Salinity encroaching on land in Bangladesh: A growing threat to coastal livelihoods

Bangladesh, with its vast deltaic coastline along the Bay of Bengal, is increasingly facing a slow but serious environmental crisis: salinity intrusion.

Rising sea levels, reduced freshwater flow from rivers and human activities such as embankment construction and unregulated shrimp farming are pushing seawater further inland.

This advancing salinity is gradually taking over fertile agricultural land, making it unsuitable for traditional crops such as rice, vegetables and freshwater fish. As a result, food security and the livelihoods of millions of coastal residents are under growing threat.

Recent studies indicate that more than one million hectares of coastal land in districts including Khulna, Satkhira, Bagerhat and Patuakhali are affected by soil salinity.

In several areas, salinity levels exceed eight deciSiemens per metre, a threshold at which most freshwater crops fail, the Food and Agriculture Organization noted in a 2021 assessment.

World Bank estimates from 2022 suggest that salinity-affected land in the southwest coastal region is expanding by about 1.5% to 2% every year.

Several natural and human factors contribute to this growing problem.

Climate change-driven sea level rise increases tidal surges and allows seawater to move further inland during storms. Reduced freshwater flow from upstream rivers during the dry season also allows saline water to penetrate deeper into coastal areas.

In addition, poorly maintained embankments and drainage systems trap saline water in low-lying land, worsening soil degradation, findings from the Bangladesh Water Development Board show.

Repeated crop failures force many households to reduce food consumption or sell assets to survive. Over time, this economic pressure drives migration.Every year, a growing number of coastal residents move to urban areas in search of employment and better living conditions. Migration that once occurred during seasonal hardship is increasingly becoming permanent. Women often bear a disproportionate share of the burden. 

Human activities have also accelerated the process.

In many coastal polders, unregulated shrimp farming requires fields to be flooded with seawater. Over time, this practice contaminates soil and groundwater with salt, making land unsuitable for traditional agriculture, according to FAO findings.

Legacy of the 1960s embankments

Many of the coastal embankments and dams built during the 1960s in areas such as Khulna, Satkhira and Bagerhat were constructed by the then Pakistani government with financial and technical assistance from the World Bank and the Food and Agriculture Organization.

Technical guidance also came from Dutch engineers experienced in polder systems.

Initially, these structures helped reduce tidal flooding and gave farmers greater control over water. Over time, however, they also disrupted natural tidal flows that carried nutrient-rich sediments into agricultural fields.

Without regular sediment deposits, soil fertility declined while trapped saline water gradually increased soil salinity, Bangladesh Water Development Board data show.

The embankments also affected wetlands and mangrove ecosystems. Reduced water exchange damaged aquatic habitats and contributed to the decline of fish, crabs and other species that local communities depend on for food and income, a United Nations Environment Programme report noted.

As farmland became less productive, many farmers were forced to adopt salt-tolerant crops or abandon cultivation entirely.

At the same time, river siltation and poor drainage increased waterlogging and flood risks in surrounding areas. Combined with the expansion of shrimp farming, these changes created long-term environmental and social challenges for coastal communities.

Financial, health and nutrition costs

Salinity intrusion carries significant financial costs for rural households.

Crop failures caused by rising soil salinity reduce agricultural income and weaken local economies. Farmers who once depended on rice and vegetable cultivation often struggle to maintain stable livelihoods.

Many families now rely on day labour or migrate to cities in search of work, as per World Bank estimates.

The economic burden is further increased by the rising cost of obtaining safe drinking water.

In many coastal villages, groundwater has become saline. Families must travel long distances to collect freshwater or invest in rainwater storage systems.

These additional costs place heavy pressure on already vulnerable households.

Health risks associated with salinity are also becoming increasingly visible.

Drinking saline water for long periods has been linked to high blood pressure, heart disease and complications during pregnancy.

Research conducted in coastal Bangladesh found that women are particularly vulnerable because they often consume saline water and are responsible for collecting drinking water for their families.

Nutrition is another growing concern.

As salinity damages agricultural land and freshwater fisheries decline, households lose important sources of protein, vitamins and minerals.

Reduced access to vegetables and freshwater fish weakens dietary diversity and increases the risk of malnutrition, particularly among children and pregnant women, UNEP findings show.

Impact on communities and migration

Small farmers are among the groups most vulnerable to salinity.

Repeated crop failures force many households to reduce food consumption or sell assets to survive. Over time, this economic pressure drives migration.

Every year, a growing number of coastal residents move to urban areas in search of employment and better living conditions.

Migration that once occurred during seasonal hardship is increasingly becoming permanent. This trend places additional pressure on cities already struggling with overcrowding and limited services, a World Bank report warned.

Women often bear a disproportionate share of the burden.

As freshwater sources become scarce, they must travel longer distances to collect safe water for their families. This increases physical hardship and reduces time available for education or income-generating activities.

Government responses and innovations

The government has taken several steps to address salinity-related challenges.

Scientists at the Bangladesh Rice Research Institute have developed salt-tolerant rice varieties such as BRRI Dhan 47 and BRRI Dhan 67, which can produce reasonable yields in moderately saline conditions.

The Bangladesh Water Development Board has also implemented programmes to rehabilitate coastal embankments, construct sluice gates and improve drainage systems.

Community-based rainwater harvesting projects have been introduced in several coastal districts to improve access to safe drinking water.

Salinity management has also been incorporated into the Bangladesh Delta Plan 2100, which aims to strengthen river dredging, improve freshwater management and promote integrated coastal zone planning.

However, limited funding and uneven implementation continue to slow progress.

Learning from global experiences

Countries facing similar salinity challenges offer important lessons.

In Australia, the Murray-Darling Basin has implemented salt interception systems and improved irrigation management to control salinity.

In Egypt, the Nile Delta uses pumping stations, improved drainage systems and salt-tolerant crops to manage saline soils.

Meanwhile, the Netherlands has developed an integrated coastal protection system combining storm surge barriers, adaptive dykes and advanced water management strategies.

These experiences demonstrate the importance of combining engineering solutions with agricultural innovation and long-term policy planning.

The way forward

Experts argue that Bangladesh must adopt a comprehensive approach to address salinity intrusion.

This includes improved freshwater management, stronger embankments and drainage systems, expanded salt-tolerant agriculture, regulation of shrimp farming and community adaptation measures such as rainwater harvesting.

Regional cooperation over shared river water will also be essential.

Without stronger and more coordinated action, the environmental, economic and social costs of salinity intrusion are likely to increase in the coming decades.

Salinity intrusion is a powerful reminder that environmental change is not a distant threat but a daily reality affecting millions of people in coastal Bangladesh.

Protecting coastal land and livelihoods is therefore not only an environmental necessity but also a social and economic priority for the country's future.

Shahiduzzaman is a freelance writer. 

Disclaimer: The views and opinions expressed in this article are those of the authors and do not necessarily reflect the opinions and views of The Business Standard.