***Original published in South Mountain Press, August 3, 2018***
Clear Lake Summer Report
Is it my imagination or has anyone else noticed that Clear Lake seems warm for this time of year instead of the usual anatomy-shriveling frigidity that I recall from my childhood?
Sean Frey, the Geomatics Coordinator for Riding Mountain National Park (RMNP), has studied and measured various metrics in the lakes of the Park. He was able to comment on their general state compared to historical norms.
Q1. Am I right to think that the water temperature of the Lake seems quite warm for this time of the year? Are there any identifiable trends in temperature, salinity, the thermocline, pollution, algae, water levels or parasite (The Itch) count between years past and now?
A1. The lake temperatures this year are warmer than usual. In the past ten years we haven’t observed June surface lake temperatures above 20°C (see the graph below) and this year they passed that mark. You can see on the graph by the dashed linear trend line there has been a general increase in May – August surface water temperatures on the lake in the past 10 years.
This appears consistent with longer term trends in climate in the area as the dates for ice off and ice on for Clear Lake show in the graph below.
Compared to records from the 1960s and 70s, the ice free period on the lake now appears to be earlier in the spring by over a week on average and later into the fall by over a week.
The good news so far is that trends in algae appear to be stable as the graph of Chlorophyll a Levels below illustrates. The levels were beginning to climb in the 1980s and 90s and have since stabilized possibly due to improved sewage and nutrient management.
As for water levels, they are lower this year than they have been in the past 20 years, though within a historical range of variation as shown in the graph below.
Q2. As for the other RMNP lakes, has there been the same type of scrutiny as Clear Lake and has there been anything particularly unusual that’s happened with any one of them compared to what’s been going on at the main lake?
A2. Riding Mountain monitors a suite of six backcountry lakes and four streams, although none has received the level of scrutiny afforded to Clear Lake. The most recent report indicates “Overall the backcountry lakes and streams in Riding Mountain appear to be in good health.” (Baird 2018). There is a detailed report graphing nutrients, turbidity, and temperature and oxygen profiles for the various lakes if people are interested.
Q3. Zebra Mussels are a great concern and the Park has extensive programs to keep them out of the water. But Whirlpool Lake is closed to the public due to a possible Zebra Mussel outbreak. Could you comment on the Park’s efforts so far and do you think you’ll be successful with keeping this invasive species out of the Park? One side effect of the bivalve molluscs in the Great Lakes was the filtering out of the pollution and actually cleaning up the water. Why is it so important to keep this species out of the Park?
A3. In managing national parks, Parks Canada maintains or restores ecological integrity, and provides Canadians with opportunities to discover and enjoy them. Parks Canada staff are working closely with visitors to keep aquatic invasive species (AIS) like Zebra Mussels out of park waters through watercraft inspections and strict decontamination procedures. The cooperation of watercraft operators is essential in preventing this threat to Park waters. 100% compliance is necessary to ensure the ecological integrity of Park waterways, as it only takes one contaminated watercraft to transport Zebra Mussels and other aquatic invasive species into the park.
Zebra Mussels are potentially the greatest threat the aquatic system in Riding Mountain has ever faced. While it is true that they filter and clean the water, they also irreversibly change the ecology and recreational value of the lakes and streams they take over. As a National Park, Riding Mountain has the mandate to protect representative plants and animals in their natural environment in a way that lets them persist for future generations of all Canadians.
If Zebra Mussels were to become established in one of the lakes in the Park, that lake would be permanently changed to a degraded ecological state and the Park would be unable to fulfill its mandate for that area. The community of fish, plants and other aquatic organisms in the lake would be changed and it is possible that some native species would disappear entirely from the lake. There is evidence that Zebra Mussel infestations can cause declines in fish populations and increase toxins in game fish.
We do not know of any treatment that is effective in eliminating Zebra Mussels, therefore the change would be permanent.
If a lake in RMNP were to become contaminated with Zebra Mussels it would threaten the integrity of all downstream water bodies and aquatic ecosystems, including streams that feed the Assiniboine River and Dauphin Lake, since the larval form of Zebra Mussels can float downstream and gradually colonize downstream waters. The risk of infestation downstream is considered very high and the watershed covers much of southwest Manitoba including many other water infrastructure and industry.
Zebra Mussels will attach to most hard surfaces and would be expected to interfere with irrigation systems at the Clear Lake Golf Course, impair water services within the community of Wasagaming including the neighboring Elkhorn Resort and portions of the RM of Harrison Park. Municipal infrastructure and services, including water services, could be impacted due to the disruptive effects of Zebra Mussels. The cost to mitigate this would be in the order of hundreds of thousands of dollars.
That is why the Park is devoting so much effort in trying to make sure Zebra Mussels do not become established here through our inspection program and monitoring of lakes. Monitoring determined that environmental DNA of Zebra Mussels was present at Whirlpool Lake so we have closed that lake, and enhanced our monitoring there. So far results are encouraging that Zebra Mussels haven’t become established there but we are continuing to make sure.
Unfortunately it is all too easy to unknowingly transport Zebra Mussels in water from an infested area via boat ballasts, bilge water, and water in the end of a canoe, kayak or paddleboard and perhaps even in a beach toy. It is our responsibility to do all we can to protect the park as it is and encourage people to help us with our conservation efforts for the future.
For more information on the Park’s efforts to halt the spread of Aquatic Invasive Species and their watercraft inspection and permit program, you can visit the RMNP website: https://www.pc.gc.ca/en/pn-np/mb/riding/visit/moto-boat
Blair is a personification of a ‘Jack of All Trades and Master of None’. He has held several careers and has all the T-shirts. Time to add the title Blogger to the list.