Contamination and Diseases

Floodwater can be contaminated with pollutants such as agricultural pesticides, industrial chemicals, debris, and sewage. If contaminated floodwater enters the ocean it can affect water quality and disrupt delicate ecosystems, such as coral reefs. In February 2019, marine biologists feared for the safety of the Great Barrier Reef off the coast of Queensland, a state in Australia, after it was inundated with polluted floodwater.

Floods are the leading cause of weather-related infectious disease outbreaks. Flooding events increase the chance of spreading waterborne diseases, such as hepatitis A and cholera. Receding floodwater can create stagnant pools of water, which provide the perfect breeding ground for mosquitoes, which can transmit malaria and other diseases. Flood events also lead to an increase in some forms of zoonosis, such as leptospirosis.