St Louis tunnel tenders

Tenders will soon be invited for the construction of a 6.4km long sewer tunnel between the Baumgartner lagoons and the proposed Lower Meramec River Wastewater Treatment Plant (WWTP), in the St Louis region of Missouri, US.

Bored at a depth of 60m through hard rock, for the Metropolitan St Louis Sewer District (MSD), the 2.4m diameter gravity tunnel will pass twice under the Meramec river. Similar projects in the US, which were bored under rivers, have faced opposition from local environmental protesters. Project manager for MSD, Mike Stewart, believes that at depths of 46m, they should not have any trouble. "We need a 'Section 10 Permit' to go under the river," he said. "But we won't have any problems obtaining that."

The Department of Natural Resources is currently reviewing the completed design, and checking for any anomalies.

The contract also includes the construction of three 9.2m diameter access shafts, and five drop shafts, between 1.8m and 3m in diameter, to connect with other sewers.

Along with a 670m long pipeline, and a lift-station (including two shafts: one 36.6m in diameter, and 61m deep; and the other 8m in diameter, and 61m deep) the contract is estimated to be in the region of US$84M. The successful contractor will have to provide the hard rock TBM.

The construction of the tunnel and the lift station is expected to start in October 2003, to be completed in 24 months. Construction on the WWTP should begin this summer, to begin operating in the autumn of 2005.

The 2.4km long, 2m diameter cut and cover outfall sewer tunnel, from the WWTP to the Mississippi river is currently being constructed by Bates Utility Construction Company. The team is making good progress and is already ahead of schedule.

The tunnel and lift-station are being designed by Horner & Shifrin, along with subconsultants TSI Engineering, David Mason & Associates, Fleming Corporation, and ERM Technologies.

Construction management services will be provided by Shannon and Wilson/Black & Veatch, with ABNA Engineering and TSI Engineering.

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