Laurentian River System facts for kids
The Southern Laurentian Channel is like a secret, ancient river flowing deep underground in southern Ontario, Canada. Imagine a river that existed long before the last ice ages! This hidden waterway was once a regular river valley. Over time, huge glaciers moved across the land. They left behind a lot of rock and dirt, filling up the old river valley. Even today, water still travels through this old path, but now it's hidden beneath the ground. The water for this underground river comes all the way from Georgian Bay, which is about 200 kilometers (124 miles) away.
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Discovering the Ancient Underground River
Where is the Laurentian Channel?
In 2003, scientists made an exciting discovery. They found that the southern part of this underground river system, called an aquifer, reaches under High Park in Toronto, Ontario. This area is believed to be where the Laurentian River System finally empties into Lake Ontario. It's amazing to think of such a large, hidden river right beneath a busy city park!
How Was It Found?
During the discovery, a special well was drilled to learn more about the channel. As the drilling happened, something unexpected occurred. A huge burst of water, along with silt and gravel, suddenly shot out of the well! This event showed that the channel's flow into Lake Ontario had been blocked. This blockage caused a lot of pressure to build up underground.
The Channel's Secrets
What is Inside the Channel?
The Laurentian Channel is quite large. In some places, it is 25 to 30 kilometers (15 to 19 miles) wide. It stretches for about 100 kilometers (62 miles) and is more than 100 meters (328 feet) deep. Even with these measurements, we still don't know its full size or all the materials inside it. Most of our information comes from special well sites. The materials, or sediments, found in the channel vary. Near the bottom, there are sands and gravels. Closer to the top, you can find clay-like silts.
Why is the Water Special?
There's an overflow pipe visible in High Park that runs into Spring Creek. This pipe always has a steady flow of water from the channel. The water helps local coldwater wildlife in the creek. It also helps relieve something called hydrostatic pressure. This is the pressure exerted by a fluid at rest. The area around the pipe's outlet looks red. This color tells us the water has a high iron content. The water itself is naturally pure and cool. Its temperature stays around 6-9 degrees Celsius (42-48 degrees Fahrenheit).
Protecting Our Waterways
The Importance of Water Pressure
The bedrock, which is the solid rock beneath the soil, under Toronto has several dips. Experts believe these dips were carved out by the ancient Laurentian River. Understanding these underground features helps us protect our water resources. The incident with the blocked flow and pressure buildup showed how important it is to study and manage these hidden natural systems.
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