A significant erosion zone observed along the downstream side of the toe berm of the embankment at a hydroelectric dam raised concerns regarding the potential infiltration of erosion through the embankment dam from the upstream side.

The dam structure comprises a 4,500-foot-long rock embankment complemented by a concrete gravity dam section. The water depth along the embankment section is measured at -110 feet. Glenn Industrial Group (GLENN) was assigned the responsibility of conducting an inspection utilizing leak detection equipment to ascertain the origin, if any, of the erosion downstream.

Given the substantial water depth and expansive surface area inherent in the embankment section, a departure from conventional diving methods is imperative. GLENN has deployed its remotely operated vehicle (ROV) equipped with dye release and positioning systems to meticulously inspect 100% of the submerged areas of the east embankment, totaling 22,000 square feet. Notably, GLENN’s dye release system is capable of dispensing dye under pressure, with a capacity of up to 68,000 gallons per mixture before requiring replenishing.

The inspection outcomes conclusively established the absence of any discernible leakage through the dam. A subsequent in-depth analysis identified the erosion as a consequence of an extraordinary volume of rainfall and substantial runoff. Upon reflection, the owner recognized the instrumental role played by GLENN’s ROV leak detection system in facilitating a thorough analysis of the event, leading to substantial cost savings for the project—an impressive amount exceeding $300,000