- Georgian Bay Association (GBA) Asks: Based on recent changes in water levels on Georgian Bay, it appears that the main factor involved is seasonal variations in our climate, rather than “climate change”. What is your take on this?
- GBA Asks: Water levels seem to be very unpredictable. Is there any way to predict the direction of water levels, or are levels too dependent on short-term factors like the amount of precipitation?
- GBA asks: Georgian Bay Forever (GBF) points out that fluctuations in water levels are important to maintaining healthy wetlands and biodiversity. Why do variations in water levels improve the health of lake ecosystems?
- GBA asks: Many people, as well as commercial interests, are very concerned by the hardships caused by very high or very low water levels. Georgian Bay cottagers and residents were very upset with the extremely low water levels that we experienced 3 to 5 years ago, but people don’t want them to go too high either! How can these extremes be managed while at the same time maintaining healthy lake ecosystems?
- GBA Asks: Recently GBF commissioned AECOM Technical Services, a widely recognized water resources engineering consultancy, to study structures or controls to address water levels in the Upper Great Lakes. What kinds of structures did they study? And what were their findings?
- GBA Asks: Is GBF’s current position that those kinds of structures AECOM recommends be installed to help to limit the extreme highs and lows of water levels in Lakes Huron and Michigan?
- GBA Asks: What would the costs be for AECOM’s proposed structures, and who would pay for them?
- GBA Asks: What should the next steps be to address these extreme water levels and Aecom’s proposed structural solutions?
- NEW 2021 – 259 Questions Answered form the GBF and GBA Symposium on Water Levels held in October 2020
GBA asks: Based on recent changes in water levels on Georgian Bay, it appears that the main factor involved is seasonal variations in our climate, rather than “climate change”. What is your take on this?
- “Weather is what you might see outside on any given day, while climate is the average of that weather over a longer time period. Climate is what you expect, weather is what you get." 1
GBA Asks: Water levels seem to be very unpredictable. Is there any way to predict the direction of water levels, or are levels too dependent on short-term factors like the amount of precipitation?
GBA Asks: GBF points out that fluctuations in water levels are important to maintaining healthy wetlands and biodiversity. Why do variations in water levels improve the health of lake ecosystems?
Seasonal variations in water levels are predictable in the Great Lakes and allow native plants to germinate in sun-warmed, wet soils and then grow in the water as levels rise over the summer. Other plants grow in deeper water at the appropriate limits of sunlight penetration. On a gradually sloping, soft lake bed, these plants can naturally “move” towards or away from the shoreline depending on the water levels so that they experience their ideal water level requirements. But much of the Eastern Georgian Bay archipelago has a more abrupt drop-off with little resilience to extreme lake levels.
An easy way to see how water levels impact wetlands and biodiversity is to look at two examples of what happens when water levels don’t fluctuate. Since 1957, the water levels in Lake Ontario have been controlled through regulations by power dams in the St. Lawrence River at Cornwall. The water regulation plan was a compromise between shippers, power generators and shoreline stakeholders that didn’t incorporate any environmental protection. As a result the Lake Ontario wetlands collapsed into mono-culture cattail marshes with limited biodiversity that supported only a few species. The International Joint Commission (IJC) just approved a new regulatory plan (Plan 2014) that with the stroke of a pen will restore over 60,000 acres of coastal wetlands by increasing the allowable range of water level fluctuation towards more natural variability.Another example in Georgian Bay started in 1998 and continued until 2013 with the water levels at sustained record low levels. Numerous coastal wetlands changed to coastal meadow with fewer species, more woody plants growing and overall reduction in ecological services. Over the past three years, as water levels have come back to average levels, those shrubs and small trees have started to die off and the more biodiverse wetland has emerged. GBF partnered with the National Aeronautics and Space Administration (NASA) and discovered that from 1987 high water levels to 2013 low water levels, the wetlands in Southern Georgian Bay declined by 10% while northern Georgian Bay wetlands, where the inner coastal waters are shallower, actually increased by 7%. Overall there was a 3% loss in Georgian Bay coastal wetlands as water levels dropped. (For more information on this study, click here ) Coupling this finding with the modelling forecasts trending towards lower water levels suggests that there may be future severe habitat impacts that could be devastating to our already numerous threatened species. While climate resilient controls would mitigate much of this, we are still missing a detailed inventory of coastal water depths and substrates available in the Bay. This detailed coastal bathymetry data collection is another ongoing GBF project. *** What does bathymetry mean? The measurement of depth of water in oceans, seas, or lakes.