Project Overview
The City of Santa Rosa required the replacement of 1,180-ft. of aged sections of the North Trunk Sewer Main by Chanate Road and Mendocino Avenue.
The project goals were improved integrity and performance, capacity increases, a comprehensive traffic control plan for the convenience of residents and businesses, reduced potential for overflow into Paulin Creek, and construction in a manner that recognizes the importance of protecting the ecology of nearby Paulin Creek.
Several options were considered for its replacement, including the installation of a lift station.
Challenges
• Residences 40-ft. below road surface and existing sewer alignment
• Extreme 45-ft. deep shaft required for tie in, thereby negating possibility of an open trench installation due to excavation depths
• Consistently heavy traffic in tight corridor
• Construction on the Mendocino Avenue during an overnight shift to minimize disruptions
• Emergency vehicle access at all times
Solution
The Project Manager identified and recommend pilot tube microtunneling as the ideal solution. The trenchless selection offered the following benefits:
• Method provides easy means for access for maintenance
• Ability to maintain traffic flow in accordance with the traffic control plan
• Ability for deep installation in ground conditions thereby eliminating a lift station
• Supports responsible construction goals for the protection of the Paulin Creek habitat
Outcome
• Successful installation of 1,180-lf. of new sewer lines, the longest run at 350-ft.
• Improved pressure and flow reliability
• Minimized construction impacts
• All line and grade tolerances met
• Ribbon cutting event to commemorate successfully managed project successes and collaborative efforts between all parties
