DATA GATHERING
Water Quality Monitoring Program
We are often asked " does our lake have problems? " or "is our lake in good shape?" Our usual response is that fortunately at the moment we do not have any crises or imminent disasters. We are however looking for trends which is why we keep checking each summer. There are a lot of parallels between tracking lake health and a regular visit to your doctor.
View the latest Water Quality Monitoring Report, and learn more about understanding the Water Quality Reports below.
Latest Water Quality Monitoring Report
The 2021 Water Quality Management (WQM) Report will be published in 2022.
Please see below for links to reports from 2016 to 2019. There was no Water Quality testing in 2020.
Understanding the WQM Report
Classifying Your Lake
Since lake water quality has so many variables it is difficult to assign a good or bad rating to a lake. Instead a method called the trophic state index (TSI) was devised which allowed the water quality between lakes or changes in a lake over time to be compared.
Trophic means nutrition or growth. The 3 basic levels are eutrophic, mesotrophic and oligotrophic. A eutrophic lake would have high nutrient levels and plant growth, usually is shallow, generally has large wetland areas, often is subject to algae blooms and supports large fish populations (usually rough fish like carp). An oligotrophic lake would have low nutrient levels and plant growth, generally is clear, deep and free of weeds and large algae blooms and doesn’t support large fish populations but may support lake trout. The watershed of oligotrophic lakes usually contains few wetlands.
Mesotrophic lakes have nutrient levels and productivity in the middle between eutrophic and oligotrophic, have some aquatic vegetation, a wide variety of fish (bass, perch, pike) and adjacent wetland areas that support a variety of wildlife. Lakes naturally age over many hundreds of years - gradually becoming more shallow from sediment and debris deposited on the lake bottom. As nutrient levels increase, plant growth accelerates and some shallow areas will eventually become a marsh.
Human impact from industrial pollution, defective septic systems, misuse of fertilizers, shoreline erosion etc. can accelerate the aging process so changes that what would normally happen over thousands of years can happen in as little as a hundred years.
One of the mechanisms for determining a lakes trophic status is based on the level of total phosphorous in the water. More on this below.
Your Lake and its Environment
All the lakes in the Kearney Watershed that we monitor are different. Some are quite deep, some are very shallow, some are headwaters lakes or part of tributaries that eventually feed into the Magnetawan River others are actually part of the Magnetawan itself.
When looking at the data for your lake there are several things to take into consideration. Start by locating your lake on a map and look at its position in the watershed. Does the source of water for your lake come from lakes or rivers upstream, from adjacent wetlands or is it perhaps spring fed. Each of these sources can be beneficial or potentially problematic.
Downstream lakes benefit from the natural flushing action of the normal water flow but also suffer from upstream abuses and pollution. Headwater lakes may not have sufficient water flowing into the lake to maintain an outflow during dry summers which can impact water temperature and lake chemistry.
Next look at the information on your lake in the Lake Profiles, Maps & Sampling Sites in Section #2 of the WQM Report. Maximum and average depth are two important parameters. It makes sense that a small shallow lake will be more sensitive to human and natural impacts then large deep lakes. Note the sampling points in the lake where we collect data and things like shoreline development and sources of water entering the lake in that area.
Finally how are people using the lake. By going through this process, you are now constructing a picture of the environment around your lake and all the things that could impact its health.
Total Phosphorous (TP) Data
Probably one of the most important pieces of data in the report is the Total Phosphorous (TP) readings for each lake that is enrolled in the Lake Partners Program (LPP) run by the Dorset Environmental Science Center (DESC). Water samples are collected each spring by local LPP volunteers who send them to DESC for TP and calcium analysis.
Most lakes have been sampled for several years and you will be able to see from the data in our report the range of readings and whether they are stable or trending up. If the readings are trending up that is not a good sign because phosphorous is one of the main engines fueling plant growth (including algae) in a lake. While algae are an essential part of the aquatic food chain, excessive algae growth can be a nuisance when it clogs water intakes, produces foul odours and makes recreational use of the lake unpleasant.
A blue green algae bloom however can be toxic to the point where any use of lake water for washing, cooking or drinking can result in illness or possibly death. As mentioned above, one of the mechanisms for determining a lake's trophic status is based on the level of total phosphorous in the water. Lakes with TP readings between 4-10 ug /L would be classified as oligotrophic which is common for many of the lakes located on the Canadian Shield. Lakes with TP readings between 11-20 ug/L are considered mesotrophic and greater then 20ug/L are eutrophic.
Secchi Data
Secchi disk (water clarity) readings are also gathered throughout the summer by the same LPP volunteer. They lower a black and white segmented disk into the lake (on a line marked off in meters ) until it disappears from view. That distance is called the secchi reading or secchi depth.
Lake water that is naturally a brown colour due to high levels of dissolved organic carbon (DOC) that comes from wetlands in a watershed will have reduced water clarity . This is not an indication of nutrient enrichment.
A long term trend of lower readings (less clarity) can indicate possible increased algae growth or other problems and should be investigated. Secchi disk readings can also be used to calculate trophic status. In lakes not coloured by DOC, secchi readings over 5 meters are considered oligotrophic, between 3-5 meters are considered Mesotrophic and less than 3 meters are eutrophic.
Secchi readings tell us how deep light can penetrate and photosynthesis (oxygen production) can occur in each lake. As discussed further on in the article - this can have a huge impact on DO (dissolved oxygen) levels in the lake.
Calcium Data
Calcium levels in the spring water sample are also being measured by DESC. Calcium levels are critical for the survival of many aquatic species. Calcium levels greater than 2.0 mg/ L would indicate the lake system is not under stress , from 1.5 - 2.0 it is vulnerable and if less than 1.5 it is under stress.
Daphnia (tiny planktonic crustaceans) are very sensitive to environmental changes and are often viewed as an early warning organism. They usually die when calcium levels are less than 1.5 mg/L. Since Daphnia eat algae and are in turn eaten by insects, water mites and small fish they are also very important in the aquatic food chain.
Conductivity & pH Data
We measure temperature, dissolved oxygen, conductivity and pH as part of our WQM program. Conductivity is the ability of water to pass an electric current and indicates the presence of dissolved salts (ions) in the water. Other than measurements taken from the stream at the graphite mine site which often were several hundred uS/cm, readings in our lakes are normally quite low (25-50) uS/cm which is good.
The provincial water quality standard for pH is between 6.5 - 8.5 . The pH scale is 1-14 with (7) being neutral, (1) being very acidic and (14) very basic. Values below 5 or above 9 are usually harmful to organisms.
Water Temperature & Dissolved Oxygen Data
Water temperature and the amount of dissolved oxygen in the water dictate which types of aquatic life live in a particular water body. In summer the deeper lakes, stratify with a layer of warm water on top ( called the epilimnion) and the cold water below (called the hypolimnion).
Because cold water is more dense than warm water the two layers don't mix. The transition area between the top & bottom layers (called the metalimnion is quite narrow). In the summer the DO levels in the top layer are generally quite good because of oxygen production due to photosynthesis and diffusion of oxygen from the atmosphere due to wind & wave action. The rule of thumb is that light can penetrate and photosynthesis can occur to 1.7 times secchi depth. The cooler the water the more oxygen it can absorb. Shallow lakes tend not to stratify in summer and remain well mixed.
In the deeper lakes that stratify the DO in the lower (hypolimnion) layer will decline over the summer because of processes like decomposition which consume oxygen. Some deep areas in the lake may even become anoxic (totally devoid of oxygen). If you look at the temperature and DO levels at various depths in a lake and then using the two charts we provided in the WQM report on DO and temperature levels preferred by various fish species you will understand why trout for example don't live in certain lakes. Trout prefer DO levels above 6 mg/L and temperatures below 10 C. Pike on the other hand can survive in DO levels of 1.5 mg/L and like a temperature range of 17-21 C.
Looking to the Future
We are hoping that the weather data that we are currently collecting on temperature, rainfall and snow accumulation along with lake levels and water temperature when correlated with the WQM data might help predict future problems like algae blooms.
We are also considering acquiring a temperature & DO instrument with the capability to do profile measurements down to 20 meters. This would allow us to check lakes during spring turnover as well as late summer. We could also do weekly or monthly studies on specific lakes or check DO levels on all the lakes in winter.