Flooding is associated with over 80% of natural disasters in the last 10 years and has affected more than 2 billion people globally in the most recent 20 years of data (1998–2017), according to the World Health Organization (WHO). Flooding isn’t just a problem for our environment or property, flooding poses major risks to human health.
Flooding poses significant risks to human health, including injury, disease, and negative mental health outcomes.
Flooding will increase with climate change, and thus, so will the negative health impacts of flooding.
If you live in a flood-prone area, it is important to learn how to keep yourself safe.
Floods pose many health risks
Floods are swells of water that submerge areas that are usually dry land. Common causes of floods are storms like hurricanes, flash flooding from intense rainfalls, or snow melts from rapidly rising temperatures.
Floods and the waters that cause floods can cause varied and substantial health impacts. Here are some of the health risks that flooding poses.
Injury and drowning
In the immediacy of high flood waters, the risk of drowning is elevated. Drowning during floods is a risk to all individuals, whether they can swim or not. Flooding can cause high-speed waters that are challenging for even the best swimmers to navigate. The risk of flooding is further heightened in children.
Floods can also increase the risk of injury. A person who is in or near flood waters may be hit by passing debris that can cause lacerations, bruising, or more severe injuries like broken bones or even concussions.
Flood waters can be contaminated with many dangerous pathogens or toxins that can make people sick. Flood waters can contain bacteria, parasites, viruses, fungi, and toxins. Flood waters can pick up contaminants from the ground surface, like chemical fertilizers from farm fields, sewage overflows, or toxins from otherwise isolated land masses.
Contaminated flood waters can contain bacteria that cause diarrheal illnesses like cholera or typhoid fever, toxins that can cause tetanus, or other infectious materials that can cause gastrointestinal illnesses, rashes, skin wounds, and more.
Increased vector habitats
Vectors are living organisms, such as insects, that can carry and transmit infections between hosts, such as humans. Examples of common vectors include mosquitoes, ticks, and black flies. Many vectors, such as mosquitoes, breed in the standing waters that can result from flooding.
A scoping review of the impacts of flooding on vector-borne diseases conducted in 2021 demonstrated various trends, including an increase in incidence for many diseases, following flooding events. These findings included increases in malaria, dengue fever, and Rift Valley Fever.
Importantly, some of the vector-borne diseases that increase following flood events can be categorized as infections known as neglected tropical diseases. The World Health Organization describes neglected tropical diseases as a diverse group of infections that cause a variety of illnesses, occurring primarily in low-income tropical countries and receiving a fraction of the world’s research energy, money, and interest, due to their relatively low frequency in high-income countries or populations. Therefore, the impact of flooding on vector-borne diseases, and specifically neglected tropical diseases, can be even starker in impoverished regions.
Floods can have dire consequences for food insecurity in many regions. Floods can damage or destroy crops, wiping out seeds that have been planted or devastating crops that are nearing harvesting.
In regions where populations of farmers grow subsistence foods, floods that damage crops may leave families and communities without food for the remainder of the growing cycle, often without options for other places to seek nutritious foods for their families. In regions with large-scale commercial farming operations, mass flooding can be detrimental to the food supply network, driving up the costs of food.
Mental health impacts
Flooding and other extreme climate events can have detrimental and lasting impacts on mental health, ranging from depression and anxiety to post-traumatic stress disorders. In the case of flooding, mental health effects may be related to events such as witnessing or experiencing drowning events or injuries, loss of property and homes, or resultant disease experiences.
Climate change and flooding
As climate change progresses, floods have been increasingly frequent and more intense in many areas around the world. Climate projections show that this will continue to be the case for many years, and we should be prepared for increasing flooding events in the future. With increasing flooding, there will also be increasing health impacts of flooding.
Climate change adaptation is an area of research that focuses on how communities can adjust to be better prepared for the realities of climate change. In the case of flooding, climate change adaptation would focus on activities that decrease the impacts of flooding events, such as reducing the negative health outcomes that result from floods in a given area. For example, if floods in a community were primarily caused by snowmelt events, increasing stormwater drainage systems may be beneficial. Similarly, if floods in a community were primarily caused by coastal or river banks not holding surge volumes, break walls may be helpful to decrease on-land flooding.
How to stay safe
When presented with a flood situation in your community, the following safety tips may help to protect you from negative health outcomes:
- Have an evacuation plan. Knowing where the highest risk flood areas are in your community and how to avoid them.
- Stay away from high waters. Do not walk in, drive through, or attempt to cross flood waters. The water is often deeper than it appears.
- Boil drinking water. If you are under a boil water advisory, make sure you boil your drinking and cooking water.
- Throw away contaminated food. If food has come into contact with flood water, it is not safe to consume.
- Dump standing water. This helps to remove potential habitats for vectors, such as mosquitoes.
Floods pose substantial risks to human health and are one of the most common climate-related disaster risks in the USA and around the world. Knowing the potential negative health impacts of flooding and how to reduce your risk is important for your health in a changing climate.
- World Health Organization. Floods.
- World Health Organization. Neglected tropical diseases.
- Environmental Health Perspectives. The Complex Epidemiological Relationship Between Flooding Events and Human Outbreaks of Mosquito-Borne Diseases: A scoping Review.