ARWA - drinking water

Clean and Sustainable Water Supply to I-35 Corridor


Project Background

Alliance Regional Water Authority (Alliance) needed to pull together a mission that would deeply impact the area south of Austin, Texas. Due to rapid growth in the Austin-San Antonio Corridor, water supply demand is steadily increasing and expected to continue for the next few decades, as population growth is projected to catapult from 4.27 to 5.71 million from 2014 to 2030. Alliance needed a solution to provide reliable water supply for years to come.  

With multiple consultants working simultaneously for Alliance, HVJ worked on tunneling and open cut pipeline on three different segments of the project simultaneously.  Success would require exceptional teamwork and communication. Our partners LAN Inc., BGE Inc., and LNV needed a “one-stop-shop” to stay on the same page and get geotechnical knowledge and expertise to complete this extensive and nearly decade long project. 

Practice: Geotechnical Engineering, CoMET

Sector: Water

Location: Austin

Services: Open Cut and Trenchless Pipeline Design, Geotechnical Baseline Report (GBR), Fill Suitability/Compaction Control, Portland Cement Concrete Testing 

ARWA - Large Dia Pipe

The Problem

Finding a new reliable potable water source was one matter, but the pipeline toward Maxwell and Lockhart was another challenge altogether. The planned water supply line goes cross-country with creek and interstate highway crossings.  Accessing the alignment for the investigation was a challenge to keep the project on schedule.  Assessing conditions at creek and highway locations requiring tunneling was a key risk for the project.  

The Goal

  • A design that would provide a sustainable water supply from Buda to San Marcos that would meet rising demand for several decades into the future
  • Staying on schedule and within budget.
  • Keeping the project on track would be especially important to meet the required demand.  

Our Solution

 HVJ Associates® listened closely to our clients and Alliance to give them a design that would accommodate the fast growth in the region south of Austin with a sustainable water supply. HVJ provided multiple drilling crews capable of drilling in sugar sand soils and hard rock along the 30-mile alignment to meet all three simultaneous project schedules.  

HVJ provided tunneling design information including Geotechnical Baseline Reports (GBR’s) for water line crossings at Plum Creek and three IH 35 crossings to manage subsurface risks for the owner and contractor. The geotechnical baseline report (GBR) was advantageous for allocating and managing subsurface risks associated with subsurface construction. 

The Results

HVJ’s recommendation for use of on-site trench material as pipe bedding dramatically reduced the use of material trucked to the project at significant cost and time savings to Alliance.  Further, upsized casing  (recommended by HVJ) allowed the contractor to overcome mixed face conditions and potential delays.  

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