Water tests raise concern about Muskoka's Lake Joseph

[Spiel]

Water tests raise concern about Muskoka's Lake Joseph

 

Mar 05, 2008

Jacqueline Lawrence / muskokan.com

 

 

An alarming rise in the phosphorus levels in Lake Joseph has local scientists scratching their heads, and calling on the community to work together to protect the health of one Muskoka’s largest and most beloved water bodies.

 

The high nutrient levels have reportedly been on the radar of staff at the District Municipality of Muskoka for some time. As part of its Lake System Health program, the municipality examines phosphorus concentrations in all lakes across Muskoka in order to determine lake health. Testing phosphorus concentrations is a common measuring tool also used by the Ministry of the Environment (MOE) to determine water quality. The higher the phosphorus levels, the greater the threat of aquatic growth such as algae blooms.

 

According to Judi Brouse, Muskoka’s director of watershed programs, recent tests of Lake Joseph show average phosphorus concentrations in the lake have almost doubled since the late 1990s. Average phosphorus concentrations, which are measured in parts per billion (ug/L) are now estimated at 5.5 ug/L in Lake Joseph, up from the relatively low level of 3.3 ug/L measured previously.

 

While the water quality in Lake Joseph is still considered good, Neil Hutchinson, senior aquatic scientist for environmental consulting group Gartner Lee Limited, said the higher reading is equivalent to constructing 2,400 new cottages on the lake.

 

“It’s a concern,” Brouse told Muskoka district councillors at their Feb. 27 meeting. Last year’s reading alone, she said, showed a measurement of 9.1 ug/L, dangerously close to the MOE’s water quality benchmark for phosphorus of 10 ug/L.

 

“It’s almost impossible to go . . . to 9.1 (ug/L) without someone dumping a whole bunch of phosphorus in the lake.”

 

Both Brouse and Hutch­ison said it is unclear what is causing the recent readings. Phosphorus concentrations can increase due to both man-made and natural causes, such as waterfront development, atmospheric changes, run-off and changes to area wetlands. All these factors are taken into account when measuring phosphorus concentrations with Muskoka’s current water quality model.

 

Hutchison, who helped create the model, said it may be time to rethink this formula.

 

“The problem is not related to how much development is there,” said Hutchison, explaining that development on Lake Joseph has not increased enough to account for the new numbers. “The problem is related to how well the model functions.”

 

Hutchison recommended reassessing Muskoka’s water quality model over the next several years.

 

Regardless of the cause, the phosphorus readings for Lake Joseph are being called a “red flag” by residents, who say more has to be done to prevent further deterioration of the water quality in the lake.

 

“It’s a real worry for all of us,” said Muskoka Lakes Mayor Susan Pryke. Pryke and Seguin Township Mayor David Conn met with Ontario Minister of the Environment John Gerretsen last week to discuss the situation. The pair reportedly asked the ministry to improve its standard of lake monitoring so municipalities such as Muskoka don’t have to wait until water quality deteriorates before taking action.

 

According to Hutchison and others, the MOE’s benchmark of 10 ug/L for phosphorus concentrations in lakes is high. The ministry, they say, needs to lower the benchmark and monitor Lake Joseph out of its London office to ensure all its data is consolidated.

 

Currently, the MOE monitors water quality in Lake Joseph from two separate offices.

 

According to Brouse, in addition to the above, a series of other steps will be initiated to protect the lake.

 

The district, in conjunction with the Dorset Environmental Science Centre and the Township of Seguin will enhance its annual monitoring program for Lake Joseph so water testing is conducted biweekly from May to August.

 

Shoreline surveys, to determine what uses are taking place along the lakefront, will also be conducted, as will a limits to growth assessment, to put in place new constraints on development.

 

Both Muskoka Lakes and Seguin townships, which border the lake, have also agreed to undertake comprehensive septic re-inspection programs, as well as proceed with tree-cutting and site alteration bylaws to enhance vegetative buffers along the shoreline.

 

Ratepayer associations such as the Muskoka Lakes Association are also being encouraged to continue stewardship programs that educate the public about protecting water quality.