Get Full Government Meeting Transcripts, Videos, & Alerts Forever!
Get email alerts on the Williamson Creek Interceptor topic
No spam. Unsubscribe anytime.
Commission approves $138 million contract and engineering amendment for Williamson Creek interceptor
Summary
The commission approved a $125.58 million construction contract (plus $12.56 million contingency, total $138.138 million) and unanimously approved a roughly $7.45 million amendment to the design engineer's contract to provide construction-phase services for the 3.5-mile Williamson Creek wastewater interceptor; staff described tunneling, odor control, environmental restoration and parkland mitigation.
The Water and Wastewater Commission on Jan. 14 approved a construction contract and an engineering-services amendment to advance the Williamson Creek wastewater interceptor project, a roughly 3.5-mile, 72-inch-diameter gravity interceptor that Austin Water said will be installed primarily by tunneling to increase capacity and reduce the risk of sanitary sewer overflows.
Kane Wei, supervising engineer for Austin Water's pipeline CIP delivery group, told commissioners the existing interceptor dates to the 1960s and ranges from 36 to 48 inches in diameter; the new 72-inch fiberglass pipe will convey three to six times more flow, resist corrosion and include operation-and-maintenance shafts, new connection points and a biological odor-control facility. The project will rehabilitate some non-tunneled sections trenchlessly, remove or abandon aging pipe and manholes in Williamson Creek, and incorporate environmental restoration and mitigation measures intended to reduce future creek impacts.
"The Williamson Creek wastewater interceptor project is about a 3 and a half mile long, 72 inch diameter gravity wastewater interceptor pipe," Kane said in the presentation, outlining the tunnel depth (20 to 90 feet below creek level), reuse of environmental mats to reduce disturbance, and park mitigation agreements that will add more than 63 acres of parkland and trail access in coordination with the Parks Department.
Action taken: Commissioners voted to authorize a construction contract with Williamson Creek Constructors JV in the amount of $125,580,000 plus a $12,558,000 contingency for a total contract amount not to exceed $138,138,000. The commission then approved an amendment to the professional services agreement with CAS Consulting and Services to add approximately $7,448,884 for construction-phase services, for a revised total not to exceed $14,490,600. Staff said funding for both items is available in Austin Water's capital budget.
Procurement and selection: Commissioners asked why the engineering amendment was negotiated rather than competitively bid for construction-phase services. Kevin Koller, division manager for Pipeline CIP Delivery, explained that engineering firms are selected via a qualifications-based selection process for the entire project and that construction-phase services are typically provided by the design engineer once the scope and costs are better defined.
Why it matters: Austin Water said the project replaces aging infrastructure, increases conveyance capacity, reduces overflow risk in a creek corridor, and provides parkland and trail mitigation. Construction was described as likely to start later this year, subject to council approval and permitting.
What happens next: Kane said the projects were intended to go to city council the following week and construction could begin later in 2026 pending approvals; the department maintains a public project website with maps, exhibits and sign-up for email updates.
