Contact(s)
The GRCA participates in several water quality monitoring programs. The information is used to understand current conditions, identify trends and make projections about future changes.
Water quality reports
Water quality reports are issued every five years to present the results from our water quality monitoring programs.
- 2017 Water Quality Board Report (PDF - 1mb)
- 2011 Water Quality Report (PDF - 12 mb)
- 2006 Water Quality Report (PDF - 5 mb)
How we monitor
Continuous Water Quality Monitoring Program
The GRCA operates nine automatic water quality stations throughout the watershed.
The information is relayed to the GRCA head office and is posted automatically to the Water quality data section of the GRCA website.
The information helps GRCA staff manage their dams and reservoirs, which provide water to the river system during the summer and fall. (This is called flow augmentation.)
The information is also used for reports on water quality conditions and to assist scientists and engineers develop computerized 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 36 locations, about eight to 10 times a year. (See a map of the locations. Note: you have to click through a disclaimer screen before the map will open.)
The GRCA sends the samples to the Ministry of the Environment and Climate Change for analysis. The analysis shows the levels of various materials in the water: nutrients such as phosphorous and nitrogen, metals and other chemicals.
The program has been in place since the 1960s so 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.
What we monitor
Physical and chemical parameters
The GRCA's Continuous Water Quality Program measures several characteristics of water quality: temperature, pH, conductivity and dissolved oxygen. The information is posted automatically 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, then plant growth will be 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 volume entering our water systems.
Invertebrates
These are organisms that live on river beds: sow bugs, crayfish, damsel fly larvae, tadpoles 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 quality 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.
