Toronto region watersheds get a ‘D’ grade in watershed report cards

April 16, 2013   ·   0 Comments

As part of Conservation Ontario’s province wide Check Up on the state of Ontario’s watersheds, Toronto and Region Conservation (TRCA), has issued a new series of nine report cards assessing the health of each of the watersheds in the Toronto region. And the marks are not impressive.
Overall, the nine watersheds receive an average “poor” grade of D, showing that continued effort and investment needs to take place in order to improve the health of the watersheds.
This marks the first time watershed report cards are being released simultaneously, providing a snapshot of the watershed health in the Toronto region. Toronto region’s watersheds were evaluated against four indicators of health: surface water quality, forest conditions, groundwater quality and stormwater management.
The report cards assess the health of the Etobicoke and Mimico Creeks, Humber River, Don River, Rouge River, Highland Creek, Petticoat Creek, Duffins Creek, Carruthers Creek, and the 72 linear kilometres of the Lake Ontario waterfront. They serve to inform people living in the region about local environmental conditions and provide a management and evaluation tool for Conservation Authorities and other practitioners to measure environmental change over the years, and implement watershed protection and restoration strategies. In addition, residents are provided with a list of actions to take on which will help make a difference in the watershed they are living in and improve environmental awareness.
The watersheds receiving the lowest grades are the Etobicoke Creek, Mimico Creek and Don River, and the healthiest watersheds in TRCA’s jurisdiction, with the highest grades are the Rouge River and Duffins Creek.
“The report cards clearly show that more work needs to be done to improve the state of the health of our watersheds in the Toronto region” said Gary Wilkins, watershed management specialist, Toronto and Region Conservation. “TRCA is the largest conservation authority in Ontario situated in the most urbanized and heavily populated area of the country. In light of this, it is paramount that we pay attention to the health of our rivers and the rest of the environment, especially with the added pressures of climate change. Improving the health of our watersheds is vital to building a healthier city region. We will do this by everyone taking responsibility, through partnerships, community engagement and educational programs.”
Key results from TRCA’s Watershed Report cards are as follows:
Stormwater management is the biggest area of concern across TRCA’s jurisdiction. Only 35 percent of the developed areas within TRCA’s jurisdiction have stormwater quality and quantity controls in place (i.e. stormwater ponds, permeable pavements etc).  All watersheds in the Toronto region receive very poor and poor grades  (D and F), with the exception of the Rouge River and Carruthers Creek watersheds which receive a B grades. The Rouge watershed has the highest level of stormwater controls in urban areas within TRCA’s jurisdiction at 77%. The Highland Creek on the other hand, only has 9  per cent controls within developed areas. This is an issue that municipalities and TRCA continue to work at by having stormwater ponds constructed in all new developments and by encouraging the use of low impact development controls such as rain gardens, green roofs and permeable parking lots, to help reduce run-off to watercourses.
Surface water quality: Humber, Rouge and Duffins watersheds have the best water quality with a C grade. Don and Mimico Watershed had the worst score with an F grade. Greater effort must be made to reduce the run-off of animal waste in rural and urban areas, and the release of contaminated waste water into streams in urban areas. Residents can reduce or eliminate the use of chemicals, fertilizers and pesticides, and the salt used to melt the ice on their driveway and sidewalks. The road salt carried away by melting snow contaminates rivers, ponds, and groundwater supplies.
Forest conditions: Duffins Creek received the highest grade of a C for its highest percentage of forest, interior forest and riparian forest. The highly urbanized Mimico Creek has received an F for poor forest conditions; the lowest grade received in TRCA’s jurisdiction. Currently less than 2 per cent of the Mimico Creek watershed is forested. Only 8 per cent of the Don River watershed is forested but 43 per cent of the existing streambank cover consists of forests. This ranks among the highest percentages of riparian forest, in the TRCA jurisdiction earning the Lower West Don an A grade. To help improve forest conditions, residents can take part in community planting events and/or plant trees and shrubs in your backyard.
Groundwater quality: Overall groundwater quality in TRCA’s watershed is good with the best water quality found in the intermediate Aquifer on the Oak Ridges Moraine. TRCA has not graded groundwater since no data exists for the Mimico, Highland, Carruthers and Petticoat watersheds, and limited data exists for the rest of TRCA’s watersheds. Over time, TRCA intends on expanding the network through partnerships with regional municipalities and the Provincial Water Quality Monitoring Network.  Improvements can be achieved by replacing hard surfaces with natural groundcovers and permeable pavement to allow rainfall to soak into the ground. Residents are also encouraged to decommission old wells and septic systems that could otherwise contaminate groundwater.
The Waterfront watershed received grades for different indicators reflecting its unique characteristics. They include: Water Quality, Recreation and Biodiversity. The Waterfront received an A grade for Recreation. Over 1,226 hectares of greenspace is owned and protected by TRCA along the waterfront representing 20 percent of the entire watershed area, including Ajax Waterfront, Rotary Frenchman’s Bay Park, the Humber Bay Park Complex and Tommy Thompson Park. There continues to be opportunities to expand the trail system from the waterfront into all nine watersheds and improve the quality of trails and the surrounding greenspace. Residents can help protect the Waterfront by participating in the annual Great Canadian Shoreline Clean-up each fall.
You can find Toronto and Region Conservation’s report cards at and other Conservation Authorities report cards at



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