Underground Surveying: Everything You Need to Know

3D Scanning

Underground surveying is a critical element of any development or construction project. Identifying what lies beneath the surface of the earth is essential, particularly if you’re planning on disrupting the ground. With comprehensive underground surveys, you can ensure that subsurface infrastructure is accurately mapped out so that project plans can be updated accordingly.

What Is an Underground Survey?

As the name suggests, an underground survey focuses on ascertaining what lies beneath the ground in a specified area. Typically, this is focused on utilities, as there is often a complex network of pipes and cabling at varying depths. With a professional underground survey, relevant subterranean utility assets, such as water pipelines, sewage systems and gas conduits, are accurately identified.

However, there are two types of underground surveys that can be utilised:

  • Desktop utility survey
  • Underground utility survey

Desktop Underground Survey

A desktop utility survey involves liaising with utility companies and requesting plans of their assets and installations across a particular site or area. Typically, utility companies will provide details of any installations they have running over, through or underneath a specified site in the form of CAD drawings.

The resulting CAD drawings from multiple utility companies are then amalgamated to provide a comprehensive depiction of the subterranean network that lies beneath the survey site.

While it is not always possible to obtain information regarding every underground installation, liaising with both local and national utility companies allows us to access a vast amount of data. This enables a good overview of the subsurface to be obtained before additional surveying works are undertaken.

Although desktop utility surveys are extremely worthwhile in their own right, they are typically carried out in advance of an underground utility survey. This enables preliminary information to be sourced and mapped via the desktop survey, with more detailed data then obtained via an underground utility survey.

Underground Utility Survey

An underground utility survey uses ground penetrating radar (GPR) technology to identify structures beneath the surface of the earth. When the radar beam penetrates the ground, electromagnetic waves are reflected back and captured by antennas when a change in the composition is detected. So, when the radar beam encounters a water pipeline, for example, the variation in electromagnetic waves allows the underground utility asset to be accurately identified and mapped.

When Is an Underground Survey Required?

Underground surveys are beneficial for a wide variety of projects, but they’re often legally required too. Construction projects that could potentially damage underground assets or structures are typically legally mandated to undertake underground surveys before the project commences, for example.

Any company that is planning a project that legally requires an underground utility survey to be carried out must ensure this is completed in accordance with their regulatory obligations. However, it isn’t just companies and projects that are legally required to carry out underground surveying that should proceed with these activities. Indeed, the valuable data and information that can be ascertained via subsurface surveying make them an essential activity for a wide variety of projects and developments.

What Is a PAS 128 Underground Utility Survey?

PAS 128 is the specification given to underground utility surveys that are compliant with the standard set out by the British Standards Institution. Officially known as BSI PAS 128:2022, underground utility surveys that are PAS 128 compliant are carried out to the highest industry standards.

The Standards sets out “clear requirements when carrying out the detection, verification and location of active, abandoned, redundant or unknown utilities” and, therefore, ensures that compliant methods are used to deliver optimal results.

When choosing a surveying company to carry out underground utility surveys on your behalf, it is well worth checking that their surveys adhere to the PAS 128 standard. By doing so, you can ensure that the resulting insights are accurate and be confident that the survey provides a comprehensive insight into the subterranean structures beneath the ground’s surface.

When Should An Underground Survey Be Carried Out?

Although some projects are legally required to carry out underground utility surveys, there are many types of projects that can benefit from this type of survey such as:

  • Property developments
  • Construction of infrastructure (e.g., roads, bridges and railways)
  • Geological evaluations
  • Tree planting
  • Archaeological sites
  • Urban planning

As you can see, there are a wide variety of projects which benefit from underground utility surveys. Indeed, any project that is likely to be impacted by or have an impact upon the substructure should involve underground utility surveys.

What Are the Benefits of An Underground Utility Survey?

Underground surveys can deliver a wide range of benefits, such as:

Optimal Planning Accuracy

By obtaining accurate data regarding subsurface utility assets, the project plans can be made and updated with access to all the relevant information. As a result, plans are less likely to be subject to last-minute modifications and enhanced accuracy will allow for more effective project preparation.

Increased project efficiency

Having an accurate map of underground utilities reduces the risk of subsequent delays once the project is underway. Being unaware of critical, subsurface utility assets means delays are highly likely to be incurred once they are uncovered during the construction phase, for example. By conducting professional underground surveys in advance, however, you can increase efficiency throughout the entirety of the project.

Enhanced site safety

When workers and project managers are fully aware of the underground assets and structures, they are likely to encounter, effective safety protocols can be implemented in advance. Similarly, companies can take steps to ensure public safety is not put at risk while works are on-going when data from underground utility surveys is used to plan the proposed works.

Reduced repair costs

If you inadvertently damage an underground utility asset while undertaking a project, it’s highly likely that you’ll be liable for the cost of repair. Depending on the severity of the damage and the requisite repair works, this can run to a substantial sum and will greatly increase the cost of your project. By using underground utility surveys to accurately identify these assets and incorporate them into your plans, however, you can reduce the risk of damage occurring and, therefore, protect your liability.

Lower project costs

The increased project efficiency that arises via the use of underground utility surveys can equate to reduced project costs. Indeed, the fewer disruptions that delay the project, the more profitable it can become. Furthermore, avoiding the need for post-construction repairs further reduces liability and expenditure.

Comprehensive Underground Surveys from GeoCart

To find out more about our range of underground utility surveys or to talk to one of our expert teams about our services, contact GeoCart now on 07397 223 267, email us at office@www.geocart.co.uk or send us a message here.