The temperature hovered around 110 degrees. Humidity levels felt like those of a sauna. Looking up, or around, one could see nothing but darkness.
Welcome to the underside of the second new cover for Newport Beach's Big Canyon reservoir, which stores up to 195 million gallons of drinking water for distribution in the city.
The cover replaces a tarp constructed in 2005 that wore down prematurely. The completed installation of the new one, expected Friday, will clear the way for the reservoir to be filled once again and bring city staff one step closer to putting its cover problem to rest.
Putting in the swath of thick, black fabric has been no small task. The rectangular, concrete tub it protects looks like a swimming pool built for giants.
The reservoir, at the base of Spyglass Hill, next to the Pacific View Memorial Park and Mortuary, is one of the largest for drinking water in Orange County, said George Murdoch, Newport Beach's utilities general manager.
On a normal operating basis, the 22-acre reservoir annually supplies water to 70% of the city's homes. The rest is imported for a fee from the Metropolitan Water District, said Patrick Thomas, the city engineer and deputy public works director.
This system is significantly cheaper than having the city buy all of its water from the district, he said. The reservoir also stores enough backup water to satisfy customer needs for at least a week in case of emergency.
"We depend on that reservoir," Murdoch said. "We're excited to get it back in service."
Maintaining this city resource has come with its fair share of headaches.
As state health requirements became increasingly stringent in the 1990s, the city faced the decision in 2003 either to abandon the facility or install a cover that would help ensure that water quality standards were met.
Officials elected to buy a polypropylene cover that they believed would last 20 years. It was lighter and less expensive than other options, according to city records.
There would be no more algae, no more African quad frogs, no more insect larvae, as in earlier decades.
"Essentially you're making it a tank," Murdoch said.
But within about five years of the first cover's installation, staff noted "a significant amount of degradation," records show.
The city filed a complaint against the contractor, Banshee Construction Co., and its subcontractors in December 2011. As of this week, the litigation remains to be resolved.
Meanwhile, the city's water still needed protection. In March 2012, the City Council approved the design of the new cover.
The city paid Irvine-based MWH Global about $550,000 — which is coming from the city's capital improvement fund — for the design of the new fabric that would keep the Newport Beach drinking water safe. This time, it would be made of a different material, chlorosulfonated polyethylene, or Hypalon, which has been used in the floating-cover industry for decades.
The reservoir stood empty during the summer months while 20 to 30 MPC workers secured the latest cover. With the reservoir drained, water has simply been pumped straight from four wells in Fountain Valley, through a treatment facility at a separate site and into Newport Beach homes.
The staff melted together 29-foot-wide panels of material to create the necessary shape and then bolted the cover's edges to the reservoir's perimeter. Then they began to look for puncture holes.
On Tuesday, the MPC team pumped air under a portion of the cover. Four men donned hard hats and reflective vests, grabbed their flashlights and slipped radios into their pockets. Then, opening a square hatch on the top, they slipped into the air pocket beneath.
The men allowed their eyes to adjust to the darkness. Stepping carefully on the wet cement, they looked for what they call "star lights" or "pin holes." Any dots of sunlight indicate an opening that needs to be sealed.
"It's always fun to get to the end," said MPC construction manager Johann Konrad. "It should go quite well."
Water will once again re-enter the reservoir Tuesday morning. The Health Department will inspect the reservoir once it's filled and disinfected.
City officials hope Newport Beach residents will be drinking from it by Thanksgiving.
"It's making the water cleaner and safer for use," said Mike Sinacori, an assistant city engineer. "I trust our water more than anybody else's."