Site C Hydroelectric Dam – Slope Monitoring

Project Snapshot

Project Overview

Introduction

Underhill conducted monitoring of high‑instability slopes in areas with increased construction traffic, worker activity, and project infrastructure. The objective was to help ensure the safety of personnel and assets on the Site C project by identifying areas prone to failure. The data collected supported engineers in making informed decisions and implementing appropriate controls in future design phases.

Innovative Solutions

Underhill’s integrated aerial and terrestrial monitoring program delivered significant benefits to BC Hydro throughout the project lifecycle. Rapid UAV deployment drastically reduced time spent in hazardous zones and provided more frequent monitoring epochs than traditional methods alone. High‑resolution point clouds, LiDAR datasets, and ortho‑imagery enabled engineers to visualize slope movement, detect early deformation trends, and verify design assumptions with confidence. Over multiple years, Underhill supplied a continuous, comparable dataset that greatly enhanced BCH’s ability to track slope stability across all high-risk areas. This proactive insight supported timely interventions, reduced potential infrastructure damage, and improved overall site safety.

Underhill’s Approach

For the Site C Clean Energy Project, Underhill Geomatics Ltd. employs a comprehensive, safety‑driven approach to monitoring high‑instability slopes across critical work areas. Our strategy combines advanced aerial technologies with proven terrestrial survey methods to deliver accurate, repeatable, and timely slope monitoring data.

To minimize personnel exposure in hazardous zones, Underhill leverages UAV‑based photogrammetry and LiDAR, supported by Transport Canada–certified advanced UAV pilots experienced in operating in complex industrial environments. These aerial platforms enable rapid, large‑area data capture while maintaining high accuracy and consistency across frequent monitoring intervals.

Complementing our aerial work, terrestrial scanning and prism‑based monitoring provide precision measurements in areas requiring detailed ground‑based analysis. All data is processed using industry‑leading software, including Agisoft Metashape, Trimble Business Center, QBase3D, and DJI Pilot, ensuring robust quality control and efficient workflow management.

With an established network of over 1,000 permanent targets and a highly refined RTK‑enabled workflow, our teams can deploy quickly and execute consistent, high‑quality surveys with minimal setup time. Support from Underhill’s additional offices enables the processing of high data volumes and ensures fast delivery of results.

This integrated approach provides BC Hydro with reliable, high‑resolution point clouds, ortho‑imagery, and comparative datasets that clearly track deformation over time. These deliverables empower engineers to assess slope stability, identify areas at risk, and implement proactive safety and design measures—ultimately enhancing project safety, reducing risk, and supporting informed decision‑making.

Client Benefits

• Ability to make informed decisions regarding safety and site infrastructure timely and efficiently.
• Aerial methods take a fraction of the time to collect vast amounts of data, ensuring that vital information is collected which may have been missed in a traditional survey.
• An ongoing snapshot of slope deformation with an increased number of epochs due to higher efficiency of aerial methods.
• For large areas such as Septimus Hill or the Left Bank Excavation (LBEx) it would take days to survey with traditional methods, where aerial methods (photogrammetry/LiDAR) can complete these tasks in hours (including target placement if required). If higher amounts of vegetation is encountered, LiDAR will help to reach ground level with multiple returns from each pulse.

Technologies Used

Equipment & Data Capture

• DJI M300/350 RTK
• Quantum Systems Trinity F90+
  • Sony UMC R10-C Mapping Camera
• Trimble SX10 1” Scanning Total Station

Software

• Agisoft Metashape
• Trimble Business Center
• DJI Pilot
• QBase3D

Unique Capabilities

• Special Expertise
  • Advanced UAV Pilots (TC Certified) with BCH AOD approval to fly at PCN  and for BCH projects.
  • Experienced high hour pilots with experience operating in adverse, complex environments.
• Rapid deployment of services with long tenure on this specific project. Targets are already placed and allow crews to conduct RTK enabled flights with a significant number of checks to ensure quality of work.
• Efficient workflow from processors allows data to be sent to client in a timely manner, allowing them to make quick decisions.