"During September 2013, the state of Colorado was hit hard by catastrophic flooding that impacted many cities. Lives were lost, property was damaged, and many structures were completely destroyed. Longmont, located less than 40 miles from metropolitan Denver, was one of the hardest hit cities. Luckily, only months before, the city had completed a mitigation project known as the Left Hand Creek Flood Control Project. This mitigation effort helped reduce the amount of damage to property and protected the majority of area residents from danger. Left Hand Creek meanders through Longmont and has a history of flooding in the city's Southmoor Park neighborhood whenever rainfall exceeded levels of only a 20-year storm. The creek channel was not large enough to carry additional water and bridges were subject to being washed out. Stormwater would overflow the channel and flood approximately 200 neighborhood homes. This repetitive result created a need for upgrading the channel and bridges so they would stand up to water flows from 100-year storms. The goal of the Left Hand Creek Project was to reduce the mapped floodplain so most of the homes in Southmoor Park would not be affected. Upgrading bridges and channel capacity would keep storm water in the channel and away from the homes in the neighborhood. The project was multi-faceted. The South Pratt Parkway Bridge was replaced, bridge structures were added at Main Street, the Left Hand Creek channel was enlarged between Main Street and South Pratt Parkway, the channel on the north side of Pike Avenue was improved, and the bike path to cross under South Pratt Parkway was reconstructed."
Federal Emergency Management Agency: http://www.fema.gov/