Flood Liability

AgriLaw: April 2008

Where a natural stream flows across adjoining properties, neighbouring landowners may have concerns about impacts on their property resulting from development on the adjacent property. When will an upstream landowner be liable for such impacts?

The Ontario Superior Court has recently considered a case in which an upstream landowner, in order to construct an access road to an equipment storage facility, raised the elevation of a portion of their land by approximately four feet and diverted a natural stream into underground piping discharging into a newly constructed pond. The pond existed adjacent to the property boundary at the time the neighbouring property was purchased by the plaintiffs. At times of heavy rain, the pond would rise and flood the plaintiffs’ land until a water pump was activated to relieve the flood water.

On the occasion giving rise to the plaintiffs’ claim, there was significant rainfall through the day and evening resulting in substantial flooding of the plaintiffs’ property to a level higher than previously experienced. The defendants refused the plaintiffs’ request to activate the pump which resulted in contamination of the plaintiffs’ well rendering the water impossible to use. The plaintiffs were required to purchase water in bottles for approximately a year before installing ultraviolet and reverse osmosis filters.

In allowing the plaintiffs’ claim against the defendants for well repairs, purchased water, filters, septic system repair, landscape restoration and damages (including compensation for emotional and psychological trauma), the court determined that the defendants’ changes to the topography and the stream on their land was a non-natural use which caused the flooding of the plaintiffs’ land and resulting damages. The court stated:

“I accept the evidence of (a neighbouring landowner) and find, on the evidence , that the defendants raised the elevation of their land some four feet in the southerly part of their acreage and that they effectively replaced the natural watercourse of the stream with PVC piping. This piping changed the natural flow, erosion and drainage of the stream that has, for a century at least, always been able to accommodate its seasons. I find the defendants’ raising of the elevation, digging of the pond, improper placement of the piping, and use of piping which was too small to properly drain this body of water, all combined to create a footing for flooding the plaintiffs’ lands that had not existed before. Consequently, water backed up onto the plaintiffs’ land when there was rain or melt floods …”

The court rejected the defendant’s position that the defendant should be relieved of liability because the pond already existed at the time the plaintiffs acquired their property and concluded:

“The facts, as I have found them to be, demonstrate a clear disruption to a natural watercourse, a dangerous accumulation of floodwater and a subsequent escape of such water. Strict liability follows. In addition, the defendants’ use of their land has unreasonably interfered with the plaintiffs’ use and enjoyment of their property. In so doing the defendants have become and continue to be, in fact and in law, a nuisance to the plaintiffs.

Equally, the defendants’ conduct was negligent. They acted in disregard of their neighbours’ safety. But for their actions the damage suffered by the plaintiffs would not have occurred. It was foreseeable that the changes to the topography would likely adversely affect the plaintiffs.”

Upstream landowners who make non-natural use of their lands and interfere with natural stream flow do so at their peril. Liability may result for adverse impacts on downstream landowners.

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