City of Joliet


City of Joliet

Market Sector

Local Government


Construction Engineering, Municipal Consulting, Water Resources

Joliet Combined Sewer Overflow Tunnel

Joliet, Illinois

  • This $21.4-million sewer improvement project included the construction of an 865-foot-long tunnel under the Des Plaines River requiring shafts, piping and other ancillary sewer structures to complete.

  • More than a half mile of pipe, as large as 72-inch diameter, is being installed for a combined sewer overflow system.

  • Because the project required tunneling with a tunnel boring machine through bedrock 30 feet under the river bed, several plans and precautions were implemented to investigate and plan for the conditions that were encountered under the river.

  • Installed pipe included centrifugally-cast fiberglass reinforced polymer mortar pipe, ductile iron pipe, reinforced concrete pipe and PVC conduit.

  • Additional work includes manholes, a watermain, a cast-in-place concrete regulator, junction structures, sluice gates, stop logs and appurtenances.

  • The cast-in-place concrete structures include two junction structures, a 1,000-square-foot screening structure, an inlet siphon control structure, a 65-foot-deep drop shaft structure and a 800-square-foot wet weather pump station, an outlet siphon control structure and a siphon control structure.

  • Significant bypass pumping, staging and sequencing of construction was necessary to complete the work and maintain operation of the existing combined sewer, including sewer flow diversion and bypass pumping.

  • Significant rock excavation via blasting and hydraulic breaking was required, as well as pavement removal and replacement, to construct the sewer structures and install pipe next to the Des Plaines river wall and nearby structures including the Interstate 80 bridge.