The International Green Construction Code (IGCC) is a model code for cities seeking to promote sustainable building practices through their building codes.  The IGCC promotes transition from the current voluntary green construction certifications, like USGBC’s LEED, to mandatory green construction codes.  As the most recent revisions of the IGCC are currently under review, Green Building Law Update hopes to promote awareness by examining some of the code sections.

IGCC Section 402.2.1: “Building and building site improvements shall not be located within a floodplain.”

What is the potential green impact on the community?

Working to remove and discourage new structures within the floodplains of rivers, streams, and lakes is not a new concept. FEMA has required flood insurance for high-risk properties in floodplains since 1968.  However, IGCC Section 402 does not simply discourage building in a floodplain but rather prohibits it completely.  This prohibition takes into account both the high risk of flooding to structures built in the floodplain as well as an increased flood risk to structures outside the floodplain due to the removal of soil surface area that naturally soaks up floodwater.

Floodplain maps (even those used by FEMA and the insurance companies) often fail to fully account for the floodplain extension caused by development, as most maps have not been updated in many years.  In fact, FEMA is currently working to update flood maps as Congress looks into renewing the National Flood Insurance Program (NFIP).

During the 500-year flood that hit Nashville, Tennessee last spring, the consequences of developing in floodplains became apparent to Tennesseans.  Many Nashville area properties were not considered to be in a floodplain and, consequently, property owners did not have flood insurance.  These uninsured landowners learned the hard way that years of development within the floodplains had helped extend the floodwaters to their front doors.   

As a result, Nashville has acknowledged the importance of protecting the integrity of the city’s floodplains.  Nashville has offered to purchase 305 properties in the floodplain through a Hazard Mitigation Home Buyout Program.  The voluntary buyout program seeks to prevent the costs of property loss and the costs to provide emergency services to these high-risk areas in the event of flooding.  Also, by removing structures in the floodplain, the city will create more open space to soak up floodwater and increase green park space.  

The IGCC seeks to mitigate damage in areas similar to the flooded parts of Tennessee through its prohibition on development in established floodplains.  Unfortunately, as the Army Corps of Engineers continues to struggle with the ever-rising Mississippi River, there may be more landowners over the coming weeks who learn the hard lessons that Nashville residents learned just a year ago.  The IGCC floodplain regulation is a prime example of how green building choices often do not only affect the owners and occupants of a particular building but also help to minimize the building’s impact on the land and people around it.

Photo Credit: southerntabitha