Groundwater quality declines in Ernakulum due to coastal erosion: study

A study by JNU researchers shows that shoreline changes between 1971 and 2007 affected groundwater quality in wells from 27 sites  

By DTE Staff
Published: Wednesday 31 October 2018
More than 80 per cent of Ernakulam’s coast is eroding. Credit: Wikimedia Commons

According to a new study, seawater intrusion into groundwater aquifers, especially along the coastal areas of Ernakulam district in Kerala, is possibly harming the quality of groundwater. A team of researchers from the Jawaharlal Nehru University (JNU) in New Delhi said that this can be a cause of concern even though water is still potable and can be used for irrigation in most coastal sites.

Researchers wanted to study the changes caused by sea level rise on groundwater quality and hence analysed the change in sea level and shoreline along the coast of Ernakulam district.

After compiling tide gauge data (a monthly measure of mean sea level) from Kochi between 1971 and 2007, and assessing satellite imagery between 2002 and 2012, the researchers noticed that the sea level in Enakulum is rising at 1.8 millimetres per year and that around 30 kilometres of the shoreline—more than 80 per cent of Ernakulam’s coast—is eroding.

Between 1990 and 2016, 45 per cent of Kerala’s coastline was eroded. Apart from natural factors such as wave action, wind action, storms, anthropogenic factors such as construction and mining are also contributing to the erosions.

Published recently in the Journal of Climate Change, the study said that shoreline changes affected groundwater quality in wells from 27 sites from South Vypeen on the coast to Muvattupuzha further inland.

Water in wells in Chellanam was high on salinity and Edavanakkad and Pallipuram showed high alkalinity, also a sign of saltwater intrusion. The study shows that low-lying areas are at higher risk and advised regulating construction and excessive extraction of groundwater if possible.

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