Downtown Tunnel

Austin, Texas

The Downtown Wastewater Tunnel is a large-scale project to improve wastewater collections and operations for Downtown Austin and the neighborhoods immediately south of Lady Bird Lake.  The project diverts current flows to the proposed tunnel, eliminating two lift stations and making capacity available in the existing wastewater collection lines for future downtown development.  The tunnel is approximately three miles long, beginning on Lamar Boulevard on the north shore of Lady Bird Lake and crossing underneath the lake to Palmer Auditorium.  From there, the tunnel proceeds east along Cesar Chavez to Comal Street and ends at Craig Fields near the Longhorn Dam.

Encotech provided Structural Engineering services for the design of three, 16-foot diameter, deep manholes/access shafts for this project ranging from 60 to 80 feet in depth, as well as a large sewer diversion structure measuring 30 feet long by 20 feet wide by 25 feet deep at West Riverside Drive.  As a result of Encotech’s attention to detail and precise calculations, the standardized diagrams of the shaft designs were implemented by the Austin Water Utility as the standard design for use on all future deep manhole projects.