Breakwater and seawall constructions have made sea erosion scenario worse, flag experts; say restoring coastal vegetation, including mangrove forestation, is need of the hour
Kerala’s 590-kilometre-long coastline — one of the most densely populated in India and exposed to rogue waves — has for long been susceptible to large-scale sea erosion.
The Pinarayi Vijayan-led Left Democratic Front (LDF) government has adopted traditional measures such as seawalls and breakwaters to brace against the perceptible impacts of climate change. But there are reasons to believe they may not save the state from the rising seas.
A recent study has flagged the possibility of coastal areas in the state witnessing an increasing trend of sea surge in the coming years, mainly due to the rise in sea surface temperature. The scientists have advocated for nature-based solutions, in such a case, involving active participation of residents of the coastal communities.
Seawalls are walls or embankments erected to prevent the sea encroaching on or eroding an area of land. The scientists involved in the study termed the present practice of erecting granite seawalls as counter-productive.
They emphasised that mineral sand mining — rampant in coastal areas of Kollam, Alappuzha, and Ernakulam districts — be confined to public sector with strict monitoring amid numerous complaints of illegal extraction of mineral sand by private agencies.
They urged the state government to focus on protecting and promoting mudflats, coastal wetlands, mangroves and sandy beaches to prevent further escalation of sea erosion, which has gained alarming proportions even before the onset of south-west monsoon.
The study flagged the need for participatory seashore management and a coastal erosion map.
The joint study was conducted by
Restore mangrove forests
The increasing calamities faced by the coastal community has elicited the need to restore coastal vegetation, including mangrove forestation, which could act as a bio-shield to the coastal belt, Sanjeev told Down to Earth.
K V Thomas said:
“More than 0.6 million people of Kerala are directly dependent on the sea for their livelihood. There is a vast segment that indirectly relies on the sea by way of fisheries, tourism, transport of goods and people, aquaculture, energy, materials for biotechnology, minerals, and metals. The sea and the seashore are the most threatened areas during the Anthropocene. The current and predicted climate change impacts threaten the very existence of seashore communities.”
He added that the most impacted communities in Kerala — bordered by the Western Ghats on the east and the Lakshadweep Sea on the west — live at the ecotone of land and the sea. This calls for urgent intervention of the state government.
Seashore erosion has worsened coastal ecological balance and we need to evolve better solutions based on nature and in tune with the integrated development of Kerala, he added.
Seashore degradation started in Kerala in the 1950s, primarily due to unscientific constructions in the seashore. Photo: Syed Shiyaz Mirza
The coastline has also been subjected to environmental dynamics of the past several thousand years that eventually led to the formation of a wide range of geomorphological features such as backwaters, bays, lagoons, salt marshes, sand dunes and sandy shores, said Thomas.
The study noted:
“Among the 44 rivers originating from Kerala in the Western Ghats, 41 empty into the Lakshadweep sea. The average distance between the seas and the Western Ghats is 55-56 km. The backwaters, formed when the seawater pushes back the river as it reaches from the plains into shallow areas, is a unique characteristic of Kerala. The vagaries of the sea level and beach barrier formed perpendicular to the shore that led to the formation of the backwaters like Vembanad, India’s largest backwater ecosystem. The nutrient richness of the shallow seas in Kerala is due to the nutrients and organic matter brought by the rivers through the estuaries…”
The ocean currents — in tune with the winds that bring cold, nutrient-rich water, which upwells in the Kerala coast — make the seashore productive, thereby ensuring good fish biomass.
Residents thrive by extracting resources from nature around them and are tied to the ecosystems they live in. Any damage to the ecosystem will be at the cost of their livelihood, the study warned.
The seashore degradation started in Kerala in the 1950s, primarily due to unscientific constructions in the seashore, said Biju Kumar. “The constructions comprising mostly harbour breakwaters ignored the ecotone landscape’s dynamic nature. The beach nourishment systems adopted the world over during the construction of harbours was not implemented.”
Hard armouring structures such as the seawall have been presented as the only solution to degradation; but they have only aggravated the issue. The degradation of rivers — that brought sand and sediments to maintain the seashore — also worsened the situation.
“The life of the lowland people became a rope walk between the sea and the land, and many lost their homes and livelihood, said Kumar.
He warned that the tourism industry has shifted to inland backwaters and the Western Ghats from the shoreless seashore. The increasing number of hurricanes in the Arabian sea and the rising sea level may aggravate the situation.
The seashore is maintained by the continuous process of accretion and erosion, according to the researchers.
According to them:
The ‘room for seashore’ must be taken up as an immediate slogan, they said. The decision to leave 50 meters distance from the shoreline for the sea to ensure the stability of beaches must be strictly enforced.
The study suggested preparing a list of hotspots based on available studies on seashore erosion and field verification reports reported by local self-governments. Based on the intensity of erosion, the seashore should be classified as:
The way ahead
According to Sajeev, the current breakwater and seawall constructions have worsened the sea erosion scenario. Better structural features are needed for seashore maintenance after careful study of the current status.
Beach nourishment methods and sand bypassing should be considered wherever possible, after site-specific studies, considering coastal geomorphology and dynamics.
“India is envisaging an integrated coastal zone management project. Local-level participatory coastal zone management projects should be implemented as part of this. The district-level management committees should lead these projects,” observed E Shaji.
Among other suggestions were:
The researchers said mining of the strategically important mineral sand should be regulated strictly and should be done only by the public sector. Mudflats, coastal wetlands, mangroves, and sandy beaches should be declared as Ecologically Sensitive Zone 1.
Dredging will be necessary at ports. It has to be made sure that the mud and soil excavated are not used to reclamation coastal wetlands. Sand mining should be prohibited at the hotspots. There should be a reliable enforcement mechanism for this. Shores, where the Olive Ridley turtles lay eggs, should be protected.
“Studies based on predictive models should be started to develop better coastal zone management. Nature-based solutions should be used to prepare green belts at the coastal buffer zone, and the activities should be linked to Rural Employment Guarantee programs and programs schemes,” said Thomas.
Meanwhile, a webinar organized by the Central Marine Fisheries Research Institute (CMFRI) in Kochi also suggested similar steps. The webinar highlighted that the entire Kerala coast recently witnessed a ‘storm surge’ during the two cyclones — Tauktae and Yaas.
“Kerala’s coastal region could be protected from the wrath of the sea to a great extent through the restoration of mangroves and other biodiversity in the region,” said CMFRI Director A Gopalakrishnan when contacted by Down to Earth.
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Kerala’s 590-kilometre-long coastline is susceptible to large-scale sea erosion. Photo: Syed Shiyaz Mirza .png)
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