The 2013 Flood significantly changed the watersheds in all of Colorado’s flood-impacted areas, including the watersheds in Boulder County. Due to these flood- related changes, floodplain maps that existed prior to September 2013 are no longer accurate. Without accurate floodplain maps, there is the potential for faulty planning and design with regard to emergency response, infrastructure rebuilding, and private development of homes, septic systems, and stream crossings.
The State legislature has allocated funds to the Colorado Water Conservation Board (CWCB) to conduct natural hazard mapping, including updating current maps and creating new floodplain maps where needed.
The revised and new maps will identify the characteristics, elevation and extents of a 100-year floodplain in the post-flood environment. The 100-year regulatory floodplain is based on the potential elevation and geographic limits of a flood that has a 1% chance of happening in any given year, depending on the topography at the time of the analysis. The 100-year floodplain is reflected on maps which are used for general information and as regulatory tools.
Additional information can be found at http://www.bouldercounty.org/.