Bragg Creek Water Monitoring
This is an overview of measurements obtained in an ongoing project to test the water quality in a creek upstream from Calgary, Alberta. The tests monitor the general condition of the creek and record data on phosphates, nitrates, chloride and turbidity of the water. Among other things the tests are intended to observe changes in water quality over time. As this creek is an important water source for the city and people living in the watershed, we need to know if industrial, agricultural, residential and other influences are having an impact on the quality of the water.
Why Chlorides Are Important
Chloride is a salt compound; some common chlorides include sodium chloride (NaCl) and magnesium chloride (MgCI2). Small amounts of chlorides are required for normal cell functions in plant and animal life. Chlorides are not usually harmful to people; however, the sodium part of table salt has been linked to heart and kidney disease. Public drinking water standards require chloride levels not to exceed 250 mg/L.
Chlorides may get into surface water from several sources including:
• Rocks containing chlorides,
• Agricultural runoff,
• Wastewater from industries,
• Oil well wastes, and
• Effluent wastewater from sewage.
We are using Chloride as an indicator of input from septic systems (with humans being the primary salt consumers and excreters in the area)
Chlorides can contaminate freshwater streams and lakes. Fish and aquatic communities cannot survive in high levels of chlorides. We measure chloride because it is a good indication of human and livestock impact and it remains stable as it moves through water.
Why Phosphate Is Important
Phosphorus is one of the key elements necessary for growth of plants and animals. Phosphorus in elemental form is subject to bioaccumulation. Phosphates PO4 — are formed from this element. Phosphates exist in three forms: orthophosphate, metaphosphate (or polyphosphate) and organically bound phosphate. Each compound contains phosphorous in a different chemical formula. Ortho forms are produced by natural processes and are found in sewage. Poly forms are used for treating boiler waters and in detergents. In water, they change into the ortho form. Organic phosphates are important in nature. Their occurrence may result from the breakdown of organic pesticides which contain phosphates. They may exist in solution, as particles, loose fragments, or in the bodies of aquatic organisms.
Phosphates matter because they are the primary determinant of plant and animal production in freshwater. Rainfall can cause of phosphates to wash from farm soils into nearby waterways. If an excess of phosphate enters the stream, algae and aquatic plants will grow wildly, choke up the waterway and use up large amounts of oxygen. This process is called “eutrophication”. The rapid growth of aquatic vegetation can cause the death and decay of vegetation and aquatic life because of the decrease in dissolved oxygen levels.
Why Nitrogen is Important
Nitrogen is one of the most abundant elements. About 78% of the air we breathe is nitrogen. It is found in the cells of all living things. Nitrogen compounds such as nitrate [NO3-] act as nutrients in streams and Nitrate reactions can cause oxygen depletion. This means certain death for aquatic organisms that depend on oxygen to survive. Nitrogen enters a body of water through municipal and industrial wastewater, septic tanks, feed lot discharges, animal wastes (including birds and fish) and discharges from car exhausts. Bacteria in water quickly convert nitrites [N02-] to nitrates [N03-]. We measure Nitrate because it is a good indication of human impact and the most stable form of nitrogen. Nitrate levels of 10mgIL in drinking water are considered dangerous. Nitrogen reactions can deplete the blood of oxygen in humans, livestock and fish.
Read more about methemoglobin and blue baby disease, “brown blood disease” in fish and eutrophication in water bodies.
Why Test Turbidity?
Turbidity is the measure of water clarity. The more suspended solids in the water, the murkier it becomes. The increased turbidity of water can reduce the diversity of life in three ways:
- Suspended particles absorb heat from sunlight and warm the water. Warmer water holds less oxygen and organisms begin to suffer. Also, some organisms can not live in the warmer water.
- Particles also block sunlight. Plants and algae grow less and release less oxygen from photosynthesis.
- Particles also settle on the bottom and can cover and suffocate fish eggs and insect larvae