Tuesday, April 21, 2009

Dykes and Aboiteau

I took a walk with my family the other day. We decided that this would be our first visit of the season to the Historic Gardens in Annapolis Royal. I am a big fan of the Gardens and the role that they play within our community. There are many heritage stories to be told in our region and they have a very innovative way of communicating heritage messages. We were enjoying our visit and we decided that we would extend our visit by taking a trip around the dyke walk.

The Annapolis Royal region, as with other areas around the Bay of Fundy settled by Acadians, is home to a unique style of agriculture. When the French returned to settle Port Royal in 1636, they immediately recognized that they had a very rich agricultural resource in the local salt marshes. The problem was how to make use of these marshes. Locally, we have about 8.8 meters (29 feet) of tide. Logistically, what this means is that a marsh which is dry for half of the day will be deep under water for the rest of the day. To use these fields the Acadians needed to find a way to keep the water off the marshes. Their solution was to employ a system of dykes which would hold back the waters of the bay. The creation of the dykes was a massive community project on the part of the Acadians. Working in teams, they would build a wooden framework and stack sod until the dyke was higher than the level of the tide. In this way they could start to reclaim land.

The next problem that they encountered was that they needed to be able to drain both fresh and salt water from the upland side of the dyke. For this, an ingenius device called an aboiteau was created. Unless you are familiar with the term, you are probably now wondering what an aboiteau is. An aboiteau was essentially a hollow log which was embedded at the bottom of the dyke. The log was fitted with a clapper valve which would allow water to run freely off of the marsh during low tide. At high tide the pressure of the water would cause the clapper to close and salt water would be prevented from pouring onto the field. With this equipment, the Acadians could drain their fields and cleanse them of their salt residue. It took about three years to clear all of the salt from the reclaimed fields. If you are interested in seeing the remains of an actual Acadian aboiteau, North Hills Museum in Granville Ferry has one found at the Melanson Settlement on display.

As with the dyke at the Historic Gardens, there are still many dykes around the Bay of Fundy. While these make an appealing place to take a walk, the farmers who maintain the dykes discourage their use as trails. If you have the desire to walk along a dyke, the Historic Gardens will be happy to provide a venue.

All for now,
RGS

2 comments:

  1. This may seem like a naive question...but why do the farmers maintaining the dykes discourage their use as trails?

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  2. It is not a naive question at all. As with the Acadians who first built the dykes, the modern dykes keep the water out. They still protect fields which would otherwise be under water. The concern of the farmers is damage to the dykes. While they seem very solid,using the dykes as active trails would start to compact the soil. Active use could cause other sorts of damage as well. Modern dykes are fixed with large machines rather than people with shovels,but there is still a ongoing cost of maintaining the dykes and protecting the fields.

    RGS

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