Metropolitan St. Louis Sewer District (MSD) manages the fourth largest sewer collection system in the United States. It has begun an ambitious program called Project Clear that will span a generation. This program is a multi-billion dollar investment addressing wastewater overflows with building community rainscaping, system improvements, and a program of maintenance and repair throughout the system serving St. Louis region. The system improvements will include construction of nine tunnels to control sewer overflows. Construction of the first project is nearing completion, while plans for the remaining eight tunnels are underway.

MSD Project Clear reached a milestone in 2014 with the completion of the first phase of the 3,200 foot long x 8 foot diameter tunnel as part of the Lemay Redundant Force Main project. The Tunnel Boring Machine (TBM) Miss Chelsea completed the digging of the tunnel between February and May 2014. The agency is expecting to finish the $20 million project later this year, when surface connections are completed. In constructing this second force main, the Lemay Wastewater Treatment Plant will be able to accept a higher volume of wastewater, and allow MSD to inspect the original force main for the first time since its construction in the 1960s.

“Construction on the eight remaining tunnels is planned to begin over the next dozen years,” said MSD Executive Director Brian Hoelscher. “These tunnels represent significant work opportunities for the construction industry with the second tunnel expected to go to bid as early as 2016, followed by four more tunnels beginning construction in 2017.These next five tunnels have an estimated construction cost of over $1 billion.”

The following map details the locations of major tunnel projects. Each tunnel is represented with a different color key. Using your mouse, click on each tunnel for a pop-up window to appear. The new window provides a chance to zoom in on that tunnel area and in many cases you will find an informative fact sheet.

As part of the overall program, construction may also include new sewer lines to convey wastewater, above-ground storage tanks to store stormwater, or deep underground tunnels to both store and convey additional flow during heavy rain events until capacity is available at the respective treatment plant.

“We want the construction industry to be aware of these upcoming opportunities and plan accordingly,” Hoelscher stated. All prospective bidders must be prequalified and certified prior to advertisement of these projects. Prequalification is based on past project experience, performance, and financial strength. If you have questions regarding the prequalification process for these projects, please contact Marie Collins P.E., Assistant Director of Engineering, at 314-768-6316 or Allen Muehlher P.E., Program Manager, at 314-768-6239.

MSD and Jacobs Engineering, the designer for three of these tunnels will present St. Louis’ Sewer Tunnel Vision paper at the 2015 Rapid Excavation and Tunneling Conference. This paper will describe the Maline Creek CSO Storage Facility, Jefferson Barracks Tunnel, and Lower & Middle River Des Peres Storage Tunnel in detail.

The following table outlines the key components of each of the remaining eight tunnels. The schedule and cost presented is tentative as determined by current planning efforts, and subject to program implementation and final budget approval.

Project (MSD Project No.)Tunnel LengthTunnel DiameterBegin** ConstructionConstruction DurationConstruction Cost Estimate
Maline Creek CSO Storage Facility* (11656)3,000 ft.28 ft.20165 years$81M
Deer Creek Sanitary Tunnel* (11731)21,000 ft.19 ft.20174 years$300M
Jefferson Barracks Tunnel* (11711)17,000 ft.7 ft.20174 years$89M
Lower & Middle River Des Peres Storage Tunnel* (11820)9 miles30 ft.20207 years$631M
University City Sanitary Storage Facility (11992)1,250 ft.30 ft.20182 years$40M
Lower Meramec Tunnel (11746)6.8 miles8 ft.20205 years$170M
River Des Peres Tributaries CSO Tunnel (12441)12,144 ft.20 ft.20247 years$375M
Upper River Des Peres CSO Storage Tunnel (12440)8,976 ft.24 ft.20287 years$226M

* Design is underway.
** Dates are estimated and shown in MSD Fiscal Years which start on July 1.

If you have specific project-related questions on the above projects, please contact Bob Wibbenmeyer at [email protected] or 314-768-6260.