Posted on November 4, 2026
U.S. Army Corps of Engineers Sacramento District recently supported flood response and post-wildfire flood-risk assessments in three southwestern states, providing technical expertise to help communities provide essential infrastructure and prepare for possible flood fights.
In Ignacio, Colorado, flood exposed a sewer line and threatened nearby infrastructure. The district’s flood fight team assessed the exposed utility and recommended installing temporary flood barriers. Local officials placed 330 linear feet of collapsible wire-mesh, heavy-duty fabric lined barriers and filled with soil or sand to create temporary floodwalls.
The effort was one of several emergency response missions underway in late October as Sacramento District deployed teams to Colorado, Nevada and the Navajo Nation in Arizona to address flooding, threatened infrastructure and potential debris flows following wildfires.
Although Sacramento District is best known for its flood risk reduction projects in California’s Central Valley, its emergency management mission extends across its assigned civil works boundaries.
“Our mission doesn’t stop at building flood risk reduction projects. When communities are facing an immediate threat, we have the expertise and authority to help them respond,” said Col. Robert McTighe, Sacramento District commander. “These deployments demonstrate the value of having experienced engineers who can quickly assess a situation, work alongside local officials and help protect the infrastructure people depend on.”
Under Public Law 84-99, USACE may provide certain types of assistance before and during qualifying flood emergencies. State governments and federally recognized tribes may request eligible assistance directly from USACE without requiring a separate federal disaster declaration.
Depending on the circumstances, assistance may include technical assessments, flood-fighting materials and temporary emergency construction. These efforts supplement state, tribal and local resources.
“Every community has different resources and levels of experience when it comes to fighting floods,” said Jonathan Yau, chief of Sacramento District’s Readiness Branch. “Our role is to bring the technical expertise they may not have available and help them determine how to protect their communities and critical infrastructure.”
In Colorado, heavy rainfall caused significant flooding along the San Juan River and surrounding waterways, eroding streambanks, changing river channels and threatening homes and utilities.
In addition to recommending protective measures in Ignacio, USACE coordinated the delivery of more than 6,000 linear feet of wire-mesh containers that can be filled with sand, soil or rock to create temporary barriers against floodwaters to Colorado ahead of another round of anticipated flooding.
Farther south, in the Rock Point Chapter of the Navajo Nation in northeastern Arizona, district engineers worked with tribal officials to assess threats to essential infrastructure.
The team identified three priorities: a food bank, a water treatment lagoon and a school serving as an evacuation shelter. Flooding at these facilities could disrupt food distribution, wastewater management and emergency shelter operations.
With local resources limited, the team recommended temporary protective structures. Sacramento District also began preparing for potential emergency construction assistance, pending an official request and additional coordination with Navajo Nation officials.
“Sometimes our assistance starts with the basics, like showing people how to properly fill sandbags or build temporary barriers,” Yau said. “Other times, we’re helping communities understand where floodwater is coming from, how it’s moving and what they can do to reduce damaging flood effects.”
Flood fight teams typically include hydraulic and hydrologic engineers, who evaluate water movement, and geotechnical engineers, who assess soil conditions and protective structures. Together, they identify vulnerable areas and recommend temporary measures to reduce flood risks.
While teams in Colorado and Arizona responded to flooding, two Sacramento District engineers traveled to northern Nevada to assess potential flooding and debris flows following the McConnell Fire.
Geotechnical engineer Noah Lyman and hydraulics engineer Suzanne Monk met with Humboldt County emergency management officials and representatives from the U.S. Forest Service and U.S. Department of Agriculture to evaluate areas near Orovada and the Santa Rosa Mountains.
Wildfires can increase flood risks by removing vegetation and altering soil conditions, allowing rainfall to produce greater runoff and carry sediment and debris downstream.
The engineers assessed watersheds and critical infrastructure, including roads, communications equipment and water supply facilities.
At Rebel Creek, they examined an area where a 1973 debris flow reached U.S. Highway 95. They also evaluated nearby homes, agricultural infrastructure and terrain within the burned watershed.
Their findings will inform recommendations to help local officials prepare for future flooding.
Unlike the active flood responses in Colorado and Arizona, the Nevada deployment operated under USACE’s Advance Measures program, which provides certain types of assistance before anticipated flooding.
According to Yau, responding to three geographically separate emergencies simultaneously is unusual but not unprecedented. In 2023, the district supported simultaneous flood fight deployments in California, Nevada, Idaho and tribal communities across the West.
The district activates flood fight teams as needed, drawing on employees who bring technical and operational expertise from their regular assignments. Deployments may last from a day to several weeks, depending on the emergency.
“We need people who are willing to meet communities where they are,” Yau said. “That might mean explaining a complicated engineering problem to local officials or teaching someone how to properly build a sandbag barrier. The goal is to help people who may be experiencing some of the worst days of their lives.”
While engineers provide much of the technical expertise, missions also require employees who can coordinate logistics, support emergency operations and communicate effectively with local officials and residents.
State emergency management agencies and federally recognized tribal governments can request eligible flood assistance directly from USACE, while local governments generally coordinate through their state emergency management agencies.
