Kochi's coastal stretches have faced severe erosion even in areas protected by seawalls in the last few decades, shows a case study of Kochi coast on erosion and protective measures by Anupama Chandran, a PhD Research Scholar with the Department of Geography, Central University of Karnataka. The study focused on different kinds of engineering structures like groynes, seawalls, revetments, breakwaters, etc.

Apart from the Munambam and Elakunnapuzha – Puthuvype stretch, the rest of the Ernakulam coastal stretch experiences erosion to some extent, though it is protected by seawall and groynes, the study notes. Fort Kochi, the immediate south of the Cochin inlet, experiences significant coastal dynamics for short periods. The seawall pathways at Fort Kochi have been destroyed due to the waves. During monsoon months (June to September), wave heights are higher in coastal Kerala. Many places in Ernakulam, like Nayarambalam, Manassery and Chellanam, experience wave attacks and erosion during this period, the paper shows.

The beach at Manassery experiences continuous erosion, though seawalls were constructed many years ago. Such failures of seawalls as protection structures have been reported from some other locations along the Ernakulam coast. After a few years, seawalls could be damaged due to continuous wave action. The stones of the seawall became rounded due to wave-induced weathering. 

“Kerala’s shorelines are very dynamic, perhaps owing to the intense monsoons and frequent cyclonic events in the region. Coastal erosion is a naturally occurring phenomenon, but the rate at which it is occurring in Kochi is not natural," said Anupama.

Her study identifies the construction of the Cochin Harbour channel as a driver of the region’s retreating shorelines, with a higher rate of erosion recorded compared to periods before it. Other areas which have been impacted by coastal erosion include Chellanam, Fort Kochi and the Manassery-Kannamali stretch.

In Chellanam, the situation is dire. The Chellanam-Kochi Janakeeya Vedhi was launched in 2019, flagging the issue of erosion in the region, calling for a comprehensive coastal protection plan to secure the life and livelihood of its residents. PT Sebastian, a leading activist for the cause, highlights coastal flooding and the resulting saline water intrusion as recurring issues which the region faces.

Earlier, the Kochi-Chellanam coast was lined with fishing units, which are now confined to man-made structures such as the Chellanam harbour, Sebastian recalls. “Some fishermen have to travel up to 8 kilometres north to reach these harbours to be able to undertake fishing activities," he says. 

Coastal erosion slowly makes beaches steeper, making them less accessible to fishing boats, according to Anupama.