hydrological phenomenon, the uneven distribution of floods in the river basin highlights the control of geomorphological and geological factors. A proper understanding of these factors is critical for a successful flood management programme. Remote sensing data is of immense value in evaluating the geomorphological and geological controls in flooding. The present paper highlights the control of geomorphology and neotectonics on flood hazard in north Bihar Plains, eastern India.