Phosphorus levels are an important indicator of water quality and the impact of human activity on the River. High phosphorus levels can facilitate algae blooms, which are detrimental to water quality. We have joined with the Ontario Lake Partners program and their long term phosphorus testing program to evaluate phosphate levels in the Wolseley Bay area. Volunteers also collect samples at other sites in the French River Watershed for a total of 13 sites presently being monitored.
Phosphorus is not the only nutrient that affects algae growth and the ability of water systems to handle nutrient loading can vary greatly. That being said, typical guidelines for phosphorus levels in water bodies such as the French river are;
• Less than 10 micrograms per litre (μg/L) indicates natural nutrient levels.
• 10 to 20 μg/L is nutrient enrichment of concern.
• Over 20 μg/L is an indication of significant water quality problems.
The table below contains the results from the Ontario Government Lake Partners Program activity on the French River. Volunteers collect multiple water samples throughout the year. These samples are done in duplicate and the phosphorus content of the samples determined by the Ontario government lab in Dorset. This graph shows the 3 year average results from the program, a data summary for each year can be viewed by clicking the appropriate link below.
In the third year of testing, a new site was added at Bear Lake (Stn# 274-1) upstream of Wolseley Bay. This station showed some of the lowest phosphorus levels in the test area, in stark contrast to the high levels seen in Wolseley Bay stations 7262-3 and 4. Levels mid way down the North Channel at Daoust Bay (Stn# 7262-1) are also typically low, indicative of a slow rate of drainage from Wolseley Bay into the North Channel. The high phosphorus levels in Wolseley Bay are a likely cause of the recent algae blooms that originated in the bay.
One area of concern is the operation of the Noelville sewage lagoon that drains into the Wolseley River between Bear Lake and Wolseley Bay. I have met with municipal officials and representatives from the Ontario Clean Water Agency, who are contracted to operate the Noelville lagoon. This led to the decision by the Municipality of French River to commission a septage plan review, which should be available shortly.
Elevated phosphorus levels were also seen in the Delta area at stations 7262-10 and 11, possibly reflecting the inflow from the Wanapitei River. The very high readings that were seen in the eastern sections 7262-2 and 12 near Dokis in 2008 were not seen in the 2009 samples. Perhaps surprisingly, the areas midway down the river around Ranger and Dry Pine Bays (stations 5 to 9) had some of the lowest phosphorus levels although this area probably has the highest shoreline population density in the study area.
