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The aboiteau has become a central part of the identity of the Acadian people, the maritime technology being so closely linked with the rise and evolution of this group of people during the 17th and 18th centuries. Even after the Deportation of the Acadian people in the 1750s, this farming practice was preserved in many of the Acadian regions (see map). The aboiteau-style dike and sluice has now become a symbolic part of the cultural heritage of the Acadian community. Throughout the colonial period, Acadians were the only people in North America to cultivate below sea level farmlands to such a large extent.
What’s in a name?
The word aboiteau has two meanings in French; it refers not only to the work associated with draining a marsh, but also to the drainage system itself, which is composed of two parts: the sluice and the levee that protects it. The sluice is equipped with a gate that opens and closes automatically with the ebb and flow of the tide. Sluices were originally made of hollowed out tree trunks placed at the bottom of a drainage ditch. Levees were then built on top of the sluices, but unlike the rest of the system, the sluices were reinforced with tree trunks mixed with mud from the marsh. It was important for the aboiteau-style sluices to be carefully secured, in order to keep it from being dislodged by the force of the tides. The levees were built perpendicular to and wider than the drainage ditches, thereby keeping the seawater from flooding the marsh with each high tide. Under normal operating conditions, the pressure of the rising tide causes the gate to close, while the pressure of the run off accumulated in the marsh at low tide pushes it open. Thus, the constant motion of the tides causes the gate to open and close twice every twenty-four hours.
These large-scale earthworks were community projects, setting them apart from similar projects undertaken elsewhere in the world. The communal effort required in building and maintaining the large network of earthen dikes consolidated Acadian identity.
The aboiteaux dike and sluice system for controlling water levels in the sub sea-level areas of the Maritimes was developed in a very unique maritime environment, the alluvial lands being shaped by the turbulent waters of the Bay Of Fundy (or Baie Française [French Bay], the bay's earliest official name). There, the tides are among the strongest ones in the world, rising to heights of up to 15 meters [50 feet]. The marshes surrounding the Bay of Fundy are the result of the ebb and flow of the tides that have deposited sediments rich in organic matter and minerals. Once drained and desalinated, the lands are exceptionally fertile, so much so that no fertilizer needs to be added to the soil even after many decades of farming.
Before the arrival of the first Acadian settlers,these low-lying, muddy, tidal flats (or waddens) flooded twice daily. The higher areas, the salt marshes (the schorre), were flooded only by the strongest tides. When the sea would recede, the mud flats and the salt marshes were scattered with muddy streams, alive with marine life. These tides made the soil rich and promised the region considerable agricultural potential once the marshes were drained and the salt removed.
When building the dikes, the Acadian settlers were able to put the region's natural resources to good use. The main construction materials came from the marshes themselves. They used sod to build and cover the levees as well as their aboiteaux-style dikes and sluices. The thick, tangled roots of halophytic plants (i.e. those that grow in saltwater environments) of the marshes grow deep, which not only helps them survive the effects of salt water, but also helps them hold fast against the push and pull of the tides. Sod was used to cover the sides of the levees, especially the side facing the sea. No other types of plants would have survived in salt water. Thus, the levee would have been quickly eroded by the powerful tides of the Bay of Fundy.
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