There are various types of floods that can be encountered through different areas and seasons. With so many different forms of flooding, it’s important to be able to identify each one individually in order to prepare and protect to the best of your abilities.
Coastal Flood (Surge Flood)
A coastal flood occurs in areas that lie on the coast of a body of water, like a sea, an ocean, or a lake. Most typically this form of flooding is the result of extreme tidal conditions caused by severe weather. Storm surge are produced when high winds from storms push water onshore and are the leading cause of coastal flooding and is often the greatest threat associated with a tropical storm. Severity is determined by strength, size, speed and direction of the storm and is classified on three different levels. While sandbags are typically used for protection from these types of floods, cofferdams offer a much better, and sustainable option.
Minor: A slight amount of erosion will occur but no major damage is expected.
Moderate: A good amount of erosion will occur as well as damage to some structures.
Major: Serious threat to life and property. Large-scale erosion will occur while roads will flood, and many structures will be damaged. Locals should take precautions and prepare to evacuate.
Fluvial Flood (River or Riverine Flood)
This type of flooding occurs with excessive rainfall over an extended period of time, heavy snow melts, and ice jams, and it causes rivers to exceed their capacity. The damage can be widespread as the overflow affects waters downstream, often causing dams and dikes to break and swamp nearby areas. Flatter areas take longer to flood as water will rise evenly and slowly, while hilly or uneven areas can experience flooding within minutes after heavy rainfalls. There are two types of flooding that fall under this classification.
Overbank: flooding occurs when water overflows the edges of a river or stream. This is the most common and can occur in any size channel, from small streams to huge rivers.
Flash: this flooding is characterized by high velocity torrent of water that occurs in an existing river with little to no notice. These are considered very dangerous and destructive due to the force of the water and the hurtling debris that is often swept up in the flow.
Pluvial Flood (Surface Flood)
A surface water flood is caused when heavy rainfall creates a flood event independent of an overflowing body of water. It’s a common misconceptions that you must be located near a body of water to be at risk, but this instance proves otherwise. There are two common types of pluvial flooding.
Intense rain saturates an urban drainage system. The system becomes overwhelmed and water flows out into streets and nearby structures.
Run-off or flowing water from rain falling on hillsides that are unable to absorb the water. Hillsides with recent forest fires are notorious sources of this flood, as are suburban communities on hillsides. Water filled cofferdams are just one way to protect these areas.
By knowing the varying types of flood that can occur, and looking at recent patterns of flooding in your area, you can be better prepared in your home by flood-proofing and preparing with a cofferdam system in your home or business. While floods can be unannounced and unexpected, researching your areas weather patterns and anomalies, you can stay informed better as to your risks. Having a cofferdam system at your disposal is always a safe bet.