Under particular wind and water conditions, drinking water intakes in the Bay of Quinte could be exposed to contamination, according to a recent study performed by the Royal Military College of Canada.
The Bay of Quinte on Lake Ontario is where about 70,000 people get their drinking water, but it’s also listed as an Area of Concern under the Great Lakes Water Quality Agreement. The area is home to a shipping port in its Picton Bay where a fuel spill of diesel, gas and some emulsives from a barge occurred in 2017, leading to water intakes and a water treatment plant being shut down for about a week.
Using GPS-powered drifters in the water, researchers have been able to get an idea of how water moves through the system and begin to figure out potential risks to water intakes and when problems may occur.
While the Bay of Quinte region has seen a number of water quality studies (predominantly around algae problems and nutrient pollution), only recently have there been any computer models (created under the Ontario’s Clean Water Act) designed to get a sense of how water moves through the bay. These models were used in a 2014 Quinte Region Assessment and to develop Source Protection Plans.
In the Picton Bay area, models indicate which areas of the bay are most vulnerable in the event of contamination, as indicated on a protection plan map. These water intakes, located about 3.3 meters (10.8 feet) under the surface, are vulnerable to risks from harmful algal blooms, due to nutrient contamination and invasive species (like Eurasian tench and quagga mussels), and other water quality threats from a changing ecosystem due to climate change.
The drinking water intakes in Picton Bay, marked in yellow, are south of the shipping port, located at the inlet near White Chapel Road and Highway 49 in the upper-left part of the bay on the map.
Unfortunately, there wasn’t much information on water flow speeds available to determine how accurate the models are until the drifters were used, said project leader Jennifer Shore, associate professor at the Royal Military College of Canada’s Department of Physics and Space Science.
The drifters are little more than a waterproof capsule containing a GPS tracker with electronics attached to a conical drogue device which catches on the water and pulls the tracker around the bay. These trackers are able to continually update and broadcast their location in the water system over the internet, Shore explained, allowing researchers to get a solid indication of how water is flowing through the bay.
The Bay of Quinte is narrow and twists on its way up, where the Trent River is located. Water is flushed out of the bay thanks primarily to the river and typically eastbound winds, though water found in smaller bays, such as Picton Bay, takes longer and tends to flow more slowly, Shore explained.
Using the location of the fuel spill in Picton Bay as a guide, researchers placed GPS drifters in the bay at different locations over the months of April through September, 2017, Shore said. These were remotely tracked to see how they’d move around Picton Bay before entering the broader bay system. Drifters also were used around the Trent River to get a sense of water flow there, where nutrient pollution has a conduit into the bay.
After coupling the results with existing models, researchers found that under most conditions, a Picton Bay fuel leak shouldn’t find its way over to the water intakes. Shore said the exception is when wind is blowing from the northeast; in 2017 that tended to push the fuel leak back toward drinking water intakes located in the bay. High water levels in the bay that year also played a role in how the water moved. Overall, Shore said they measured surface water speeds throughout the summer ranging from 0.5 to 11 centimeters per second (0.19 to 4.33 inches per second)
The Royal Military College returned to the Bay of Quinte in the summer months of 2018 to continue the flow sampling for the study; full results have not been published at this time.
The project is funded through the Royal Military College’s Academic Research Program.