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​Planning for a flood resilient future

As recently as 2016, Edmonton has been impacted by significant flooding caused by large rainfall storms. The costs of flooding to citizens, the environment, society and property are substantial.

We're working to reduce the risk of flooding in Edmonton caused by extreme weather. Our goals are to:

  Identify areas of Edmonton that have the highest risk of impact from flooding
  Develop drainage infrastructure and program improvements
  Educate homeowners on the actions they can take to reduce their risk

Our Stormwater Integrated Resource Plan (SIRP) builds on initial work by the City of Edmonton before September 2017.

 Potential flood impacts

When a flood happens, there are typically 4 different types of potential impacts.

  • Public health and safety
    For example: ability to access hospital services, risk of illness or injury and the possibility of loss of life
  • Social issues
    For example: loss of essential utilities and emergency services, displacement of vulnerable populations, mental health and major inconveniences
  • Environmental damage
    Including: damage to natural habitat, loss of wildlife and vegetation and waste management
  • Financial losses
    Including: property damage, costly repairs, loss of business and loss of work

 Edmontonians' priorities for flood impacts

We conducted public engagement in summer 2018 to understand citizens' priorities for protecting against floods and inform our risk model. Through the comprehensive survey, Edmontonians ranked their priorities for flood protection as follows:

1. Essential services

Edmontonians reported that their highest priorities for flood protection were hospitals and urgent care facilities and essential services such as fire, police, EMS and essential utilities.

2. Social agencies

The next most important priorities for protection were against risks to human life and agencies that provide services to or housing for vulnerable populations.

3. Health and safety and social impacts

For the city overall, citizens put the greatest priority on protecting against health and safety and social impacts from flooding.

4. Financial and environmental damages

Financial and environmental impacts were ranked as less important. Impacts that were reversible, temporary or insurable were of lower relative importance.

 Our proposed plan

Based on public input and the risk rankings of Edmonton's 1,300 drainage sub-basins, we are proposing a plan to the City's Utility Committee to:

  1. Protect hospitals, essential services, and social services by reducing their flood risk exposure.
  2. Prioritize flood mitigation work at locations where flooding could put human life and social service agencies at risk.
  3. Target sub-basins in risk classes A - E (as shown on the maps below), and reduce their flood risk to be no greater than Medium (Class G).

 

Understanding risk

In a risk-based model, we consider both the potential impacts and the likelihood that they could occur over multiple storm intensities over the life of a property. This model is a process of continuous improvement and design choice based on a range of factors including community input, risk assessments, financial analysis, planning and operational responses and environmental concerns.


 

 

What's a sub-basin?

A sub-basin is the combination of local storm water pipes and topographical depressions into which storm water collects. The water then drains to a network of larger storm pipes that ultimately connect to creeks and rivers. There are more than 1,300 sub-basins in Edmonton, about three-quarters of which are considered medium or low-risk in terms of potential flood impact.


 

 Flood impact maps

As a part of our plan, we've developed 3 scenarios to inform the framework for how we identify flood mitigation solutions. These maps illustrate how we prioritize where to focus flood mitigation efforts first, according to health and safety, environmental, social and financial impacts.

Note: these maps will evolve as we get more input.

Scenario 1: equal weighting

Scenario 1: equal weighting

 Health and safety: 25%
 Environment: 25%
 Social: 25%
 Financial: 25%

 

Scenario 2: public opinion

Scenario 2: public opinion

 Health and safety: 30%
 Environment: 15%
 Social: 30%
 Financial: 25%

Scenario 3: property damage

Scenario 3: property damage

 Health and safety: 20%
 Environment: 20%
 Social: 20%
 Financial: 40%

 

 Timeline for action

In April 2019, we'll present recommendations for infrastructure and programming that will reduce the risk of flooding in the highest-risk areas of the city. Once that plan is approved, we'll be informing the public and seeking input about the design of specific projects.

Potential improvements

Solutions for every sub-basin will be determined based on a number of factors and could include any of the measures below.

  • Trunks and sewer separation
  • Outfalls and control gates
  • Dry ponds
  • Maintenance programs
  • Emergency response
  • Weather forecasting
  • Low-impact developments
  • Homeowner responsibilities

 What you can do to protect your property against flooding

In many neighbourhoods throughout Edmonton, flood mitigation projects have been completed or are underway to reduce the risk of flooding. Maintaining good drainage on your residential property is also an important part of the flood prevention equation.

We're responsible for the drainage system up to your property line. Property owners are responsible for infrastructure and surface drainage on their property.

The most effective ways for property owners to protect homes are to:

  1. Maintain good drainage on your residential property.
  2. Sign up for our free home flood protection inspection that will provide homeowners with information on how best to protect their property from flooding.
  3. Install a backwater valve — we're offering qualifying homeowners a subsidy of up to $800 to help reduce the costs. (Note: homes built after 1989 will have a backwater valve; anything prior to that year will not likely have one).