ASI Group

Navigating the Depths


ASI’s Underwater Inspection at a Hydroelectric Power Plant

ASI embarked on an underwater assignment to inspect the general condition of a hydroelectric power plant set against the backdrop of the scenic northeastern United States.

The primary mandate was to complete a comprehensive underwater inspection encompassing vital infrastructure components. These included the examination of trash racks, gate slots, main access ladders, intake forebay, and tail race areas. The overarching objective was to discern and evaluate the condition of these elements, ensuring seamless power generation for the plant.

To achieve this scope of work, ASI enlisted the capabilities of an inspection-class remotely operated vehicle (ROV). This ROV was customized with a state-of-the-art HD video camera, real-time 2D sonar imagery, and a mechanical scanning multibeam sonar for gathering 3D point cloud data from every submerged surface.

seabotix vlbv300

Navigating through Murky Waters

However, the mission was not without its challenges. The waters were murky, rendering visibility a near-impossibility due to excessive turbidity within the water column. In such conditions, ASI’s deployment of 2D and 3D sonar technologies was instrumental. These advanced sonar instruments enabled the capture of detailed underwater data. The data collected identified areas of concern and the information required for the general assessment.

ASI collected multibeam sonar scans in a consistent manner throughout each draft tube and each side of the water passage. The scans covered the full tube and tailrace area to identify potential scour and undermining areas. The selected scan positions provided overlap with the adjacent scan, ensuring complete coverage in the final presentation of data. Extracted cross-sectional profiles from the 3D point cloud data were used to analyze the elevation of the river bottom at the downstream face of the power plant.

hydroelectric plant 3d point cloud of trash racks gate slot and draft tube
3D Point Cloud Data

The Conclusion

As the final deliverables, ASI provided the client with a comprehensive inspection report, replete with intricate insights. Additionally, the client received captured 2D sonar images, sonar profiles, contoured bathymetric plans, and 3D point cloud data. These deliverables served as a key component towards optimal operational efficiency for the assessment and maintenance planning of the hydroelectric power plant. This project underscored the importance of condition assessments for maintaining infrastructure. At ASI, we take pride in our unwavering commitment to pushing the boundaries of technological innovation, all in pursuit of safeguarding the critical infrastructure that powers our modern world.