Dave Conn has become frustrated with the water that comes out of the faucets in his Coos Bay home. During the summer months, it often has a dirty brown color and doesn’t taste very good, either. World Photos by Madeline Steege

COOS BAY — More than two months ago, Dave Conn decided he had had enough.

A devoted Diet Pepsi drinker who routinely went through four or five cans a day, Conn wanted to cut back on his caffeine. So he quit drinking the bubbly brown beverage cold turkey.

It was not a pleasant experience. He suffered caffeine-withdrawal headaches. But he also got headaches because of his frustration over his replacement drink: discolored tap water.

Conn was aware that the quality of water from the Coos Bay-North Bend Water Board declines in the summer when manganese dissolves into it.

“It’s hard enough to break away from caffeine from pop, but then to have to drink foul water is just not right,” he said.

Conn is not alone in his distaste of Water Board water. General Manager Rob Schab said the Water Board can receive 50 complaints a day when manganese levels are at their highest.

Schab has been grappling with manganese-related water problems since 2001. That was the year the board tripled the volume of its Pony Creek Reservoir. The increase was made to satiate the thirst of a growing population and avoid the need for rationing during drought years. But it also created an environment in which manganese in the soil at the bottom of the reservoir frequently leaches into the water supply during summer months. Every year, crews have endeavored to find a solution to the problem. Every year they learn more about the problem, but never completely eradicate it.

Although he sees improvement, Schab said it will probably not be until 2011 that a permanent solution can be achieved with upgrades to the treatment plant.

“We know it’s a huge inconvenience to our customers and we are dedicated to finding a long-term solution,” he said.

Prior to the expansion, the water depth was 38 feet. Manganese was something the Water Board had to pay attention to, but it wasn’t a big problem. That changed with the expansion, when the depth increased to 59 feet.

“That first year, we were caught off guard,” he said. “It was not on our radar screen.”

But it didn’t take too long to determine what the problem was. With the arrival of summer weather, the reservoir water separates into different levels depending upon its temperature. Warmer water remains near the top and cooler water stays at the bottom. No longer in contact with the surface, this low-lying water becomes oxygen-deficient.

That causes manganese to leach out of the adjacent soil. Although it does not pose a health risk, the metal discolors water and produces an unpleasant taste.

The battle joined

At first, there seemed to be a simple remedy: add chlorine at the beginning of the water treatment process to get the manganese to drop out. Schab said this tactic worked rather well, but the solution created an even worse problem.

The additional chlorine created compounds that taste and smell bad. Worse still, disinfection byproducts, which can pose health risks, were appearing in water tests.

“Given the choice between an unseen health risk and discolored water with a non-health risk, there really wasn’t any decision to be made,” Schab said.

The Water Board’s next step was to bring out an engineer who specializes in manganese removal. He recommended coating filters with potassium permanganate, but this also failed to take the metal out of the water.

By this time, Schab said, the tactic changed from getting the manganese out of the water to supplying customers with water that didn’t have it in the first place. So last summer, the Water Board opened up the bottom of the dam at the beginning of the summer to allow manganese-tainted water to flow out over a couple of weeks.

Schab said they saw improvement in water quality until September, when the reservoir restratifed.

“By this time, we knew we can’t treat it. We can’t flush it out. What if we built a floating intake and take water from the top of the reservoir?” he said.

In the middle of June, the Water Board shut off the lower intake pipe and started collecting water from the top of the reservoir. This idea faltered until the Water Board realized the wetlands at the head of Merritt Lake, located below the reservoir, had manganese, too. An 800-foot pipe was devised to send it directly into the lake, and subsequently into the water pipelines.

“Around the first of August, we saw better water. And then within 10 days, we started getting really good water,” he said.

Most people can start tasting manganese in water when its concentration is 0.05 milligrams per liter. At times during the summer, some Water Board customers might have been drinking water with 0.3 milligrams per liter. Schab said the highest result was .526, collected in early August near the intersection of Newmark Street and Tremont Avenue in North Bend. By the middle of August, overall levels were back down to between 0.05 and 0.07 milligrams per liter.

“Now we are looking for the ‘sweet spot,’ so instead of taking water from three feet below the surface, we go down to nine feet and avoid the (biological) activity and not get into high manganese,” Schab said.

Next step

At this point, Schab says the ultimate solution might involve having the option of taking water from different levels of the reservoir and lake.

“We are dealing with nature, not a vessel we can easily control,” Schab said. “Finding that sweet spot depends on sunlight and wind and what’s going on at the bottom.”

The board also will be revisiting the original approach of treating the water for manganese. Schab said the Water Board is starting to plan upgrades for the treatment facility. Designs could be reviewed by late 2008, with two years of construction starting in 2009. The new facility would be specifically designed to ensure manganese levels remain below 0.05 milligrams per liter, even during the worst conditions.

There also is an idea floating around that the water could be aerated. Schab noted there are machines that run for about $30,000 that could be installed in the reservoir. The question is: How many machines are needed to prevent stratification?

“Do you buy one? Do you buy seven? Do you buy 20?” he said. “That’s something we would need to explore.”