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Preserving the Natural Environment Through Trenchless Technology

Mark Onken, PE, Municipal Project Engineer and Nick Pawlak, EIT, Trenchless Design Engineer

You can’t see everything going on underneath your feet, but you trust it’s working well. If these essential systems we take for granted weren’t functioning, you’d definitely notice— whether it’s your water and sewer pipes, gas lines, or electrical wires. Despite underground systems being out of sight, their effectiveness is undeniable. To keep things running smoothly and to preserve the natural environment, we turn to the expertise of engineers, who use underground trenchless technology. 

What is Trenchless Technology and How is it Better?

Trenchless technology is the process of replacing or rehabilitating underground existing pipes and public infrastructure while minimizing disruptions to daily life, keeping the surrounding community connected and functioning smoothly.

Trenchless technology offers several advantages over traditional excavation methods:

• This method causes less disruption, significantly reducing the impact on traffic, businesses, and daily activities.
• While the initial investment can be higher, trenchless technology saves money over time with reduced restoration expenses and environmental preservation.
• Projects can be completed faster, reducing the duration of inconvenience for the community.

How Can Trenchless Technology Preserve and Protect Community Spaces? 
By enhancing the reliability and efficiency of underground utilities using trenchless technology, the ecological footprint of construction activities is reduced, minimizing noise, dust, and traffic disruptions during resident’s everyday activities. By decreasing the need for extensive excavation and restoration work, trenchless technologies can allow for preservation of parks, roads, and public areas, ensuring these spaces remain available for community use and enjoyment. 

In the short term, trenchless technology reduces construction costs and minimizes disruptions; in the long term, it ensures sustainable infrastructure improvements, protecting both natural and urban environments for future generations. 

Saving Time and Money Through Trenchless Technology

In the City of Golden Valley, MN, the city experienced 10 watermain breaks in three years across their 3,500 LF of watermain beneath Glenwood Avenue. The watermain often broke in the winter, and excessive pavement thickness resulted in challenging and expensive watermain break repairs. This prompted the city to investigate repair methods that were cost-effective and had minimal impact on residents and the country roadway. 

The solution was to use a trenchless Cured-in-Place Pipe (CIPP) liner to rehabilitate the existing watermain. During the feasibility study, the team also explored the option of open cutting and replacing this deteriorating watermain, directional drilling, pipe bursting, and slip lining but the cost was almost twice that of CIPP Lining. Nick Pawlak, municipal design engineer at Bolton & Menk, noted, “this trenchless technology method was the most cost-effective solution and was the least disruptive to the city, which allowed the roadway to remain open throughout the process.” 

A downtown 4th street urban reconstruction project in another metro city included building-to-building refurbishment and spot improvements to utilities and stormwater systems. The Bolton & Menk design team consulted the trenchless team to find an effective rehabilitation method that eliminated the need for full excavation. They determined that replacing a 20-foot-deep sanitary manhole would necessitate extensive excavation in a busy four-way intersection. These excavation limits would also impact service to newly installed private utilities situated near the structure designated for removal and replacement.

To address the issue, trenchless methods for the structural rehabilitation of the sanitary manhole were proposed to the city. After thorough discussion, the structural rehabilitation plan received approval. Multiple city departments, including public works, engineering, and transportation, were involved in the process, and community members were kept informed about the project timeline and anticipated impacts.

This trenchless technology approach saved valuable weeks on the project schedule, minimized crucial transportation route shutdowns through the busy intersection, and saved money. By avoiding extensive excavation, the project was able to proceed more efficiently, reducing the overall impact on the community and ensuring a smoother, quicker completion.

Building a Sustainable Future from the (Under)Ground Up

Trenchless technology represents a significant advancement in the field of underground infrastructure. By minimizing disruptions to daily life, preserving community spaces, and offering cost-effective solutions, trenchless methods ensure that essential systems remain functional and reliable. The expertise of trenchless engineers plays a crucial role in maintaining and improving these unseen, yet vital components of our cities. As we continue to implement these technologies, we not only enhance the efficiency and sustainability of our infrastructure but also protect the natural and urban environments for future generations. Embracing trenchless technology is a step toward a more resilient and connected community.

Authors:

Mark Onken, PE, Municipal Project Engineer
Mark.Onken@bolton-menk.com

Nick Pawlak, EIT, Trenchless Design Engineer
Nick.Pawlak@bolton-menk.com