Construction has begun on the largest and most complex sanitary sewer improvement project that the San Antonio, Texas Water System (SAWS) has ever undertaken. This “W-6 Upper Segment” main serves approximately 500,000 residents, a far larger and growing population than when the original line was installed. This section of sewer main has been called the City’s “most significant capacity constraint in the SAWS system.”
For the massive 5-mile long pipeline project, “W-6 Upper Segment: US Hwy. 90 to SW Military Drive Sewer Main, “the SAWS’ plan replaces the deteriorating and inadequate line with a product designed to last 100 years.” SAWS chose Hobas CCFRPM (centrifugally cast fiberglass reinforced polymer mortar) pipe due to the fiberglass pipe’s long life expectancy, corrosion resistance and ease of installation. Hobas has supplied CCFRPM pipe for more than 20 SAWS sewer projects since 2013.
The W-6 Upper Segment project extends 5.5 miles, along US Hwy 90 from just east of Leon Creek to SW Military Drive, then southeastward along Military to the Pearsall Road intersection. The project will replace approximately 19,000 linear feet (LF) of existing 54-inch sanitary sewer main with 29,000 LF of 60-inch and 104-inch gravity sanitary sewer pipelines.
The project’s civil engineering firm of Kimley-Horn and Associates Inc. timely completed the plans. Kimley-Horn has a history of designing successful projects throughout San Antonio.
SAK Construction LLC was selected as the “best value” contractor to perform the $167.7 million upgrade. SAK is a national industry leader in infrastructure installation and rehabilitation with a history of successful tunneling projects in San Antonio and Central Texas. The project was awarded July 7, 2020, with a notice to proceed given mid-July and is scheduled for completion in July 2023, before the consent decree deadline of 2025.
SAK will install approximately 26,750 LF of 104-inch diameter Hobas pipe via deep tunneling up to depths of 140 feet utilizing two full-faced tunnel boring machines (TBMs). An additional 2,250 LF of 60-inch Hobas pipe will be installed via tunneling along US Hwy 90. SAK will also construct a total of 9 shafts ranging from 33 to 143 feet in depth. The ultimate wastewater conveyance required for the project has been projected to be 137.6 million gallons per day (MGD) at Peak Wet Weather Flow (PWWF).
Since 2013, the San Antonio Water System has been aggressively investing in improving their sewer infrastructure for their city’s future.