For an assignment for my class on water resource systems modelling, we were asked to go somewhere, observe flow, and write about it. I was advised to go check out a tiny pipe with a crazy back story in High Park.
At the Spring Creek footbridge adjacent to the off-leash dog park, two streams of water join and create one stream. One stream is from a stormwater management pond. Stormwater ponds are receivers of overland flow and storm sewers within a “sewershed” for an urbanized area. The land upstream of these stormwater ponds, so to the north, east and west of High Park, drains into this stormwater pond. The water colour in the pond is black/grey, and the surface of the pond contains silver strands that vary between being filamentous, streaks and blobs. The silver streaks may be organic (from algae) or from gasoline and oil from our roadways. The ponds have a strong sulphur smell, and that smell of sulphur permeates throughout the northern end of the park. There were a few items of garbage present in the pond when I visited, though none of it near to where people frequent. Sanitary sewers that overflow into the combined sewer system during rain events may contribute human waste to this pond, leading to the sulphurous odour when stagnant.
The other stream of water is sourced from groundwater. Groundwater is higher in minerals and metals than surface water, due to the contact between soil and rocks that contain these minerals. The red staining from the oxidation of iron is evidence of water with high mineral content, and so this is why I assume that this source of water is groundwater. Based on conversations with Helen Mills (from Lost Rivers TO), and searching on the internet for discussion, I find that my observations are correct. Even more interestingly, this is the outlet of an underground creek, called the Laurentian Channel, that is 110 km long and 30 km wide at some points. In 2003, there were construction workers present for some work on the ponds, and while draining the ponds, they found several capped wells, which indicated this natural spring. They also dug a borehole to investigate this spring, and a geyser erupted from that borehole, indicating the huge pressure the confined aquifer must be under.
I hope you enjoyed this random water post. I was glad to have the push needed to go out and explore new and cool aspects of our water systems.
 High Park Nature Newsletter, November 2012, written by Karen Klaire Koski. http://www.gordperks.ca/wp-content/uploads/2012/11/High-Parks-Hidden-Waters.pdf