Floods of 1998 in Bangladesh and Shrewsbury
Causes, Effects and responses to flooding In Shrewsbury
The Severn Valley floods, Shrewsbury, UK 1998:
Causes
The human causes of the floods were summed up by the then Shadow Countryside Minister Tim Yeo MP, he said 'the flooding had increased because of the housing developments on Greenfield sites.' By this he means that by covering the land with tarmac in urban areas humans have increased the rate of surface runoff and decreased the saturation levels of the ground. When surface runoff is high rainwater reaches the river faster. It would appear that the speed in which the water reached the river was too fast for the river to handle. The river filled up reaching bank-full discharge and then overflowing its banks onto the flood plain. The flood plain of the River Severn is built on, therefore, when the river floods it floods onto residential areas. With the building of these urban areas the amount of vegetation in the area surrounding the river was reduced, this affects the river two ways. It reduces the amount of interception, which in turn increases the speed of runoff into the river. The lack of vegetation also leads to the saturation of the ground. During the months of October and November the rainfall in the Severn Valley was high, as the water soaked into the ground it became saturated. More vegetation in the area would have meant the vegetation using the water would have decreased the amount of water in ground storage.
Physical factors of the flood in 1998 are many; however, the most important one was the amount of rainfall. In October 1998 many areas received record amounts of rainfall caused by a 'hurricane'. This 'hurricane' brought very heavy rain and strong winds. The fact the rain was heavy means that the river did not have time to dissipate the water quick enough and the runoff was too fast, making the river rise t such an extent that it flooded. The area of the river upstream was worst effected, the area drown stream was not so badly effected because the river widens down stream. The saturation of the ground meant that any precipitation after the ground began saturated just added to the floodwaters. Other physical factors include the flat and low-lying nature of the landscape surrounding the Severn. This meant that as the water breached the banks it just spread across the land:
Effects
The floods caused major disruption to people's lives. Many people in the areas where the floodwaters hit had to be rescued from their houses. They became trapped or stranded on the top floor of their houses, as the ground floor was flooded with polluted water. Elderly people were particularly vulnerable to becoming trapped. The floods led to at least 12 deaths. The effects
of the floods were not solely felt in the urban areas, farmers had to move cattle to higher ground. Thousands of homes were marooned by floodwater, experts estimated the total damage ...
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Effects
The floods caused major disruption to people's lives. Many people in the areas where the floodwaters hit had to be rescued from their houses. They became trapped or stranded on the top floor of their houses, as the ground floor was flooded with polluted water. Elderly people were particularly vulnerable to becoming trapped. The floods led to at least 12 deaths. The effects
of the floods were not solely felt in the urban areas, farmers had to move cattle to higher ground. Thousands of homes were marooned by floodwater, experts estimated the total damage bill could exceed £100 million. Shrewsbury, which turned down a £5 million flood defence package four years previous to the floods, suffered its worst flooding in more than 30 years. Two bridges into the town were closed and water covered some streets to a depth of up to 5ft. Tewkesbury was reported to be surrounded by floodwater with the council distributing 1,500 sandbags to residents. The wet weather also played havoc with sporting fixtures. Aston Villa's game at Chelsea was called off, with matches at Portsmouth, Bournemouth, Luton and Brentford also falling foul of the week's downpours. Shrewsbury was left with only a privately owned toll bridge open. Tolls were suspended and the council discussed compensation with the bridge's owners. Rescue services used boats to reach people trapped in their houses and motorists marooned on flooded roads. At Lower Bullingham, Hereford, 28 elderly people, eight of them bedridden, were rescued by boat from Manor Rise residential nursing home. With 13 red alert flood warnings on the Rivers Vyrnwy, Wye, Lugg and Upper Severn, many councils set up emergency shelters in schools and community centres for flood refugees.
Responses
Several authorities responded to the flooding in the long and short term, some of which have already been mentioned.Insurance companies paid between £100 and £400 million worth of claims after the severe weather which left at least 12 people dead, and a trail of damage across Wales and the west of England.More than 1,000 Environment Agency staff remained on full alert at monitoring centres across the region for the duration of the floods. According to Dr Sue Walker of the Agency, "The efforts of Agency staff ensured that people received prompt flood warnings and were able to take action to protect themselves and their property." However, people living within the Severn Valley complained that the warnings given were not clear enough and few people knew how bad it was.
In the wake of the chaos, the Environment Agency demanded tighter controls on building on flood plain land. Lord De Ramsey, Chairman of the Environment Agency said: "Although we will never be able to stop flooding altogether, we must do everything we can to minimise the risk. Preventing development on flood plains is the first crucial step. The agency will continue to oppose such development, which not only increases the risk to life and property on the flood plain itself but also for adjoining areas." In Herefordshire more than 2,000 homes were cut off by flood waters for two days. The Army was put on standby to help, and RNLI lifeboats were drafted in, 70 miles from the sea, to provide care for the elderly.
BANGLADESH FLOOD 1998
I. MAIN CAUSES OF THE FLOOD:
Heavy rainfall in the upper catchment of the cross- boundary rivers as well as inside the country. Onrush of hill waters from the upstream of the Ganges and the Brahmaputra rivers due to heavy downpours in the Himalayas and the Mehgalaya hilly terrain's aggravated the flood situation.
Normal flow of floodwater through rivers was hindered due to existence of high tide in the sea. The high tide was measured at a record 5.52 metres above the sea level and the low tide was 4.72 metres, it was recorded by FFWC on 10th September, 1998. This was again aggravated by the lunar influences i.e. effect of fullmoon and newmoon. It is also learnt that sea level further rose due to earthquakes in the Bay of Bengal. Effect of "Global warming" around the world is another reason of the rise of water level at the sea.
Effect of "Global warming" around the world is another reason of the rise of water level at the sea.
Reduction of 'deltaic flood plain' due to unplanned construction of roads, bridges, culverts, homesteads etc.
Abnormal rise of bed-level of almost all the rivers due to heavy siltation. Many of our rivers already lost their navigability during summer and lean season. The river system as a whole could 'hold' or `contain' normal water flow during the monsoon.
This year China, Korea, Belgium, Florida of US and India have also experienced severe floods due to the effects of 'La Nina' and global warming.
II. FLOODS IN 1988 AND IN 1998:
Flood is an annual feature in Bangladesh. It usually begins in the month of July and ends in mid August every year and it takes three weeks for the water to recede.
In 1988,floods continued only for 21days and affected 89,970sq.km. area. But the 1998 flood continued for more than 65 days and affected 1,00,000sq.km.areas and destroyed basic infrastructures like roads, bridges, houses, standing crops of the fields, killed birds, animal and cattle heads and 918 humen death.
III LONG TERM PLAN:
About the long term programme to face the recurrent floods in the country, the government will go for massive river dredging. Through dredging, the depth of rivers and navigability will be increased, which will help in reducing the extent of flood. On the other hand the soil recovered from the river dredging will be used for reclamation of marshy lands beside the rivers. These lands will be used for township, housing and setting up of industries
IV. SURFACE WATER MANAGEMENT:
The government is taking long term plan for the surface water management. Plenty of water during the monsoon will be preserved and will be used later in the dry season. The proposal of 'Ganga Barrage' is in the offing by the present government. The government may need foreign assistance and technical know how for these programmes, particularly for river dredging, land reclamation, and rehabilitation of the homeless flood affected people and the construction of the proposed 'Ganga Barrage'.
Rainfall and Weather
The average annual rainfall varies from a maximum of 5,690 mm in the northeast of the country to a minimum of 1,110 mm in the west. The groundwater, however, provides adequate storage to compensate for annual variations in rainfall and streamflow. The average annual discharge from the three major rivers-at total of 35,000 cumec-is second only to the Amazon. They carry billions of tons of sediment load every year.
As it is situated in the tropic, the country is prone to cyclones associated with tidal surges, especially in the pre-monsoon and post-monsoon months. Because of high density of population in the flat deltaic coastal region, the loss of human lives in such cyclones has a time been very heavy. The country experiences a hot summer of high humidity from late March to late June, a somewhat cooler but still a hot and humid monsoon from late June through October and a coll dry winter from November to the end of February. Day temperature ranges from 7 to 12degree centigrade in the cool months and in the other month it varies between 23 to 30 degree centigrade.
DAMAGES CAUSED BY FLOOD 1998
LOSSES AND DAMAGES AS ON OCTOBER 04, 1998:
. Total area affected by flood - about 1,00,000sq.km.
(Area of Bangladesh is 1,48,393sq.km.)
2. Total Shortfall of production will be about 2.2 million MT
3. Number of District - 52
4. Number of Police Stations -366
5. Number of Affected Union Parishad - 3, 323
6. Number of Affected People - 3,09,16,351
7. Affected Standing Crops in Acre - 14,23,320
8. Number of Affected Homesteads - 9,80,571
9. Number of Death - 918
0. Cattle heads killed - 26,564
1. Road Damaged (km)- 15,927
2. Embankment Damaged (km)- 4,528
3. Number of Damaged Bridge /Culverts- 6,890
4. Number of Educational Institutions - 1,718
5. Number of Flood Shelter - 2,716
6. Number of People take refuge - 10,49,525
Bangladesh - Floods OCHA Situation Report
The Ministry of Disaster Management and Relief as of 15 September 1998 provided the following update on flood damage:
Districts Affected: 52
Thanas affected: 366
Persons affected: 30.6 million
Total dead: 783
Crops damaged: 1,497,500 (acres)
Houses damaged: 894,015
Roads damaged: 15,900 (km)
Embankment damaged: 4,451 (km)
Shelters: 2,661
Sheltered people: 1 million