A view of 2008 Bihar flood

Bihar is India's most flood-prone state, with 76% of the population of North Bihar living under the recurring threat of devastating flooding.[1][2] Bihar makes up 16.5% of India's flood-affected area and contains 22.1% of India's flood-affected population.[3] About 73.06% of Bihar's geographical area, 68,800 square kilometres (26,600 sq mi) out of 94,160 square kilometres (36,360 sq mi), is affected. Each year, floods kill many and damage livestock and other assets worth millions.[4][2] In total, floods have claimed 9,500 lives since the government started publishing figures in 1979.[5] North Bihar districts are vulnerable to at least five major flood-causing rivers during monsoon – the Mahananda, Koshi, Bagmati, Burhi Gandak, and Gandak rivers – which originate in Nepal. Some South Bihar districts have also become vulnerable to floods, from the Son, Punpun, and Phalgu rivers.[6] The 2013 flood affected over 5.9 million people in 3,768 villages in 20 districts in the state.[7] The 2017 flood affected 19 districts in North Bihar, killing 514 people[8][9][10][11][12][13][14] and affecting over 17 million.[15][16][17][18]

Causes of flooding

Manmohan Singh carried out an aerial survey of the flood-affected areas of Bihar with Chairperson, UPA, Smt. Sonia Gandhi, the Union Home Minister, Shri Shivraj V. Patil, the Union Minister for Railways, Shri Lalu Prasad.

Geographically, Nepal is a mountainous region. When heavy rains occur in the mountains of central and eastern Nepal the water flows into the major drainages of the Narayani, Bagmati, and Koshi rivers. As these rivers cross into India they break their banks and flood the plains and lowlands of Bihar. To protect the Koshi River's embankments as well as the Koshi Barrage, or sluice gates, Indian engineers who are in charge of the dam in Nepal, open the sluice gates, which can cause flooding downriver in Bihar. In 2008, during a high-flow episode, a breach in the East Koshi afflux embankment, above the barrage, occurred and the Koshi river, known as the Sorrow of Bihar, found an old channel, near the border with Nepal and India, it had abandoned over 100 years previously. Approximately 15 million people were affected as the river broke its embankment at Kusaha in Nepal, submerging several districts of Nepal and India. 95% of the Koshi's total flowed through the new course.

Embankments

A recent fact-finding report on the Kosi floods of 2008 – prepared by a civilian organization, the Fact Finding Mission on the Kosi, composed of various experts such as Sudhirendar Sharma, Dinesh Kumar Mishra, and Gopal Krishna – highlighted the fact that although India has built over 3000 km of embankments in Bihar over the last few decades, the propensity for flooding has increased by 2.5 times during the same time period, not to mention that embankments failed during each major flooding event.[19]

The report, titled Kosi Deluge: The Worst is Still to Come, stressed that embankments straitjacket the river. In the case of the Kosi, it found that because of siltation the river bed had risen several feet in relation to the adjoining land. The high and low lands separated by embankments have created a situation where the lowlands have become permanently waterlogged. Sixteen per cent of the land mass of north Bihar is permanently waterlogged.[19]

In 1954, when Bihar's flood policy was introduced, Bihar had approximately 160 km of embankments. At that time, the flood-prone area in the state was estimated to be 2.5 million hectares. Upon completion of the system of embankments, 3,465 km had been constructed and were administered by the Water Resources Department (WRD). However, the amount of flood-prone land had increased to 6.89 million hectares by 2004.

Farakka Barrage

The recent period has seen serious interruption in the dynamic equilibrium of the river, hindering the natural oscillation of the river within its meandering belt. The meandering belt of the Ganges in Malda and Murshidabad districts is 10 km wide. Upstream of the Farakka Barrage, the water level of the Ganges has risen about 8 meters. The river, which flowed in a South Easterly course between Rajmahal and Farakka during early decades of this century, has now formed a concentration of meander loops to accommodate the additional discharge due to the barrage. Due to the obstruction caused by the Barrage, each year nearly 640 million tonnes of silt are accumulated in the riverbed.[20] In the last three decades this has resulted in the accumulation of nearly 18.56 billion tonnes of silt.

Farakka barrage has led to following problems upstream of the barrage:

  • Interception of the flow channel being changed from straight to oblique
  • Sedimentation (640 x106 metric tonnes per year)
  • Reduction of the cross-sectional area
  • Declining slope of the long profile
  • Widening of the river and increasing length
  • Increase in flood frequency and magnitude

A 2016 Central Water Commission (CWC) report on Bihar floods states that the Farakka Barrage, even under the worst scenario, can impact areas up to 42 km upstream, due to a backwater effect.[21] Patna is located about 400 km upstream. The report blamed the number of banana plantations on the river bank between Patna and Bhagalpur as one of the reasons for the floods, based on the assessment of 100 years of flooding of the Ganga. The CWC report stated that the sedimentation in Ganga, in Bihar, is basically due to huge sediment load contributed from its northern tributaries – the Ghaghra, Gandak and Kosi rivers. The flood-affected area in Bihar was 2.5 million hectares in 1954 when the length of all embankments in Bihar was 160 km, but the flood-affected area increased to 7.295 million hectares in 2016, after the construction of 3731 km of embankments.[22]

Contributing water sources

North Bihar is within the flood plains of eight major rivers, all of which are tributaries of the Ganges.

Statistics

Damages in Bihar Due to Flood, 1979–2006[23][24]
YearDistrictsBlocksPanchayatsVillagesHumans
(100,000)		Animals
(100,000)		Total Area
(100,000 ha)		Farmed Areas
(100,000 ha)		Crop Damage
(100,000 INR)		Houses DamagedPublic Property Damaged
(100,000 INR)
2006146337595910.890.11.810.87706.6318,6378,456.17
200512815621,46421.045.354.61.351,164.505,538305
2004202112,7889,346212.9986.862713.9952,205.64929,773103,049.60
2003241721,4965,07776.0211.9615.086.16,266.1345,2621,035.16
20022562,5048,318160.1852.5119.699.451,149.61419,01440,892.19
2001221941,9926,40590.9111.711.956.526,721.79222,07418,353.78
2000332132,32712,35190.188.098.054.438,303.70343,0913,780.66
1999241501,6045,05765.6613.588.453.0424,203.8891,8135,409.99
1998282602,7398,347134.730.9325.1212.8436,696.68199,6119,284.04
1997261691,9027,04369.6510.1114.716.555,737.66174,3792,038.09
1996291952,0496,41767.336.611.897.347,169.29116,1941,035.70
1995261771,9018,23366.298.159.264.2419,514.32297,7652,183.57
1994211121,0452,75540.1215.036.323.55,616.3333,876151.66
1993181241,2633,42253.526.6815.6411.3513,950.17219,8263,040.86
19928191704145.560.750.760.2558.091,2810.75
1991241371,3364,09648.235.139.84.052,361.0327,324139.93
1990241621,2594,17839.572.78.733.211,818.8811,009182.27
198916746521,82118.790.354.711.65704.887,74683.7
1988231811,6165,68762.340.2110.523.954,986.3214,759150.64
1987303826,11224,518286.6233.2547.525.767,881.001,704,999680.86
1986231891,8286,50975.8-19.187.9710,513.51136,7743,201.99
1985201621,2455,31553.09-7.944.383,129.52103,279204.64
1984232393,20911,154135-30.515.8718,543.85310,4052,717.72
1983221381,2244,06042.41-18.135.782,629.2538,679258.14
1982151101,1123,70846.8145.149.323.239,700.0068,242955.33
1981212012,1387,36769.4774.8312.617.717,213.1975,776-
1980211931,8697,01074.45-17.869.437,608.43118,507-
197913110--37.38-8.062.741,901.5227,816-

See also

References

  1. ↑ "District-level flood maps for Bihar ready".
  2. 1 2 "FMIS". fmis.bih.nic.in.
  3. ↑ India Water Portal - Bihar Floods 2008 Archived 1 February 2009 at the Wayback Machine
  4. ↑ "Flood threat grows to 37 districts". Archived from the original on 12 June 2018.
  5. ↑ "Bihar's scary new flood".
  6. ↑ "Bihar gears up to fight annual floods". The Times of India.
  7. ↑ "Bihar speeds up Flood Relief and Rescue Operations". Retrieved 5 September 2013.
  8. ↑ "Floods in state not man-made, says minister". The Times of India.
  9. ↑ "Flood Situation Improves In Bihar, Number Of Dead At 514".
  10. ↑ "Bihar Floods: Number Of Deaths Rises To 341".
  11. ↑ "Death toll in Bihar floods mounts to 304; situation grim in UP". The Times of India.
  12. ↑ "Flood situation worsens in Bihar, death toll rises to 253". The Times of India.
  13. ↑ "Bihar floods: 119 dead; bridge collapse caught on camera". The Times of India.
  14. ↑ "Bihar floods: Death toll rises to 202 in 18 districts; thundershowers likely to continue today".
  15. ↑ "Bihar Flood Deaths Rise To 440; Prime Minister Announces Rs. 500 Crore Relief".
  16. ↑ "Bihar floods' death toll touches 440, 1.71 crore people still affected".
  17. ↑ "Bihar floods cost 39 more lives, UP staggers".
  18. ↑ "Bihar floods: Death toll rises to 304, 1.38 crore people still battling deluge in 18 districts".
  19. 1 2 Sharma, Sudhirendar; Krishna, Gopal (2008). Kosi Deluge – the Worst is Still to Come: the Report of the Fact Finding Mission on the Kosi. New Delhi: Ashoka Fellowship Initiative. OCLC 649085026.
  20. ↑ "Over 50 years ago, Bengal's chief engineer predicted that the Farakka dam would flood Bihar".
  21. ↑ "Farakka not to blame for Bihar floods: CWC". The Times of India.
  22. ↑ "BJP leader Sushil Modi questions Nitish demand for decommissioning Farakka barrage".
  23. ↑ "Disaster Management". disastermgmt.bih.nic.in. Archived from the original on 23 October 2008. Retrieved 26 November 2008.
  24. ↑ "Loss of Public Property". disastermgmt.bih.nic.in. Archived from the original on 19 October 2008. Retrieved 26 November 2008.
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