Trenchless Education and Training Help Mitigate Risks and Advance Technologies


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The North American Society for Trenchless Technology (NASTT) is a 501(c) (3) not-for-profit educational society comprised of engineers/consultants, manufacturers/suppliers, public works/utilities and academia, representing the United States, Canada, and Mexico. NASTT has a network of 12 Regional Chapters and 18 Student Chapters, and is affiliated with the International Society for Trenchless Technology (ISTT), who share the same basic concerns for the environment and the social costs of utility construction and rehabilitation.

Since its founding in 1990, NASTT has promoted trenchless technology through education, publishing, training, and research for the public benefit. Trenchless technology covers any techniques, processes, or procedures, including the equipment, machines, and materials involved, which minimizes or eliminates the need for surface excavation or reduces environmental damage or the associated costs for underground work; also known as “no-dig” or “low-dig” methods.

Seattle Public Utilities Pump Station 043 Emergency Force Main Repair, Hiram M. Chittenden Locks (the Ballard Locks), Seattle, WA.
Seattle Public Utilities Pump Station 043 Emergency Force Main Repair, Hiram M. Chittenden Locks (the Ballard Locks), Seattle, WA.

NASTT’s mission is to continuously improve infrastructure management through trenchless technology, and its vision is to be the premier resource for knowledge and education in trenchless technology. This is delivered through non-commercial, peer-reviewed Good Practice publications and courses on systems and applications, the annual NASTT No-Dig Show exhibition and conference, providing peer-reviewed, noncommercial technical papers and networking events, career development pathways, and grant funding for student scholarship and municipal programs.

Pipeline construction is booming, and the need for installation beneath structures using trenchless technologies is increasing. Horizontal directional drilling, microtunneling, pipe ramming and pipe bursting offer positive solutions to installing pipelines with minimal disruption. Pipeline construction can pose risks to a project if the construction is not approached properly. Risk mitigation is critical to the success of the project. NASTT education and training can help mitigate these risks and advance the state of practice.

Hot Springs, Arkansas Intake project guillotine gate seal used at entry portal to prevent uncontrolled release of Lake Ouachita through intake tunnel.
Hot Springs, Arkansas Intake project guillotine gate seal used at entry portal to prevent uncontrolled release of Lake Ouachita through intake tunnel.

With recently implemented important updates in permitting guidance for trenchless crossings beneath embankment dams and levees, trenchless design firms must now elevate their permitting expertise and skill sets to address the new requirements for proposed projects.

As one step to assist in this process, NASTT has recently accepted an abstract for a proposed technical paper for presentation at the 2023 No-Dig Show ( in Portland, Oregon, presenting updated guidance and measures which can be used by design firms and permit applicants to ensure criteria are met. Two projects summarized below also serve as examples of the benefits of trenchless technology to complete important infrastructure projects while protecting critical facilities and environmentally sensitive features.

Hot Springs, Arkansas Intake project Herrenknecht MTBM at start of project.

As part of an overall program to reduce CSOs per consent order decree, trenchless technology was used to install a CSO outfall under a flood protection levee in New Hampshire to convey partially treated CSO effluent to a local river. A 74-inch diameter tunnel was excavated 550 feet through gravels and sands by pressure slurry MTBM at an average depth of 14 feet. The bore was a one-pass tunnel jacked with reinforced concrete jacking pipe, and was successfully in stalled by continuous construction over three 24-hour workdays. Retrieval of the MTBM was in the dry in a steel sheet pile coffer cell.

A more recent example can be found in Hot Springs, Arkansas, where a 61-inch diameter Herrenknecht microtunneling machine is being used with a pipe thruster to install 2,600 feet of 56-inch steel pipeline through rock beneath Blakely Mountain into Lake Ouachita for a water supply intake. This design-build project is a testament to the benefits of working closely with federal and state agencies to ensure that their permitting concerns were proactively addressed. Numerous project features were designed and implemented to ensure that the updated permitting guidelines were met or exceeded.

Affiliate Members of NASTT work collaboratively toward the betterment of the tunneling, underground, and trenchless technology industries, and receive the following benefits:

• Individual NASTT Membership, providing full membership benefits.
• Unlimited access to library to over 3,500 technical papers and conference proceedings.
• Personnel can purchase all NASTT products at Member rates where available.

NASTT communications and promotional material including:
• NASTT No-Dig Show
• NASTT E-News Bulletin
• NASTT Membership magazine, Trenchless North America
• In-person and virtual Good Practices trenchless technology courses –CEUs available
• Free trenchless technology webinars

NASTT is your link to thousands of trenchless professionals and leaders working at the regional, national and international levels. An active network of more than 2,500 members includes contractors, researchers, engineers, manufacturers, owners, government agencies, consultants, and developers interested in underground systems as well as the green applications and financial benefits of trenchless technology.

NASTT is proud to continue to ensure facilities are protected during trenchless crossings by maintaining its leadership in providing up-to-date technical resources, training, and public outreach.
For more information on trenchless technologies, visit
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