Cooling off with a refreshing swim is one of the great pleasures of the Canadian summer.

Unfortunately, as summer moves into its late stages, finding somewhere to go for a dip is becoming harder and harder. This past weekend, only four of 14 beaches monitored by Durham Region were safe for swimming.

(That doesn’t include the Rotary Park beach in Ajax, which is closed for work.)

Jacques Perreault, manager, environmental health at the Region, says, “My guesstimate is it has to do with the rain.”

There was a heavy rainfall on Aug. 15, and that would have affected the water quality, he notes.

“It seems we had a lot of rainfall a day or two before. We do sampling on Mondays,” Mr. Perreault states.

“It’s the worst kind. The ground is so hard. Water runs to a ditch. It doesn’t soak in,” Mr. Perreault says. “There’s agricultural run-off and street-level grates. It all adds up. It all makes its way to tributaries and creeks. It’s not usual to have postings.”

As it’s later in the summer, the water has had time to warm up and “bacteria breeds more efficiently. From the beginning of the year to the end of the year, we usually see an increase.”

Krystyn Tully, with the environmental watchdog group Lake Ontario Waterkeeper says the number of beaches posted as unsafe increases during the dog days of August.

“We’re seeing similar trends. Right about this time of year, we see more postings. The water has warmed up and E. coli thrives in it,” Ms. Tully says.

“There’s an increased number now and an increased number in June, when it was warm and there was heavy rainfall. There’s definitely a higher number of postings.”

A disturbing sign the LOW has seen is “seeing beaches posted when they hadn’t seen a heavy rainfall,” Ms. Tully says.

That means water quality is being affected by other factors than just overflows from sewers, she notes.

It’s “hard to make generalizations” when it comes to causes of poor water quality, Ms. Tully says. However, reasons could be the “proximity of combined sewer systems,” where storm and sanitary sewers are combined, such as in Kingston.

Another is bird and goose droppings. There are, however, places where there are “tons and tons of birds and the place is fine. Others aren’t.”

Rotary Park in Ajax is one area where a solution is being sought. There’s the creek, which carries storm and agriculture runoff, and the nearby water pollution control plant.

Officials have responded “in the best possible way,” she says, noting the beach was posted almost 100 per cent of the time over previous summers, forcing the Town and Region to find solutions.

Mr. Perreault notes the intensity of storms also affects the water.

“This summer has been very hot. I imagine the water is very warm this year,” he adds. “We get a lot of run-off. There’s a lot of contamination running down into the creek.”

Six years ago, LOW starting putting beach conditions around the entire lake on its website.

“Most places, you can find out if a beach is open today, but you won’t know what the water quality was the day before,” Ms. Tully notes. “We put together the historical information.”

With the historical information, “we can compare best practices across regions and to get the best information available for the local beaches.”

The group doesn’t want to scare people away from going to beaches, she says.

“There’s a perception it’s not as important or serious. It’s connecting communities to the lake,” she says. “We want to get people there to enjoy the lake as a free resource.”

The beach information is “the No. 1 reason why people contact our website,” Ms. Tully says. “Traffic is 10 to one looking for safe places to swim.”â?¨ Having that information is a “high demand,” she says.

The response of municipalities to having their beaches postings listed “varies. Some municipalities don’t appreciate what they perceive as airing dirty laundry.”

Toronto, she notes, took a report the group did on Bluffer’s Beach and made improvements.

“We’ve seen significant improvement in water quality there.”

For more on water quality, visit www.durham.ca or www.waterkeeper.ca.

via durhamregion.com | Why are Durham beaches posted?.