Changes to Colorado’s Flood Plain Maps Stall Developments

By Ryan Sugden

With fall in full swing and summer’s monsoon season at an end, Colorado’s risk of seasonal flooding has waned. But the risk of flood plain regulations has only increased. Delays in changing area flood plain maps have affected or frozen developments, and the costs for landowners and developers will be sure to rise once the long-awaited maps are approved.

Federal, state and local governments share responsibility for managing areas at risk of flooding. The Federal Emergency Management Agency is responsible for approving and adopting maps showing the "100-year flood plain"—so-called because the land is at a 1% risk of flooding, meaning it will, on average, flood once every 100 years. Local governments can choose to adopt and enforce preapproved regulations for land within the flood plain. If the municipality does so (most do), the property owners are eligible for federally subsidized flood insurance.

Historic Front Range flooding in September 2013 showed that FEMA's flood plain maps were severely outdated. Some were based on decades-old studies that climate change and development had rendered obsolete. State and local authorities began a process of redrawing the flood plain maps and planning flood mitigation projects. The years-long project, known as the Colorado Hazard Mapping Project, or CHAMP, redrew the regulatory landscape in Colorado. Under the CHAMP maps, a lot of land previously free of flood plain regulation would be subject to it, greatly impacting affected properties. Some land would be removed from the flood plain altogether, freeing it up for development.

Building in the flood plain can be difficult. Structures typically must be elevated so their lowest floor is one foot above expected floodwaters, which can require fill. Structures cannot greatly block or divert floodwaters, which limits density. Some property within river channels, and adjacent land, known as the “floodway,” cannot be developed in any meaningful way. And, as anyone who has found him or herself developing land in the flood plain can tell you, permitting a project can be harder, slower and more expensive.

Of course, accurate flood plain maps are important regulatory tools. Climate change has made weather events stronger, causing flooding to be more unpredictable. Damage can easily reach into the billions. New and existing developments must be hardened to protect the safety of residents. Accurate maps ensure that buildings are not modified or built where they will be regularly inundated.

In 2019, FEMA approved preliminary maps based on the CHAMP project data. FEMA then began a public comment and review period that precedes FEMA approving the preliminary maps and officially replacing the outdated maps. But approval has not come. More than two years later, FEMA still is reviewing the CHAMP-based maps, creating a flood plain legal limbo.

The uncertainty arises from how municipalities have treated the CHAMP-based maps. Many municipalities have adopted the maps while FEMA completes its formal review, through the municipality’s discretion to rely on “best available information” to regulate flood plains. This creates discrepancies between FEMA's old maps and the new CHAMP-based maps. Regulators must apply whichever map is the most “restrictive” in each context. In essence, regulators must cherry-pick the worst data points from each map, potentially relying on the flood plain’s location from one map but the height of expected floodwaters from another to create a patchwork regulatory scheme that does not remotely reflect actual field conditions.

There are other problems. During FEMA’s lengthy review of the CHAMP-based maps, flood mitigation projects have continued. They have succeeded in reducing the risk of flooding, which serves to remove land from the flood plain. However, the CHAMP-based maps have not changed, meaning they already are outdated, and landowners and municipalities alike have asked FEMA not to adopt parts of them because they are so inaccurate. State and local officials have prepared amendments to the maps, but the amendments will not become official until FEMA approves the CHAMP-based maps. Landowners are stuck in the middle. Based on actual field conditions, the landowner may no longer be in the flood plain. Yet, the land remains subject to flood plain regulations because the CHAMP-based maps say that they are in the flood plain, even though everyone agrees the maps are inaccurate. Ironically, the CHAMP-based maps are causing the same problem as the maps they are trying to replace.

There may be ways out of this flood plain purgatory. Landowners can petition FEMA for preapproval of their project. Boulder County entered into an agreement with FEMA allowing landowners to use the more accurate CHAMP-based maps for evaluating the proposed project’s impact on the flood plain. Unfortunately, this pre-approval process is time consuming and costly, and even if FEMA preapproves a project, landowners might not be able to start construction immediately. And so, all eyes remain on FEMA. Its final approval of the CHAMP-based maps is anticipated sometime in 2022.

Landowners looking for flood plain mapping and regulatory information can visit the CHAMP website, contact their local flood plain administrator, or consult with a flood plain engineer or attorney.

This article was published in the October 20, 2021 issue of the Colorado Real Estate Journal.


Subscribe to Stinson's
News & Insights
Jump to Page

We use cookies on our website to improve functionality and performance, analyze website traffic and enable social media features. For more information, please see our Cookie Policy.