Imagine you are in the sky above the Himalayas. Now look down. You will see a mountainous region, covered with snow and rugged vegetation, devoid of human habitation. Then, if you look southeast, you will discover a vast floodplain between the mountains and the sea. This immense, shimmering green region is Bangladesh.
You may wonder why a book about Bangladesh begins with the Himalayas. The reason is important: without the Himalayas, Bangladesh would not exist. In a sense, the part of the Himalayas that flattened into a plain is essentially what Bangladesh is.
Every spring, the snow on the mountains begins to melt. This water mixes with soil particles, turns into numerous rivers, and eventually flows into the sea. When the rivers reach the low-lying plains, their speed slows down.
The soil particles mixed with the water deposit silt and create the delta. This centuries-old process has created the region that we now know as Bangladesh. Due to the constant deposit of new silt in this land, the sea recedes little by little each year.
The Bengal delta is vast in size. This is because the immense volume of water descending from the world's highest mountain range, the Himalayas, has to pass through this region. South of the Himalayas, countless tributaries and rivers combine to form the mighty Ganges.
This river flows hundreds of kilometers eastward through India, then enters Bangladesh through its western border and takes on the name Padma.
To the north of the Himalayas lies another major river – the Brahmaputra, which originates in Tibet. It flows past the capital Lhasa, then sharply turns and changes course.
After flowing through the mountains, it enters India through the far northeastern corner and then turns west, entering Bangladesh's northern region as the Jamuna. It merges with the Ganges in central Bangladesh and flows together into the sea. Both rivers are massive: the Ganges is up to 8 kilometers wide, and unbelievably, the Brahmaputra is up to 18 kilometers wide in places.
This is, broadly, the river geography of Bangladesh.
If one observes the geography of this delta closely, one will see countless rivers meandering through the country.
The third largest river in Bangladesh is the Meghna, which enters the country from the east. More than 50 rivers enter Bangladesh after crossing the Indian border. These rivers sometimes merge, sometimes split, and merge again to create a complex waterway—river channels, canals, beels, and haors.
In ancient times, the smaller and larger rivers of the delta tended to flow eastward. As a result, the western river channels (now inside India) would dry up. Countless rivers deposited thick layers of fertile silt to form the world's largest river delta. However, not all the silt was deposited in Bangladesh.
Each year, more than one billion metric tonnes of silt flow into the Indian Ocean, creating the world's largest submerged delta. Its maximum thickness exceeds 16 kilometres and it stretches 3,000 kilometres south along the ocean floor, reaching beyond Sri Lanka.
The Bengal delta is surrounded by highlands and hills on the east, north, and west and functions like a narrow funnel through which water from an area more than 10 times the size of the delta flows into the sea every year. The volume of this water is astonishing—about 650 billion cubic meters. Most of the silt-laden water flows through the delta between May and mid-October. During this time, the rivers swell.
These powerful forces have shaped Bangladesh's natural environment and still have a widespread impact on daily life. However, the main rivers of the delta are not the only source of water in this land. Two other sources have always played significant roles in Bangladesh—rainwater and seawater.
Every year, when the rivers swell in June, the sky of Bangladesh also begins to change. In winter, the sky remains blue, and rainfall is rare. But by late May or early June, as temperatures rise, thick clouds begin to form over the southern part of the country. Winds flowing over the sea carry large amounts of water vapor into the interior of the country and cause torrential rainfall. This continues until September.
Thus begins the monsoon. In this tropical region of Asia, the monsoon is truly remarkable. It not only rains day and night but also creates knee-deep mud. The volume of water flowing through Bangladesh during this time is immense. For meteorologists, the rainfall in Cherrapunji has become legendary. It is said that this small village on the northeastern border of Bangladesh and India receives the highest rainfall in the world. Here, monsoon winds collide with Meghalaya's hills, causing intense rainfall that continues for several months. On average, Cherrapunji receives 11 meters of rain per year. More than 1 meter of rainfall has been recorded in 24 hours here.
The third source of water in the lives of Bangladeshi people is the sea. During the dry season (October to May), saline water from the Bay of Bengal enters up to 100 kilometers inland through various channels. As a result, the lower delta becomes saline. Furthermore, the lower delta region is quite flat: its elevation is less than three meters above sea level. Therefore, at least once a year, tidal surges caused by tropical cyclones inundate the area. Coastal regions of Bangladesh and the nearby islands then face adverse conditions.
The mangrove forest Sundarbans, surrounding the delta's coastal area, provides some protection during this time. However, since the eighteenth century, human activity has gradually reduced the forest's area. This largest mangrove forest in the world is not entirely indomitable when facing tropical storms. In 2007, a powerful cyclone directly hit the Sundarbans and destroyed countless trees.
The three water sources discussed above—rivers, rain, and sea—have given Bangladesh dual natural characteristics. In winter, the rivers dry up and become narrow. The sky is a blazing blue, and saline water slowly intrudes. Nature seems kind then and turns into a nurturer. But in summer, nature goes out of control.
Bangladesh becomes a land of dual personalities. Rivers widen, heavy rainfall occurs, and when storm surges arise in the sea, the flow of all incoming water is obstructed. This results in floods.
Summer floods are a part of life in this country. Every summer, about 20% of Bangladesh's land is flooded, primarily due to rain.
Flooding can also occur if all the rivers experience high tides at the same time, causing the banks to overflow. In this way, the rivers create new courses, which is a characteristic of an active delta.
Year after year, the flow of water along the same course causes the riverbed to accumulate silt and become shallow. As a result, the river's speed slows and sometimes comes to a standstill. To maintain the same course of flow, embankments of silt may rise along the two banks.
Even so, the riverbed may rise to become level with or even higher than the floodplain. However, if an abnormal amount of water flows through this course, the banks erode, and the river overflows, trying to create new, lower channels. In such cases, the old river courses may remain as oxbow lakes or become covered with vegetation.
Such traces of wandering rivers can be found throughout Bangladesh's topography. In the delta, floods usually occur due to excessive rainfall and river overflows, but they can also result from excessive rainfall in the hills or tidal surges from the sea.
Due to the combined effect of rainfall, river floods, hill runoff, and coastal tidal surges, flood control in Bangladesh is an impossible task. Even today, it is difficult to predict the timing, location, or extent of an impending flood, let alone control it.
The extent of flooding also varies from year to year. Major floods occur every few years, and sometimes nearly 70 percent of the country is submerged.
From the perspective of everyday life, it can be said that floods have both positive and negative aspects. When floods occur year after year, they continuously enhance the fertility of what is already the most fertile soil in the world. Because of this fertile silt, crop abundance has been achieved, and success in agriculture has been possible from the beginning.
But the uncontrollable nature of floods and the recurrence of severe flooding every 10 years or so bring devastation to people's lives. The damage caused by a flood cannot be measured by the volume of water alone. We will see that the people of Bangladesh have gradually been able to adapt to regular flooding. Some floods become more terrifying than others due to the intensity and speed of water flow and the duration of waterlogging on land.
Therefore, even though the volume of water from hill runoff and coastal storm surges may be low and may inundate relatively small areas, the damage can be severe.
In 1991, a cyclone hit Chattogram on the southeastern coast of Bangladesh. Massive waves surged through various water channels and struck nearby areas and islands around Chattogram. This caused extensive damage. Despite early warnings, about 70 percent of the population in coastal villages were swept away by water even after 3 million people were evacuated to safety. According to official estimates, about 140,000 people died in this cyclone. Due to the lack of a coordinated national cyclone warning system, the number of casualties was even higher in 1970. A cyclone and tidal surge that struck the Noakhali coast caused the death of at least 325,000 people.
On the other hand, compared to such devastating cyclone-induced floods, if floods caused by rain or river overflow inundate a vast area but last for a short time, the damage is relatively low. In fact, such floods are usually followed by bumper crop harvests. However, prolonged flooding creates serious problems. In the 1988 flood, 66 percent of Bangladesh was submerged. As this flood lasted for 15 to 20 days, it caused severe damage to crops, property, farmed fish, and other resources. In addition, countless people lost their lives. Ten years later, another flood inundated 60 percent of the country. As this one lasted for 65 days, its damage was greater than the previous one.
Living in a landscape with such natural features means living along ever-changing land and water boundaries. This shifting frontier has long controlled the history of Bangladesh and the way of life of its people. Despite regular disasters, people have successfully managed to utilize all types of resources in this risky and waterlogged deltaic environment.
Bangladesh is one of the most densely populated countries in the world. Here, 1,342 people live per square kilometer. The pressure of people on land indirectly highlights the significance of the original ecological boundary. Over time, life near the water's edge has become more difficult than ever before. Now, the boundary between habitable and inundated areas in Bangladesh is gradually shrinking. People are having to settle in lowlands, coastal areas, and islands exposed to storms and floods. In the face of storms and rains, Bangladeshi inhabitants living in coastal and char regions are increasingly being forced to confront adverse weather. In this way, a segment of the Bangladeshi population is constantly being compelled to surrender themselves to a perilous life close to water.
The floodplain, formed by flooding, controls the way of life in Bangladesh. About 80 percent of the country falls within the floodplain. However, the entire territory of Bangladesh is not flat. Some steep hills surrounding the delta along the eastern boundary have been included within the country's national territory, adding a distinctly different type of landscape to the country's geography. The hills located in the Chittagong Hill Tracts and Sylhet point to the occurrence of deep geological processes beneath Bangladesh's soft soil. Here, tectonic plates collide: the Himalayas and the hills of Bangladesh (along with some hills in Myanmar and northeastern India) were formed as a result of these collisions.
As a result of the tectonic movements occurring beneath Bangladesh, some areas of the Bengal Delta have risen while others have subsided. The uplifted lands appear like islands within the floodplains (such as the Barind Tract in the northwest and the Madhupur Tract in central Bangladesh), while the subsided areas (haors, bils) have turned into vast seasonal lakes. The movement of tectonic plates is tilting the delta's structure, gradually pushing rivers eastward. This unstable geological structure has caused frequent earthquakes in Bangladesh. Although most of these earthquakes are weak, there remains the possibility of one occurring that could cause extensive destruction.
In the social/human history of Bangladesh, the natural environment has never merely served as a backdrop around which history has formed. Rather, time and natural forces have played central roles here, disrupting social arrangements and toppling ruling groups. For example, mention can be made of the earthquake and flood of 1780. As a result, the course of the Brahmaputra River changed, and numerous villages were submerged. The riverbank commercial centers of the time collapsed. In more recent history, it can be seen that the extensive damage caused by the 1970 cyclone and the government's failure to manage it effectively led to controversy and a loss of ruling legitimacy. This, in turn, sparked the Liberation War. The damage caused by the 1988 flood exceeded the national development budget for that year.
For all communities and ruling groups occupying the Bengal Delta, proper management of the natural environment has always been a primary concern. The people of Bangladesh have never consoled themselves with the false assurance that they have gained control over nature. They live in an environment where land and water coexist, and the boundaries between these elements are continuously changing. As a result, settlement patterns are always in flux and sometimes temporary. Villages in Bangladesh are said to be changeable.
The villages are not clustered around a central courtyard. They have no protective boundary, nor are they united for joint irrigation efforts. Rather, the villages are divided into scattered houses or small neighborhoods. In case of moderate floods, houses are built on raised mounds to avoid being submerged. During the monsoon, the houses or neighborhoods appear as individual islands.
Few rural settlements are built in a permanent or sustainable manner. And since traditional irrigation methods depend heavily on rainwater, there is little need to develop joint irrigation systems. Due to the changing nature of land in this active delta, villagers often have to relocate and are compelled to establish new settlements.
In this way, changes in geomorphological features act as determinants for the transformation of social and economic resources. This shifting and fragmented settlement pattern has shaped the characteristics of rural politics. Bangladeshi villages are not closely united communities under the leadership of a single village head. Rather, rural society is governed by ever-changing alliances formed by family and neighborhood leaders. For this reason, ruling groups have always had to find ways to deal with the changing boundaries of land and water in order to control rural populations.
To face any future changes, the inhabitants of Bangladesh will have to find new ways or renew existing solutions. It is assumed that deforestation, soil erosion, and melting glaciers of the Himalayas will increase both sediment deposition and water flow in rivers during peak seasons. Climate experts agree that due to global warming, if sea levels rise, Bangladesh will be among the countries most severely affected.
However, based on the data available so far, the commonly held notion that global warming has led to increased flood occurrences, seasonal storms, and droughts in Bangladesh is not accurate. On the other hand, while the world grows increasingly concerned about water scarcity, the abundance of fresh water in Bangladesh could become a special asset. It is certain that the coexistence of land and the three types of water sources—rivers, rain, and the sea—will continue in Bangladesh in the future as well.
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