The city is planning to build a floodwall on the CU South property in South Boulder. The $66 million South Boulder Creek flood mitigation project is one of many the city is planning. Credit: John Herrick

The Boulder City Council unanimously approved a new citywide flood protection plan on Thursday, Sept. 15, that seeks to prioritize projects that benefit disadvantaged neighborhoods — rather than those with the highest property values.

The new Comprehensive Flood and Stormwater Master Plan, last updated in 2004, will help guide how the city builds more than 30 flood projects across the city in the coming decades. The projects total about $350 million, according to city officials. 

The long-term vision for flood planning comes as the city moves ahead with several large-scale projects designed to slow down and divert floodwaters amid a worsening climate crisis. 

The city manager’s 2023 budget request, released on Aug. 26, includes $10 million to replace culverts along the Gregory Canyon Creek, which flows under Flagstaff Road to Boulder Creek through the Chautauqua and University Hill neighborhoods. The $21.5 million project is already underway and planned for completion in 2027. Under the plan, which was finalized in 2015, the city will purchase homes built in the high-hazard floodplain and tear them down. 

The city is seeking to spend another $3 million to continue work on the South Boulder Creek flood mitigation project — located on the property known as CU South — which is still in the planning phase. Preliminary designs for the $66 million project include building a floodwall near US 36 to slow down flooding. The project is slated for completion in 2025, according to city officials. Uncertainty looms as residents are expected to vote on a November 2022 ballot measure that, if it were to pass, would at least temporarily block construction. 

The infrastructure investments come as the city prepares for more intense storms, fires and heat in the region as a result of climate change from fossil fuel emissions. In September 2013, a storm dumped more rain on Boulder in one week than the city gets during some calendar years, killing three people, destroying more than 260 homes and damaging hundreds of others. 

Boulder, which is nestled up against the foothills to the Rockies, is particularly vulnerable to surges of mountain runoff. Running through the city are 16 streams that pose some level of flood risk to about 2,600 structures, according to city officials. Like most cities across the United States, Boulder was built before federal regulations restricted development in certain high-risk flood plains. 

In the last decade, the city has developed flood mitigation plans for about 10 major drainages flowing through the city that include more than 30 projects. They involve replacing culverts, restoring stream banks and building floodwalls to retain water and release it more slowly. 

‘Boulder is saying it wants to do it differently.’

When and how these projects are built will likely be determined by a new set of criteria proposed in the new Comprehensive Flood and Stormwater Master Plan. The new ranking system favors projects that protect people rather than property. 

Historically, the city prioritized flood mitigation projects largely based on property values, according to city officials. Those guidelines favored “implementing projects in affluent areas with the highest property values as opposed to areas where the life safety risk and community needs are the highest,” the master plan states. 

The new ranking system weights social vulnerability using an index created by the Centers for Diseases Control and Prevention that reflects the number of racial and ethnic minorities, poverty, and lack of access to a vehicle, among other factors. 

“By including racial equity considerations, using metrics such as the social vulnerability index, the project prioritization framework prioritizes projects in areas where people need them the most,” Joanna Bloom, the deputy director of the Utilities Department, told the Boulder City Council on Thursday. 

Such a ranking system has been put in place in Houston, Texas. But few other cities have followed suit, according to Jacob Lindsey, a former Boulder city planner who left in December 2021 to work for a real estate developer in Charleston, South Carolina. Lindsey is helping to plan and design a major seaport threatened by rising sea levels. 

“Very few cities have been as sophisticated about their flood projects as Boulder is in this forthcoming plan, based on the way I read it,” Lindsey said in an interview. “Boulder is saying it wants to do it differently and it wants to do it equitably.” 

To move future flood projects toward construction sooner, the city proposes raising monthly utility service fees by about 12% annually, according to the master plan.

The city still faces challenges to building certain flood projects due to pushback from residents. 

One high-profile example is the South Boulder Creek project, which is located on a South Boulder property owned by the University of Colorado. As part of a 2021 annexation agreement, the university plans to give the city land to build the flood project in exchange for building housing and university facilities on the CU South property. 

Residents have opposed developing the land for decades, in part due to the potential impacts on wetlands and wildlife. Opponents of the city’s annexation agreement say if constructed, it should be built to mitigate a 500-year flood event given worsening climate change. The city is planning to build a 100-year flood mitigation project. This means it would help protect areas that have a 1% chance of flooding in any year. 

That is the highest level of flood protection for any project in the city, in part because of the costs and the impacts on the surrounding areas, according to the city. The Gregory Canyon Creek project is designed to handle a less severe, 10-year flood event, partly due to constraints from existing development along the creek. 

Joe Taddeucci, the director of the Utilities Department, said he acknowledges some residents want more protection than that, especially given that climate change is causing more extreme weather events to happen more frequently. 

“There is just a reality in terms of the amount of funds available and what’s practical and reasonable,” Taddeucci said. “On Gregory Creek, a 10-year level of protection still provides a lot of benefits.” 

John Herrick is senior reporter for Boulder Reporting Lab, covering housing, transportation, policing and local government. He previously covered the state Capitol for The Colorado Independent and environmental policy for He is interested in stories about people, power and fairness. Email:

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