Missouri River flooding: myths and facts


Missouri River flooding: myths and facts

Last Wednesday’s Congressional hearing on the Missouri River Flood of 2011 was a reminder that, in addition to needing to end the blame game, we still have a lot of work to do to move beyond the myths surrounding flood management.

The top four myths we heard at the hearing are:

  1. We can build our way out of floods
  2. 500-year floods will come once every 500 years
  3. Climate change isn’t happening
  4. Habitat restoration is a waste of funds

Myth: We can build our way out of floods.

Congress must refocus the Corps of Engineers priorities and direct their efforts toward flood control and fixing levees.  It can all start today with a renewed commitment from Congress to put the Corps back to building and engineering, instead of spending time on studies, meetings, conference calls and senseless science experiments.” said Tom Waters, chairman of the Missouri Levee and Drainage District Association.

Fact: Comprehensive, flexible flood management is needed to protect communities from more frequent and extreme floods.

Statements by Waters and others at the congressional hearing is a reminder that the old approach of trying to out-build Mother Nature with bigger and bigger levees is still the go-to flood control approach for many people and politicians.

While we certainly agree that levees that protect communities need to be repaired as soon as possible, we were glad to hear Brigadier General John McMahon assert the need for a “comprehensive” approach to managing flood risk within the basin. While many Members questioned the Corps’ management of the reservoirs and whether they leave enough space for catching floodwaters, he explained that much of the flood water came from tributaries and runoff that isn’t caught by the reservoirs.

As we plan for how to manage those flood waters in the future, it’s important to learn from the past. The Missouri River levee system definitely saved many lives and prevented even future property damage in 2011, but as we invest $500 Million to $1 billion in repairing those systems, we need to keep in mind that it’s only a matter of time before we’re right back in the same place having the same debate when the next big flood occurs. Rather than look at levees as the only option for stopping future floods, we need to figure out ways to work with the river to accommodate flood waters.

Myth: 500-year floods will come once every 500 years.

We have 150 years of record and they are declaring a 500 year event.  If you had 10,000 years of record and if it happened a couple times a millennia, you might be able to say it was a 500-year event. No moral can tell you it was a 500 year event.” said Rep. Steve King (R-Iowa). 

Fact: There is a small chance that a 500-year flood will happen in any given year.
Rep. King exemplified the misunderstanding that the majority of people have about the “500-year flood”. The simple answer is that just because it happened one year, doesn’t eliminate the chance of it happening the next year. Terms like “500-year flood” are based on probability of an event happening. A more accurate term is the “0.2% annual chance flood” because there is a 0.2 percent chance of a flood that size happening in any given year. There is still a 0.2% chance that a flood of the 500-year size could happen in 2012.

Myth: Climate change isn’t happening.
Lord knows why I’ve had to live through so many 500-year weather events in my short time on this Earth.” said Rep. Steve King (R-Iowa).  

Fact: Climate change is happening and communities are already feeling the impacts. It will result in more frequent and extreme floods.

The above quote by Rep. King also reminds us that many folks have yet to acknowledge and act on the fact that we are experiencing more frequent and severe storm events due to a changing climate. American Rivers’ recent blog Making Communities SAFE by Fay Augustyn highlights the Intergovernmental Panel on Climate Change’s (IPCC) new report that finds that indeed, the number of extreme events including increasing temperature, drought, rainfall and flooding, is in fact a long term trend.  While hearings on the Missouri River flooding are critical, we also must ensure that long term trends due to a changing climate are part of the conversation.  Augustyn’s blog also spoke to the leadership of Senators Whitehouse (RI) and Baucus (MT) who took a first step in helping Federal Agencies and States to prepare by introducing Securing America’s Future and Environment (SAFE) Act. The SAFE Act outlines how important healthy natural resources are to communities, and emphasizes the urgent need to help States adapt to a changing climate.  Here’s to hoping that this type of leadership finds its way into the discussions on the Missouri River flooding.

Myth: Habitat restoration is a waste of funds.

“I certainly hope that there will not be one single dollar spent this year on habitat reclamation,” said Rep. Sam Graves (R-Mo.), “If a single dollar is spent on habitat reclamation or restoration, that would be a colossal mismanagement of funds.”

Fact: Restoration projects that benefit wildlife habitat can also improve flood protection.

The Corps has been engineering the Missouri River and regulating its flow for navigation and flood control since the 1800’s. The construction of levees, dams, and navigation structures and dredging actions have been incredibly damaging to the natural ecosystems on the Missouri River and there are now several endangered species. The Corps works with the Fish and Wildlife Service, tribes, states, and others to try to repair some of the damage that’s been done.

Some of the damage that’s being repaired is the ability of the river’s floodplain to hold flood waters. Many of the restoration projects that the Corps and Fish and Wildlife Service are undertaking in the basin will restore cottonwood forests and wetlands on the floodplains which will help reduce flood risk. Moving some of the most floodprone people out of the floodplain removes the risk of flooding.