Deep Ocean Engineering uses ROV to inspect intake riser at Cherry Lake Dam

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Deep Ocean Engineering, Inc.’s Phantom T4H remotely operated vehicle (ROV) has successfully completed an inspection of the intake riser at Cherry Lake Dam near Yosemite in California.

During the inspection, the ROV successfully chronicled the “state of the dam’s water intake riser and the position of the gates at a depth of 258 feet (78.6m),” which is approximately a quarter of the ROV’s rated capability.

A Dynamic Positioning (DP) capable triple pontoon boat with a forward mounted ROV Launch and Recovery System (LARS) was used during the inspection, as it sent the ROV to the intake riser’s coordinates, while maintaining a steady position.

The ROV used an Imagenex 881 Sonar as it descended to scan the area, and after quickly and easily locating the intake riser, it flew to it.

Thanks to powerful LED and HID lights from Deep Sea Power and Light (DSPL), the ROV inspected the structure and observed the internal condition of the dam without entering it.

According to Deep Ocean Engineering, the video images were so clear that the “dangers of using saturation divers and further intervention were completely unnecessary,” which saved the city money, time and hassle.

The San Francisco Public Utilities Commission was able to use the video feed provided by the Phantom T4H to determine the condition of the dam’s intake riser, and the Commission is preparing for major rehabilitation construction later this summer.

For over 60 years, the Cherry Lake Dam has provided water and power to the San Francisco Bay Area, Modesto, and Turlock districts. The structure has not been seen since its construction in 1956.