Flood Risk – It’s About More Than Being Under Water
It has been over five years since Tropical Storm Irene ravaged our region. Most of the damage from that storm was caused by rivers leaving their channels and carving new routes through fields and homes. The Association of State Flood Plain Managers (ASFPM) released a white paper stressing the dangers posed by erosion hazards. The paper was co-authored by Mike Kline and Rebecca Pfeiffer of the Vermont Department of Environmental Conservation.
Underestimating the role of erosion in causing flooding leads to poor policies for dealing with flood disasters. We have learned that lesson well in the Champlain watershed thanks to Irene, but it is often lost in national discussions. ASFPM promotes education, policies and activities that mitigate current and future losses, costs and human suffering caused by flooding. They promote policies and education opportunities to protect the natural and beneficial functions of floodplains.
Floods are the most common natural disaster in America. A flood occurs when water covers land not normally covered by water. We typically think of floods happening when water levels rise to cover land. However, in mountainous terrain, flooding more frequently occurs when rivers leave or widen their channels and carve new channels. Flooding in such systems results more from erosion than inundation.
Our country spends billions of dollars trying to control and mitigate floods, and yet losses from flood damage continue to increase. An important driver of flood damage is the continued development of floodplains. Once the floodplains are developed society tries to protect those investments by channeling rivers, building levees, or creating water control structures. While these steps sometimes reduce the risk of inundation, they can increase the risk of erosive flooding.
The white paper places great hope that an Executive Order (13690) can be used to drive improvements in floodplain management. The order directs that federal actions minimize harm, utilize climate-informed science, and restore and preserve natural and beneficial values of floodplains. President Obama signed the order in January of 2015.
The ASFPW wrote their white paper to encourage state and local governments to begin mapping riverine erosion hazard areas. The paper offered 11 recommendations that would further such flood mapping. They include steps to improve acceptance of the scientific principles of river dynamics and increase education and outreach about these principles. They also call for changes in federal, state and local policies to account for erosion hazards from flooding and reward efforts to reduce such risks. Many of the recommendations are targeted to changes in how the Federal Emergency Management Agency (FEMA) assesses flood risk and incentivizes preparations to avoid flood damages.
In our region, state and local officials struggled getting FEMA to understand and account for erosion hazards in the response to Irene. For too many years federal agencies have focused only on the inundation risk posed by flooding. It is a major accomplishment for the ASFPW to formally call attention to risks posed by erosion hazards. These are the types of hazards most likely to affect our area. Click here to download a PDF of the white paper.