Groundwater is an important consideration in the design of the Sunnyside flood barrier. As part of the project, we completed extensive studies to understand the groundwater flow in the area and determine the risk that seepage from the river under the barrier poses during a flood.

To address the area where the flood barrier will impact groundwater conditions and threaten the stability of the barrier and Memorial Drive, we’ll be installing a seepage trench.

For more information on this recommendation, please review these slides.

Sunnyside is one of several vulnerable locations along the Bow River that remains at risk from another 2013-level flood.

Over the last two years, we’ve been working with the community to explore different options for a flood barrier in Sunnyside to help prevent another devastating flood like Calgary experienced in 2013.

We heard from residents that a higher flood barrier is desired and their feedback helped re-shape the barrier option being proposed. A What We Heard, What We Did Report is available and outlines the overall engagement process and how feedback was used.

Following the results of the evaluation that included a full social, economic and environmental assessment, we will be recommending to Council to move forward with design and construction of a 1 in 100-year flood barrier for the Sunnyside community.

For more information about the process that led to this recommendation, please review these slides.

This recommendation is going forward to Council through the Utilities and Corporate Services Committee on April 15. Please see the Next Steps section below for details on how you can participate.

We are holding some live online Q&A sessions for people to ask questions of the project manager and the technical team. If you would like to participate, please see the dates on the right side of this page and register here.

In Sunnyside, flooding can happen when the flow rate is approximately 927 cubic metres per second (m3/s), which has a 10 per cent chance of occurring each year. Because the community was developed so close to the Bow River, there will always be a risk of flood. That said, we can also work to lessen this risk by implementing flood mitigation measures: a key one being the construction of a permanent flood barrier along the riverbanks of the community.

Currently, The City is proposing to design and construct a permanent flood barrier in Sunnyside. The proposed Sunnyside flood barrier is a foundational piece of the City of Calgary’s Flood Mitigation and Resiliency Plan. In conjunction with upstream storage, provided by construction of a new reservoir and modified operations of TransAlta’s Ghost reservoir for five years, it will help us manage flood water and avoid the type of damage we saw in 2013.

We’re completing the detailed design of the flood barrier and will be exploring potential opportunities for community input on design aesthetics. Further details will be shared with the community when they are available.

Pending regulatory approvals, construction is tentatively scheduled to begin in spring 2021 and be completed in time for the 2023 flood season.

We recognize that input from you is key to making this project a success. As we kick off the project, we are collecting input on the unique characteristics of the Sunnyside community that will need to be considered in the design. This information will help to guide the engineers and landscape architects who are working on the preliminary design for the barrier.

Please see the boards that were presented at the public session here.

The What We Heard Report for Phase 1 of the engagement can be found here.

PROVIDE YOUR INPUT

Your input is essential as we continue to consider potential options for a flood barrier in Sunnyside. You can learn more about flood mitigation options for Sunnyside in the informational boards from the September 24 Open House. These boards also show the early design options for the different flood barrier heights and their potential impacts on the community.

The maps with proposed barrier alignments can be found here (please note that these are large files and may take more time than normal to download; they also may be difficult to view on a mobile device):

• 1 in 20-year option
• 1 in 50-year option
• 1 in 100-year option
• 1 in 200-year option

Your input on the social criteria for the barrier options will be included in the triple bottom line analysis to determine the best option for Sunnyside. This analysis also includes environmental and economic criteria which will be evaluated based on regulatory requirements and subject matter expertise. The decision on what design recommendation will be provided to Council will be made using this triple bottom line analysis and will be presented first to the community, along with results from groundwater studies, in early 2020.

If you have any questions or would like further explanation on some of the technical information included in the boards, please email sunnysidebarrier@calgary.ca.

NEXT STEPS

We’re completing the detailed design of the flood barrier and will be exploring potential opportunities for community input on design aesthetics. Further details will be shared with the community when they are available.

Pending regulatory approvals, construction is tentatively scheduled to begin in spring 2021 and be completed in time for the 2023 flood season.