High-water line

Generally speaking, the high-water line is the boundary between water property in the domain of the State and private property.

To establish your position on the ground, we recommend the services of a land surveyor.

State ownership of the bed of public lakes and watercourses extends to the high-water line.

For tidal areas, the high-water line is the average elevation of the highest March tides observed over a 19-year period of time. 

In areas not subject to tides, the high-water line corresponds to where the body of water touches land when it is as its highest level, without causing overflow or flooding. 

High-water line of natural shorelines

For lakes and watercourses whose shorelines are in their natural state, i.e., unaltered by human intervention, the high-water line is a dynamic limit. In other words, its position can change over time as a result of natural erosion and alluviation (natural sediment deposition).

High-water line of anthropogenic shores

Human intervention on the shore, such as excavation or backfilling, can change the high-water line. The shoreline is then said to be anthropogenic.

When shoreline becomes anthropic, the high-water line boundary no longer varies and must be set to its position prior to human intervention.

The high-water line used as a property boundary is determined on the basis of surveyor analysis. 

For the Rivière Richelieu, the boundaries are set by the Act respecting the boundaries of the waters in the domain of the State and the protection of wetlands along part of the Richelieu River (in French: Loi concernant la délimitation du domaine hydrique de l'État et la protection de milieux humides le long d’une partie de la rivière Richelieu.)