Bangladesh: Drinking water turns saline

A look at the map of Bangladesh shows that the country is awash with water. The sea encroaches the land and vast rivers flow southwards from the low lying land to the sea. So, water is everywhere in coastal Bangladesh, but is increasingly undrinkable as sea levels rise and land sinks.

As climate change has (supposedly) raised sea levels, most scientists forget to mention that excessive population growth also results in ever decreasing groundwater levels. Coastal Bangladesh is sinking because of a phenomenon called subsidence. This happens when extraction of groundwater causes layers of rock and sediment to slowly pancake on top of each other. The effect is worsened by the sheer weight of all the buildings to house the ever increasing population.

Higher seas, sinking cities, and more people mean worsening impacts from storms and floods. And the frequency of these events is increasing, too. Recorded floods and severe storms in Southeast Asia have risen sixfold, from fewer than 20 from 1960 to 1969 to nearly 120 from 2000 to 2008, according to an Asian Development Bank study. At the same time. drinking water turns saline and undrinkable.

Back in 2011, a study estimated salt intake from drinking water in Bangladesh’s coastal population exceeded recommended limits[1]. Things have worsened since then.

Many studies have shown that people in coastal Bangladesh are suffering more and more as saltwater intrudes into their water supply.

A 2014 World Bank report, forecasts that by 2050 climate change will cause major changes in river salinity in the south-west coastal region during the October-May dry season[2]. This will result in a shortage of drinking and irrigation water, with changes in aquatic ecosystems.

The shortage is here already. And all over coastal Bangladesh, it has spawned a new business: selling potable water.

The saltwater invasion of drinking water sources has been worsened even more by commercial shrimp farming, which started in coastal Bangladesh in the 1980s. Shrimp farmers flooded plots of land with saltwater because shrimps grow best in brackish water. That saltwater has seeped into aquifers everywhere. 

The problem isn't isolated to Southeast-Asia. Even Venice is sinking.

[1] Khan et al: Drinking Water Salinity and Maternal Health in Coastal Bangladesh: Implications of Climate Change in Environmental Health Perspectives – 2011
[2] Dasgupta et al: River Salinity and Climate Change Evidence from Coastal Bangladesh - The World Bank Development Research Group Environment and Energy Team – 2014. See here.