Surface water quality

Continuous Water Quality Monitoring Program

We operate nine automatic water quality stations throughout the watershed. The information is relayed automatically to our head office and updated hourly in the water quality data section of our website.

The information helps us manage our dams and reservoirs, which provide water to the river system during the summer and fall. The information is also used for reports on water quality conditions and to assist scientists and engineers to develop computer models of the river system. These models are used for long-range planning of water-related projects and programs.

Provincial Water Quality Monitoring Program

Water samples are taken from rivers and streams at 35 locations, about eight to 10 times a year. You can view the location of these sampling points on our webGIS application. Note: you have to click through a disclaimer screen before the map will open.

We send the samples to the Ministry of the Environment, Conservation and Parks for analysis. The analysis shows the levels of nutrients (such as phosphorous and nitrogen), metals and other chemicals.

The program has been in place since the 1960s so it provides insight into long-term changes in water quality.

Monitoring for specific projects

The GRCA, municipalities and other partners monitor water quality in specific sections of the watershed such as a stream, a subwatershed or part of a river. The data is used to evaluate the potential impact new development may have on that part of the watershed. The information is used to develop subwatershed plans, which include policies to reduce the impact from the development.

Physical and chemical parameters

Our Continuous Water Quality Program measures several characteristics of water quality including temperature, pH, conductivity and dissolved oxygen. The information is automatically posted on an hourly basis in the water quality data section.

Nutrients

Nutrients such as phosphorous and nitrogen are chemicals found in animal and human waste. They also come from decaying vegetation.

Nutrients are important to aquatic ecosystems because they feed algae and aquatic plants. The plants and algae, in turn, are food for fish and other organisms. However, when nutrient levels are too high, plant and growth can become excessive. The plants use up too much oxygen, hurting fish and other creatures.

Nutrients are found in the treated effluent coming from municipal wastewater treatment plants. They are also found in runoff from farm fields and city streets. Understanding changes in nutrient levels helps water management agencies develop projects and programs to reduce the quantity of nutrients entering our river systems.

Benthic invertebrates

These are organisms that live on river beds such as sow bugs, crayfish, damsel fly larvae and others. They are sensitive to water quality. Lots of sow bugs indicates poor water quality. Lots of mayfly or stonefly larvae is a sign of good water quality. Counting the number of these organisms in a particular location provides insight into water quality conditions.

Fish

The presence or absence of some species of fish can help to understand the general health of a river or stream. Some fish prefer cool, clear water. Others can survive in warm, murky water.

Hydrology

Hydrology - the movement, distribution and quantity of water - is an important part of the health of the river system. Changes in flows, from the high water of spring floods, to the lows of summer droughts, can affect water quality and the life cycle of fish and other organisms in the water.