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," according to the press release.
For the massive five-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 that are designed to last 100 years.
SAWS chose Hobas centrifugally cast fiberglass reinforced polymer mortar (CCFRPM) 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 of existing 54-inch sanitary sewer main with 29,000 linear feet of 60-inch and 104-inch gravity sanitary sewer pipelines.
The project’s civil engineering firm of Kimley-Horn and Associates, Inc. completed the plans, according to the press release.
SAK will install approximately 26,750 linear feet 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 linear feet 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).