Extreme rainfall
The nature and extent of the adaptation measures that should be implemented to deal with extreme rainfall vary depending on the area and the concerns.
In the same way that high water levels and floods in rivers are addressed, adaptation strategies for extreme rainfall rely on effective management of the excess water added to human and natural systems. The measures taken must be complementary, based on a combination of infrastructure, regulation and awareness.
You will find on this page :
Adapting water management systems
Adapting the electric grid
Adapting buildings
Resources to support awareness and planning
Adapting water management systems
There are several adaptation strategies to make water management systems more resilient. They include infrastructure planning, land use planning, and the protection of natural environments.
To limit the consequences of flooding, sewer backups and runoff, municipalities can take various measures to improve their infrastructure, such as:
Integrated stormwater management planning
The upgrade and modernization of old drainage pipes to accommodate larger volumes, where possible
Increased water retention and flow control capacity
There are several ways to absorb and control the flow of water:
Dykes and barriers to divert water
Dams to control high river flows following heavy rain
Bioretention basins for temporarily storing excess water
Measures to make use of vegetation and natural environments to absorb excess water can also be taken:
The protection and restoration of natural environments like woodlands, marshes and urban parks in or around municipalities
The construction of green infrastructure such as green roofs and walls, cellular paving, and bioretention structures (rain gardens, swales, trenches, vegetated basins).
These measures also have the co-benefit of reducing the effects of urban heat islands and promoting biodiversity.
Adapting the electric grid
Various adaptation measures can ensure a stable electricity supply and prevent power outages caused by extreme rainfall, including:
Reinforcing infrastructure like pylons and poles to better withstand heavy rain and flooding
Vegetation management around power lines to prevent damage from falling trees or branches during strong winds
Burying certain sections of power distribution lines
Adapting buildings
It’s important to understand and identify where and how water can damage a building before considering an adaptation measure.
Three elements are combined to take the risk of flooding into account when planning the adaptation of buildings:
The risk of flooding, depending on its intensity and the way climate change is affecting it
Vulnerabilities, based on the sensitivity of the elements exposed to the impacts of flooding, including their capacity to resist it and to recover from it
The level of exposure, depending on the position of vulnerable elements in relation to the hazard
Two types of adaptation strategies can limit the risk.
First, support systems are needed to reduce the amount and flow of water reaching an exposed building element. Such measures may include:
Structures at the neighbourhood level or higher levels to retain or divert water (retention basins, walls, green infrastructure and natural environments)
Blocking all possible entry points and cracks in the building
Installing waterproof membranes where necessary
Choosing impermeable building materials
Installing a backflow preventer
Adjusting the structure and foundation to withstand the pressure of larger volumes and flows of water on roofs and exterior walls during floods
These measures maximize water infiltration into the soil by temporarily accumulating it, blocking it, or directing it away from vulnerable elements.
The other type of strategy reduces the vulnerability of elements exposed to flooding and/or reduces their exposure. This includes measures such as:
Designing interior walls and floors to withstand the forces exerted by the additional volume and flow of water during a flood
Choosing water-resistant construction and finishing materials
Ensuring that assemblies of materials are able to dry out
Equipping buildings with systems to drain water
Moving water-sensitive assets such as appliances, computer servers, and living areas above the potential water level
Building on an embankment or on stilts, raising the ground floor, or using amphibious architecture
Locating the building in an area that is less susceptible to flooding and water accumulation
To learn more:
https://www.asf-quebec.org/resilience/ (French only)
Resources to support awareness and planning
Protecting populations from the health and safety impacts of extreme rainfall, in addition to the financial impacts, requires various awareness and planning measures. They can be implemented at several scales.
At the provincial and municipal level
Establishing a disaster management plan with clear delineation of the responsibilities of ministries and public organizations
Identifying areas that are vulnerable to heavy rainfall to improve urban planning using tools such as the Montréal runoff water retention basin map
Establishing pre-defined shelters and emergency services
Conducting awareness campaigns on the risks of extreme rain and what to do in emergency situations
Establishing an alert system and issuing mandatory evacuation notices as necessary
Healthcare establishments
Adopting a disaster management plan
Training staff for emergency situations
Anticipating patients’ needs
Implementing redundant systems, such as generators
Planning for psychosocial interventions after major events
Individuals
Preparing an emergency kit (first aid, flashlight, non-perishable food)
Reading the information made available by municipal and provincial governments on the measures to take and what to do in the event of an emergency
Return to the impacts of extreme rainfall
