Climate change is here: Lake Simcoe floating high phosphorus levels

Lake Simcoe Region Conservation Authority working on climate-change adaptation plan

Yorkregion.com
Feb. 18, 2020
Amanda Persico

Climate change is here, and the impact on the health of Lake Simcoe is starting to show.

The Lake Simcoe Region Conservation Authority released its latest phosphorus load report for 2015 to 2017.

According to the report, phosphorus levels spiked to about 131 tonnes between June 1, 2017, and May 31, 2018.

That’s well above the five-year average of about 93 tonnes between 2013 and 2017 and about 86 tonnes between 2010 and 2014.

Not to mention the fact that the high-phosphorus numbers found in 2017 outpace the 10-year average of about 91 tonnes between 2007 and 2017.

The conservation authority pegs high phosphorus levels in 2017 on a wetter-than-average year with more rain and more flooding.

Two major events -- a massive storm in June and heavy rain combined with melting snow in February -- amounted to about 20 per cent of the phosphorus load for the 2017 hydrologic year.

While 2017 was an atypical year in terms of precipitation, wetter weather is a growing trend in the watershed, said conservation authority chief administrative officer Mike Walters.

“Climate change is here,” he said. “Wetter summers, warmer winters, plenty of rain when the ground is still frozen and flooding like we’ve never seen.”

As we experience more offbeat weather, such as wetter springs and dryer summers, more municipalities are declaring a climate change emergency.

According to the International Climate Emergency Forum, more than 1,300 town, cities and governments in 26 countries have declared a climate change emergency.

In Canada, that number is close to 500 and includes declarations from Barrie, Newmarket, Vaughan and King Township, as well as the federal government.

Weather patterns and rainwater distribution are changing, Walters added, with more rain during the early summer days when the ground is already saturated, as well as rain during the winter when the ground is frozen.

In both cases, rain beads off the ground and flows right into local creeks and streams and into Lake Simcoe, taking dirt and grime along with it, adding to the phosphorus load, he said.

While phosphorus levels in Lake Simcoe are high, it’s not all doom and gloom for the lake, Walters said.

The phosphorus-load report also acknowledged an upward trend of dissolved oxygen levels deep within the lake, which is unusual.

Usually, high-phosphorus levels bring down the oxygen level, Walters said.

In this case, higher, dissolved oxygen levels mean more cold-water fish are reaching the bottom to spawn, increasing the cold-water fish population and putting the lake on a self-sustaining track.

Oxygen levels are a better indicator of the lake’s overall health -- not solely phosphorus levels.

“Oxygen is the more important measure because we know how dependent fish are on cold, clean, oxygen-rich water,” Walters said.

A good portion of 2020 will be spent on data collection to better understand the upward trend in oxygen levels, he added.

The conservation authority is also working to establish a climate change adaption plan to be released later this year.

The focus of the adaptation plan is actionable items that help mitigate the effects of climate change, from building low-impact development and green infrastructure to carbon offsetting.

The LSRCA has already committed to reducing its corporate footprint, with a target of reducing carb emissions by 28 per cent by 2026.

Part of that commitment involved "greening" the LSRCA fleet, adding two hybrid-electric vehicles and charging stations last year.

Residents and municipalities can also help offset carbon missions.

“The best way to offset your carbon footprint is to plant a tree,” Walters said.

And even this idea is getting a second look in terms of what trees are more suitable for the region’s changing climate.

Moving forward, the conservation authority is looking at switching spruce, fir, birch and aspen trees for more enduring trees like as maple, oak and pine. In the future, we could also see more tulip, sycamore and hickory trees in local woodlots.