Water Levels

Using Google Earth for Local Navigation

If you boat among the 30,000 Islands of Georgian Bay you are well aware of the many hidden rocks and shoals that seem to wait, daring you to come their way. A couple of days ago I saw a 40-foot power boat onshore with its bow ripped apart following an unadvised shortcut between channels. That’s life exploring the Georgian Bay Biosphere. Stay in the small craft route and you are guaranteed to have no surprises. Wander off the ‘beaten track’ into the more interesting areas and you take responsibility for what happens.

In a series of reviews last year I looked at how iPad apps from Navionics, iSailor and iNavX made it much easier to head off the small craft routes and explore some of the thirty thousand islands. Well these apps are great but they are not perfect as I found out last weekend on a trip from Parry Sound to Little McCoy Island (45.458303, -80.481705). This was a new destination for us and I spoke with couple of people about the best route to take as well as consulting with the Navionics and iSailor apps on my iPad. On route I was careful to ensure I stayed on my planned route using the Navionics app. Here’s a snapshot of the path once beyond the charted small craft route. The darker blue represents a depth of less than 6 feet while white represents depths of more than 6 feet. Boating with our 21-foot Scout and 150-hp Yamaha outboard I’m pretty comfortable with depths of 4-feet or more, and right now we are dealing with water levels at or slightly above chart datum.

LittleMcCoy_v1Heading west of Franklin Island towards Little McCoy.

Here’s a closer look as you approach the McCoy’s. It’s pretty obvious that there is a safe seam running east of the McCoy Islands with issues just as you approach Little McCoy Island. Or so you would think.


On the way in I managed to ding the prop, not too seriously, about where you see the Number 2 on the Navionics chart. (Click image for a larger view.) On the way back I suffered a separate ding, at higher speed, between points 3 and 4. According to the charts I was in an area that should have had more than 6-feet of water. In particular the ding beyond point 3 (heading south) was a surprise, as evidenced by the fact that I was confidently moving at about 40 kph (25 mph) – ouch, ouch, ouch. There had been no problem on the way in and I was pretty much on the same track. (That’s another nice feature of Navionics and iSailor, you are able to lay down a track that you can follow when returning.)

Now about Google Earth. In this part of the world Google Earth and Google maps have on and off coverage, here’s an example of the area around Franklin Island and the McCoys. In those areas where there is a stretch of open water they generally choose to blur out the area with a not very aqua blue. (Hey it’s just water what else is there to show?)


Looking closer (below), Google Earth can explain what I ‘discovered’ on my way in and out of Little McCoy. It’s pretty obvious that there is a seam in the channel that is consistent with the Navionics charts. But they are not perfect seams as you can see looking a little closer. I’ve tried to approximate the ‘ding points’ on the Google Earth projection and you can see what I discovered with the bottom of my outboard. What Navionics didn’t catch were the several shallow points in the area identified as 6-feet or deeper. No criticism of the app, they can’t be expected to have information on every square foot of Georgian Bay.


What is interesting is the area north of Big McCoy Island (below). Contrary to what is indicated by Navionics it seems the safer route is closer, not further away, from the island.


Lesson learned and a look at Google Earth will be part of my standard operating procedure when wandering too far off the well charted areas. Actually I will  pay better attention to the Google Earth information and plot some of the more challenging points on the Navionics charts. The irony is that I did look at the Google Earth maps before heading out but failed to look close enough and map it against the Navionics chart data.

Google Earth and Navionics seem to be a natural fit and worth exploring before heading out. Whatever type of ding the prop and skeg took it didn’t impact performance on the way back, but I haven’t yet had the courage to tilt the engine forward and take a look.

JB – Communications Officer


Water Levels – High, Low or Normal?

After last year’s remarkably low water levels in the Parry Sound region of Georgian Bay this year has seen a welcome rebound. The question now is whether the levels are still low, somewhat high, or perhaps ‘normal’. Well the levels certainly aren’t ‘normal’ in as much as there is seemingly no real normal with anything remotely impacted by weather and climate. What can be reasonably asked is whether water levels in this part of Georgian Bay are close to the historical averages and/or chart datum.

With respect to chart datum in June it seems we are about 0.6 meters above the mean average low water levels and 0.8 meters below the average high water levels. Comfortable average perhaps? Here’s a link to the most revcent Canadian Hydrographic Service data.

Here’s a simpler measure of water levels – a photograph of Zhiishib Rock in the Big Sound just outside Parry Sound harbour. Taken last week with calm conditions  it suggests we are probably close to average in terms of water level. There doesn’t seem to be a high water mark, the topmost dark line, much above the current level, perhaps 20 centimeters (8 inches) or so. This may well represent the mean high water mark for the last few  decades where there has been a fluctuation between alarming high and low water levels. (Click on the photo below for a larger version.)


Regardless, the water levels make boating a bit more comfortable in the area. I was talking to one sailboater who said he was able to get into the government dock at The Pancakes for the first time in a decade.

Despite the high water levels it seems boating traffic is down in this part of Georgian Bay. It might be the higher price of fuel, but it’s probably the cooler and less predictable weather. Temperatures certainly seem to be ‘comfortably cool’ for this time of year with a bit more rain than might be expected. That’s based on my realization that the lawn and garden haven’t yet required watering, and there hasn’t been a need for fans in the windows.

Boating this year is wonderful – lots of water and not too hot. Come on up and enjoy it while summer is still around to welcome you.

JB – Communications Officer

An American Perspective on Low Water Levels

We in Georgian Bay are not the only ones wringing our hands with the prospect of low water levels this summer. Water levels are just that, level. Despite scientists telling us that Georgian Bay is likely to face even lower water levels over the centuries and millennia to come as the land continues to experience post-glacial isostatic rebound, the reality now is that low water levels in Georgian Bay mean lower levels in Lake Michigan and the west coast of Lake Huron. So if there is a ‘conspiracy’ to steal Great Lakes water the impact will be felt by both nations. With that out of the way, here’s a link to a report (USA Today – Low Great Lakes water levels plague shipping, recreation) that suggests the water levels will rebound this summer, but not as much as we would like.

That means paying more attention to the charts. What was known to be close to the surface, and a hazard, will now be visible and easily avoided. But what wasn’t a problem last year or the year before will now be lurking just below the surface, ready to ding a prop, or take off the whole lower unit. So to take a line from the television show Hill Street Blues, “Be careful out there”.

Low Water? Better Than No Water for These Guys. (March 2013)

Low Water Meeting Reports

Provided below is a list of the many documents that were prepared before and after the low water meeting that was held February 6th in Parry Sound. This meeting involved the Mayors, Chiefs and Reeves of Parry Sound and the surrounding communities. I was unable to attend because the meeting was closed to all but participants and the ‘official media’. But the North Star did a nice summary of the meeting, here’s a link to their article if you haven’t seen it already.

The Town of Parry Sound has, since the meeting, posted up the meeting report, the agreed meeting resolution, and the various presentations. You can access the town’s webpage through this link. Or you can open the individual documents through the links below. The Parry Sound Power and Sail Squadron has ‘inventoried’ these documents on this site to ensure continued access to them. Also note that the Town of Parry Sound webpage has a very useful link to the Township of the Archipelago’s website where there are associated documents on the low water issue.

Here are the links to the individual documents hosted on this site related to the low water discussions. They are also available on the Town of Parry Sound’s website through this link.

Mayors, Reeves, Chiefs, Meeting Notes
Mayors, Reeves, Chiefs, Meeting Resolution
Archipelago Presentation
Georgian Bay Association Presentation
Owen Sound Meeting Notes
Midland Meeting Notes

Do We Have A Tide or What?

I’m betting on what. It’s not always easy to see how low the water has dropped in the last month; floating docks can disguise the difference. This shot clearly shows the drop. While it is a common seasonal event the drop in water levels still is disturbing for those of us who depend on another foot of water to stay out of trouble.

Coming soon, a new adventure from our favourite sailor. It promises to be a tale of challenge and lessons remembered – The Old Man and the Sound. Check back this weekend.

Parry Sound Harbour, October 18, 2012Parry Sound - 2012-10-18