I feel like I'm taking Great Lakes 101, and you guys are getting your PHD's. I need some basics,...
I may have missed it but can you explain the causes of the sudden high water levels? Is it the high rainfall the last several seasons or the politics of dams/shipping, or both? What is being done to improve water levels or is this just a temporary problem?
What does this mean for you - your sailing, in different areas/lakes? Are you worried about access to docks etc. due to high spring water levels?
@TomY to give you the short answer, yes to all of the above questions.
Depending on your definition of sudden, water level changes are not sudden like tidal changes or flooding at this year's
Annapolis Boat Show. There is a normal seasonal variations in water levels, the levels go up in the spring due to increased spring rainfall and melting snow and gradually decrease through the summer, fall and winter due to decreased rainfall and evaporation (especially in the winter). Even though we are still at extremely high water levels this year, that still holds, water levels are lower now than they were in July. For the most part short term increases in rainfall have little effect on water levels. If a major hurricane comes through and dumps a foot of rain (it's happened) we'll see a quick rise of an inch or two but that's not a big deal. We do get
seiches that can cause a change reminiscent of tides, but we'll cover that in GLL 201.
The primary cause of the high water levels is increased precipitation in the Great Lakes basin. The catchment area is quite large and all that water has to go somewhere. The water levels between four of the Great Lakes is not controlled. There is a dam in Sault Ste Marie that controls water leaving Lake Superior, after that the next barrier is the
Moses-Saunders Dam on the St Lawrence River. Once the water falls from the sky there is no stopping it until it reaches the Moses Saunders Dam.
There is lots of misinformation floating around about water levels on the Great Lakes. Take this quote from a
Windsor, Ont newspaper referencing high water levels and currents on the Detroit River:
"The reason for the higher water speed has to do with the Moses-Saunders dam on the St. Lawrence River near Cornwall which has been opened more because of high water levels in the Great Lakes."
The Windsor Star needs to hire better fact-checkers. Between the Detroit River and the Moses Saunders dam there is this little Natural Wonder called
Niagara Falls. The Moses-Saunders Dam is tall, but it is not taller than Niagara Falls at ~170 feet. But I digress.
The key takeaway is that if it rains in Duluth MN, eventually that water will reach Lake Ontario and the speed at which it reaches Ontario is, for the most part, not controlled by humans.
Lake Ontario is the smallest, by surface area, of the 5 Great Lakes. The next smallest lake is Erie and that is about 30% larger; a foot of water on Erie is equal to 16 inches on Ontario. Someone else can do the math on the relative size of the other lakes.
All of the water on Lake Ontario leaves the lake through the St. Lawrence River, there is a series of dams and locks between Cornwall Ontario and Montreal to allow for ocean going vessels to access the Great Lakes. The was the great
St. Lawrence Seaway Project of the 1950s. (Sorry,
@Will Gilmore Montreal is tidal.) Global access via the St Lawrence was seen as a having a tremendous economic impact on the midwest providing an economical way for midwest business to access global markets and providing an alternative to the Mississippi River route. The Seaway is particularly busy in the fall taking agricultural products to global markets. When I was in college the really big kids in the dorm got to work as stevedores unloading bags of cocoa beans from Africa for the nearby Nestle` plant in Fulton, NY. Anyway, the Seaway project was and is an economic benefit to both US and Canadian industries.
I am not a hydrology expert (nor do I play one on the internet), however, it is my understanding that any waterway has a maximum flow that it can sustain. It doesn't matter if there are dams or not, there is just a maximum amount of water the creek, stream, or river can accommodate. For the St. Lawrence, the maximum is somewhere about 10K to 11K cubic meters/second. If the dam is there and opened, 10K cm/s flows through, remove the dam and 10K flows through. If the inflow to Ontario is greater than 10K, then the lake level rises, if it is lower then the level lowers.
The
IJC is tasked with managing the water levels on the St. Lawrence River. Their website will give a much more detailed description of their charge, however it boils down to several factors in no particular order:
- Maintain safe shipping, i.e, deep enough water and manageable currents
- Control downstream flooding.
- Control upstream flooding (sorry Windsor CA, the IJC can't help you).
- Maintain more normal (uncontrolled) water levels for environmental reasons
Shipping may seem to be a minor issue, however, there is billions of dollars of commerce that comes through the St Lawrence Seaway and that involves thousands of jobs, particularly in the Midwest of the US and Canada. Shipping is important.
For sailors on Lake Ontario it means docks under water, travel lifts stuck in the mud, marinas out of business. The plus side is we can get into anchorages and bays that are normally too shallow and we get to have fashion shows for the muck boots we all wear to access our boats. Seriously, it is costly for marinas, businesses and homeowners near the lake. By this summer, my marina owner will have spent several hundred thousand dollars to protect the marina and address flooding issues.
There is no long term solution save for addressing climate change which seems to be the cause of increased precipitation in the Midwest. In the mean time don't buy lake front property.