Halifax area residents hoping to hit the water will have to look beyond Birch Cove Beach at Lake Banook in Dartmouth.

The popular beach remains closed after beachgoers and staff came down with flu-like symptoms. Roughly 30 people have fallen ill with gastrointestinal problems since swimming at the beach.

"One of our staff ended up having to go in for medical attention and was in the hospital for some time," says John Henry, manager for HRM Aquatics. "I understand she's doing OK at this time. Certainly there are varying degrees because others haven't had to seek medical attention."

Water quality testing is underway but it's still unclear whether the flu-like illness is waterborne.

In the meantime, lifeguards are telling people to stay out of the lake. Still, some are choosing to swim at their own risk.

"The water looked so clear," says Rosemary Kristof, who was swimming in the lake Wednesday. "We had rain yesterday so I figured it's fine."

The beach has closed in the past due to cases of swimmers' itch - a temporary skin irritation caused by an invisible parasite found in lakes and ponds - but staff members say they've never seen anything like this before.

"I think in terms of my career, I've never heard of this extent of the number of persons becoming ill," says Henry.

Some of the city's busiest canoe clubs sit across from the beach, on the opposite side of the lake. Some are operating as usual, but others are taking extra precautions.

The Mic Mac Amateur Aquatic Club has cancelled its swimming lessons and is keeping its members out of the water. The club's paddling program is still running, but some adjustments have been made.

"If kids end up getting wet, if they tip, we have showers inside that they shower off on and we make sure that they're cleaning themselves off any time they come out of the water," says Chris Chaisson, the head coach at the club.

The Department of Health and Wellness Department is also investigating the area to determine what is making people sick.

Early test results show that there are E. coli bacteria in the lake, but the levels are very low and they are at a normal amount for any lake.

Further testing is underway and the beach will remain closed until officials can ensure it is safe.

With files from CTV Atlantic's Jill Matthews