Flood and Drainage Schemes in Bihar
Bihar is the most flood affected state of the country, accounting for 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 Prone Districts – Maximum Inundation (1995–2010)
| Sl. No. |
District |
Geographical Area
(Sq. Km) |
Maximum Inundation
(1995–2010) (Sq. Km) |
| North Bihar |
| 1 |
Araria |
2830 |
1690 |
| 2 |
Begusarai |
1918 |
820 |
| 3 |
Darbhanga |
2279 |
2020 |
| 4 |
Purvi Champaran |
3968 |
2600 |
| 5 |
Gopalganj |
2033 |
1970 |
| 6 |
Katihar |
3057 |
1850 |
| 7 |
Khagaria |
1486 |
1150 |
| 8 |
Kishanganj |
1884 |
490 |
| 9 |
Madhepura |
1788 |
1030 |
| 10 |
Madhubani |
3501 |
2460 |
| 11 |
Muzaffarpur |
3172 |
2330 |
| 12 |
Purnia |
3229 |
1260 |
| 13 |
Saharsa |
1692 |
1680 |
| 14 |
Samastipur |
2904 |
1620 |
| 15 |
Saran |
2641 |
950 |
| 16 |
Sheohar |
443 |
330 |
| 17 |
Sitamarhi |
2200 |
2180 |
| 18 |
Siwan |
2219 |
450 |
| 19 |
Supaul |
2420 |
1930 |
| 20 |
Vaishali |
2036 |
1220 |
| 21 |
Pashchim Champaran |
5228 |
1930 |
| Total of North Bihar |
52928 |
31960 |
| South Bihar |
| 22 |
Bhagalpur |
2570 |
1130 |
| 23 |
Bhojpur |
2474 |
475 |
| 24 |
Buxar |
1624 |
435 |
| 25 |
Lakhisarai |
1299 |
340 |
| 26 |
Nalanda |
2367 |
903 |
| 27 |
Patna |
3202 |
878 |
| 28 |
Sheikhpura |
606 |
400 |
| Total of South Bihar |
14142 |
4561 |
| Grand Total (North + South) |
67070 |
36521 |
Flood management works so far implemented comprise 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 flow 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 acquire international dimensions.
As a long term measure construction of storage reservoirs and extensive watershed 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.
Basin-wise Flood Prone & Protected Area
| Sl. No. |
Name of Basin |
Catchment Area (Sq. Km.) |
Length of River in Bihar (km) |
Embankment Constructed (km) |
Flood Prone Area (Sq. Km) |
Protected Area (Sq. Km) |
| 1 |
Ganga |
19322 |
445 |
596.92 |
12920.00 |
2440.00 |
| 2 |
Kosi/Adhwara |
11410 |
260 |
637.41 |
10150.00 |
9720.00 |
| 3 |
Burhi Gandak |
9601 |
320 |
779.26 |
8210.00 |
6730.00 |
| 4 |
Kiul/Harohar |
17225 |
41 |
14.00 |
6340.00 |
60.00 |
| 5 |
Punpun |
9026 |
235 |
37.62 |
6130.00 |
200.00 |
| 6 |
Mahananda |
6150 |
376 |
225.33 |
5150.00 |
1010.00 |
| 7 |
Sone |
15820 |
202 |
59.54 |
3700.00 |
210.00 |
| 8 |
Bagmati |
6500 |
394 |
478.14 |
4440.00 |
1800.00 |
| 9 |
Kamla Balan |
4488 |
120 |
190.00 |
3700.00 |
5620.00 |
| 10 |
Gandak |
4188 |
260 |
511.66 |
3350.00 |
6240.00 |
| 11 |
Ghaghra |
2995 |
83 |
132.90 |
2530.00 |
790.00 |
| 12 |
Chandan |
4093 |
118 |
83.18 |
1130.00 |
1640.00 |
| 13 |
Badua |
2215 |
130 |
1050.00 |
— |
| Total |
|
113033 |
2984 |
3745.96 |
68800.00 |
36460.00 |
Year-wise statement of lengths of embankment constructed and areas protected
| Year |
Cumulative Length of Embankment (in Km) |
Cumulative area protected (in LHa) |
Remarks |
| upto 1992 |
3454.00 |
28.34 |
As per report of 2nd Bihar State Irrigation Commission |
| 1992-2005 |
3540.00 |
29.16 |
3454 Km embankment length subsequently revised to 3540 Km by including Forward Embkt Chharkies |
| 2005-2010 |
3610.00 |
29.46 |
Champaran Embkt. (Gandak) 10.40 Km
Bagmati 29.60 Km
Tirmuhani Kursela (Kosi) 30.00 Km
Total 70.00 Km |
| 2010-2012 |
3677.09 |
30.50 |
Bagmati 53.37 Km
Bhutahi Balan 1.72 Km
Kamala 12.00 Km
Total 67.09 Km |
| 2012-2013 |
3732.00 |
36.33 |
Bagmati 6.00 Km
Kamla 4.00 Km
Adhwara (Jhim Jamura) 4.70 Km
Chandan 40.21 Km
Total 54.91 Km |
| Upto March 2016 |
3745.96 |
36.46 |
|
| Upto March 2017 |
3745.96 + 13.98 (New) |
36.46 + 0.46 (New) |
Kamala Balan – 13.98 Km (Proposed) |
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:
Basinwise Water Logged Areas
| Sl.No. |
Name of Basin & adjoining areas. |
Total Water logged area in Lha. |
Area freed from water logging in Lha. |
| 1. |
Ganga |
1.98 |
— |
| 2. |
Kosi |
1.82 |
1.10 |
| 3. |
Burhi Gandak |
2.08 |
0.25 |
| 4. |
Gandak |
1.19 |
0.14 |
| 5. |
Ghaghra |
1.25 |
0.01 |
| 6. |
Kiul Harohar (Mokama Tal) |
1.06 |
(1.1 Lha proposed upto March 2019) |
| 7. |
Mahananda |
0.03 |
— |
| Total |
|
9.41 |
1.50 |