As an Engineering Surveyor, I have come to appreciate the importance of mapping underground utilities after working in this niche space for 17 years. Underground utility mapping refers to the process of creating a map or plan of the underground infrastructure, including water pipes, gas lines, and electric cables. These utilities are essential for the functioning of our cities and towns, and mapping them is crucial in ensuring their safety and reliability. In this article, I will discuss the importance of underground utility mapping, the methods used, and the advantages it offers.
Importance of Mapping Underground Utilities
Underground utilities form the backbone of our cities and towns. They provide us with electricity, water, gas, and other essential services. Despite their importance, these utilities are often neglected, and their location is not accurately recorded. I have seen it too many times where new conduits, optic fibre or pipes are installed and the as-built survey is an afterthought or no thought. This lack of information can result in accidents and injuries, such as gas leaks and electrical shocks. Furthermore, the lack of accurate mapping can lead to delays in construction projects, as workers may accidentally damage utility lines, resulting in costly repairs.
Mapping underground utilities is essential to ensuring public safety and reliable service delivery. By accurately mapping these utilities, we can identify potential hazards and take steps to mitigate them. We can also plan construction projects more efficiently, reducing the risk of damage to utility lines and minimising delays.
Risks of Not Mapping Underground Utilities
The risks of not mapping underground utilities can be severe. Accidentally damaging gas or electric lines can result in fires or explosions, which can cause property damage and injuries. Water lines that are damaged can cause flooding, property damage, and even contamination of the water supply. These accidents can result in costly repairs, lawsuits, and even loss of life. Accurately mapping underground utilities can help prevent these accidents by providing accurate information about the location, depth, material type, asset owner and another important attribute that gets overlooked, date of survey.
Methods of Underground Utility Mapping
Various methods can be used for underground utility mapping. These include:
Ground Penetrating Radar (GPR)
GPR is a non-destructive method of mapping underground utilities. It uses electromagnetic waves to detect changes in the subsurface, which can indicate the presence of underground utilities. GPR is a quick and effective method of mapping underground utilities, but it can be limited by the type of soil and the depth of the utilities.
Electromagnetic Locating (EML)
EML is a method of mapping underground utilities that uses electromagnetic signals to locate underground utilities. It is a quick and effective method that can be used in a variety of soil types. However, it can be limited by the presence of other underground utilities, structures and conductive material.
Non-Destructive Digging (NDD)
NDD is a method of mapping underground utilities that uses high-pressure water or air to loosen the soil around the utility. The loosened soil is then removed using a vacuum system, allowing the utility to be exposed and mapped. Vacuum excavation is a precise method of mapping underground utilities, but it can be time-consuming and costly.
Advantages of Underground Utility Mapping
Three main reasons why accurate mapping of underground services is advantageous for project stakeholders:
- Efficient Project Planning: Accurate mapping provides design teams with vital information about the location, depth, and layout of underground utilities. This knowledge enables them to plan projects more efficiently, avoiding clashes with existing services and streamlining construction workflows. Efficient project planning minimizes the risk of costly delays and revisions, ensuring timely project completion.
- Cost Savings: Precise mapping helps design teams identify potential utility conflicts early in the planning stage. By avoiding accidental damage to underground services during construction, costly repairs and associated disruptions can be mitigated. Design teams can optimize resource allocation and reduce the need for expensive modifications, leading to significant cost savings.
- Enhanced Safety and Risk Mitigation: Knowing the exact positions of underground utilities enhances safety on construction sites. Design teams can implement proactive safety measures to prevent utility strikes, protecting workers and the public from potential hazards. By reducing the likelihood of accidents, they also minimize the risk of legal liabilities and associated expenses.
Challenges of Underground Utility Mapping
Mapping underground utilities can be a challenging task. Some of the challenges include:
Inaccurate Records
Many underground utilities are not accurately recorded, making it challenging to locate them.
In some cases, certain contractors may provide sketches indicating the placement of underground services with the assumption that as long as the services exist and cater to the new property, the precise alignment and location are of little significance to them. This approach can lead to potential inaccuracies and complications during construction or excavation, as the true layout of utilities might not be adequately documented. To ensure optimal safety, efficiency, and reliability, it remains crucial for stakeholders to prioritize accurate utility surveys and as-built documentation, promoting informed decision-making and minimising risks associated with underground utility management.
Complexity
Underground utilities are often complexin urban areas due to increasing demands, shared infrastructure, and historical growth. Multiple services are often placed in a single trench to optimise space, leading to intricate layouts with multiple banks of conduits branching off to service different properties.To address these complexities, accurate mapping, comprehensive records, and advanced surveying techniques are essential for effective planning and maintenance while mitigating the risks associated with complex underground utility systems.
Soil Condition
Soils with high electrical conductivity, such as clay or wet soils, can absorb or dissipate the electromagnetic signals emitted by the EML equipment. This absorption can reduce the signal’s range and make it challenging to accurately locate cables buried beneath such soils.The depth and type of cable also play a role. Deeper cables might exhibit weaker signals, while certain cables with non-conductive coatings or armor can reduce the ability to detect electromagnetic fields.To overcome these challenges, experienced utility surveyors and technicians may need to employ complementary methods like Ground Penetrating Radar (GPR) or conductive tracing techniques to improve the accuracy of locating cables under challenging soil conditions. A combination of multiple methods often provides more reliable and precise results, ensuring the safe and efficient identification of underground utilities.
Technological Advancements in Underground Mapping
Technological advancements have made underground utility mapping more accurate and efficient. The development of GPR and EML has made it possible to map underground utilities quickly and accurately. The use of drones has also allowed for more efficient mapping of large areas.
Best Practices for Underground Mapping Projects
The best practice for accurately mapping underground utilities involves a collaborative effort between an experienced Telstra accredited Locator and an adept Surveyor who specialises in underground service surveys. The Telstra accredited Locator possesses specialised expertise in using advanced locating technologies. They have an in-depth understanding of utility networks and can effectively detect and map complex utility layouts. Paired with an experienced Surveyor, who routinely conducts underground service surveys, this dynamic duo forms a powerful team that combines practical field knowledge with cutting-edge technology. The Surveyor’s skills in accurately measuring, recording, and interpreting survey data complement the Locator’s expertise, resulting in comprehensive and reliable underground utility maps.
Verifying Results
The QA process of verifying and comparing surveyed underground services with existing records is crucial. Additionally, drafting the accuracies or quality of the surveyed Nodes in accordance with the Australian Standard AS 5488 is vital. This ensures that the mapped data aligns with the actual infrastructure and meets the established accuracy standards, enhancing the reliability and safety of construction projects. By adhering to AS 5488, design teams and stakeholders can confidently make informed decisions based on precise and validated underground utility information, minimizing risks and optimizing project outcomes.
Conclusion and Future of Underground Mapping
In the future, mapping utilities are likely to become more automated and digitized, leveraging technologies like Artificial Intelligence (AI), Machine Learning (ML), and Internet of Things (IoT). Drones and advanced sensors may play a significant role in conducting surveys and gathering real-time data, enhancing the accuracy and efficiency of utility mapping. Moreover, cloud-based GIS platforms will enable seamless collaboration and data sharing among stakeholders, leading to better-informed decision-making. Additionally, advancements in Augmented Reality (AR) and Virtual Reality (VR) may enable on-site utility visualization and planning, simplifying construction processes. Overall, the future of mapping utilities is expected to be more interconnected, intelligent, and streamlined, empowering cities and industries with enhanced infrastructure management and development.
Takeaway
As an Engineering Surveyor, I have come to appreciate the importance of mapping underground utilities. I am committed to contributing to the field and leveraging emerging technologies to ensure improved productivity, reducing costs, and mitigating potential risks to achieve optimal outcomes.The lessons learned have inspired me to dedicate myself to a career that stays at the forefront of innovation and seeks to overcome the challenges posed by complex utility networks, ultimately making a lasting impact on the industry.
Braydon Storm
Director, Storm Spatial