Jammu and Kashmir
Mir Mosharref Hossain Pakbir

Geological challenges remain crucial in controlling floods in Bangladesh

Mir Mosharref Hossain Pakbir

MNA Editorial Desk: Geographically Bangladesh is mostly a low land area which is prone to severe floods every year especially, during the rainy season. Although altitudes in the northern part of the plain reaches up to 105 meters (344 feet) above sea level, most elevations throughout the country are less than 10 meters (33 feet) above sea level. With such low elevations and numerous rivers, canals, ponds and other water bodies, recurring floods are a predominant physical feature of our country. About 10,000 square kilometers of the total area of Bangladesh is covered with water and larger areas are routinely flooded significantly during the monsoon season.

During every rainy season, thousands of lives are affected by floods and this scenario is getting bizarre not only in Bangladesh but also in adjacent parts of India in the face of global warming. It is now time to think about preventive measures to reduce the influence of floods in Bangladesh and all relevant parties should start working on that right now rather than waiting for getting hit by floods next year.

A total of 75 people, including 56 children and six women, have so far died in 14 districts in the ongoing floods across the country this year. Among the victims, 67 people drowned in floodwater while eight people died in the incidents of boat capsize. Besides, 6,30,383 people were fully devastated by the sweeping flood while 54,44,032 partially in 163 upazilas of 28 districts. Moreover, around 33,735 houses were fully damaged while 5,32,643 partially and 8,200 hectares of cropland were fully damaged while 1,45,533 partially during the flood. These floods have huge impact not only on the victims’ lives but also on the economy of the country.
The rivers of Bangladesh mark both the physiography of the nation and the life of the people. About 700 in number, these rivers generally flow south. The profusion of rivers can be divided into five major networks. The Jamuna-Brahmaputra, the first one, extends from northern Bangladesh to its confluence with the Padma. Originating as the Yarlung Tsangpo River in China’s Xizang Autonomous Region (Tibet) and flowing through India’s state of Arunachal Pradesh, where it becomes known as the Brahmaputra, it receives waters from five major tributaries that total some 740 kilometers in length.

The second system is the Padma-Ganges, which is divided into two sections – a 258 kilometres segment, the Ganges, which extends from the western border with India to its confluence with the Jamuna some 72 kilometres west of Dhaka and a 126 kilometres segment, the Padma, which runs from the Ganges-Jamuna confluence to where it joins the Meghna River at Chandpur.

The third network is the Surma-Meghna River System, which courses from the northeastern border with India to Chandpur, where it joins the Padma. The Surma-Meghna, at 669 kilometres by itself the longest river in Bangladesh, is formed by the union of six lesser rivers.

The numerous channels of the Padma-Meghna, its distributaries, and smaller parallel rivers that flow into the Bay of Bengal are referred to as the Mouths of the Ganges is the fourth network. Like the Jamuna, the Padma-Meghna and other estuaries on the Bay of Bengal are also known for their many chars.

A fifth river system, unconnected to the other four, is the Karnaphuli. Flowing through the region of Chittagong and the Chittagong Hills, it cuts across the hills and runs rapidly downhill to the west and southwest and then to the sea. The Karnaphuli Reservoir and Karnaphuli Dam are located in this area. The dam impounds the Karnaphuli River’s waters in the reservoir for the generation of hydroelectric power.
Other than these five major river networks, there are many other small river networks active in Bangladesh. But the main thing is the source of these rivers. Most of these rivers are generated from India or China and linked even with the Himalayas. Bangladesh is actually at the lowest part of the water flow of these rivers. When these rivers hit the plains of Bangladesh, the flow comes hard and creates lots of silt which usually makes the soil of Bangladesh highly fertile. But the piling of silts over the years is also turning out to be a cause of floods in Bangladesh today. The main problem here is being a delta and very flat land, the rush of waters is huge and without any barrier. Hence, this is a natural disadvantage of ours for being a downstream country.

As the ice of the Himalayans are melting due to global warming very fast, the water flow from the upstream to downstream is going to incline fast in the near future and the flood scenario is going to be much worse. As we can see from the pictures of Indian states like Assam, we can see how devastating floods can be and we are at much more risk than them. There is huge risks of human lives loss as well as grave economic consequences which will halt the development and progress of the country significantly.

Excessive and heavy rainfall is the main cause of flood in this country. Bangladesh experiences heavy monsoon rains, especially over the highlands. Tropical storms also bring heavy rains and coastal flooding. Above average & long period of heavy rains causes all major rivers to have their peak flow at the same time. When there is heavy rain for number of days the river cannot hold and carry down so much water to the sea. As a result, the water overflows the bank of river and submerges a huge area of land.
Moreover, sudden release of the water from the Farakka barrage during rainy season also overflows rivers and causes floods in different parts of the country. Additionally, melting of snow from the Himalayas in the spring and summer further increases the flood risks as torrents of melt water enter the rivers at their source during the rainy season which comes immediately after the melting season.

Deforestation is another great manmade reason of flood in this country. A rapid increase in population of Bangladesh has resulted in an acceleration of deforestation to meet the increasing demand for food and fuel wood. Also intense deforestation in the Himalayas has led to less trees and more soil erosion. This leads to less interception and more flow of water and silt in the river resulting in less water carriage capacity with higher sludge and this greatly contributes to floods in the rainy season.

Unfortunately due to greenhouse effect global warming has become unavoidable. Bangladesh is going to face severe consequences from the rising sea-level. The height of land is measured with respect to the sea-level of an area. Hence, any change in the sea-level causes land height to change. Around the coastal areas of Bangladesh, the rate of rise of the sea-level is 7mm per year. An increase in the sea-level raises the base level of rivers. This reduces the river flow. Eventually, the discharge of rivers decreases as the water flow becomes slow, creating a backwater effect further inland. This certainly seems to be one of the reasons for the increase in flood intensity in recent years in Bangladesh.

Moreover, unlawful grabbing of canals, rivers, lakes and other bodies along with severe construction capturing lowland throughout the country is decreasing the water carriage capacity dangerously. Though the government recently took some initiatives to free these canal and rivers, due to corruption it is hard to find any significant result.
The government needs to act soon to contain flood in the future years. Though a 100 year Delta Plan was initiated recently depicting wise movements of the government under the leadership and guidance of Prime Minister Sheikh Hasina, it misses out on detail work plans. As we face downstream water flow, the government should build enormous water reservoirs on the way of these flows to contain rushing waters. These should be placed on the upper part of the water flow path. Several reservoirs as such should be built at the border areas from where the water enters into our country. The stored water can also later be used for irrigation during the dry season.

The dredging system should be planned and modernized. To increase the water carriage capacity, the rivers should be dredged in an organized manner rather than focusing on business prospect. The government should instruct the relevant authority to take necessary steps to increase the depth of river base by removing the stored silt.

Planned forestation especially at the water entering areas is highly required as it will slow down the pace of water flow resulting in less soil erosion and will also contain excess flow of sludge. The rivers, canals and lakes must be cleared from the grabbers and wetlands must be preserved. But most importantly, all these should be done in a coordinated manner simultaneously if we need to see any result in the future years. Addressing geopolitics especially with neighboring India, located at the upstream from us, is also important to contain floods in Bangladesh.

By initiating the Bangladesh Delta Plan, the government showed intent to adopt long term policies to strengthen the ongoing developments. It will truly help the countrymen if implemented. But along with that we need to implement flood containment plans immediately to reduce the fierce impact of floods in the upcoming years. We believe if the relevant authority shows commitment, we can fight floods in a much better way as we should not risk halting our economic developments as floods are great in that.

The writer is a Chief Editor at Mohammadi News Agency (MNA), Editor at Kishore Bangla and Vice-Chairman, Democracy Research Center (DRC)

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