Wave Action: Physical processes and movements associated with the propagation of waves in a fluid medium, such as water or air. It influences coastal erosion, weather patterns, and the design of structures like bridges and offshore platforms.

• The IPCC (2013) has projected global sea-level rise for the period 2081-2100, compared with 1986-2005, to be 0.29-0.82 metres.
• These projections now include a contribution from changes in ice-sheet out-flow, for which the central projection is 0.11 metres.
• It is very likely that the rate of global mean sea-level rise during the 21st century will exceed the rate observed during the period 1970-2010 for all scenarios.
• About 70 % of the global coastlines are projected to experience a sea-level change within 20 % of the global mean sea-level change.
• Some models suggest sea-level rises of between 1 metre and 3 metres in response to carbon dioxide (CO2) concentrations above 700 parts per million.
• Studies of the last interglacial period (e.g. Kopp et al., 2009) indicate a very high probability of a sea-level rise of 2 metres over 1 000 years, and cannot rule out values in excess of 4 metres.

States Prone:

1. Gujarat: The coastline of Gujarat along the Arabian Sea is exposed to significant wave action and coastal erosion.
2. Maharashtra: Coastal areas of Maharashtra, including cities like Mumbai, are vulnerable to monsoon storms, tidal waves, and wave action.
3. Goa: Goa faces risks associated with cyclones and storm surges, leading to wave action and erosion.
4. Karnataka: It is susceptible to wave action during monsoon seasons and cyclonic events.
5. Kerala: Kerala is prone to wave action, particularly during the southwest monsoon, and faces risks from storm surges.
6. Tamil Nadu: Exposed to cyclonic activity, leading to wave action and coastal erosion.
7. Andhra Pradesh: Vulnerable to cyclones and associated wave action, especially along the Bay of Bengal coast.
8. Odisha: The extensive coastline along the Bay of Bengal makes it susceptible to cyclones, storm surges, and wave action.
9. West Bengal: Coastal regions of West Bengal, including the Sundarbans delta, are at risk of tidal waves and wave action during cyclones.
10. Andaman and Nicobar Islands: Located in the Bay of Bengal, these islands are prone to wave action and coastal hazards, including tsunamis and storm surges.

Nodal Ministry: Min. of Earth Sciences (MOES)

Types:

1. Wind Waves: Generated by local winds, often seen on the ocean’s surface. Example: Ripples on a pond or whitecaps on the sea.
2. Swells: Long-period waves that have traveled far from their area of origin. Example: Groundswell generated by distant storms in the ocean.
3. Tsunamis: Large, long-period waves usually caused by undersea earthquakes or volcanic eruptions. Example: The 2004 Indian Ocean tsunami.
4. Tidal Waves: Caused by the gravitational pull of the moon and the sun, leading to rising and falling tides. Example: Daily high and low tides in coastal areas.

Criteria to Declare:

It typically doesn’t follow specific criteria, declaring a specific event related to wave action (e.g., a storm surge or tsunami) as a disaster or emergency may include:

1. Magnitude and Impact: The severity of wave height, energy, and potential impact on human life, property, and the environment.
2. Forecast and Warning: The issuance of official forecasts and warnings by IMD and NDMA.
3. Extent of Damage: Caused by impact on infrastructure, transportation, and essential services.
4. Local Jurisdictional Authority: Declarations of emergencies or disasters typically made at the local or regional level by municipal governments or state disaster management agencies.
5. Coordination: The coordination of first responders, and organizations involved in disaster management.

Causes of Wave Action :

1. Wind: Wind blowing over the water body generates friction with the water, creating ripples that evolve into waves. Strong winds can lead to larger and more powerful waves.
2. Seismic Activity: Earthquakes or volcanic eruptions beneath the ocean can generate tsunamis, which are large and destructive waves with extremely long wavelengths.
3. Gravitational Pull of the Moon and Sun: Tides are caused by the gravitational attraction of the Moon and the Sun. This gravitational pull results in the ebb and flow of water and can create wave-like motions.
4. Underwater Geological Features: Submerged features such as underwater ridges, seamounts, and continental shelves can influence the formation and behavior of waves.
5. Human Activities: Activities like ship traffic, coastal construction, and dredging lead to altered wave action along coastlines.

Mitigation:

• Coastal Engineering Structures:
  1. Seawalls: Constructing seawalls or revetments along the coastline can help absorb and deflect wave energy,
  2. Breakwaters: Breakwaters are structures built offshore to reduce the energy of incoming waves.
  3. Groynes and Jetties: designed to trap sand and sediment, helped to build and maintain beaches.
• Beach Nourishment: Adding sand or other sediments to eroded beaches enhancing their ability to absorb wave energy.
• Dune Restoration: Restoring or creating dunes with vegetation can help stabilize coastlines and provide protection.
• Coastal Zoning and Land-Use Planning: Implementing zoning regulations in high-risk coastal areas can reduce exposure to wave hazards.
• Early Warning Systems: In areas prone to tsunamis or storm surges, early warning systems can provide advance notice to residents, allowing them to evacuate to safer areas.
• Ecosystem-Based Approaches: Protecting and restoring coastal ecosystems like mangroves and wetlands can act as natural buffers against wave energy.
• Climate Adaptation Strategies: As climate change intensifies wave action, long-term adaptation strategies are essential for coastal resilience.
• Education and Awareness: Public awareness campaigns can inform about the risks associated.
• International Cooperation: In cases of transboundary wave hazards, international cooperation and agreements can help coordinate efforts to mitigate risks and respond to disasters.

NDMA Guidelines:

1. You should continue using a Weather Radio or staying tuned to a Coast Guard emergency frequency station or a local radio or television station for updated emergency information.
2. Check yourself for injuries and get first aid if necessary before helping injured or trapped persons.
3. Help people who require special assistance—Infants, elderly people,
4. Use the telephone only for emergency calls. Telephone lines are frequently overwhelmed in disaster situations. They need to be clear for emergency calls to get through.
5. Wear long pants, a long-sleeved shirt, and sturdy shoes. The most common injury following a disaster is cut feet.
6. Use battery-powered lanterns or flashlights when examining buildings. Battery-powered lighting is the safest and easiest to use, and it does not present a fire hazard for the user, occupants, or building. DO NOT USE CANDLES.
7. Check for gas leaks.
8. Look for electrical system damage.
9. Watch for loose plaster, drywall, and ceilings that could fall.
10. Take pictures of the damage, both of the building and its contents, for insurance claims. Open the windows and doors to help dry the building.

Way Forward:

1. It involves further research, sustainable harnessing of wave energy, and environmental impact assessment.
2. It’s essential to develop efficient wave energy technologies while minimizing ecological disruption and ensuring long-term viability.
3. Collaboration between scientists, engineers, and policymakers is key to advancing this renewable energy source.