Flood Ready Durham: Developing Risk Assessment Outputs and Improving Capacity in the Region of Durham

In early 2021, the Region of Durham (“the Region”), in collaboration with several Conservation Authority (CA) partners and a consulting team, successfully obtained National Disaster Mitigation Program (NDMP) funding to undertake a project focused on improving and developing flood risk assessment-ready data and outputs for the Region. One major objective of this project was to improve capacity and raise awareness on the impacts of climate change and flooding amongst local government decision makers and Durham Region residents. The Region is one of the fastest growing municipalities in Ontario, with its population expected to double to 1.3 million people by 2051. The area is characterized by a variety of landscapes and communities, including a series of major lakeshore urban communities and a variety of small towns, villages, hamlets, and farms which lie inland. Expected population growth, coupled with a changing climate, can exacerbate flood risk in the Region and put a strain on existing public infrastructure such as roads. From an asset management perspective, the Region recognized that it would be more expensive to operate reactively and opted to take a proactive approach by better understanding its vulnerabilities and potential adaptation options. As Durham is a large Region with a socioeconomically diverse population, different areas within the Region will be impacted by different types and magnitudes of flooding, meaning that tailored risk mitigation approaches are required. The Flood Ready Durham project is an initiative that seeks to address this issue by collecting and synthesizing knowledge, engaging with people, assessing flood risks, and developing a suite of communication products to build awareness and capacity. Data and research results were disseminated through a public facing website that houses information on the risk of flooding and actions that promote emergency preparedness and resilience.

Understanding and Assessing Impacts

Flooding is common in Ontario, and while it is a natural process, it can become hazardous when people, property or natural systems are exposed. While Durham Region has been fortunate to avoid major catastrophic events, it has experienced numerous localized flooding incidents, with the record breaking 2017 and 2019 Lake Ontario Floods being recent examples. High water levels, particularly along the lakeshore, coupled with both incremental and gradual changes in precipitation patterns and storm events drove the need for action. Between 2012 and 2014, the Region of Durham undertook a climate modeling exercise with SENES Consultants Ltd. to predict future climate in the Region for the 2040-2049 period. This study was one of the first steps towards the development of the Durham Region Community Climate Adaptation Plan which was published and endorsed by regional council in 2016, and subsequently received a Sustainable Communities Award from the Federation of Canadian Municipalities. In 2020, the Ontario Climate Consortium (OCC) determined the North American Coordinated Regional Climate Downscaling Experiment (NA-CORDEX) as the best-suited climate model ensemble to conduct the climate modeling for Durham Region. The data from this model captures the influence of the Great Lakes, which was important since Lake Ontario has a great influence on Durham Region’s weather and climate patterns. Using this data source, bias corrected climate projections were produced for 52 climate parameters for RCP 8.5 (high emissions) and RCP 4.5 (medium emissions) scenarios for the short (2011-2040), mid (2041-2070), and long (2071-2100) term. This analysis demonstrates that Durham Region will likely experience a warmer and wetter climate, with a longer growing season. The Region is also expected to experience more variable weather patterns and experience higher intensity storms with greater amounts of precipitation in all seasons. This may impose threats to the health of communities, its natural systems, infrastructure, agriculture, economy, and services within the Region.

Identifying Actions

The Flood Ready Durham project aimed to build on previous assessments by improving flood risk data and raising flood risk awareness amongst local government and the public. The project was comprised of four major phases of work. The four phases were:

  1. Input (Stakeholder) Consultation: This phase involved engagement with CAs and local municipalities to learn how flooding is being assessed and characterized across the Region and share current research in flood risk communication and preparedness.
  2. Dataset Preparation, Collection and Flood Risk Assessment Preparation: In this phase, datasets from previous adaptation work were collected for further analysis and identifying critical gaps. Analysis focused on mapping-built infrastructure elements such as public roads, buildings, and their exposures to flooding.
  3. Flood Risk Assessment and Synthesis to Curate Messaging: This phase involved combining available flood risk data with demographic data to highlight social vulnerability and identify “Priority Areas” for flood risk communication work. Social vulnerability encompasses the characteristics of a person or group and their situation that influence their capacity to anticipate, cope with, resist and recover from the impact of a natural hazard.
  4. Output (Public) Engagement and Knowledge Mobilization: The final phase of the project focused on disseminating the information products developed through a public facing website that focuses on raising awareness and providing tools and guidance to get flood ready.

The project involved several teams coming together for the successful implementation of the project. These include:

  1. The Regional Municipality of Durham
  2. Conservation Authorities:
    • TRCA: Toronto Region Conservation Authority
    • CLOCA: Central Lake Ontario Conservation Authority
    • GRCA: Ganaraska Region Conservation Authority
    • LSRCA: Lake Simcoe Region Conservation Authority
    • KRCA: Kawartha Region Conservation Authority
  3. Local Area Municipalities:
    • Town of Ajax
    • Town of Brock
    • Municipality of Clarington
    • City of Oshawa
    • City of Pickering
    • Township of Scugog
    • Township of Uxbridge
    • Town of Whitby
  4. Consulting team:
    • Climate Risk Institute (CRI)
    • Smooth River Consulting (SRC)


Developing and executing the components of work was a collaborative effort with consultation and engagement led by CRI & SRC. Capacity building and information products were simultaneously developed to inform the public and municipal staff on flood risks and preparedness. Some of the actions completed during each phase are outlined below.

  1. Input (Stakeholder) Consultation:
    • Flood Risk Communication Best Practices research was conducted by examining 25 different jurisdictions spread across the local, provincial, and national scale to identify best practices. (Summer & Fall 2021):
    • Flood Risk in Durham Workshops (Fall 2021): CRI, SRC and ROD facilitated two workshops that identified current flood risk & preparedness work ongoing in the Region, the gaps and challenges being faced and shared best practices for flood risk communication.
  2. Pre-Riverine Flood Risk Assessment:
    • The TRCA led analysis which concluded in 2021 led to the development of a methodology to assess the vulnerability of culverts and road segments to riverine flooding. The methodology included the development of a geodatabase which included fields that describe the return periods and depths under which they are flooded, and GIS mapping of high-risk roads and culverts based on frequency of flooding and criticality.
  3. Riverine Flood Risk Assessment and Social Vulnerability Mapping:
    • CLOCA subsequently completed the riverine flood risk assessment using the methodology developed by TRCA.
    • Social Vulnerability and Priority Areas Mapping: Geospatial (GIS) data for demographic – vulnerability information was obtained from Open Data site; and overlaid with flood hazard data in GIS to identify and propose a list of geo-targeted areas across Durham Region. The following indicators were considered for this exercise.
    • Population age groups – Population aged 0-14
    • Population age groups – Population aged 65+
    • Seniors living alone
    • Income – Low income
    • Education – No high school completion, ages 25-64
    • Unemployment
    • Indigenous population
    • Immigrants – Recent immigrants
    • Visible Minorities
    • Housing – Not suitable housing
  4. Output (Public) Engagement and Knowledge Mobilization:
    • The Flood Ready Durham website was launched to the public in 2023 as a hub for information on flooding. It provides numerous resources on flood and emergency preparedness such as infographics that illustrate the steps homeowners/renters could take to reduce their risk. The communication products were tailored to the different kinds of population groups such as business and associations, the agricultural community, shoreline homeowners and more.

Outcomes and Monitoring Progress

As a result of this project, the Region has incorporated flood data into internal geospatial (GIS) databases and decision-making platforms. It was evident in this project that regional planning is essential in advancing flood risk work that covers multiple municipal and conservation authority jurisdictions. The smaller municipalities couldn’t have done this work without support as they lack the capacity to undertake such large-scale studies. The Region was able to lead by establishing a consistent methodology, bringing municipalities together, and keeping various interests in mind when making decisions. Some key challenges and lessons learned from this project include:

  • Lack of funding and budget is a significant barrier to implementation. Completing case studies and comparative analysis can help inform prioritization of actions in the context of limited capacity and resources.
  • There is a need for additional human resources and internal capacity to coordinate adaptation efforts. An adaptation planner that plays a strategic role by connecting all departments and dedicated specifically to this work is crucial as it will be challenging to sustain momentum of work being done. 

Next Steps

Moving forward, the Region is working to mainstream the data collected and analyzed for this project into capital planning and asset management processes. This approach will help to overcome cost barriers that can slow down adaptation action by factoring adaptation into annual operating budget considerations. Furthermore, Regional staff are working to integrate climate information into existing GIS platforms to have it readily available for access across departments. To supplement this work, the Region has hired a full time Adaptation Staff lead that will be responsible for coordinating follow up and monitoring efforts. The Region is working with the GRCA to complete further data analysis in their jurisdiction. Funding is an important aspect of this initiative, without which much of the work wouldn’t have been possible, therefore the Region is looking for additional funding to enhance data analysis and continue monitoring flood risk for the identified risk areas. The Federation of Canadian Municipalities’ “Green Municipal Fund” is one such fund that is being closely monitored for opportunities. Lastly, the Region is developing a program to support homeowners with retrofits to reduce flood risk at the lot level.