Water Testing/Monitoring Program

During the summer 2012 ( for the third summer in a row),  volunteers are taking weekly visibility and temperature readings at 6 different sites around Crystal Lake and 3 different depths.  To carry out their work, volunteers launch into the lake in a rowboat, equipped with a GPS device, laminated maps, thermometers, secchi disks, reporting sheets and markers, To test water visibility, volunteers use a “Secchi disk”, which is an 8-inch disk with alternating black and white quadrants used.  They lower the disk into the water until it can no longer be seen by the observer. This depth of disappearance, called the Secchi depth, is a measure of the transparency of the water.  Transparency of the water decreases as color, suspended sediments, or algal abundance increases.  Transparency can be an indicator of the impact of human activity on the land surrounding the lake. If transparency is measured through the season and from year to year, trends in transparency may be observed. Transparency can serve as an early-warning that activities on the land are having an effect on a lake. 

To measure water temperature, volunteers used water-proof thermometers at 3 different depths in 6 different locations around the lake. Water temperatures are an important factor for the health of the lake.  As water temperature rises, its ability to dissolve oxygen reduces. At lower temperatures, water will dissolve greater levels of oxygen. Diverse populations of micro-organisms as well as fish rely on a supply of oxygen. Without oxygen, filter bacteria cannot oxidize (and detoxify) ammonia into nitrite and then into nitrate. If a pond or filter are allowed to become oxygen deficient for any period of time, anaerobic conditions will prevail causing unstable water conditions and the tell-tale bad-egg smell. Water Temperature can also affect fish metabolism. The metabolic rate of fish is dependant on water temperature. In winter their metabolism slows right down and speeds up as the water gets warmer in spring. This dependence on water temperature also affects their immune system, wound healing and digestion.

The chart below shows changes and trends in water temperature between March and August of 2010.