CHARLESTON — It could be the birds in the sky, the elk in the field or septic tanks near Big Creek.

With a year of research behind them, investigators still can’t say for sure what is the culprit behind water contamination at Sunset Bay.

What they do know is the recurring bacterial infestation comes from the creek, which extends to Seven Devils Road. The bacteria is dependent on rain and it stays in the water a much shorter time than originally believed.

“The greatest concentration of bacteria were mostly at the mouth of Big Creek (but) we don’t know what the actual source is,” said Dr. Steve Rumrill, a marine biologist with the South Slough National Estuarine Research Reserve and primary investigator for the Sunset Bay State Park bacteria study.

Identifying what among the usual suspects — elk, deer, beaver, geese, nutria, domestic animals, septic tanks and decaying vegetation — is to blame, can be done only conclusively via DNA fingerprinting. That big ticket item could cost as much as $200,000 and Rumrill said he doesn’t know if he will be able to obtain funding to do it.

Instead, Rumrill and his assistant, Ben Grupe, have focused on changing how state departments protect the public from dirty water.

A swim at the beach

Within the past four years, beachgoers have at times encountered signs from the state’s Human Services and Environmental Quality departments warning them to stay out of the water.

They post signs when monthly tests show high levels of fecal coliform bacteria, including E. coli and enterococcus. Swimming or playing in contaminated water could turn a day of surf and sand into a painful memory of gastroenteritis, skin rashes, upper respiratory infections and other illnesses, depending on a person’s age and health. Children and the elderly are the most susceptible.

However, because of low staffing levels, DHS beach monitors rarely are able to return in a timely manner to re-test and remove warnings. This was one, if not the main, inspiration for the study. While the DEQ has a policy to warn of bacteria when it is discovered, it has no procedure preemptively to deal with it.

“DEQ doesn’t have an easy job because, ideally, water should be tested every day. But, that would take a lot of money and a lot of  time,” Grupe said. “What I would definitely say, is that hopefully DEQ can use this information to improve the way they post health advisories and enhance the public’s understanding of what a water contact advisory means.”

The science

Rumrill and Grupe began their mission with funding from an Environmental Protection Agency grant.

From January to November, the men conducted experiments to understand potential factors behind the contamination. They took water samples — before and after rainstorms — and placed a water data logger in a portion of Big Creek that runs through Sunset Bay. About 200 yards from the bay, the device tracked the amount of freshwater that entered it via the creek. It tracked salinity, temperature, pH and conductivity. On the less technical side, but an equally important test, researchers floated hand-numbered oranges with the bay’s currents to grasp how water moves.

They learned the bay flushes in winter every 2 to 3 days.

“That’s important because we have health advisories that last much longer than two days,” Grupe said.

In the summer, the bacteria remains in the water for 3 to 6 days before the bay purges itself.

Rumrill said this information can be used by DHS and DEQ to decide how quickly health advisories can be lifted after the rain has stopped.

“With this, they should be able to cut down the amount of days the health advisory is in effect,” Rumrill said.

Beach advisories have been in place for about 15 percent of the year as of late.

“Hopefully, we can decrease that number to about 10,” he said.

They also discovered bacteria is more likely to increase in the summer after a heavy rainstorm. That’s because feces from animals or other sources accumulate and dry near the creek. Then, a rainstorm will loosen the matter, which flows into the creek and then Sunset Bay.

“When the rain really does come down, it really spikes it up,” Rumrill said of bacteria levels.

But what will all this mean for the people who use and manage the beaches? Rumrill said the DEQ could restructure the length of advisories, or possibly allow beachgoers to call in when they see a warning, to find out when its safe to re-enter the water.

In a final report by Rumrill and Grupe given to officials from DEQ and other stakeholders, the researchers recommended additional steps to deal with the bacterial blooms (see sidebar).

End users

Preson Phillips, manager of Sunset Bay State Park, said thanks to the study, he can pass the information to visitors, especially when they see a water contact advisory in place.

“Certainly knowing more about the issue ... would help them be more relaxed and informed about their Sunset Bay experience,” Phillips said, adding the popular beach was named one of the top 10 state parks in the country by the Web site Americasbestonline.net.

Park staff are working to maintain septic systems to avoid contributing to the problem, he added.

“You want to fix it before it’s broken, so that’s a good thing,” Phillips said.

Larry Becker, the South Coast district manager for Oregon Parks and Recreation, reviewed Rumrill and Grupe’s report. He said it gave department officials ideas on how to educate visitors — such as asking them not to drop pet feces in the creek.

While health advisories ask people not to come into contact with contaminated water, that doesn’t mean they have to avoid the beach, he said.

“The beach itself is open. Day-use is open. The park is open,” Becker said. “A day or two and we’re back to normal use.”

The DEQ

At this point, DEQ staff and officials aren’t sure exactly how they will use Rumrill and Grupe’s study.

David Waltz, the South Coast basin specialist for DEQ in Eugene, said he’s had about 30 days to chew on the results, and has distributed the final report to the Oregon Beach Monitoring Program, asking it for review.

Some of the recommendations, including DNA fingerprinting and creating a predictive numerical model, could take more resources than the DEQ can provide, he said.

“The fork in the road is to decide if you want to further identify sources — is it elk or leaking septic tanks or is it some other source, livestock etc.?” Waltz said.

He isn’t sure if DNA fingerprinting is a necessary step at the state park, especially if wild animals are involved. Instead, Waltz said work could be done with nearby landowners to implement best practices such as installing fences to keep livestock out of the creek.

He said using such low-cost measures to keep Big Creek clean just might be the best way to go.