River Erosion in Bangladesh: The Complaint-free Crying Sound of People on the Coast (Part I)

River erosion is the name of terror to the riverbank’s inhabitants. When we hear the words, a picture of some lost and helpless people floats in the corner of our eyes. Every year a vast amount of land in the riverbank’s goes into the riverbed.

From a survey, we know that about 6,000 hectares of land are being merged into the river every year. As a result, thousands of families are losing their homesteads and lands. Roads, ghats, markets, schools, colleges, mosques, and madrasas are disappeared.

How long is the ‘continuous erosion line’ of river erosion in Bangladesh? According to one research, this erosion line is not a village, market, town, or district; it is about 12 hundred kilometers long.  According to the Bangladesh Water Development Board, there are about 300 clear erosion-prone areas in different rivers of the country.

Almost every year there are more, or less erosion happens. For example, in the current season, erosion has occurred in 262 places in 52 districts.

The most erosion prone districts of Bangladesh are Bogra, Sirajganj, Kurigram, Lalmonirhat, Gaibandha, Rangpur, Chandpur, Manikganj, Rajbari, Shariatpur, Faridpur, Tangail, Jamalpur and Patuakhali.

According to a survey by CEGIS, the most erosion-prone district is Sirajganj, and there has been a total of 622.2 hectares of erosion.

We are trying to make a series reporting on the cause of catastrophic river erosion, what factors can influence the severity of river erosion, and the severity of the season.

In addition, we will try to discuss the impact of river erosion in a community, how to prevent this river erosion, and what we can do for helpless people who have lost everything in river erosion. Today is the first episode, we will discuss the main reasons for river erosion.

Though river erosion is a natural process, various human activities can increase the intensity of river erosion. Due to ignorance of these topics, we do not know the actual cause of river erosion. It is possible to reduce river erosion by taking the initiative and being aware of some issues.

Today let us look at some of the natural and human-made causes of river erosion.

Some natural causes of river erosion

Bangladesh is a delta

Bangladesh is known as the Ganges-Brahmaputra Delta or the Bengal Delta; the land is mainly made of silt. Due to silt, the soil structure is very weak.

Due to the formation of this type of soil, it breaks down easily due to the strong current of river water. This causes river erosion when a slightly stronger current comes.

Flood

One of the major causes of river erosion is floods. The incidence of floods in our country usually increases during the monsoon. Due to the high flow of water in the river during floods, water flow acquires enough strength to break the soil layer.

During this time, the water speed on the river banks is high and the water hits the shoreline causing the river to break. This increases the intensity of river erosion during floods.

Extreme rainfall

Because of heavy rains, the water flow in the river increases and the river water becomes turbulent due to wind. This causes strong waves in the river during heavy rains.

Then the river waves put extra pressure on its shoreline. This breaks the soil on the weaker part of the river bank and gradually increases the erosion process.

Sediment accumulation in the bottom of the river

Due to various deviations of nature, silt accumulates on the river’s bottom. This reduces the water holding capacity of the river. This increases the water level of the river, creates pressure on the banks, and changes the course of the river by breaking the banks. Thus, river erosion accelerates.

Strong current in the river

Some rivers have strong currents due to the amount of water flow or the slope of the hill. River erosion can occur due to the rapid water flow in these rivers. If the riverbank structure of these places is not strong, then river erosion accelerates.

The width of the river

River width relates to river erosion. The greater the river width, the greater the possibility of river erosion. So, river width also can cause river erosion.

Creation of new char in the river

Chars form by siltation in the river. When new chars form in the middle of the river, the course of the river often changes. This causes a rupture on one side of the river and the river changes course and moves to the other side.

Human-made causes of river erosion

There are not only natural but also human-made causes of river erosion. Let us look at the human-made causes of river erosion.

Deforestation:

The tree’s roots go deep into the soil and strengthen the soil structure. This strengthens of the soil found along the river.

The riverbank’s soil is getting weaker day by day due to deforestation by the people for their own needs. Because of not being able to cope with the river’s strong current, the soil broke and the river broke.

Construction of houses and structures on the banks of the river

We construct houses and structures on the riverbank. Due to the construction of houses and other structures on the banks of the river, the soil load capacity decreases, and it collapses. Therefore, it is a cause of river erosion and river erosion.

Extraction of sand from the river

We often see sand being lifted from rivers. Because of this sand extraction, the river loses its balance and begins to erode. So responsible for sand extraction and river erosion from the river.

Obstruction of the river

We often try to control the flow of river water by building dams on the river. Let us build power plants, irrigation projects. While this may be of temporary benefit to us, it does create long-term problems. Dams created in the river disrupt the normal course of the river and cause river erosion.

Construction of city protection dam

The banks of various rivers have been built along the banks of the river for ages. This prevents erosion on one side of the river but causes erosion on the other side.

Unplanned dredging in the river

We are familiar to see dredging in the river regularly. Dredging does not always bring benefits. Because of unplanned dredging, there is unbalance between the depth and width of the river. This also may cause river erosion. Thus, due to unplanned river dredging, sometimes riverbank’s land is getting lost into the riverbed.

Today we have discussed various causes of river erosion.

(I hope it will discuss more issues of river erosion in the next episode. Keep an eye on our site regularly).