The debate about whether or not to build on floodplains will always follow flooding disasters. LEED and other sustainable design certification systems encourage teams to locate development above certain floodplains. However, referencing this information is not something architects and engineers do everyday. Do you know how to determine if your project is in a flood hazard area? In the digital age, it is very easy to do.
A floodplain can be defined as a flood hazard area shown on a legally adopted flood hazard map or otherwise legally designated by the local jurisdiction or the state. For projects in locations without legally adopted flood hazard maps or legal designations, it is good practice to locate development on a site that is entirely outside any floodplain subject to a 1% or greater chance of flooding in any given year. Best practice is for a development to avoid the flood hazard area shown on a legally adopted flood hazard map instead of specifically referencing the 100-year floodplain.
In order to ascertain the proximity of flood hazard areas, design teams should consult legally adopted flood hazard maps of the project site area.
In the U.S., most local governments, flood management agencies, or other local entities maintain flood hazard maps, which may include flood hazard areas designated by both the Federal Emergency Management Agency (FEMA) and a local agency.