Visualizing Flood-Related Impacts of Under-investment in Tribal Roadway Networks in Northeastern Arizona

Detour Ahead is an infographic illustration of roadway flood risks across the Navajo Nation and Hopi in northeastern Arizona, highlighting the impacts of underinvestment in critical infrastructure. This includes working with 90m SRTM Digital Elevation Model (DEM) data to produce water modeling datasets, including slope, aspect, overall elevation, and more. Additional datasets used include precipitation and watershed data from University of Arizona, additional multispectral imagery from Landsat 9 (used for vegetation/land cover data), and an open source roadway network from OpenStreetMap. From the poster:

“The tribal lands of the Navajo and Hopi people in northeastern Arizona have experience numerous long-term challenges relating to underinvestment and underservice, especially in regard to infrastructure development. Specifically, inadequate transportation infrastructure funding at the federal level has create a reliance upon dirt roads and low water crossings for travel throughout tribal northeastern Arizona, making these lands highly susceptible to flooding. Further, considerable precipitation in the region amplifies the effects of the lack of resilient roadways, resulting in roads washing out and becoming impassable, as well as residents and travelers becoming stranded away from home, work, or other essential destinations. These conditions have been acknowledged by the region’s “disadvantaged” status through the Justice40 Initiative, a White House program which highlights communities overburdened and marginalized by underinvestment, but this status must be supported with ample data and ongoing advocacy for action to be taken.

One of the primary obstacles hindering surface transportation infrastructure development is the lack of granular data to guide and justify meaningful investment decisions. The map (right) shows a characterization of northeastern Arizona’s roadway network by flood risk severity, aggregating a variety of data (as described below) to increase the resolution of flood risk data for tribal Arizona and help justify funding for priority roadway improvement projects.

Addressing the persistent challenges faced by residents of the Navajo and Hopi tribal lands necessitates increased investment in infrastructure, including improved roadway networks and stronger flood management efforts. Granular flood risk data plays a vital role in justifying federal investment in roadway projects for tribal communities, specifically to enhance the resilience of critical routes such as those used by school buses, those used for evacuation, and those carrying emergency response vehicles. By maintaining comprehensive flood hazard data, one can demonstrate the heightened risk faced by their communities and emphasize the need for roadway infrastructure funding. This data allows tribes to present a compelling case for federal funding, highlighting the potential consequences of inadequate roadways during rainy seasons, including compromised access to education, delayed emergency response, and limited capacity for evacuation.

By harnessing data-driven insights to justify network improvement projects, these tribal nations can begin to mitigate the effects of long-term underinvestment, disadvantage, and overburden to strategically advocate for roadway priorities and safeguard their lands for future generations.”

Wordy, right?

This map was honored with the “Communicating Science Spatially” award at the ESRI User Conference 2023. The map can be viewed and downloaded here.

© 2025 Michael Huff | HuffMaps.com | Cartography, design, and spatial storytelling