SAWS BPC Central Large Diameter Package I

To meet the requirements of the Consent Decree with the Environmental Protection Agency, the San Antonio Water System (SAWS) rehabilitated over 12,000 linear feet of 24- to 60-inch pipeline via cured-in-place pipe (CIPP) throughout the city. The existing pipelines were determined to be in poor condition and required rehabilitation to prevent future pipeline failures and leaks, making the project a high priority for reducing potential public health and environmental hazards.

The project was undertaken as part of the SAWS Sanitary Sewer Overflow Reduction Program. As the prime consultant, our team led design for the CIPP, bypass pumping, and traffic control. We also managed a variety of subconsultants and coordinated with TxDOT, San Antonio Independent School District, the San Antonio River Authority (SARA), and various City departments.

The project spanned eight locations across San Antonio, many in developed and environmentally sensitive areas. As such, effective traffic control, impact mitigation, and stakeholder coordination were required to minimize impacts to residents, businesses, and the environment, as well as the project cost and schedule. The various project locations posed a unique set of challenges that KFA worked to resolve. Several rehabilitation sites were in high traffic areas, requiring the team to design complex traffic control plans in coordination with TxDOT and to plan road closures and detours with the City of San Antonio.

The team developed conceptual designs for bypass at each project site, including one site which required bypassing flows of 70 million gallons per day. The bypass allowed for construction work to proceed without interrupting service. At one project site, the only available location for the large bypass pumping setup was on the property of a high-end restaurant, causing stakeholders to raise concerns about potential impacts to the business. KFA coordinated directly with the property owner to obtain right-of-entry agreements and developed specific contractual milestones in the bid documents to minimize impacts during major events at the nearby Alamodome. The segment along Alazan Creek near Tafolla Middle School required additional coordination due to a concurrent SARA project. Our team identified this potential issue during design and collaborated with SARA to avoid cost or schedule impacts due to overlap in work areas.

Due to budgeting concerns, SAWS prioritized certain segments of pipeline within the overall rehabilitation program, which resulted in gaps in the project limits at several locations that would require rehabilitation as part of a future project. Our team evaluated the gap segments during design and determined it would be more cost efficient to incorporate the gaps into the project, which would make longer shot lengths possible and use the bypass setup that was already in place for this work. The team calculated that by including the gap segments, 40% more footage could be rehabilitated for less than a 20% increase in the project cost. SAWS accepted the recommendation, and the team designed an additional 1,440 linear feet of 24 to 33-inch pipe. The increased footage was estimated to save SAWS approximately $1M by increasing the shot lengths, which reduced labor cost on a per-unit basis, and by avoiding the overhead, mobilization, and bypass pumping costs of a separate rehabilitation project to address the gaps.

Construction is complete and the rehabilitation of pipelines extends their useful lifespan, helping to prevent pipe failures and other overflow events for years to come.