Low Water

[SailingSloop]

Wow, in the last few weeks, Lake Huron has dramatically in levels. Bigger boats had to find alternate haul out places. It isn't clear there will be enough water to float our boat out in the spring.

[Barquito]

Low lake levels suck. I went hard aground on a rock I did not even know about in our mooring field in Milwaukee (same body of water as Huron). Lake levels are 15 inches below last year at this time. I understand that along with lower precipitation in the upper midwest, the St. Claire river was dredged. This increased the outflow of water from the system.

Hopefully we get a bunch of snow this winter... or they build a dam in Detroit.

[nodders]

Same issues in lake Ontario (downstream from the St clair river). Our bay (Mimico) is down about 18 inches and geting some of th bigger boats out for the season was a challenge. Despite good depth, some slips were too shallow for some of the larger boats.

during haul out a few weeks ago, I watched one boat motoring over to the crane and all of a sudden the boat stopped and the stern lifted up 8 inches or so. It was able to power through in reach of the crane so it all worked out.

Despite all the rain we have had, levels are still low. Georgian Bay is even worse. I drove by a few weeks ago and around Port Severn, could see docks ending a good 20 feet from the water!

have heard lots of stories about rocks being "discovered" in areas that were never an issue.

[chantler]

Fun Fact. I used to live near Sans Souci and still work in the area . The highest I ever saw the water was in an October storm in 1986. I marked the level then and measured it on Monday.----- 7' 4" difference. File that under useless trivia to bring up next time you run aground.
Cheers

[sailortjk1]

What we need is an ice cap over the winter to stop the evaporation, but it does not look promising as it is in the mid 40's in Mid December.
My slip still has 13' and our channel is dredged every other year as it is a commercial port.
Everybody pray for the rest of the winter to absolutely brutal and we might have a chance.

[MSN2Travelers]

Water levels are down roughly 15 inches since July 20th and continue to drop. I had 8’ in my slip in June and it was less than 6.9’ three weeks ago (I need 5’6”). The yacht club is planning to do involuntary relocation of boats between slips to ensure deep-draft boats will have a chance to float next season. Roughly 60% of the main channel that services SSYC and the public mooring fields north & south of the YC is so shallow the lake birds are walking on the sandy bottom.

We need cold & snow this winter and we’re not off to a good start.

[sailortjk1]

Well it looks like a lot of ice in Southern Lake Michigan, but I fear it is not nearly enough.

Typically we see huge mounds of pushed up ice at the shoreline; mounds as high as 50 feet or so were common in past years. This year the ice is expansive but the large mounds are just not there, these along the shoreline are of about 10 feet or less.

[MikeOReilly]

There is an excellent resource at the Great Lakes Environmental Research Laboratory where you look at actual data over time. A cursory examination of the trends suggests (to me) that the upper lakes (Superior, Huron & Michigan) are into a significant declining period which may be unprecedented. Since the late 1990s these lakes have been well below the long-term average. There was a similar low-level period in the late 1950s to early 1960s, but the current levels appear to be deeper, and more stable at their low level rates.

For Erie and Ontario, what strikes me is how stable the depths have been since the late 1990s. There's more variability with Erie vs Ontario, but both appear to be hovering right around the long-term average depth. This suggests that the lower lakes' water levels are being more actively managed.

So the reality indicates that the lower lakes are pretty stable around the long-term average depths, while the upper lakes are into a decline which may become unprecedented. The major reasons for the lower water levels in the upper lakes appears to be decreased inflow from precipitation in the basin, but more importantly, the increased evaporation rates due to diminishing ice coverage in the winter.

According to a recent NOAA paper, "Total annual average ice cover on the Great Lakes has shown an overall decline of 71%, while the annual maximum ice cover shows an overall decline of 52% over the period 1973-2010 (38 years)." According to another recent paper published in the Journal of Great Lakes Research looking at Lake Superior's ice rates, "Analysis of the data indicates that the duration of ice cover on Lake Superior at Bayfield, Wisconsin has decreased over the past 150 years at the rate of approximately 3 days/decade or 45 days over the course of the study."

With regard to the St. Claire River dredging, the research I've read suggests that while there is some contribution to lowering Huron, Michigan and Superior, it remains a small effect compared to evaporation and diminished water inputs (rain and snow).

[MSN2Travelers]

Originally Posted by MikeOReilly

...

With regard to the St. Claire River dredging, the research I've read suggests that while there is some contribution to lowering Huron, Michigan and Superior, it remains a small effect compared to evaporation and diminished water inputs (rain and snow).

Mike, I beg to differ with your information. This is a current report that indicates human intervention on the St. Claire has lowered Michigan/Huron by roughly 2 feet. Great Lakes | Update - Lakes Michigan, Huron hit record low water level

[MikeOReilly]

Originally Posted by MSN2Travelers

Mike, I beg to differ with your information. This is a current report that indicates human intervention on the St. Claire has lowered Michigan/Huron by roughly 2 feet. Great Lakes | Update - Lakes Michigan, Huron hit record low water level

News media is notoriously poor at digesting and presenting research. Here's one recent paper based on actual research. It says what I said, that the St. Clair dredging has had a small contribution to lowering Huron/Michigan:

http://pub.iugls.org/en/Other_Public..._Report_EN.pdf

"The Study Board concluded that:
1. The difference in water levels between Lake Michigan-Huron and Lake Erie has declined by about 23 centimetres (cm) (9 inches) between 1963 (following the last major navigational channel dredging in the St. Clair River) and 2006.

2. Three key factors contributed to this 23 cm (9 inches) change:
- A change in the conveyance (water-carrying capacity) of the St. Clair River accounts for an estimated 7 to 14 cm (2.8 to 5.5 inches) of the decline.
- Glacial isostatic adjustment (the uneven shifts of the earth’s crust since the last period of continental glaciations ended) accounts for about 4 to 5 cm (1.6 to 2.0 inches) of the fall.
- Changes in climatic patterns account for 9 to 17 cm (3.5 to 6.7 inches); this factor has become even more important in recent years, accounting for an estimated 58 to 76 percent of the decline between 1996 and 2005.

3. There has been no significant erosion of the channel along the length of the St. Clair River bed since at least 2000. Based on survey data collected in 1971, there appears to have been some enlargement of the channel between 1971 and 2000. However, the changes in the channel are within the error of the surveys. In addition, there are issues regarding the reliability of the 1971 data."

Perhaps there is more recent research on the subject. If so, please post the link (to the paper, not to media reports).