Excavation Damage to Underground Utilities Expert Article

When underground utilities are damaged during development and infrastructure improvement projects, the consequences can range from minor setbacks to serious delays, loss of service and repair costs, environmental impacts, and/or personal injury.

Civil engineers at Robson Forensic are frequently retained to investigate and analyze circumstances surrounding various types of utility conflict incidents. In this article, Land Development Expert, Donald Hemphill, P.E., explores some of the intricacies and issues where underground utilities are encountered during construction activities.

Investigating Underground Utility Conflict & Damage Incidents

During project planning and design phases, engineers often review utility records and marked field location to understand and avoid existing utilities on new development and infrastructure improvement projects. Contractors must take reasonable measures to locate and avoid underground facilities prior to digging and excavating.

Despite precautionary measures taken, unknown utilities can be encountered during construction and may result in:

• Safety hazards (e.g., high voltage electricity, flammable substances, flooded work areas, etc.)
• Construction schedule delays
• Additional design work and redesigns
• Environmental contamination and/or violations from spills and releases
• Construction cost increases associated with idle equipment and crews
• Cost of relocations or repairs of damaged utility infrastructure
• Costs associated with the “loss of use” of the service being provided by the damaged utility

Underground Utility Types

New or existing utilities involved in conflicts may include:

• Fiber optic, cable TV, and telecommunications lines
• Natural gas and petroleum pipelines
• Power / electricity lines
• Water mains
• Sanitary sewers
• Stormwater drainage systems
• Water reuse and/or irrigation systems
• Steam lines

Public utilities are owned and operated by a utility company or municipal entity, and are commonly located in roadway rights-of-way or utility easements. Private utilities and service lines are typically located on private property.

One-call notification centers coordinate with utility operators to identify and mark public lines only. Private lines typically require a third-party utility locating company to locate and mark utilities. Standardized paint colors are widely used in marking utilities based on the American Public Works Association color coding standards.

Records of utility locations are often schematic in nature or non-existent, providing minimal benefit during the design stage beyond increased awareness that a utility might be present. Records commonly provide only an approximate horizontal location and often no information on depth.

In many cases, the engineer will investigate the potential for existing utilities during the preparation of construction drawings and bid documents. In most cases, the contractor is responsible for conducting a one-call notification and marking request prior to excavating.

Easements, Right-of-Way Plats, Encroachment Agreements

Language in a recorded utility easement or Right-of-Way plat is important to consider early in the design process, ideally matching the requirements defined in the construction contract. Encroachment agreements may be required by the utility company to permit the crossing of a new utility, or infrastructure improvement, through an existing utility corridor.

Easement and right-of-way documents may also contain language related to:

• Obligation for a utility company to relocate their utilities within a specified period of time after a request
• Obligation for a utility company to pay additional costs if their utilities are not relocated in a timely manner

Some Department of Transportation contracts provide a mechanism of compensation for situations when unmarked/mismarked utilities are encountered, or when utility relocations are late. Other types of construction contracts can also include mechanisms to address additional work situations resulting from unexpected utility conflicts.

Excavation and Trenchless Technologies

Construction activities commonly include excavations and open cut trenches but may also include trenchless technologies such as horizontal directional drilling, pipe bursting, auger boring, and jack & bore or pipe ramming. Utility strikes and other damage to roads and structures can occur when utilizing trenchless technologies due to:

• Miscalculated drilling or pipe ramming angles
• Alignment issues during installation (e.g. bore veering off course)
• Miscalculated soil assessment or host material
• Potential for ground heave
• Existence of unknown buried utilities

State codes and regulations often define the responsibilities of the “excavator,” the one-call notification center, and the “utility company/operator” during standard and emergency situations. Exceptions to the duty of excavators may exist for work in, or related to:

• Cemeteries
• Secured facilities with no conflicting easement or ROW
• Railroad maintenance within 15 ft either side
• County road repairs to 24” depth
• Agriculture

Contractors’ personnel should be trained to recognize utility line markings, respond to emergency situations, and understand local safety regulations. When a utility strike occurs, the Contractor is typically required to stop work, notify the Utility Company, and coordinate the repair or modification.

Expert Analysis of Utility Incidents

A forensic analysis of incidents involving a utility strike, or utility unexpectedly discovered during construction, may include review of the following:

• Utility company record drawings
• Recorded easement agreements and right-of-way plats
• Subgrade Utility Engineering (SUE) investigations - nondestructive testing (NDT) by a utility locator (using ground penetrating radar, electromagnetic locating, or video pipe inspections)
• Hydro or vacuum excavation / potholing to expose top of pipe or line
• Design drawings & specifications
• Construction contract documents
• Communication records during construction

At Robson Forensic, we have civil engineering experts with experience with utility conflict matters who can assist in providing clarity around the circumstances of an incident and actions taken by the parties involved.

For more information, submit an inquiry or call us at 800.813.6736.

Featured Expert

Donald M. Hemphill, P.E.

Civil Engineer & Land Development Expert

Donald is a civil engineer with nearly three decades of experience in land development and infrastructure projects. He understands the development process from the beginning of concept planning and… read more.