Rising water salinity has become a common problem in Bangladesh, impacting negatively on the agricultural sector, drinking water sources, and the livelihood of coastal communities. Additionally, more frequent natural disasters such as tidal waves caused by depression in the Bay of Bengal, and rising sea levels are causing damage to the coastal infrastructure and archeological sites.
A recent study conducted by Khulna University revealed that historical sites located in coastal districts are suffering more structural damage than those located inland.
“Archaeological sites situated in southern Bangladesh, where the salinity is significantly higher, have been experiencing efflorescence, which is ruining the structures,” Khandokar Mahfuz-ud-Darain, professor in the architecture department at Khulna University, said.
Efflorescence is the migration of salt to the surface of a porous material, where it forms a coating.
Efflorescence is the migration of salt to the surface of a porous material, where it forms a coating [image by: Khulna University]
Professor Darain blamed the salinity and increasing trends of natural disasters as the main factors for the accelerated damage at the sites.
According to the Department of Archaeology (DoA), out of 461 heritage locations in Bangladesh, 108 are situated in Khulna and Barisal divisions, while 59 are located in the exposed coastal region.
One of the remarkable historical structures currently at risk is the Shat Gambuj Mosque in Bagerhat district, which was declared a world heritage site by UNESCO in 1985.
Using this historical landmark as an example, Prof Darain told the Bengal Delta: “Our research showed that the mosque’s southern wall, which faces the bay, has suffered the highest level of efflorescence.”
Too much at stake
The 5th Assessment Report of the Inter-governmental Panel on Climate Change (IPCC) identified Bangladesh as being at risk from climate change due to its exposure to rising sea-level and extreme events like salinity intrusion, drought, erratic rainfall, and tidal surges.
The report warns that climate change will gradually affect Bangladesh’s food production rate, livelihoods, and public health.
According to the Soil Resource Development Institute (SRDI), salinity affected areas in the coastal region of Bangladesh increased by 26% from 1973 to 2009.
A recent study conducted by SRDI identified moderate, high, and very high salinity (4-15dS/m) in the southwestern and central zone of the coastal region.
With an aim to protect the historical sites from the negative impacts of global warming, the government is planning to take projects to reduce the damaging risk of the archaeological infrastructures.
Regarding this, Afroza Khan Mita, regional director of the Department of Archaeology told the Bengal Delta that, “Right now, we are preparing a project proposal to get adequate resources for protecting the sites which will be submitted to Green Climate Fund (GCF).”