Divers Get to the Bottom of Irvine Ranch Water District Reservoirs

June 18, 2012 - PRLog -- It isn’t necessary to drain a tank reservoir for maintenance inspections, just send a professional diver in to check things out. That’s just what has been taking place for the past several weeks at various Irvine Ranch Water District reservoir sites.

“We need to do this about every five years,” said Tom Roberts, IRWD Manager of Systems Operations. “During the inspection, the diver can check the condition of the hatches, examine the interior hinges, the condition of the ladder and assess overall condition of the tank.”

The operation can take up to eight hours, depending on the amount of sediment on the tank’s floor. The latest session took place at the Zone 3 Reservoir north of the former El Toro Maine Corps Air Station. This tank, built in the late 1970s, is a 154-foot diameter tank, 32 feet deep with 54 support columns.

Divers from the Colorado-based Inland Potable Services assembled at the reservoir and began the complex series of steps to set up operations. The three-man crew rotates duties every day. Every third day, one of them dives on the tanks.

“We have found IRWD’s water to be very clean, there is hardly any sediment,” said James Bingham, one of the crew members serving as dive attendant for the day.

The trailer is the nerve center of the task. It houses a console containing a video screen. A microphone allows the diver controller to maintain constant communication with the diver while he is in the tank. A camera mounted on the diver’s helmet displays video images on the screen of the diver’s progress inside the tank.

The diver attendant sets up the various hoses and cables that act as the diver’s lifeline while he is in the tank. Once the preliminary setup takes place, diver James Cullen is ready to don his vulcanized rubber dive suit. A hood, gloves, boots, weight belt and helmet complete the ensemble. An auxiliary air tank is included as a backup. Looking like something out of “20,000 Leagues Under the Sea,” the diver is ready to enter the tank. After all safety equipment is rechecked, Bingham sprays Cullen down with a chlorine disinfection solution, something that is done each time the diver enters the tank.

Inside the trailer, Ryan Torgerson adjusts the focus on the screen and the volume on the speakers. By now, the diver has splashed into the tank. The camera picks up images of a pitch black tank, only illuminated where the diver’s headlamp shines. He describes what he sees while pushing a large vacuum cleaner with a 48-inch-wide head to clean the sediment from the floor. A clear swath where the area is cleaned show on the screen. Sediment and water picked up is fed out of the reservoir through a hose and runs into a large filter bag, where it’s dechlorinated. The cleaned water is discharged into a storm drain.

Throughout the operation, staff members from Systems Operations and Water Quality take water samples from a sample point, where they are analyzed in the IRWD Water Quality laboratory.

More information about IRWD water quality is available on our website.