By: TrueNorth Steel
Summary
The MDT Wolf Creek project earned The NCSPA’s 2026 Connections Project of the Year award for delivering an innovative interstate drainage access solution along Interstate 15 near Wolf Creek, Montana. As project conditions evolved during construction, the drainage system required a major extension while still meeting updated Montana Department of Transportation standards and maintaining reliable runoff flow.
To solve the challenge, TrueNorth Steel designed and fabricated a custom corrugated steel structure featuring a 72-inch diameter, 40-foot-tall access riser, a custom-welded interior ladder, reinforced structural components, and a precision-engineered 36-inch tee connection. Additionally, the project used controlled staged backfilling with on-site material to maintain stability throughout installation. Through close coordination between MDT, Riverside Contracting, and TrueNorth Steel, the project successfully improved long-term maintenance access while preserving critical interstate drainage performance.
A Custom Solution for Changing Site Conditions
The MDT Wolf Creek project earned recognition as The NCSPA’s 2026 Connections Project of the Year because it transformed a complicated drainage challenge into a durable, maintainable infrastructure solution.
As construction progressed along Interstate 15 near Wolf Creek, Montana, project conditions evolved quickly. Excavated material needed placement over an area where an existing 36-inch galvanized corrugated steel pipe daylighted near the southbound interstate corridor. Consequently, drainage had to be rerouted without disrupting performance or compromising long-term maintenance access.
However, this was not a simple pipe extension. The Montana Department of Transportation required the system to meet updated standards while also providing permanent and safe maintenance access within a constrained interstate corridor. Therefore, the solution needed to balance hydraulic performance, safety, and constructability all at once.
Interstate Drainage Access Designed for Long-Term Performance
To address the challenge, TrueNorth Steel engineered and fabricated a custom drainage structure in Billings, Montana. At the center of the design stood a massive 72-inch diameter, 10-gauge corrugated steel access riser reaching 40 feet tall.
The interstate drainage access system incorporated several purpose-built safety features. A custom-welded interior ladder allowed secure maintenance entry, while a reinforced steel plate base provided structural stability throughout installation and long-term operation. Additionally, the structure included a lockable lid to prevent unauthorized access.
Although the riser itself was impressive in scale, the true innovation came from how every component worked together. The final design successfully integrated updated MDT requirements, hydraulic efficiency, maintenance accessibility, and field constructability into a single cohesive system.
Precision Connections Preserve Hydraulic Flow
The project’s hydraulic design required careful engineering because maintaining uninterrupted drainage flow along Interstate 15 remained critical throughout the project. Therefore, the connection geometry had to function precisely within the existing runoff network.
To accomplish this, the system utilized a 36-inch tee connection offset at 110 degrees. That deliberate alignment preserved proper flow while directing discharge into the established runoff area without reducing system capacity.
As a result, the interstate drainage access solution functioned seamlessly within the existing drainage infrastructure. Furthermore, the custom connection demonstrated the adaptability corrugated steel solutions can provide when site conditions shift during active transportation projects.
Constructability Matters in Real-World Infrastructure
Field installation also played a major role in the project’s success. Because the riser extended approximately 40 feet vertically, maintaining structural stability during installation required a carefully controlled process.
Crews backfilled the structure in stages using on-site material as elevation increased. This approach minimized installation risks while preserving stability throughout construction.
That detail matters because constructability often determines whether complex infrastructure solutions succeed in the field. In this case, the project team combined engineering precision with practical installation methods to deliver reliable long-term performance.
Collaboration Delivered an Award-Winning Result
The success of the MDT Wolf Creek project reflected close coordination between the Montana Department of Transportation, Riverside Contracting, and TrueNorth Steel. Together, the team delivered a solution that addressed changing site conditions while improving safety and maintaining reliable drainage along a critical interstate corridor.
Ultimately, the project demonstrated why corrugated steel infrastructure continues to provide flexible and effective solutions for transportation drainage systems. When evolving field conditions demand innovation, custom-engineered steel systems can adapt quickly while still meeting strict performance and maintenance requirements.
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