Stormwater interceptor Project Aims to Reduce Downtown Urban Flooding

City of Tacoma announcement.

Mayor Victoria Woodards, City Manager Elizabeth Pauli, and Environmental Services Director Mike Slevin attended a ribbon-cutting event on March 18, 2022, for the “Thea Christiansen” tunneling machine. The machine will be used as part of the City of Tacoma’s Jefferson and Hood Street Surface Water Interceptor project to improve existing stormwater capacity, reduce urban flooding events downtown, and support future growth.

“This project is part of our continuing efforts to protect our businesses, museums, university, and all of downtown from local urbanized flooding caused by climate change which we have been experiencing over the last decade,” said Director Mike Slevin.

Construction of the 60-inch diameter interceptor and new outfall into the Thea Foss Waterway began in fall 2021 and will take approximately one year to complete. The new outfall is designed to support stormwater drainage of more than 90,000 gallons per minute.

“This is quite a complex project within our urban setting,” said Project Manager Christa Lee. “The project alignment runs through the heart of our city and has technically challenging site conditions. Due to the need to cross a few significant transportation corridors, we selected the micro-tunneling method.”

The project includes both “open cut” construction and trenchless micro-tunneling methods, which will allow roadways to remain open during some portions of the work. The tunneling machine has launched its first of three tunnel drives the week of March 21, 2022.

For more information on the City’s stormwater project, visit cityoftacoma.org/jeffersonhood or call (253) 279-5509.