COOS BAY — The phones have been unusually quiet this summer at the Coos Bay-North Bend Water Board.

Around this time last year, receptionists were taking as many as 50 calls a day from customers complaining about their water. The culprit was manganese.

The metal is naturally occurring in the area’s soil and can be found in local water year-round. But when it’s in high enough concentrations, manganese discolors water, stains fixtures in people’s homes and makes the water taste bad.

Since the board tripled the volume of water in the Upper Pony Creek Reservoir, it has grappled with manganese-related problems, mostly without success.

Until this year.

Rob Schab, the agency’s general manager, is hesitant to declare victory, but the lack of phone calls is a telling sign. So, too, are the latest test results, which show manganese levels far below the marks of previous years.

Water Board staffers aren’t the only ones noticing a drop in complaints.

Joseph Monahan, general manager of the Coos Bay Red Lion Hotel, said in past summers, his staff answered at least three or four calls a day from guests.

“They would complain their toilet wasn’t cleaned. Then they would flush and see it was the water,” said Monahan.

But Monahan’s employees haven’t had to field such calls in a while.

“It is a whole lot better than last year,” he said.

The apparent success comes from several years of trial and error on the part of the Water Board, a floating water intake system and some help from an expert in Connecticut.

Too much water

The problem first appeared in 2003, two years after the Water Board completed construction on a new dam for the reservoir. The improvement increased water capacity three-fold, but it also set the stage for manganese problems. 

Manganese likes water that doesn’t have oxygen. That became more plentiful by the summer of 2003 when the reservoir had filled. During the summer, water near the surface is heated by the sun, making it less dense than the deeper water.

The water near the bottom slowly loses its oxygen, creating a climate in which the manganese leaches out of the soil.

“The reservoir always stratified, but never as severe as what started in 2003,” Schab said.

At first, the Water Board tried to solve the problem by treating the water with chlorine. Chlorine gets rid of manganese, but it also creates bad-tasting compounds and byproducts that could have posed a health risk. Eventually, Schab’s staff shifted its focus to getting better water into the treatment plant.

In 2006, the Water Board opened the bottom of the dam at the start of the summer to flush out the manganese-tainted water. It didn’t work. There was less manganese for several weeks, but eventually it returned.

The light at the end of the tunnel first appeared last summer. Since the top of the reservoir remained oxygen rich, and thus manganese-poor, the Water Board decided to use a floating intake system to collect water nine feet below the surface. This should have been the end of the problem. It wasn’t.

The reason manganese continued to plague customers last year was because the water didn’t go directly from the reservoir to their taps. It first went through Merritt Lake. And the warmer water coming from the surface of the reservoir caused severe stratification of the lake, creating a manganese problem there, too.

The Water Board brought in Robert Kortmann. He’s a principal at Ecosystems Consulting of Connecticut and specializes in solving reservoir stratification problems. He said the Water Board was on the right track, then offered the last piece of the puzzle. He suggested taking water from a level about 7 feet from the bottom of Merritt Lake. It wasn’t deep enough to draw water with high manganese levels, but it was low enough to somewhat mix the lake and keep it from severely stratifying.

This year, it seems to have worked.

Out of sight

The metal may make a return visit this fall. When the weather begins to cool, the water at the top of the reservoir and lake will cool, and mix with the lower strata, where manganese is present.

The new approach to collecting water may solve this problem, too, but if not, a more permanent fix may be available soon.

Schab said the Water Board is planning a treatment plant expansion, which it hopes to complete by 2011. The renovation will allow the agency an opportunity to see if it might find a way to treat the water to get rid of the manganese.

“That’s our next hurdle,” he said.

For now, Schab is happy to report he hasn’t received a single complaint about colored water this summer. Well, almost none.

At the end of June, treatment plant staff got a call from a customer who wanted to know where the manganese was, since it usually appeared that time of year.

“We try to please every customer, but in this case, we just couldn’t,” Schab said.

(Staff Writer Alexander Rich covers Coos Bay-North Bend Water Board issues for The World. He can be reached by calling 269-1222, ext. 234; or by e-mailing to arich@theworldlink.com.)