Urban-CAT—improving resiliency one community at a time

Mar 07, 2016

Two Oak Ridge National Laboratory (ORNL) institutes, the Climate Change Science Institute (CCSI) and the Urban Dynamics Institute (UDI), have joined forces to address one of the most pressing problems facing midsize cities today: how best to allocate scarce resources to deal with climate change. The solution they have devised is a unique web-based decision support tool, the Urban Climate Adaptation Tool, or Urban-CAT.

To ensure that Urban-CAT will be useful and accessible to urban decision makers, the project team, which includes Olufemi Omitaomu, Esther Parish, and Phil Nugent, is collaborating with the City of Knoxville. “As scientists we can perform all kinds of calculations, but in the end, if they are not comprehensible by decision makers or don’t result in something that people can use, then we have failed,” says Omitaomu.

Nearly 50% of the world’s population lives in midsize cities like Knoxville, with populations around 250,000. And the World Health Organization projects more than 60% of the world’s population will live in midsize cities by 2030. Big cities such as Chicago or New York have more resources to deal with climate change scenarios says Omitaomu. Midsize cities need tools to develop adaptation strategies they can integrate into their policies gradually, to be ready when change comes.

And change is coming; in some cases, it is already here. For example, the western United States is experiencing more frequent and severe droughts, forcing cities to ration water. Conversely, heavy downpours are causing flooding in many locales, forcing city planners to develop flood mitigation strategies. Hurricanes now appear to be traveling up the eastern coast more frequently so that northern cities are seeing their effects. In short, the exception has become the norm. Climatologists and Earth system modelers are saying that these types of extreme weather events are going to be more frequent and more powerful in the future—and more costly.

Screenshot of the Urban-CAT tool.  This map shows perviousness and tree canopy in the city of Knoxville. 

The challenge in helping cities plan for this type of change, according to Omitaomu, who works for both CCSI and UDI, is that most climate models don’t provide enough information at a usable scale for local planners to make decisions, to understand what adaptation measures they need to put in place to alleviate repercussions from some of the impending climate changes such as rising sea levels, increased rainfall, or drought.  

The Urban-CAT platform addresses this by coupling climate projections with socioeconomic and infrastructure data at scales useful for urban planning. The platform also provides connectivity to multiple data sources for comparison and assessment of local project scenarios under different climate conditions. Finally, the project team has developed a set of urban resilience indicators to be used in assessing resilience and in monitoring and evaluating the effectiveness of selected adaptation actions in reducing risk.

Changing storm water runoff amounts and patterns have been identified by various sources as among the likely impacts of a changing climate for many cities, including Knoxville. So for the prototype Urban-CAT tool the team is focusing on storm water runoff and using green infrastructures such as trees to alleviate urban flooding and costly storm water management. This simple yet elegant solution has multiple benefits beyond the immediate one of flood control, including health benefits, air quality benefits, and canopy benefits. In addition, water quality benefits are achieved through reducing the amount of impervious surface, which helps minimize runoff (carrying dirt and oil), ultimately decreasing the need to use chemicals for water treatment (a health and a cost benefit). Planting trees also minimizes the amount of cement used, reducing the carbon footprint from cement plants, which is quite large.

So where should trees be planted? Which are the vulnerable areas that should be focused on? And how should cities prioritize those areas?

These are the types of questions Urban-CAT is being designed to answer.

Funded through ORNL’s Laboratory Directed Research and Development program, the project is a direct response to the President’s Climate Data Initiative, a broad effort to leverage open government data resources with tools to help communities become more resilient to climate change.

At the end of FY 2016, the second year of the project, Omitaomu says they will have a tangible product for Knoxville to test and start using. The ultimate goal is a full-suite climate adaptation toolkit, which will be widely available through the US Climate Resilience Toolkit.

“Different cities will face different challenges,” Omitaomu says. “If we can develop a useful tool for the City of Knoxville, we can customize it for other cities.”

For more information on Urban-CAT, contact Olufemi Omitaomu, 865-241-4310.

By VJ Ewing