In Focus: Flooding in Iowa

By Derek Tate

Flooding in Iowa has been a topic of great concern due to spring flooding. Devastating floods occurred along the Missouri River Basin, after sudden warm temperatures melted winter snow and rapidly rising waters breached levees. This led to record flooding and serious damage to communities across Iowa, Missouri, Nebraska, and South Dakota. In Iowa, the flood is believed to have caused more than $1.6 billion in damages.

More recently, flood waters reached a record high in Davenport after the rising levels of the Mississippi River led to the failure of a temporary flood barrier. Flooding reached a record high of 22.7 feet in the city and continues to cause damage.

This summer, more flooding is possible as meteorologists expect greater than average rainfall between April and September and because damaged levees may not be repaired in time to protect communities if the water rises above the river banks again. How should Iowans prepare and how is flooding expected to impact local water quality? CHEEC took a closer look at the impact flooding has on public health in this installment of CHEEC: In Focus.

Flooding poses many threats. Floods can damage homes, farms, vehicles, and public infrastructure. They can also lead to injury or death and can impact health in more subtle ways by causing illness due to water contamination.

Floodwaters can carry many harmful contaminants, including bacteria and hazardous chemicals.  Common illnesses caused by exposure may include gastrointestinal illness caused by ingestion of contaminated water or food and skin and tissue infections from cuts, scratches or wounds that are exposed to the water. 

Floodwater can also infiltrate and contaminate wells. Older and shallow wells are especially vulnerable to contamination. Older wells typically have weaker casting, and inadequate surface sealing, while shallow wells, less than 100 feet, are at risk because the water is closer to the surface and at greater risk of contact with floodwater. The Iowa DNR explains that well-owners should be wary of using their water following a flood and should be prepared to use an alternative water source. Households who rely on public water systems should also be cautious and should listen to local advisories that will tell you when it is safe to drink and bathe with water.

So what can Iowans do in preparation for flooding? The CDC recommends having an emergency plan ready. This normally involves practicing a flood evacuation route and establishing an out-of-town family contact. Iowans should also know if their home is within a flood plain or in a flash-flood prone area. They can get this information by contacting the local county health department or by visiting the Iowa Flood Center’s Floodplain Mapping Portal.

To prepare homes for flooding, the CDC recommends tying down potential hazards – like lawn furniture, buying fire extinguishers, installing sump pumps, and preparing an emergency water supply that can last at least three days. An emergency water supply can be made by filling sanitized sinks or bathtubs, or bottles with clean water. Households should also make sure that important documents like insurance papers, medical records, bank account information, birth and marriage certificates, and social security cards are accessible and stored in fire and waterproof containers.

During the flood, it’s important to monitor the radio or television and avoid areas prone to flooding like floodplains and other low lying areas. If local authorities order an evacuation, take only the most essential items, such as food, water, clothes, and first aid kits. Prior to evacuation make sure you turn off all utilities at the main power switch and close the main gas valve. This is to minimize the risk of fire or electrocution should your home become flooded. During the evacuation, avoid driving through flooded areas and standing water.

After the flood has subsided and it is safe to return home, well-owners should refrain from drinking household water until it is determined safe to do so. In the meantime, bottled water or another alternative potable water source should be used. As a last resort, water can be disinfected by boiling for at least 1 minute or using a disinfectant, such as bleach. Eight drops of unscented household bleach, or approximately 1/8 teaspoon, can be added to 1 gallon of water. The solution should be mixed and then let stand for 30 minutes before using.

Wells contaminated by bacteria carried by floodwaters should be properly disinfected before being used for drinking or bathing. After the flood waters have receded a Iowa DNR Certified Well Contractor should be called to assess the safety of your water.  The contractor can also safely flush and disinfect the well with chlorinate. During the disinfection process, stay away from the well pump to avoid electrical shock. After treatment, owners can request water testing kits from the sanitarian at their local health department or by contacting the State Hygienic Laboratory at the University of Iowa.

If your interested in learning more about this topic, Iowa DNR also provides a helpful resource, What Should I Do When My Well Floods.  This document answers common questions regarding well flood preparation, maintenance, and post-flood clean-up and treatment.