Subsurface Utility Engineering

Subsurface Utility Engineering was formalized as a discipline in the 1980s and is governed by ASCE Standard 38, "Standard Guideline for the Collection and Depiction of Existing Subsurface Utility Data." SUE combines geophysical surveying methods such as ground-penetrating radar and electromagnetic locating with physical verification through test holes (potholing) to build an accurate picture of what lies beneath a project site.

The ASCE 38 standard defines four quality levels of subsurface utility data: Quality Level D (existing records review), Quality Level C (survey of visible surface features), Quality Level B (geophysical designation), and Quality Level A (physical verification through test holes). Each successively higher quality level provides more accurate and reliable information about the position, depth, material, and condition of buried utilities.

Hydrovac excavation is the primary tool used to achieve Quality Level A data, the highest and most reliable level. SUE firms routinely deploy hydrovac trucks to pothole utilities at critical points along a project corridor, verifying the information gathered through desktop research and geophysical surveys. The data collected through SUE prevents utility conflicts, reduces change orders, and significantly lowers the total cost of infrastructure projects.