News highlights
Over the past few years, Chellanam, a coastal village in Kerala, has hit the headlines during the monsoons for massive sea incursions. However, during this monsoon, Chellanam has remained largely unaffected because of the construction of a new tetrapod-based seawall.
News takeaways
- Earlier, the conventional seawall of Chellanam failed to check sea ingress, which resulted in massive ruin and destruction.
- Coastal erosion, which intensified after Cyclone Ockhi in 2017, further worsened with Cyclone Tauktae.
Tetrapod
- It is a form of wave-dissipating concrete block used to prevent erosion caused by weather and longshore drift.
- It is primarily to enforce coastal structures such as seawalls and breakwaters.
How do they work?
- The tetrapod’s are designed in such a way that they dissipate the force of incoming waves by making the water flow around rather than against them.
- Due to their weight and design, tetrapod’s can remain stable even under the most extreme weather conditions.
- A number of tetrapod’s are arranged together to form an interlocking, porous barrier that dissipates the power of waves and currents.
What is seawater incursion?
- It is the movement of seawater into freshwater aquifers due to natural processes or human activities.
- Seawater intrusion is caused by decreases in groundwater levels or by rises in seawater levels.
- Reasons for seawater intrusion:
- Thermal Expansion:
- When water heats up, it expands.
- Global warming further amplified the thermal expansion, which triggered seawater incursion into coastal areas.
- Melting glaciers:
- Large ice formations, such as mountain glaciers, naturally melt a bit each summer.
- Higher temperatures caused by global warming have led to greater-than-average summer melting of large ice formations.
- That creates an imbalance between runoff and ocean evaporation, causing seawater incursion.
- Lack of a sea wall:
- The lack of proper sea walls and barriers makes it easy for water to enter coastal areas.
Consequences of seawater intrusion:
- Coastal Flooding:
- India has around 7,500 kilometers of coastline. The seawater incursion of these coastal areas would have a devastating impact, such as the demolition of coastal settlements and saltwater intrusion into nearby areas.
- Destruction of Coastal Biodiversity:
- The seawater incursion can cause destructive erosion, wetland flooding, aquifer and agricultural soil contamination with salt, and habitat loss for biodiversity.
- Refugee crisis:
- Flooding in low-lying coastal areas due to seawater incursion is forcing people to migrate to higher ground, causing displacement and dispossession and, in turn, a refugee crisis.
- Loss of economic advantages:
- Coastal areas such as beaches and lagoons, attract both domestic and international tourists.
- the seawater incursion may destroy these geographical features, leading to a loss of economic advantages from tourism.
Way forward
- Building seawalls:
- Building sea walls, like tetrapod’s, would mitigate the impact of seawater incursion.
- Relocation:
- Relocation of people from vulnerable areas of sea incursion would lower the death toll and associated issues.
- Dissemination of information:
- Dissemination of information about seawater incursion and other sea-related information would help to mitigate the impacts of the disasters.
Pic Courtesy: The Hindu
Content Source: The Hindu