How the Future of Underground Mapping Can be Found in the Cloud

underground mapping illustration

By Michael A. Twohig

In the late 1800s, America experienced a monumental shift as people moved from rural areas into growing industrial and trade centers. Boston was one of those great American cities that experienced the resulting population boom. To respond to the growing demands on Boston’s antiquated infrastructure, city planners and urban designers needed to rebuild outdated systems, replace failing facilities and develop new transportation systems to move the masses.

To design these new systems, designers had to be very creative. Open excavation methods could only be tolerated in certain locations, and with hundreds of years’ worth of buried foundations and utilities to contend with below increasingly congested city streets, designers need to map the underground to understand the existing site conditions. Before the work of building a new Boston could begin, our predecessors excavated around buried utilities, underground structures, and foundation elements to develop a picture of what lay beneath the ground. The results of these subsurface investigations were plotted and depicted on plans and prints, often in meticulous detail.

There are some documented cases where the streets were so crowded that the subsurface utility mapping teams tunneled under streets from the edge of roads, below busy thoroughfares, and located the bottom of the utilities. Tunneling under the clamor of pedestrians, horse-drawn delivery carts, streetcars and bicycles rather than relying on open-trench excavations required a profound commitment to mitigate disruption to the daily lives of citizens – a truly amazing trenchless technique, even by today’s standards.

It was also a commitment to seek out trenchless techniques for the betterment of all parties. What our predecessors left us from that era was not only some excellent projects, but also subsurface plans that depict the underground environment in two and three dimensions. As subsurface utility mapping professionals, we have adopted many of the best practices from that era.

Since then, the underground construction industry has seen a dramatic technological evolution. Non-destructive vacuum excavation equipment has replaced the steam-powered shovels and “test-pitting” incline machines. Remote sensing devices help trace the path of buried facilities without having to unearth them. GPS and terrestrial LiDAR systems have replaced old surveyors’ transits and levels to augment survey systems.

These evolutions have taken the subsurface mapping industry to a new level of sophistication. The next evolution will overcome an obstacle that our forefathers faced in the 1800s, and that we still face today: how do we collect, store and retrieve valuable subsurface utility information for generations to come?

We believe the answer to that question isn’t below our feet, but in the cloud. Cloud-based data collection, storage, and dissemination systems that are transforming the subsurface utility mapping industry.

2D sum plan

The Plague of Lost and Mismanaged As-built Records

There are constant challenges involved in every step of collecting, storing, sharing, and recording surface utility data. For industry practitioners like myself, the challenge of locating deep, non-traceable facilities and extremely complex networks is a daily challenge. Existing trenchless techniques are often stymied by these challenges as more systems are buried deeper in the existing utility corridors to mitigate utility conflicts, hitting depths below the limits of our conventional utility locating equipment.

While this “drill deeper” approach decades ago mitigated some construction challenges, the failure to provide retrievable and reliable “as-built” plans and records leaves future projects in jeopardy.

Over the past few decades, many vital utility records have been lost and discarded, and with them went critical details that could help asset owners protect underground facilities from damage during construction and other work. Retrieval and storage of the records that have been preserved are often time consuming, expensive, and seen as undue burdens on asset owners.

In the utility location and mapping communities, there is an urgent need to standardize workflows in utility tracing, surveying, and data sharing. This is not only true of traditional utility constructors, but also of specialized trenchless utility providers.

tunnel plans

The Challenge of Storing and Retrieving Trenchless Project “As-builts”

In a successful trenchless technology project, there is often a project plan, geotechnical investigation, utility locating data, non-destructive vacuum excavation test holes, drill path planning, and a final report documenting the work. All of this information is very important for future projects and asset owners trying to maintain these facilities, but it is discouraging to see how many of these records – often made on paper – are lost and forgotten with no digital trace.

This data is critical for maintaining accurate GIS databases, which in some instances is required by law, yet as a global practitioner it is a rarity to uncover a record from a trenchless project. Even on smaller projects, there are vital sketches, planning approval, and “swing-tie” measurements and photographs that could assist future practitioners in locating, mapping, and flagging buried facilities.

This data is often submitted to the engineer and the project owner, but the industry does not have practical and appropriate workflows to ensure the information is updated in GIS geodatabases.

Benefits of Cloud-based Systems for Underground Projects

Fortunately, the advancements in cloud-based acquisition, storage and retrievable systems can bring the trenchless technology industry into a new era. Cloud-based data storage and exchange, utilizing connections available on the job site, can change the way we collect and store pertinent utility information.

In conjunction with software developers, cloud-based storage designers have begun creating systems aimed at improving workflows for subsurface location and mapping professionals. Utility locators and surveyors have long used electromagnetic utility locating devices (EMI) and ground-penetrating radar (GPR) systems to detect and identify buried infrastructure, but with little or no electronic data to support the accuracy of the field data investigation work. Today, cloud-based systems used in unison with GPS and Bluetooth transmissions enable those professionals to capture, locate, store, and share quality utility work right from the site.

In many cases, these programs can provide a “positive response” to a utility locate request and help document the response from One-Call responders. The attached metadata, EMI, GPR, photographs, and vacuum test holes data can easily be survey-located with geocoding. A cloud-based storage and retrieval system will help us store this data by geographical position rather than on a project-based system, thereby making it easier to access the data for future projects.

Moreover, the attribution and metadata will improve the workflows for inclusion in GIS records, positioning the work in conjunction with the necessary attribution. Cloud solutions also enable the data to be geofenced for future use, billing, sharing, and querying.

A cloud-based system even opens the possibility of financial monetarization of a digital cache that could be used by future project teams to uncover a lead to valuable subsurface information in close proximity to proposed work.

3D urban

Getting our Heads in the Cloud

For trenchless contractors, the possibilities of improved safety, access to current data and the ability to transmit that data in real-time with the corporate office are obvious. By using cloud-based storage, the data can be shared with supervisors who can provide live oversight of on-site progress and provide timely information to engineers and project owners.

Direct involvement from remote senior managers will bring enormous improvement to QA/QC measures, ensuring the work is performed in accordance with industry practices and the defined standard of care. Making informed decisions on a complex site can be challenging for any crew, but with oversight via the cloud, those decisions can be made in a collaborative environment.

The people who transformed the ground below Boston in the late 1800s sought better ways to manage surveying, planning, and construction in an increasingly challenging setting. Now, as then, we should always look for new and innovative ideas to improve project safety and provide a higher level of confidence in mapping the underground. It’s not just a good idea; it’s a shared responsibility.

Michael A. Twohig
Director of Subsurface Utility Mapping | DGT Associates

Michael A. Twohig is project director for subsurface utility mapping at DGT Associates, a Boston-based surveying and engineering firm. Twohig focuses on the fundamental practices of locating and mapping utilities at the highest levels utilizing modern technology, including lidar and BIM to map projects in true 3D.

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