Exploring Types Of Floods In The US

According to organizations like the RFF and the US Environmental Protection Agency, heavy rainfall and flash floods are on the rise.

While coastal areas often experience flood damage from excessive rainfall, this is now a more common occurrence across the US. In fact, This National Oceanic and Atmospheric Association report, states that "by 2050, 'moderate' (typically damaging) flooding is expected to occur, on average, more than 10 times as often as it does today".

Homes in a residential area in Florida, surrounded by hurricane Ian rainfall flood waters.

So, what does this risk mean for business owners and commercial entities? How will excessive rain increase flood risk for companies based in coastal regions and other high-risk areas? How will the types of floods Americans experience impact everyday people, homeowners and consumers? And why should anyone care?

The impact of flood events

From a commercial perspective, rainfall intensity can impact everything from supply to operations, sales and risk management.

Flood damage to critical infrastructure can involve preventable insurance claims, premium increases, significant structural damage, a delay in service delivery, and even the loss of human life. Similarly, community infrastructure like medical and safety facilities can suffer operational losses that keep them stagnant and rebuilding for years.

For the average consumer, coastal flooding, storm surges and even river floods in more rural areas can impact humans and animals, destroying houses and creating a significant safety and financial risk for people who often aren't prepared.

What is causing an increase in these types of floods?

There are some who argue that climate change is the main culprit behind the increase in river flooding, etc. in the United States. However, more specifically increased intense rainfall, melting snow and changing weather patterns seem to have the biggest impact on the rapid rise of flooding we've seen over recent years. Coastal flooding can often be traced back to extreme weather events and the rising sea level which can make storms and high tides a particularly vulnerable time for business and property owners nearby.

And, as urbanization grows and cities expand, more impervious surfaces (made of materials like concrete and asphalt) mean more urban flooding damage. Why? Because water can't get through them, which stops or slows down its absorption into the soil. At the same time, the drainage system throughout the US becomes less effective as more homes and businesses are built.

The result? In less than six hours (flash flooding) whole areas can be devastated, and flood water flows can cause severe damage to properties and people. With this in mind, it's important to know the various types of floods and how they can impact the areas where you work, operate or live.

Types of floods to prepare for

Flash flood

We briefly mentioned flash floods above, which are characterized by their short onset. Intense rainfall (pluvial flooding), dam breakage or rapidly melting snow can trigger these types of floods, which are especially dangerous given how fast they happen. With little-to-no preparation, entire populations are often forced to react and usually unprepared to mitigate the risks of the flood damage or get to safer ground fast enough.

You can typically spot a flash flood by its quick rise or where it is. While they occur on any kind of terrain, they're most likely to happen in low-lying areas and valleys where water can collect quickly - especially if there is not enough ground penetration.

Flood barriers, improved drainage systems and maintaining drainage infrastructure can be valuable tools in the fight against flood damage. However, locals need to take matters into their own hands and work with governments to setup effective protection and prevention.

River floods

River flooding is defined by its location and sometimes occurs gradually, expanding beyond its banks and flooding surrounding areas and homes (fluvial floods). In some cases, this is the result of an ice jam where ice builds up during winter, then breaks in Spring, causing the sudden release of water. However, urbanization, deforestation and other changes to the surrounding environment can easily impact how water flows downstream, as well as how much of it moves at once.

When a river flood occurs, barriers and reservoirs can help contain water flow, but prevention and preparation are equally important. Flood-plain zoning helps limit development in areas prone to heavy rainfall or flash floods, helping to mitigate and prevent damage. Early warning systems can also help with this, as well as restoring natural infrastructure and respecting the surrounding environment.

Urban flooding

By definition urban flooding applies to cities that are built up and have less natural ground space for heavy rain to run into. We've touched on how a developed drainage system can help here but often, it's no match for heavy rainfall - so inhabitants should be extra aware and prepared for a storm surge or combined rainfall.

Groundwater floods

Saturated soil and aquifers can cause groundwater flooding, especially in areas where it snows or there is prolonged rainfall. These typically take longer to develop than their surface-flood counterparts but can also take longer to resolve. These types of floods can also be particularly complex as they might affect water supply to cities.

This can cause water contamination that impacts everyone who lives there and on neighboring land. Luckily floodplain restoration and monitoring groundplain levels can help keep these in check but it's important to have systems in place to mitigate damage.

Storm surges

Strong, high winds and low atmospheric pressure from storms can cause coastal flooding and storm surges. As the water gets pushed towards the shoreline, storm surges rapidly flood beyond the natural borders. The severity of these can depend on everything from tidal conditions to storm track and forward speed. Ironically, a slow-moving storm can cause the most damage because the resulting surges are more significant. Tropical storms are often most devastating because of the surges they create.

Respecting nature and human life

This is no easy task, but it takes the commitment of communities to preserve life and land - and Geodesign Barriers wants to be part of this change. Find out more here.