Hurricane Helene overwhelmed culverts, triggering erosion, moving debris, and ultimately causing many to fail. Few places in Georgia were hit harder than the Tallulah River watershed in the Chattahoochee section of the Chattahoochee-Oconee National Forest.

Hurricanes and other severe storms continue to put a strain on infrastructure, threatening community access and increasing emergency costs. The Atlantic hurricane season of 2025 resulted in four major hurricanes and more than 13 named storms. Addressing these vulnerabilities now helps protect lives and reduce taxpayer expenses.

Thankfully, there is a new tool to help land managers identify culverts that may be too small or vulnerable to erosion—and prioritize their replacement.  

It’s called CULVERT—a tool designed to improve infrastructure resilience and reduce long-term maintenance costs (Climate and Upland Loading Vulnerability Evaluation and Risk Analysis Tool).

“We analyzed 25 culverts on Tallulah River Road and found that 33% of them were hydrologically vulnerable to 100-year and beyond events like we experienced with Hurricane Helene,” said Taylor Hughes, forest soil scientist on the Chattahoochee-Oconee National Forest.

Tallulah River Road is the only access point for Tate City, Georgia. If it’s not passable, people become stranded and emergency responses are delayed.

That’s why land managers with the Forest Service took time to learn more about CULVERT from its developer, Dr. Mukherjee, a research fellow with the University of Idaho and collaborator Dr. Devendra Amatya from the Southern Research Station.  

Why culverts matter

Right-sized culverts improve stream connectivity and reduce erosion, which protects roads, reduces repair costs, and ensures safe access for communities. They are a critical part of Hurricane Helene recovery and broader efforts to make infrastructure more resilient to future storms.  

“Properly sized and installed culverts will be more resilient to large storms and, therefore, improve public safety. Additionally, resilient structures should reduce maintenance costs over time,” Hughes explained.  

Learning about the tool

Dr. Mukherjee walked professionals from engineering, hydrology, geographic information systems, topography, stream network, soils, and land management through each component of the tool, describing its foundation in long-standing hydrologic science.  

“We use empirical methods that engineers and hydrologists have relied on for years. By embedding precipitation intensities of interest for a specific region, we can estimate peak discharges and understand how a storm might overload a culvert,” Dr. Mukherjee explained.  

The tool also evaluates sediment deposition, streambank erosion, and debris flow potential. Dr. Mukherjee highlighted how the system blends multiple models to provide a full vulnerability picture.  

“We stack multiple layers of watershed data to determine an integrated risk score from multiple models for each culvert, which helps us figure out which structures are more vulnerable,” he explained.

Identifying these hotspots can greatly assist the Forest Service in prioritizing repairs on routes that matter most for the people who visit the forest or drive its roads.

According to Dr. Mukherjee, “The goal is to help land managers identify and prioritize the most vulnerable culverts.”

The CULVERT project, funded by the U.S. Department of Transportation and the U.S. Forest Service, aims to maximize taxpayer value by reducing emergency repair costs and improving long-term infrastructure resilience. Built using available data and scientific modeling approaches, the project is led by Dr. Devendra Amatya at the Southern Research Station in collaboration with the universities of North Georgia and Idaho. It is now entering its second phase to include modeling assessment of culverts potentially vulnerable to post-wildfire flood, sediment, and debris discharge.  

Editor’s Note: Additional information on the CULVERT application is available at https://culvert-at-risk.org and through the Southern Research Station’s project page.