What are the causes of coastal flooding?

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What are the causes of coastal flooding?

Coastal floods arise from several factors, including storm surges, tsunamis, and, more frequently due to global climate change. Often, the most severe floods result from a combination of these factors. A storm surge refers to a swift rise in sea level driven by high wind speeds. Tsunamis, on the other hand, are substantial sea waves triggered by submarine earthquakes. Tsunamis originating closer to the shoreline typically have a larger impact than those generated at sea. Climate change contributes to the increasing occurrence and severity of coastal flooding by adding more energy to the atmosphere.

Prediction of Coastal Floods

The focus of coastal flood predictions lies in anticipating high-magnitude waves, high tides and/or storm surges, whether separately or simultaneously. Satellites mainly track storms, particularly by high-income countries (HICs), and predictions about their likely course are made. Given the speed of tsunamis, providing much warning is challenging, although a Pacific Tsunami Warning System does exist. Enhanced forecasting enables many communities to take preventative measures such as evacuation or seeking shelter before coastal flooding occurs. For instance, early warning systems in Bangladesh monitor tropical storms and monsoon rains, providing regular updates on storm paths and probable impacts.

Building Design to Combat Coastal Floods

The primary objective of coastal flood engineering is to avert coastal erosion and flooding. Two main strategies have been utilised. One is to raise the height of buildings, allowing floodwaters to pass beneath them. The other involves flood-proofing structures via raised foundations, reinforced barriers, dry flood-proofing (rendering a property impermeable to floodwaters), and wet flood-proofing (permitting partial flooding of buildings).

Raising the height of buildings to reduce the impact of flooding

Raising the height of buildings to reduce the impact of flooding


  • Coastal floods result from storm surges, tsunamis, and global climate change, with the worst floods often being a combination of these elements.

  • Predicting coastal floods involves tracking high-magnitude waves, tides, and storm surges, with improved forecasting allowing communities to take preventive measures such as evacuations or seeking shelter.

  • To combat coastal floods, buildings are either elevated to allow floodwaters to pass underneath or flood-proofed using techniques such as raised foundations and reinforced barriers.

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