Water Resource Department

Flood and Drainage Schemes

Bihar is the most flood affected state of the country, accounting around 17.2% of the flood prone area of the country. Out of 94.16 lakh ha of geographical area, 68.80 lakh ha (76% of North Bihar and 73% of South Bihar) is flood prone. Presently 28 out of 38 districts of Bihar are flood-prone.

Flood management works so far implemented comprise of construction and maintenance of embankments, revetment in selected portions of river banks, land spurs and other necessary flood protection works. All the rivers excluding the Burhi Gandak joining the Ganga on its left bank in Bihar flows through a considerable length in Nepal. A large part of their catchments fall in the glacial regions of great Himalayas. Thus the remedial measures of the flood problem of Bihar acquires international dimensions. As a long term measure construction of storage reservoirs and extensive water shed treatment in upper catchments of river is essential. As a short term protective measure, construction of embankments along rivers have been taken up. By constructing about 3745.96 km of embankment, around 36.46 Lakh ha of area has been brought under reasonable protection.

The existing embankments are under increasing pressure due to rise in the bed level of rivers due to heavy silts brought by the rivers from Nepal. Due to abnormal changes in river courses, anti erosion works for protection of embankment and some very essential flood fighting works become essential every year.

Drainage Sector

In Bihar, nearly 9.41 lakh ha (8.32 lakh ha in north Bihar and 1.09 lakh ha in south Bihar), i.e. 10% of the total geographical area of the State is water logged. The reasons of water-logging are: spilling of silted small rivers, encroachment of drainage channels, embankment induced water-logging and presence of saucer type depression. By the end of financial year 2010-11, 1.75 lakh ha area has been freed from water logging problem. 2.50 lakh ha of water logged area is not economically and geographically viable for draining. 5.16 lakh ha area is to be drained. The basin wise water logged area vis-a-vis proposed area to be drained out and the probable estimated amount are as below: