Sugar Lake Association Stewardship Program

The Association’s Lake Steward is responsible for leading the Association’s Stewardship Program through the following programs:

  • Aquatic Phosphorus Testing
  • Water Clarity Testing
  • Zebra Mussel Testing
  • Lake Level Tracking
  • Personal Stewardship Guidance (Click Here)

Any questions for Julie Thompson, the Sugar Lake Association Lake Steward? Click here Lake Steward

Aquatic Phosphorous Testing

Total phosphorus concentrations are used to interpret nutrient status since phosphorus is the element that controls algae growth in most Ontario lakes. Increases in phosphorus will decrease water clarity by stimulating algae growth. Artificial sources of phosphorus include: fertilizers, septic runoff, & detergents.


Phosphorus testing involves the measurement of Total phosphorus (TP) which is measured in micrograms (ug) per litre (L). Phosphorous testing is conducted in the spring with two water samples taken at the Secchi depth (see Water Clarity Testing). The samples are then sent to the Ministry of the Environment which conducts chemical tests on the samples for TP concentration. The results are posted on the Data & Resources section of the Ministry of the Environment’s Website for the Lake Partner Program. This link can be used to compare our lake’s results with those of other lakes of interest. Historically, due to the fact that our lake is close to the top of the local watershed, our test results have been favourable compared to other lakes in the region. However, personal diligence with respect to septic maintenance and minimized personal impact on the natural environment remain crucial to the retention of our high water quality.

Water Clarity Testing

Transparency decreases as the amount of particulate materials such as algae and suspended materials increase. Transparency readings are done by taking a Secchi depth measurements. A Secchi disk is a small black and white disk (8”-9”). The instrument was named after its inventor, Father Pierro Angelo Secchi, who first used it on April 20, 1865. The disk is lowered into the water until the observer can no longer see it. The depth of disappearance, called the Secchi depth, is a measure of the transparency of the water.


Transparency measurements can be used to indirectly determine phosphorous levels because algae growth affects transparency and algae growth is controlled by Phosphorus levels. Transparency tests are particularly effective when done in conjunction with periodic Phosphorus testing to calibrate the Secchi results. For example, a Secchi reading of 4.3 meters taken in the same location/depth/time as a Phosphorus reading of 6.6 ug/L can be used to imply higher phosphorus readings at Secchi readings less than 4.3m.


Transparency measurements can be done inexpensively without the need for costly chemical analysis in the lab, and so can be done more frequently and therefore can be done throughout the year from spring to fall to monitor the changes in algae growth as a result of summer loading due to human activities.


Our Secchi observations are sent to the Ministry of the Environment (MOE) which keeps a database for all Lake Partner volunteers. The average yearly Secchi data collected by our volunteers and submitted to the MOE for Sugar Lake can be accessed on the Data and Resources section of the Ministry of the Environment’s Website for the Lake Partner Program. This link can be used to compare our lake’s results with those of other lakes of interest.

Zebra Mussel Testing

Invasive species are those species not natural to the local environment that have invaded the local environment as a result of the activities of humans. Many such aquatic species come accidentally from Asia as a result of international trade and shipping practices. Some species come as a result of deliberate introduction for profit or to combat some other invasive species. The spread of invasive aquatic species within Ontario, once they get here from their foreign home, move from lake to lake through fishing practices involving the use of bait or boats and trailers taken from one lake to another.


The Ministry of Natural Resources describes a number of aquatic invasive species that are a problem in Ontario on their Invasive Species Webpage link.


Zebra Mussels are believed to have been introduced in the late 1980′s by ballast water from transoceanic ships carrying veligers (larvae), juveniles or adult mussels. Zebra mussels are capable of heavily colonizing hard and soft surfaces, including, docks, boats, break walls and beaches, can clog the intakes of water lines, and can cut the bare feet of swimmers. Details and pictures of Zebra Mussels can be seen at the following MNR website: Invaders.


We do Zebra Mussel testing annually through a program sponsored by the Ontario Federation of Anglers and Hunters. Water samples are taken during the larvae stage in the spring at three locations on the lake. The GPS coordinates and the samples are then sent to the OFHA for analysis. These tests have been ongoing for a number of years with test results that show no evidence of mussels. Although negative test results cannot prove definitively that there are no Zebra Mussels in the lake, it does show that if they are present, their numbers are still small. An ongoing high level of vigilance on the part of boaters is necessary to ensure that an invasion does not occur on our lake since these mussels can be found in many lakes in the area, and once they gain a foot-hold in a lake there is no possible way to eliminate them.

Updates July 2015: Part of the lake testing the SLA Lake Steward does is for two invasive species, spiny waterfleas and zebra mussel velagers. Velagers are the immature stage of zebra mussels. The samples are analyzed by the Ontario Federation of Anglers and Hunters. The results are uploaded to the EDDMapS where they can be publicly viewed (Click here). Please Note: There was an error in the data submitted by OFAH. The map indicated positive findings for velagers in Sugar Lake in 2013. However, the actual tests did not show the presence of zebra mussel velagers. The Lake Steward discovered this error after the 2015 AGM. The OFAH has confirmed with the Lake Steward that they are correcting the map to reflect the negative findings.

Lake Level Tracking

Water levels change naturally as a result of normal summer seasonal variation, and the interaction of natural habitat species such as beavers. Water levels may also change as a result of the intervention of man. The maintenance of natural water level is important to water quality because unnaturally low water volume contributes to increased water temperatures, increased runoff of soil nutrients, and extended exposure of the lake bottom to light, all of which artificially promote increasing bottom plant growth and algae formation. On the other hand, unnaturally high water levels can lead to flooding and shoreline erosion which also increases plant growth and algae formation from the nutrients of soil erosion.


Lake level measurements are taken using the lake’s high water mark (HWM) as the reference point. In reality, the HWM varies from year to year, and from location to location on the lake, however, a dominant HWM can be seen on shoreline rocks and a reading of this HWM has been designated as the “official” reference for purposes of consistent measurement. A water level measurement of 0 inches corresponds to a water level at the designated HWM. All positive measurements are therefore higher than the HWM and those measurements that are negative are lower than the HWM. The validity of the designated HWM can be seen by the fact that water level measurements taken just after the ice has broken up in years where there has been no artificial tampering with water levels, will be close to 0 inches (+/- 2 inches or so).


From a practical point of view, the water level is measured with reference to a lake bottom mark where the bottom is composed of bedrock to ensure consistent measurements. To track seasonal variation, and any artificial tampering, measurements are taken monthly, or after unusual events such as unusually heavy periods of drought or rainfall.


Historical water level readings, now including back to 2004-2006, can be found here. Sugar Lake Water Level Log (December 2017)