Exceptional flooding is no longer the exception. The weather is changing in Ontario and it’s getting wetter. The number of days with heavy rain or snow in Ontario has been beating the average since 2008. Our snowmelts are getting quicker and more unpredictable.
This change has also brought more extreme rainfall events. Toronto’s 2012 report titled Toronto’s Future Weather and Climate Driver Study: Outcomes Report outlined that not only is rainfall expected to increase, but more extreme rainfall is expected as well. Recent studies have also shown similar projections with a 2017 climate change vulnerability study for the City of Welland noting that the 100-year-storm is becoming the future 50-year-storm.
With more intense rainfalls and more precipitation comes damage. Flowing from that damage are, more often than not, disputes and litigation. As culverts and dams and waterways become overrun with rainfall and snowmelt in the spring and fall and during heavy rains or snowmelts, the problem becomes obvious and the questions around liability start.
Who is liable?
The rule with respect overland flow is such that a downhill owner is not required to take overland water from an uphill neighbour and can erect obstructions to reasonably protect their property. The limitation here is to not cause additional damage to neighbouring properties. However, the law with respect to flow through a watercourse is different.
The law has long been that anyone who blocks, substitutes, or otherwise interferes with a ‘natural watercourse’ is responsible for flooding damage, even in exceptional rainfall or snowmelt. Note that a ‘natural watercourse’ is broadly defined as having a bottom and banks (i.e. a channel) and can flow continuously, seasonally, or less even frequently. See Southern Canada Power Co. Ltd. v. The King, [1936] SCR 4.
What’s more is that even in the event of a natural obstruction of a watercourse that causes flooding, there is liability to the landowner where that obstruction lies. One of the easiest examples are beaver dams. With the recent weather changes, these dams are either holding back more and more water upstream or they are breaking more frequently, flooding downstream properties and roadways. Here, courts have held that owners can be liable for natural causes of flooding, including beaver dams, according to a modified standard of care. See 270233 Ontario Ltd v. Weall Cullen Nurseries Ltd (1997), 41 CCLT (2d) 239 (Ont CA).
Owners need to take all due care to ensure that the flows through their waterways and culverts are not overwhelming the infrastructure and posing a risk to their property or to neighbouring properties. Even in “extraordinary” rainfall or snowmelt, the alterations of a natural watercourse will likely give rise to liability for any flooding damage.
What’s next?
Municipalities have started taking notice. Major cities are already building the capacity to deal with changes in rainfall and snowmelt. Insurance companies have started offering more overland water protection. And landowners are more careful to consider flooding when purchasing land and homes.
The law will also need to be flexible. The connection between the cause, the flooding, and the damage can be uncertain. Experts will likely be key and they are not easy to come by. Hydrological and Hydrogeological engineers are specialized and their work is often expensive to undertake. It will take a keen eye to be able to manage those needs and costs in order to allow the successful resolution of flooding disputes.
In the meantime while everyone adapts, there will be floods, there will be damage, and there will be disputes. Navigating and avoiding liability from changing weather will be a challenge and will no doubt take some getting used to for both landowners and lawyers alike.