Floods in Bihar

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Deaths in Bihar due to flood
Flooded Bihar.JPG

Bihar is India's most flood-prone State, with 76% of the population in the north Bihar living under the recurring threat of flood devastation.[3] According to some historical data, 16.5% of the total flood affected area in India is located in Bihar while 22.1% of the flood affected population in India lives in Bihar.[4] About 68,800 square kilometres (26,600 sq mi) out of total geographical area of 94,160 square kilometres (36,360 sq mi) comprising 73.06% is flood affected. Floods in Bihar are a recurring disaster which on an annual basis destroys thousands of human lives apart from livestock and assets worth millions.[3] The 2013 Flood in Bihar affected more than 5.9 million people in 3,768 villages in 20 districts of the state.[5]

History[edit]

Recent Chronology[edit]

Recent year in which human death due to flood is more than 100.

Map of floods in India showing North Bihar as a flood-prone area

Reason for flooding[edit]

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 Narayani, Bagmati, and Koshi rivers. As these rivers cross into India they flow into the plains and lowlands of Bihar and break their banks. To protect the Koshi River dam as well as the Koshi Barrage Pool's embankments, Indian engineers who are in charge of the dam in Nepal, further open the dam's gates which can cause flooding down river in Bihar. In 2008 during a high flow episode a breach in the East Koshi afflux embankment above the dam occurred and the Koshi river, known for centuries as the Sorrow of Bihar, picked up an old channel it had abandoned over 100 years previously near the border with Nepal and India. Approximately 2.7 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[edit]

A recent fact finding report for the Kosi floods of 2008, prepared by a civil society organization by various experts like Dr. Sudhir Sharma, Dr. Dinesh Kumar Mishra, and Gopal Krishna, highlighted that although India has built over 3000 km of embankments in Bihar over the last few decades, the flooding propensity has increased by 2.5 times during the same time period, not to mention that embankments failed during each major flooding event.

The Fact Finding Mission recently released a report titled Kosi Deluge: The Worst is Still to Come, in which it stressed that embankments straitjacket the river. In the case of the Kosi, it found that because of siltation the river bed was in fact several feet higher than the adjoining land. The high and low lands separated by embankments have created a situation where the low lands have become permanently waterlogged. Sixteen per cent of the land mass of north Bihar is subject to permanent waterlogging.

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

Deforestation[edit]

Deforestation in the catchment area has led to increase in the silt content of the river flow. The total catchment area of the Kosi is 74,030 km2, excluding the catchment areas of its two important tributaries, the Kamla (7,232 km2) and the Bagmati (14,384 km2). These tributaries of the Kosi are important in themselves and are generally dealt with separately. Out of the total catchment of the Kosi, only 11,410 km2 are located in India and the rest (62,620 km2) lie in Nepal and Tibet. The river's catchment area at Triveni in Nepal is 59,550 km2. The average rainfall in the upper catchment of the Kosi is 1,589 mm while in the lower areas it is 1,323 mm. The average annual silt load of the river is 92,400 acre feet (114,000,000 m3).

Farrakha barrage[edit]

The period has caused serious interception in the dynamic equilibrium of the river hindering the natural oscillation of the river within its meandering belt. The meandering belt of Ganges in Malda and Murshidabad is 10 km wide. The water level of the Ganges rose about 8 m upstream of the Farakka barrage. The river which flowed in a South Easterly course between Rajmahal and Farakka during early decades of this century has now formed a mighty meander loop concentration to accommodate the additional discharge accumulated due to the barrage. Due to the obstruction caused by the Barrage each year nearly 640 million tonnes of silt is accumulated in the riverbed. In the last three decades this has resulted in the accumulation of nearly 18.56 billion tonnes of silt.

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

  • Interception of the flow channel/ changed from straight to oblique
  • Sedimentation (640 x106 metric tonnes/ 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

Affected rivers[edit]

North Bihar is a playfield of eight major rivers. All these rivers end up in Ganges.

Statistics[edit]

Total Affected and Damaged in Bihar due to flood 1979–2006[1][2]
Year District Blocks Panchayat Village Human
(in Lakh)
Animal
(in Lakh)
Total Area
(in Lakh ha)
Cropped area
(in Lakh ha)
Crop Damaged
(in Lakh INR)
House Affected Public Property Damaged
(in Lakh INR)
2006 14 63 375 959 10.89 0.1 1.81 0.87 706.63 18,637 8,456.17
2005 12 81 562 1,464 21.04 5.35 4.6 1.35 1,164.50 5,538 305
2004 20 211 2,788 9,346 212.99 86.86 27 13.99 52,205.64 929,773 103,049.60
2003 24 172 1,496 5,077 76.02 11.96 15.08 6.1 6,266.13 45,262 1,035.16
2002 25 6 2,504 8,318 160.18 52.51 19.69 9.4 51,149.61 419,014 40,892.19
2001 22 194 1,992 6,405 90.91 11.7 11.95 6.5 26,721.79 222,074 18,353.78
2000 33 213 2,327 12,351 90.18 8.09 8.05 4.43 8,303.70 343,091 3,780.66
1999 24 150 1,604 5,057 65.66 13.58 8.45 3.04 24,203.88 91,813 5,409.99
1998 28 260 2,739 8,347 134.7 30.93 25.12 12.84 36,696.68 199,611 9,284.04
1997 26 169 1,902 7,043 69.65 10.11 14.71 6.55 5,737.66 174,379 2,038.09
1996 29 195 2,049 6,417 67.33 6.6 11.89 7.34 7,169.29 116,194 1,035.70
1995 26 177 1,901 8,233 66.29 8.15 9.26 4.24 19,514.32 297,765 2,183.57
1994 21 112 1,045 2,755 40.12 15.03 6.32 3.5 5,616.33 33,876 151.66
1993 18 124 1,263 3,422 53.52 6.68 15.64 11.35 13,950.17 219,826 3,040.86
1992 8 19 170 414 5.56 0.75 0.76 0.25 58.09 1,281 0.75
1991 24 137 1,336 4,096 48.23 5.13 9.8 4.05 2,361.03 27,324 139.93
1990 24 162 1,259 4,178 39.57 2.7 8.73 3.21 1,818.88 11,009 182.27
1989 16 74 652 1,821 18.79 0.35 4.71 1.65 704.88 7,746 83.7
1988 23 181 1,616 5,687 62.34 0.21 10.52 3.95 4,986.32 14,759 150.64
1987 30 382 6,112 24,518 286.62 33.25 47.5 25.7 67,881.00 1,704,999 680.86
1986 23 189 1,828 6,509 75.8 XXXX 19.18 7.97 10,513.51 136,774 3,201.99
1985 20 162 1,245 5,315 53.09 XXXX 7.94 4.38 3,129.52 103,279 204.64
1984 23 239 3,209 11,154 135 XXXX 30.5 15.87 18,543.85 310,405 2,717.72
1983 22 138 1,224 4,060 42.41 XXXX 18.13 5.78 2,629.25 38,679 258.14
1982 15 110 1,112 3,708 46.81 45.14 9.32 3.23 9,700.00 68,242 955.33
1981 21 201 2,138 7,367 69.47 74.83 12.61 7.71 7,213.19 75,776 XXXX
1980 21 193 1,869 7,010 74.45 XXXX 17.86 9.43 7,608.43 118,507 XXXX
1979 13 110 XXXX XXXX 37.38 XXXX 8.06 2.74 1,901.52 27,816 XXXX

See also[edit]

Gallery[edit]

References[edit]