Good water quality, to many people, is based on seeing clear water and being able to enjoy activities in and on the lake: swimming; boating and having grandkids play in the shallows.
Science measures the water qualities chemical, physical and biological characteristics and looks to compare against what is known about healthy lake bodies.
Water quality is important for many reasons, including:
- Ecological reasons: the health of the aqua-system, including all the living organisms in the lake.
- Economic reasons: while some people have tried to assess the impacts of water quality on the value of businesses and properties in the watershed, we know from other sources that when water quality goes down so does the value of lots in the watershed, and businesses suffer.
- Recreational enjoyment and family time: Many activities can be curtailed when water quality and not as many people want to spend time at the lake.
The water quality in Pigeon Lake has declined over the last 50 or more years.
The PLWMP committee wanted to know more about the water quality to help focus our work to improve the health of the lake. More specifically we need to be able to:
- Eventually compare ‘before’ and ‘after’ implementing many watershed measures to see the difference we’re making.
- Have a Nutrient Budget help to make decisions on what and where we make changes.
- Complement the work the Fisheries Management Department is doing to better determine the water quality factors that trigger fish die-offs.
- Better know what the water sampling frequency requirements are for Pigeon Lake.
Both by then Alberta Environment and Sustainable Development and the Alberta Lake Management Society (ALMS) worked with the Pigeon Lake Watershed Association (PLWA) volunteers to complete an intensive in-depth water sampling study over 2012 and 2o13 of streams, in-lake and shoreline to meet these objectives.
The Alberta Government Reports generated by this initiative that are now available are:
- The Pigeon Lake Phosphorus Budget (2014) and its Executive Summary
- (2013) Overview of Pigeon Lake Water Quality, Sediment Quality, and Non-Fish Biota
Water Quality Information
Water Quality: what does that mean?
Water quality describes the general properties of a waterbody based on its chemical, physical and biological characteristics.
– Physical characteristics: such as temperature, colour, suspended solids and turbidity
– Chemical characteristics: such as nutrients, minerals, metals, oxygen, and organic compounds
– Biological characteristics: such as the types and quantities of aquatic plants, animals, algae, bacteria and protozoan parasites.
There is no single or simple measure for water quality. Water quality is evaluated differently depending on what the ultimate use of the water is, such as:
-Aquatic ecosystem health
Current monitoring programs measures parameters that are specific to aquatic ecosystem health and recreational water users. These parameters include:
Aquatic Ecosystem Health:
Temperature influences chemical reactions which influence water quality. Aquatic plants and animals require water temperature to be within a certain range for optimal health and survival.
Dissolved oxygen describes the amount of oxygen molecules that are held by the water. It is a measure of the amount of oxygen available to aquatic plants and animals. The amount of oxygen needed by aquatic organisms to survive varies by species; fish like Northern Pike cannot survive in less than 6 milligrams of dissolved oxygen per liter of water (6 mg/L). Oxygen is added to the water by photosynthetic activity of plants and re-aeration from the atmosphere. It is removed from the water by respiration of bacteria, plants and animals and various chemical processes.
pH is a measure of how acidic or basic the water is. pH affects water chemistry and the biological state of aquatic organisms. Changes in pH can be very stressful on aquatic life and at low pH levels certain compounds like heavy metals become highly toxic to plants and animals. The best pH range for most aquatic life is between 6.5 and 8.2.
Turbidity is a measure of how clear the water is. Water clarity changes depending on the amount of floating or suspended materials (such as mud, silt, sediment, and algae) in the waterbody. Turbidity is not a measurement of the amount of suspended solids present since it only measures the amount of light that is scattered by suspended particles. Turbidity affects the amount of light reaching aquatic plants, water temperature, the ability for aquatic organisms to see, dissolved oxygen levels and odor.
Phosphorus and Nitrogen are important determinants of lake productivity. These typically promote excessive growth of algae. As the algae die and decompose, high levels of organic matter and the decomposing organisms deplete the water of available oxygen, causing the death of other organisms, such as fish. Eutrophication is a natural, slow-aging process for a water body, but human activity greatly speeds up the process.
Canadian Water Quality Guidelines for the Protection of Aquatic Life list water quality guidelines for nutrients.
Chlorophyll – a
Chlorophyll – a is a photosynthetic pigment in plants, algae, and cyanobacteria. It is used as an indicator of overall biological productivity in lakes. Chlorophyll is also an important link between the nutrient levels in water and the plant growth.
A total of 61 different metals are measured due to the potentially severe impacts of metals to aquatic life. The toxicity of metals increase as the pH and temperature of a waterbody increase. Canadian Council of Ministers of the Environment (CCME) currently regulates metal concentrations for the Protection of Aquatic Life.
Recreational Water Quality:
Fecal coliforms are bacteria commonly found in the intestinal tracts of mammals. Their presence in water is an indicator of pollution and may indicate the potential presence of disease-carrying organisms, which live in the same environment as the fecal coliform bacteria. Pathogens are relatively scarce in water, making it time-consuming and expensive to sample them directly. Instead, fecal coliform samples are taken due to the possible correlation between fecal coliform and the probability of contracting a disease from the water. Fecal coliforms are measured by lab analysis of water samples.
The Alberta Public Health Act Nuisance and General Sanitation Regulation Part 3 sets out the acceptable limits for fecal coliforms for Public Beaches. It indicates that the geometric mean of bacteriological counts of 5 samples of water taken over a 30-day period does not exceed 200 FC/100mL of water and that no 2 consecutive samples of water contain in excess 400 FC/100mL of water. When levels of fecal coliforms exceed the above acceptable limits a notice is posted to indicate the beach is unfit for swimming or bathing.
Microcystin sampling provides a measurement of water toxicity. Microcystin is one of many highly stable toxins produced by Cyanobacteria. Specifically, Microcystin is a Hepatotoxin (liver toxin) which can cause vomiting, diarrhea, fever and cramps. In severe cases, it can bind to liver cells causing them to lose shape and collapse this leads to hemorrhaging of the liver, severe pain, and death. Microcystin is the most studied cyanobacteria toxin, it measured though lab analysis of water samples and tends to be what the health regulations are based on.
Recreational Water Quality Guidelines (Health Canada, 2011) and the Alberta Public Health Act, Nuisance & General Sanitation Regulation for Public Beaches the limits are outlined as follows:
- Total Cyanobacteria < 100,000 cells/ml (skin irritation)
- Total Microcystin 20?g/L (ingestion)
ESRD regulates drinking water treatment facilities based on the Drinking Water Quality Guidelines (Health Canada, 2001). This guideline indicates total Microcystin of 1.5 ug/L as the limit.
Alberta Environment Cyanobacteria brochure http://environment.gov.ab.ca/info/library/7976.pdf
What is the status of these parameters in Pigeon Lake?
Based on the 2012 Pigeon Lake Watershed Quality Assessment Report (by Chris Teichrib, Alberta Environment and Sustainable Resource Development):
Temperature was relatively constant throughout the water column for all months in Pigeon Lake in 2012, only declining by a few degrees at most from the surface to deeper depths. Temperature increased from around 16 degrees in June.
Dissolved oxygen concentrations were around 8.5mg/L throughout the water column during June. In July, concentrations were observed to decline around 6m depth to near anoxic conditions at 9m depth. A similar trend was observed in August, with concentrations dropping rapidly at 5m depth. By September, dissolved oxygen concentrations were much like June, being relatively consistent throughout the water column.
pH was relatively constant through the water column in June and September, but showing decreases at deeper depths in July and August, with very high pH’s near the surface in August. Pigeon Lake pH ranged from 8.40 in June to 8.76 in August; the elevated pH in August is likely reflective of increased primary productivity in the lake.
The inflow stream concentrations of Pigeon Lake for both total nitrogen and total phosphorus were higher relative to the lake concentrations. Peak concentrations for both nutrients typically occurred in spring for most streams, decreased through May and June, increased again in July and August and continued to decline afterwards until late October.
Chlorophyll – a concentrations were lowest in June, increased in July, peaked in August, and decreased slightly in September.
Metal status for Pigeon Lake is not available at this time as metals have recently been added to the monitoring program.
Secchi depth increased from June to July (3.6 to 5.0m), then decreased significantly in August (1.9m) and improved slightly in September (2.1m). It is likely that the lower Secchi depth in June relatively to July was a result of greater wind mixing suspending more material in Pigeon Lake.
Total microcystin concentrations peaked at 0.48?g/L in August. This is below the drinking water guideline of 1.5?g/L and well below the recreational contact guideline of 20?g/L.
Pigeon Lake is being monitored in different ways:
- In depth water quality assessment of the physical and chemical water characteristics. 2011 Pigeon Lake LakeWatch Report.
aland Sustainable Resources Development (ESRD) and Alberta Lake Management Society (ALMS) LakeWatch program are working together to collect data necessary to produce a nutrient budget for the lake. Sampling has been expanded to include weekly to bi-weekly (depending on flows) of streams within the Pigeon Lake watershed (from April to October) and weekly lake monitoring (June to late September) as well as additional groundwater and air monitoring samples.
- Alberta Health Services monitors beaches and swimming areas in accordance with current guidelines and regulations, and posts advisories for public health reasons. Alberta Health Services (AHS) Beach Monitoring Program http://www.calgaryhealthregion.ca/publichealth/envhealth/beach_sampling/beach_index.html
- Provincial Fisheries Department monitoring is done to learn more specifically about the lake water’s physical conditions and characteristics that trigger fish die-offs.
Alberta Health Services Recreational Advisories Report
The Alberta Health Services (AHS) Beach Monitoring Program conducts a routine water sampling of recreational waters, to establish baseline water quality levels, identify risks to public health, assess the risk and manage notify the public on how to protect themselves. The 2013 AHS beach sampling will be done weekly between May and August. This will include visual inspection for Cyanobacteria (blue-green algae), microbial samples, and microcystin analysis.
In 2012 AHS monitored 36 and 57 public beaches across the province for fecal coliforms and cyanobacteria. AHS also partnered with Alberta Environment and Sustainable Resources Development (ESRD) to test for microcystin toxins in fish tissue.
What still needs to be done?
Water quality management is a continuous and long term process. On-going monitoring and watershed management is needed to ensure changes are made and maintained. A great first step will be the competition of the Pigeon Lake nutrient budget and the initiation of the watershed management plan. Public participation and awareness is also needed to facilitate action to overcome and manage water quality concerns.
How can you find out more about water quality?
For more information about Pigeon Lake water quality go to www.plwa.ca website, documents and Resources, click on ‘water quality / level’.
Additional resources can be found at:
-Alberta Environment and Sustainable Resources Development (ESRD) www.srd.alberta.ca
-Alberta Health Services www.albertahealthservices.ca
-Alberta Lake Management Society www.alms.ca
-Alberta Water Quality Awareness – www.awqa.ca
-Canadian Council of Minister of the Environment – http://ceqg-rcqe.ccme.ca/
-Nature Alberta – Living By water project www. naturealberta.ca/programs/living-by-water/
-Swim Guide – www.theswimguide.org