Grading for the 2013 Watershed Report Card is based on four resource categories: surface water quality, forest conditions, groundwater quality, and wetland conditions. These categories were chosen because they are linked to overall watershed health and the health of our communities, including the local economy, and residential, agricultural, industrial, and recreational uses of lakes and rivers. Given our daily reliance on natural resources, it is critical we build resilient local watersheds in order to ensure healthy people and a reliable economy.
Each of the following categories includes specific indicators that provide information on the condition and health of the resource categories.
Surface Water Quality
Surface water is the water that moves through streams, rivers and lakes. We looked at the levels of nutrients, bacteria, and the health of aquatic organisms in these waters to assess their overall health.
Total Phosphorus (TP) is the limiting nutrient for aquatic plant growth. This means aquatic plants will respond the most to the amount of TP in the water. TP is commonly found in soaps and detergents, fertilizers, sewage, and naturally in soil. It is required in lakes and streams in order for organisms to survive, but too much can cause excessive algae and aquatic plant growth. Therefore, managing the amount of TP that enters lakes and streams is an effective way to control algae and aquatic plants that lead to eutrophication.
Benthic Macroinvertebrates are small aquatic insects that live in the bottom of streams, ponds, lakes, and wetlands. They are used to assess the biological health of aquatic ecosystems because they are excellent bioindicators. Bioindicators are organisms used to monitor changes in environmental conditions.
Changes in Benthic Macroinvertebrate communities can reflect pollutant levels in water, which is why they are often used to monitor water quality. For example, some insects are only found in clean water with very little or no pollution, which, when found, means the water is clean.
Escherichia coli. (E.coli)
E.coli is a form of bacteria found in human and animal waste, and often makes its way into rivers and lakes through runoff. Health Units often monitor E.coli levels at public beaches during the summer months when there are higher levels of recreational activity. Large amounts of bacteria can pose a risk to human and wildlife health.
Forests and other naturally vegetated areas help improve water quality by slowing runoff, reducing erosion, and filtering the water that passes through them. Forests also filter the air, and provide important habitat for native species of plants and animals. Their quality and quantity can impact greatly on biodiversity and the ability of wildlife to thrive.
Forest Cover measures the percentage of a watershed that is forested. This includes upland and wetland forest as well as shrub land and thickets.
Forest Interior is the percentage of forest that remains after a 100 metre buffer of the forest edge or from any human created opening such as a field, roadway, railway line, or hydro right-of-way, has been subtracted. The edge of a forest is more vulnerable to predation, invasive species, and damage from severe weather. The interior of a forest, which has more protection, provides critical habitat for a diversity of species.
Forested Riparian Zone
Forested Riparian Zone is the percentage of area that is forested within a 30 metre buffer on either side of a watercourse, such as a river or lake. Riparian areas are important because they provide habitat, stabilize soil, and filter runoff before it enters lakes and streams. Removing riparian vegetation and manicuring property to the water’s edge can have significant negative impacts on water quality.
Groundwater is the water that is stored beneath the surface of the earth. It generally flows in the same direction as the slope of the land, like surface water, but sometimes moves in other directions due to rock formations and other underground obstructions.
Groundwater is an important part of our watershed. It maintains the flow in rivers and streams, in addition to supplying water to wells.
Nitrates + Nitrites
Nitrates and Nitrites are forms of Nitrogen that can be found in groundwater. Nitrogen occurs naturally in soil but can also be found in animal waste, fertilizers, and septic sewage. If high levels of Nitrates and Nitrites seep into groundwater, they can contaminate drinking water and pose a health risk to humans and other living organisms.
Chloride is an anion of Chlorine. It forms compounds that are found naturally in soil and in products such as road salt. The application of road salt is a contributing factor to increased chloride levels in groundwater, which can threaten the health of all living organisms including humans. Reducing the amount of road salt applied to roads, driveways, and walkways can limit ground and surface water contamination.
Wetlands are a very important part of the natural ecosystem and the water cycle. They provide habitat for plants and animals, and act as filters by removing sediment, nutrients, and bacteria from water that travels through them. Wetlands also provide natural flood control, acting like a sponge to absorb water, and gradually release it over a longer period of time instead of all at once.
Wetland Cover is the percentage of a watershed that is covered by wetlands. This includes marshes, bogs, fens, and swamps (treed and thicket).