Flood Protection Update
Good news about the Sunnyside flood barrier and groundwater protection!
In the May update we passed on the City’s plans for a flood barrier capable of protecting the Sunnyside community in a 1:100 flood. This means a barrier about 1m higher than the current berm. The HSCA EPARC Infrastructure Group applauds this City plan for flood barrier height. We thank the many community members who advocated for this result.
There is more good news in this update. The City has communicated to HSCA their plan for Groundwater Protection as part of the Sunnyside Flood Barrier project.
Specifically, the City is proposing a partial depth seepage trench in Sunnyside along Memorial Drive between the Calgary Curling Club and 8th Street (trench placed average 3m deep), and using one or both of the new pump stations to return the water to the river. We believe that this solution provides the best balance between effectiveness and efficiency to address high river level induced groundwater seepage in Sunnyside.
The City shared with HSCA the results of their considerable investigations into the geology of Sunnyside, and that geology is very complex. Fortunately there are members of the EPARC Infrastructure Group with expertise in geology who could help our understanding. The geological studies showed that the permeability of the material underground is not as high as previously feared, making groundwater seepage mitigation feasible (it could be characterized as high, but not extremely high, permeability).
The degree of protection that the partial depth seepage trench will provide and whom it will protect is a matter of some debate because of geologic uncertainties. There will continue to be a risk of basement flooding in the community because of these uncertainties, and of course in the case of groundwater seepage not caused by a high river level. Regardless, the EPARC Infrastructure Group believes that the city project is the most effective, reasonable alternative to provide protection from high river induced groundwater.
The City will be communicating the groundwater results and the next steps to the community in late August.
Residents advocate for community-enhanced flood infrastructure
With flood mitigation infrastructure now confirmed by the City of Calgary, the new Sunnyside Brightening Committee (SBC) has organized to advocate for community-oriented customizations. The SBC feels these infrastructures could be customized help create a sense of place through art, aesthetics, and recreation without compromising the projects’ technical aspects nor incurring significant cost increases. The three priority areas are:
Connecting to the Bow– With the construction of a higher 1:100 flood barrier, SBC plans to (A) engage with Parks on the design of the planned boat launch at 3 St NW to better serve the community; (B) advocate for accessibility to the wooded riverside area between 7 St NW and 4a St NW.
Brightening the Barrier– Municipal plans currently show the construction of a new floodwall. SBC will advocate for this infrastructure be brightened through concrete texturing, murals, mosaic, and seating or other features.
Stormwater Lift Station Art– Station #1 plans have previously indicated wall space for community art. SBC will engage with the municipality to secure and develop community-led art projects.
Call to action: Time limited opportunity to join your fellow Sunnysiders. Let's improve the Bow River Pathway and our interaction with the Bow River and build and create art projects throughout the community. If you would like to do so please contact the SBC group chair, Preston Welker, at preston.welker@ucalgary.ca.