Arnold Air Force Base, Tenn. -- AEDC's John Berlan and John Richardson, standing on the secondary reservoir's west bank recently watched in awe as a fire truck drove onto the bottom of the drained 56-million gallon capacity reservoir. 

The vehicles' occupants were there to provide support to a team repairing the 1950s-era reservoir. 

It was the first time the two men, as well as most of those conducting the repairs, had ever seen the reservoir empty for such an extended period of time. Berlan and Richardson remarked on how the fire truck, other vehicles and people below were dwarfed by the size of the emptied reservoir. 

"The job underway is to patch a hole in a section of the 60-inch diameter pipe where it enters the reservoir through what is called the stand pipe," explained Jeff Quattlebaum, the cooling water system engineer with ATA's reliability engineering branch. "We usually drain the reservoir once a year for cleaning out the sedimentation, but it only stays dry for a couple of hours versus the months it has been empty this time. 

"It is not possible to excavate the pipe without removing part of the earth berm that makes up the east wall of the reservoir, so we had to enter the 25-foot high-by-60-inch-diameter stand pipe to make the repairs from the inside of the pipe." 

The secondary reservoir supplies water to the pumps in the secondary pumping station, which routes water to the rest of the base in support of ground testing and associated operations. 

Quattlebaum said members of Arnold's fire department were on hand to provide a rescue standby while personnel were inside the pipe line making repairs. The only way in or out of the pipe was through the end of the 25-foot vertical pipe. 

"This whole effort had been planned since the first part of July," he continued. "It required significant support from the base's civil engineering shops, including folks from the pipe shop, roads and grounds, carpenters and masons. We also had support from the cooling water operators, the Mission Operations Control Center planners and schedulers, and Tactical Integration Group. It all culminated in the mason and cooling water system engineer entering the pipe for about three hours to seal the leak with 20 to 30 gallons of grout." 

Quattlebaum also said critical support for the project came from the safety office and industrial hygiene personnel who checked the confined space before entry and provided general safety oversight during the entire effort. 

"This is the longest the secondary reservoir has been empty since it was constructed in the early 1950s" he said. "This extended outage period was made possible by some piping additions installed under the Alter-Cooling Water Military Construction Project that was completed in the late 1990s and some other modification that were accomplished under the PPS Cone Valve Replacement Project (2007) and the Water Treatment Plant Upgrade Project in 2006."