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Upper NW Interceptor Sections 1 & 2
New Tunneling Machine
Updated December 2008
Construction crews will begin tunneling work along the East Drainage Canal in mid-December. Crews will be using a tunnel boring machine (TBM) to dig below the surface. The TBM was designed specifically for the UNWI 1 & 2 project based on ground conditions.
Throughout the tunneling work, approximately 14 months, a group of miners will operate the TBM to dig the 3.65-mile tunnel. The tunneling method reduces community impacts.
Tunneling will begin at the New Natomas Pump Station, near the intersection of Interstates 5 and 80. From there, it will run north along the East Drainage Canal adjacent to Natomas Boulevard and Truxel Road. The UNWI 1 & 2 segment will end at Bridgecross Drive where it will connect to the previously constructed UNWI 3 & 4 segment (see map).
Sacramento Regional County Sanitation District (SRCSD) divided the entire UNWI project into nine sections to promote efficient construction management and activities. Sections 5 & 6 and 7 & 8 are complete. Sections 3 & 4 were complete by the end of November, weeks ahead of schedule. Section 9 will be complete in December and Sections 1&2 will be complete in winter 2010.
Currently, the existing wastewater system is nearing capacity. When complete, the UNWI sewer pipeline will better ensure reliable sewer service and will meet future demands for increased capacity.
UNWI 1 & 2 by the Numbers:
- 19,300 feet of 144-inch pipe
- 54 feet of 120-inch interceptor pipeline
- 20 manholes spaced 1,000 feet apart
- 84-inch by 144-inch transition structure (to connect UNWI sections 1 & 2 and 3 & 4)
- 144-inch by 120-inch transition structure (to connect UNWI sections 1 & 2 and the New Natomas Pump Station)
- 3 connections to small, existing sewer lines
What to Expect During Construction
UNWI 1 & 2 construction hours are between 7 a.m. and 7 p.m., Monday through Friday, and between 8 a.m. and 7 p.m. on Saturday. Additionally, underground tunneling will occur 24 hours-a-day, seven days-a-week at the New Natomas Pump Station. This underground method was selected to minimize impacts to the public. The only excavation visible along the alignment will be for manhole installation.
The bicycle path adjacent to the East Drainage Canal may experience short-term closures and long-term detours. Possible lane shifts and lane closures may be necessary where roads cross the project alignment.
Throughout construction, the project team will do everything possible to minimize impacts to the community. However, certain disruptions may be unavoidable, such as:
- Increased noise and dust
- Occasional lane closures/lane shifts
Maintaining communication with residents and businesses throughout the construction process, and responding to questions and concerns, is very important to the team. If you want to speak with us regarding an issue or impact, please call our toll-free 24-hour hotline at (866) 479-0600.