One of the most pressing issues in the battle for climate justice is the lack of accurate and accessible flood maps for underserved communities.

But one University of Arizona professor is leading the charge to tackle this challenge.

Beth Tellman, co-founder and chief science officer of Floodbase, has been working for years to spotlight the critical issue of outdated flood data—especially in vulnerable areas, where reliable flood maps are either outdated or completely missing.

The Federal Emergency Management Agency is tasked with creating flood hazard maps that determine flood zones, guide disaster response, and set flood insurance requirements.

But in many regions, these maps are either inaccurate or just don’t exist, leaving communities dangerously unprepared for flooding risks.

"Very few tribal nations in the U.S. have any flood maps from FEMA whatsoever," Tellman said.

FEMA’s flood mapping program requires local governments to prepay a portion of the costs for remapping flood zones. But many counties, especially those that are economically disadvantaged, cannot afford to update or digitize their maps.

These communities, many of which also lack access to basic infrastructure, are disproportionately impacted by climate change, Tellman said.

And the absence of flood maps means that these areas have limited access to vital information for planning, evacuations, and rebuilding efforts after disasters. 

The lack of flood mapping on tribal lands is particularly concerning, she said.

Many tribal nations have developed their own flood response plans, but without federal recognition of their flood risks, these efforts remain largely uncoordinated and underfunded.

The City of Tucson has also struggled with flood management dating back to the 1970s, despite its role as the regulatory agency for its own Floodplain ordinance, according to a recent memo.

Tucson also has to contend with aging infrastructure, including 383 miles of storm drains and more than 1,600 basins that require constant upkeep. Some areas also still lack all-weather access, leaving neighborhoods vulnerable during heavy rains.

The city’s 2020 update to the Floodplain Management Plan aimed to reduce risks and improve drainage systems, but progress has been slow. A formal 5-year update is set to be adopted by December 2025, with officials saying there’s hope for meaningful change.

While Floodbase has made significant strides in flood detection globally, capturing monsoon floods in Tucson remains a challenge, Tellman said.

Despite working with Pima County Flood Control to test commercial satellites, she said, most monsoon events were missed because flood waters move too quickly for satellites to capture.

Tellman’s research aims to address these gaps by using satellite data to create more accurate flood maps for areas that lack official FEMA coverage, which will provide better insight into flood risks and help local governments and communities.

Her work also aims to increase the resilience of underserved communities by equipping them with the tools to prepare for extreme weather events and take proactive measures to protect their homes and livelihoods.

Tellman said further testing in Tucson and comparisons with past flood events will be essential to determine whether the technology can be effectively applied in the region.

“We need to rethink building in floodplains and consider how it impacts downstream communities,” she said. “Tucson’s work on rainwater capture and green infrastructure is promising, but we need more of it.”

Evaluating other data out there could also go a long way, Tellman said, pointing to the Department of Transportation tracking of road closures during floods,which could help predict risks and warn residents in vulnerable neighborhoods.

Tellman’s research is not confined to just the Tucson region. She also works alongside her PhD student, Lucas Belury, in southeastern Texas, along the U.S.-Mexico border.

Belury is focusing on the Rio Grande Valley, a four-county region that experiences frequent flooding but lacks up-to-date flood maps. 

"Across the U.S., we see a long history of development, particularly the construction of dams, and the impact it has on certain communities,” Belury on his podcast Journal of Southwest Radio. “It raises questions about whose homes, lives, and well-being are deemed less valuable."

The Rio Grande Valley, home to a large immigrant population, faces unique challenges in accessing aid and support after natural disasters, often due to language and cultural barriers.

Their research aims to bridge this gap by creating digital flood maps tailored to the region, while also offering bilingual flood justice education and advocacy. The focus is on providing accurate, community-specific flood risk data to ensure that vulnerable populations are equipped with the resources they need to protect themselves.

Tellman said that addressing these gaps in flood mapping is an essential part of climate adaptation, as these communities are already disproportionately affected by the economic and social impacts of climate change.

“People in these communities are often the least responsible for climate change but are the first to experience its consequences,” she said. “By providing them with accurate flood hazard information, we can help level the playing field and ensure that everyone has the opportunity to protect their homes and families.”

Her work also connects to broader efforts in climate justice, which recognize that the impacts of climate change are not felt equally across all populations.

While wealthier areas have the resources to invest in flood defenses, warning systems, and insurance, marginalized communities — particularly low-income, Indigenous, and border communities — are often left to face the consequences of climate change with little support.

Tellman is working alongside Aaron Flores, principal investigator on grant from Arizona State University, to launch the Flood Justice Coordination Network next month.

The network’s goal is to connect scientists with community-based organizations to address climate and environmental justice issues. By offering data and analysis, the network aims to support these communities in advocating for more resources and building stronger coalitions for action. 

Tellman encourages any organization, especially those working on flood and climate justice issues, to reach out. The network is designed to bridge the gap between scientific research and the needs of communities, helping them tackle challenges like outdated flood mapping and the growing risks of climate change.

In the long-term, Tellman hopes her work will not only improve flood resilience, but also shift the way policymakers think about climate adaptation.

“We need to move beyond the idea that climate change is just an environmental issue,” she said. “It’s a justice issue. If we are serious about addressing climate change, we need to ensure that the most vulnerable communities are given the tools and resources to survive and thrive.”

Angelina Maynes is a journalism major at the University of Arizona and reporter with Tucson Spotlight. Contact her at angelinamaynes@arizona.edu.

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