Trenchless technologies are emerging solutions for installing, replacing, repairing and restoring underground utilities. As the ever-present demand for reliable water resources continues to grow, and our existing infrastructure continues to age, communities are turning to trenchless technologies to improve their water infrastructure with minimal disruption to the community.
Here’s a look at how our team provided the City of Westminster, Colorado, with a trenchless technology solution that not only improved the service life of the city’s water main, but was completed with minimal inconveniences to residents, commuters and the community.
Evaluating Trenchless Technology Options
There’s not a one-size-fits-all application for trenchless technology. With an increasing number of options for rehabilitation and renewal projects, choosing the right technique can be a challenge. For the City of Westminster, we evaluated five trenchless waterline rehabilitation and replacement methods:
- Open-cut replacement
- Cured-in-place pipe (CIPP)
- Horizontal directional drilling (HDD)
- Pipe bursting with different materials
- High-density polyethylene pipe (HDPE) rolled down/tight lining
Understanding the different trenchless technologies, project requirements and the client’s goals are critical to the overall success of any project. Taking these elements into consideration, our team evaluated and prioritized each technique, followed by a thorough analysis of the cost/benefit for each technology specific to the project. By taking the time to go through this process, the engineer is able to use that data analysis to select the best rehabilitation technique to bring value-added design focused on team-determined goals.
While trenchless rehabilitation construction of potable waterlines presents significant design challenges, the improved service life, cost savings and community-impact benefits that no-dig rehabilitation ultimately provide make this a viable — and valuable – solution for cities.
Westminster had an old and failing 12-inch, cast-iron, potable waterline originally installed in 1966. The waterline required frequent maintenance and repair due to corrosion-related breaks. Site conditions — including existing utility clearances, high traffic volumes and expensive restoration — made traditional open-cut construction methods impracticable. Based on the site, pipeline conditions and our alternatives analysis, we ultimately landed on two different trenchless technologies: CIPP and pipe bursting.
During Phase I, we designed a project rehabilitating approximately 1,700 linear feet of waterline with CIPP. The CIPP was fully structural, pressure capable and suitable for potable water use. Phase II of the project included the design of approximately 2,000 linear feet of fused PVC through the process of pipe bursting. The 12-inch cast iron pipe was replaced with 12-inch PVC. Both projects included the installation/reactivation of valves, fire hydrants, fire lines, water services and connections to the existing distribution system.
The result was the restoration of nearly 4,000 linear feet of high-pressure waterline with a very small construction footprint. The use of trenchless technologies allowed the renewal of the pipelines with minimal digging, which not only saved money but also reduced construction impacts. With only a small work area required by the trenchless installations, the project produced several additional benefits: improved worker/community safety, reduced noise and dust, shortened the construction schedule, and minimal commuter delays and traffic. The restored waterlines are currently operating exceptionally and are expected to serve this growing community for the next 60 years.
If you’d like to learn more about Westminster’s Lowell Waterline Rehabilitation Project, check out this video:
And if you’d like to learn more about the benefits of trenchless technology, feel free to comment below or reach out on LinkedIn.