According to the Office of Disaster Preparedness and Emergency Management (ODPEM), a flood is the most common natural hazard in causing loss of life, human suffering, inconvenience, widespread damage to buildings, structures, crop, infrastructure, and other national assets.
Severe weather conditions which lead to intense rainfall such as tropical depressions and hurricanes often lead to flooding. It’s important to keep this in mind as we are currently in the hurricane season.
Types of floods
There are four types of flooding that affect Jamaica and the wider Caribbean:
- Flash floods – Flash floods are the result of heavy rainfall or cloudburst over a relatively small drainage area. Flash floods carry highly destructive flood waves and are most common in mountainous areas or in steep places that have streams flowing though narrow canyons.
- Riverine floods – These occur when a large amount of rain falls in river systems with tributaries that drain large areas containing many independent river basins. They may last a few hours or many days depending on the intensity, amount and the distribution of the rainfall.
- Tidal flood – This results when large bodies of water, like the sea or lakes, overflow onto bordering lands. They are mainly caused by high tides, the heavy rains that accompany hurricanes, waves created by high wind surges created by storms, and long waves produced by earthquakes out at sea.
- Ponding– This is a slow build up of water in depressions, sinks, areas with clay base soil, and slow percolation rate, for example, flooding in New Market.
What causes floods?
- Heavy rainfall resulting from tropical weather disturbances
- Improper agricultural practices
- Inadequate design of drainage channels and structures
- Inadequate maintenance of drainage facilities, blockage by debris brought by flood waters
- Construction of settlements in flood plains
Flooding is also a natural feature of drainage systems and of rivers and streams.
Areas susceptible to flooding
- Low-lying coastal areas
- Areas near gully banks
- Flood plains of major rivers
- Lower sections of closed limestone valleys (e.g. New Market)
- Areas vulnerable to landslides
- Low-lying coastal towns and villages
Persons who live close to these areas are urged to be on the alert in case of a disaster as they are most vulnerable to flooding.
Effects of floods
- Disrupt one’s personal, economic and social activities.
- Set back the nation’s security and development by damaging or destroying roads, buildings and other infrastructure.
- Cause death by drowning.
- Lead to insufficient food supply, which can lead to famine.
- Destroy crops and livestock.