Engineering Beneath the Surface: The Pipeline Crossing

Installing an Irrigation Pipeline Beneath the Interstate in Hazen

To move water across the Grand Prairie without disrupting major infrastructure, the White River Irrigation District uses a method that allows pipelines to pass beneath highways without digging them up. In Hazen, where the system must cross under the interstate, this approach is essential, as state regulations do not allow excavation that would interrupt traffic or damage the roadway.

Instead of trenching, crews use a horizontal boring process. A boring machine is set on one side of the interstate and drills underground to the opposite side, creating a controlled path beneath the road. Once the initial bore is complete, the opening is gradually enlarged using specialized reaming equipment until it reaches the required diameter.

A steel casing pipe—approximately 500 feet long and 36 inches in diameter—is then welded together and pulled through the enlarged bore. This casing acts as a protective sleeve beneath the interstate. Inside it, a smaller 24-inch irrigation pipeline is installed, which will ultimately carry water through the system.

This method allows the pipeline to pass safely under the interstate without disturbing the surface above. It protects both the roadway and the surrounding prairie landscape while ensuring uninterrupted water delivery for farms across the region.

Steel casing pipe sections, each welded together to form a continuous 500-foot line, are staged before being installed beneath the interstate.

A horizontal boring machine drills beneath the roadway, creating a path for the pipeline without disturbing the surface above.

The pipeline route crosses beneath Highway 70 near Hazen, allowing water to move through the landscape without impacting traffic or the surrounding prairie.