The course of the Padma River, Bangladesh’s principal river, is gradually changing. On one side, erosion continues, while on the other, new sandbars are emerging and fresh land is forming along the banks. River researchers say the river’s course will undergo even more changes over the next decade. Climate change and Padma Bridge’s impact will play major roles in this transformation, they further say. Concerned experts believe that the rapidly changing course of the river could significantly affect Bangladesh’s geography, public life, and economy.

Researchers say that the Padma River’s course has become even more dynamic in 2026. Compared to the past, the river is now flowing in a more winding pattern and has split into multiple channels. Alongside natural causes, the construction of the Padma Bridge has also accelerated changes in the river’s course and structure. Some areas are consequently facing severe riverbank erosion, while others are witnessing rapid sediment accumulation and the emergence of new chars (sandbars).

Several satellite image–based studies conducted over different periods on the erosion patterns of the Padma River show that the rates of erosion and char formation are nearly equal. In some cases, the amount of newly emerged land has even exceeded the extent of erosion. An analysis of satellite images from the United States Geological Survey Earth Explorer between 2005 and 2025 found that around the Padma Bridge area, 155.6 square kilometres — or 15,560 hectares — of land disappeared into the river over the past 20 years. On the other hand, 125.2 square kilometres, or 12,520 hectares, of new chars emerged during the same period. This means that approximately 30.4 square kilometres, or 3,040 hectares, of land were permanently lost to the river.

A recent study found that the most severe erosion in the Padma River between 2005 and 2025 occurred during the 2015–2020 period, when construction work on the Padma Bridge was underway. The research showed that both before and after the bridge construction period, the rates of erosion and char formation were comparatively lower.

During the bridge construction period, erosion in the Padma surpassed all previous records. At that time, 137.66 square kilometres of land were eroded, while 98.76 square kilometres of chars emerged. During this two-decade period of the most intense erosion and land formation, the river’s total area expanded by 38.9 square kilometres. The amount of stable river area during that period was also the lowest in 20 years, at 208.26 square kilometres. These findings emerged from a study on the hydrodynamics and nature of the Padma River conducted by three researchers from Chittagong University of Engineering and Technology (CUET).

River researchers working on erosion along the Padma River say the river’s erosion pattern is no longer following any predictable course. Instead, it is increasingly advancing toward settlements in a random manner. As a result, the entire Char Janajat area of Madaripur was eroded and disappeared during the construction period of the Padma Bridge. On the other hand, new chars are emerging in uninhabited areas.

After the construction of the Padma Bridge, the rate of char formation began to exceed the rate of erosion. Between 2020 and 2025, around 78.71 square kilometres of new chars emerged in the river, while 68.94 square kilometres of land were eroded. This means that nearly 10 square kilometres of new land or chars were added to the river during those five years.

In the five years prior to the bridge construction period, from 2010 to 2015, the river eroded 81.53 square kilometres of land, while 76.21 square kilometres of chars emerged. Since erosion exceeded land formation during that period, the river continued to widen. As a result, the river’s total area expanded by approximately 5.32 square kilometres.

From 2005 to 2010, the river remained relatively calm. During those five years, the Padma eroded around 76.1 square kilometres of land, while 80.31 square kilometres of chars emerged. As a result, the river shrank by about 4.3 square kilometres during that period.

River and water resources researcher Ainun Nishat told Bonik Barta, “River erosion is part of a river’s natural character. If we want to prevent erosion, river training measures must be implemented on both sides of the river. And erosion never follows a fixed pattern. But in the areas where we carried out river training work for the Padma Bridge, erosion will no longer occur there.”

At present, the banks of the Padma River are changing frequently. Erosion is especially severe along the western and south-western banks, while sediment deposition on the eastern bank is creating new land. However, studies show that after the completion of the bridge construction, the river’s course in some surrounding areas has become comparatively more stable. On the other hand, the Padma-Meghna confluence remains highly unstable, particularly during the monsoon season, when the river’s course changes rapidly.

Researchers believe several major factors are responsible for these changes in the river. One of the most significant is the Padma Bridge itself, which has altered the river’s natural water flow and increased erosion in certain areas. The riverbank areas of Madaripur and Shariatpur, particularly Char Janajat, are considered to be at the highest risk. Due to changes in the river’s course, many families there have already lost land, while many others remain under threat of losing theirs. In addition, Rajbari is also facing a major risk of river erosion.

River researcher ARM Khalequzzaman told Bonik Barta, “In 2021, I worked with the National River Conservation Commission (NRCC) on a morphology study of 57 rivers. At that time, we directly observed the erosion of the Padma and surrounding rivers. River currents have a natural flow pattern. This flow gets obstructed by chars. When the current collides with a char, it spreads in different directions. As a result, erosion doesn’t occur on one side only; it spreads across multiple areas.”

“In the settlement areas along the Padma River, there is a layer of sand about 30 to 35 feet beneath the soil. When the current spreads in this way, the sand gets washed away with the flow, causing the area to collapse. Through geo-bags or other modern engineering methods, if the sand can be held in place at the level where it’s being displaced, particularly if the flow of the Padma can be kept within a single current after Goalanda, then the Padma Bridge will remain safe, and erosion will also decrease,” he added.

The Padma is the second-longest river in Bangladesh. The river has continuously changed its size and course over the past three decades, according to NASA data. Another study by the Bangladesh River Research Institute (RRI) found that erosion tendencies increased not only in downstream areas but also in the upstream sections of the Padma between 2015 and 2019. Alongside erosion, new chars are also emerging in the river.

Several years ago, four researchers from the Department of Geography and Environment at University of Dhaka conducted a study on erosion in the Padma River. They found that between 2012 and 2022, the amount of newly emerged char land exceeded the extent of erosion. Regarding the nature of the Padma’s erosion, they said that it is impossible to predict in advance, as erosion often occurs suddenly. However, during those 10 years, around 6,601 hectares of land were added as chars beyond the amount lost to erosion. Each year, approximately 908 hectares of land disappear into the river, while around 1,568 hectares emerge as new chars.

Researchers say that although the amount of newly emerged char land has increased, much of it remains unusable. As a result, while it adds to the country’s land area statistically, it has little practical value. In contrast, when settlements, schools, colleges, and infrastructure disappear into the river, the newly emerged char land cannot compensate for those losses.

Asked about changes in the course of the Padma River, SM Abu Horayra, director general of RRI told Bonik Barta, “To my knowledge, no research has been conducted by our institute over the past three years. If our hydrology department receives funding from the government, they will certainly carry out research.”