Hard Rock Tunnels for the Plateau Creek Pipeline Replacement

GEI was retained by the Ute Water Conservancy District to provide resident construction engineering services for all geotechnical and tunnel construction aspects of the Plateau Creek Pipeline project. The Plateau Creek Pipeline serves as the lifeline for over 60,000 rural and urban customers of the Ute Water Conservancy District in Mesa County, Colorado.

GEI provided design services for two tunnels and geologic hazard and geotechnical evaluations along the pipeline route as part of a team responsible for the successful completion of the Plateau Creek Pipeline Replacement.

The two 10-foot-diameter tunnels are 9,896 and 3,360 feet long and were sized to permit access to the 48-inch-diameter steel water pipe they carry. GEI drilled over 130 borings, several required helicopter access and a number were over 700 feet deep.

Key geotechnical issues addressed during the design included landslides, subsidence, collapsible soils, and highly corrosive soils.

Construction engineering services included tunnel mapping, assessment of temporary and permanent support for tunnels and portals, coordination of disputes, Review Board Meetings, and management support of construction engineering activities.

In addition, GEI performed field inspections of the cut and cover portion of pipeline, including welding, backfill, structural concrete and steel, cathodic protection, and general civil engineering.

GEI’s decision support process for this project involved working closely with Ute Water, several federal permitting agencies, and other consultants to develop a coarse screening of alternatives consistent with requirements of the Clean Water Act and the National Environmental Policy Act.

“Your group dealt with problems efficiently and as quickly as could be reasonably expected, and certainly made us feel that we were the most important thing in your lives during the project.”

— Ralph W. Ohm, District Engineer Ute Water Conservancy District