Services Provided: Geotechnical Investigation, Waterline Design Support, Horizontal Directional Drilling (HDD) Evaluation

The BBN9 Water Supply Project was designed to deliver a critical waterline to support the Navajo Nation near Gallup, New Mexico. The new 30-mile-long waterline enhances water supply reliability for the region and incorporates horizontal directional drilling (HDD) to safely cross beneath key surface features. HDD depths ranged between 20 and 40 feet below ground surface (bgs), requiring careful geotechnical planning and design support.

Our team conducted a thorough geotechnical investigation at the site to assess subsurface conditions along the proposed alignment. Site reconnaissance was performed to evaluate drill rig access and stake test boring locations prior to mobilization. Areas inaccessible to a two-wheel-drive drill rig were identified and coordinated with stakeholders to determine adjustments.

The scope included:

• Up to 90 test borings along the waterline alignment to depths of 6 feet bgs.
• 30 test borings drilled to 10 feet bgs, or until auger refusal.
• 6 specialized borings drilled at HDD entry and exit points, extending between 30 and 50 feet bgs.

In total, the investigation accounted for 1,080 linear feet of drilling, providing detailed subsurface data for both traditional waterline construction and complex HDD operations.