Teams of volunteers fanned out across the headwaters of the Credit River recently to do a quick check on the state of its health.
About 75 people took part in Credit Valley Conservation's first Check Your Watershed Day on July 16, including at least a dozen from Erin Trails and the Climate Change Action Group of Erin.
On a sweltering Saturday afternoon, we measured the temperature of water in shady sections of the river, took photos and made sketches of bridges and culverts, and looked for obstacles to the movement of fish.
"It's not going to go into a box and never be looked at again – the information we are collecting today is real data that will help direct restoration projects in the future," said CVC Aquatic Biologist Jon Clayton. In spite of the many dams on the river, CVC tries to reconnect fish habitat areas where possible.
"There may be spots where fish can't get upstream as a result of a drop coming out of a culvert, and the fish populations are fragmented as a result," said Clayton. "The temperature information is used to assess where dams are having an impact. If we notice a big temperature increase downstream of a pond, that might be an area we come back to and target for stream restoration or riparian (shoreline) planting."
Bill Dinwoody and I worked as a team, assigned to check five sites in Hillsburgh. Measurements at three locations upstream of the dams showed temperatures from 19.1° to 19.9° C. In the pond at the Station Street, and downstream at 22 Sideroad, the readings were just above 26° C.
Checking the Station Street dam.
We saw no blockages of fish traffic apart from the dams, which form three large ponds between downtown Hillsburgh and 22 Sideroad. Clayton said the lower temperatures upstream seemed normal, as did the high reading in the pond, but he was surprised that the water had not cooled more by the time it reached 22 Sideroad.
"I have seen quite a few Brook Trout there before in the summer so that would indicate colder water. Maybe there was a spring or upwelling directly underneath them or just upstream. It also speaks to the need to allow fish to move around to find coldwater refuge during hotter summer periods," he said.
Vegetation next to the river helps cool the water, but incoming groundwater and air temperatures have a more direct impact, he said.
Rehabilitation work was done at the 22 Sideroad crossing a few years ago, with rocks strategically placed to help fish navigate into the culvert. CVC also planted trees in the nearby meadow, but they have not survived.
A Check Your Watershed Day enables a large amount of data to be collected at the same time. Measurements were done throughout the upper watershed, including Orangeville/Caledon (the East Branch), Hillsburgh/Erin (the West Branch) and Georgetown.
The concept has been used successfully by other conservation authorities. It has been promoted by EcoSpark, an organization that works with communities and schools, providing them with knowledge and tools to monitor their environment and take action for positive environmental change.
The group has a special interest in the Oak Ridges Moraine, a prominent ridge north of Toronto, stretching 160 kilometres from the Niagara Escarpment in the west to the Trent River system in the east. It was created between two lobes of receding glacial ice, where the melting water deposited huge quantities of rocky debris.
Moraine landscapes, also prominent in Erin, are good at collecting rainwater, filtering it through sand and gravel, and recharging aquifers deep underground. These supply drinking water for many communities and deliver clean, cold water into river systems.
The Credit River is a unique cold water system that is home to sensitive Brook Trout and is one of three rivers targeted for re-introduction of Atlantic Salmon. It is 90 km long, with 1,500 km of tributaries, draining about 1,000 square kilometres of land.
