When the Levee Breaks: Damage Caused by Floodplain Development & Faulty Dams
Along with catastrophic earthquakes, tsunamis, and hurricanes that have caused substantial devastation in recent years, flooding along the East Coast and in the Midwest constitutes additional evidence of what seems to be an epidemic of severe weather wreaking havoc around the world. Many believe such phenomena is Mother Nature’s reaction to years of abuse at the hands of humankind, which may or may not be true, but we do know that incidents of flooding are often the direct result of people manipulating the earth’s surface and its waterways.
Building in Floodplain Areas
Local governments can prohibit building in floodplains, but few municipalities have taken this important step. Rather, the opposite is true: urbanization and development often place buildings in harm’s way. Municipalities have an interest in floodplain development because they derive income based on the number of homes they are able to tax in their jurisdiction, whether it be low income housing crammed into low lying areas or high-priced homes along waterfront property.
By continuing to build on floodplains, draining wetlands, and controlling the flow of water, people have increased the likelihood of flooding and the extent of damage done by floodwaters, ranging from loss of property to loss of life. Areas that were once effective sponges for storing precipitation have been replaced by buildings and pavement that make the land increasingly impervious. As a result, floods have become far larger than in the past, and more frequent.
Flooding May Trigger Dam Failures and Collapses
If an intense storm produces a flood in an area with an improperly functioning dam or levee, the chance of severe damage, injury, or death is substantial, as dam failure often occurs with little warning. According to the Federal Emergency Management Agency (FEMA), there are more than 80,000 dams in the United States, approximately one third of which pose a “high” or “significant” hazard to life and property if failure occurs. Many factors can contribute to a dam or levee failure, such as:
- Sub-standard construction materials and/or techniques
- Spillway design error
- Geological instability caused by changes to water levels during filling
- Poor surveying
- Poor maintenance, especially of outlet pipes
- Extreme inflow
- Human, computer, or design error
- Internal erosion, especially in earthen dams
Engineering Design & Construction Expert Witness
The risk of property damage and life threatening situations from flooding is very real. If you live near a dam or in a floodplain area, talk to your city’s floodplain or drainage representative about your individual risk, and if you are involved in such a case and need an expert to advise you or appear as a witness, contact Engineering Expert Witness for a free initial consultation. Pierre Handl, P.E. evaluates disasters in California and nationwide to identify their cause and determine whether design or construction played a role in the catastrophe.