Elbow River Flood Mitigation Projects: Damage Assessment Study and McLean Creek Environmental Overview

On February 27^th 2015 the eagerly anticipated Damage Assessments of the three proposed infrastructure projects for flood mitigation on the Elbow River and the McLean Creek Environmental Overview were released. The Government of Alberta released a fact sheet along with the reports.

Overall Costs of Flood Damage

The City of Calgary flood damage estimates were created though updated stage-damage curves and the Provincial Rapid Flood Damages Assessment Model. Additional information about how these damage estimates were developed can be found in the document “City of Calgary: Assessment of Flood Damages” and its appendices.

Detailed flood damage studies have not been completed outside of the City of Calgary. Areas such as Bragg Creek, Redwood Meadows and infrastructure within Rocky View County would not be protected by the Springbank Off-Steam Flood Storage project or the Glenmore Reservoir Diversion (Calgary Tunnel). To accommodate for this gap, information was taken from 2013 Southern Alberta Disaster Recovery Program and an Alberta Environment Planning Division publication from 1987 for Bragg Creek.

• The 2013 Southern Alberta Disaster Recovery Program estimated amount for flood recovery projects between the McLean Creek dam site and the City of Calgary is approximately $5.6 million.
• The Alberta Environment Planning Division publication from 1987 in Bragg Creek estimates damages on the order of $12.7 million would be incurred by Bragg Creek in the event of a 1:100 year flood.

Benefit/Cost Ratio

The benefit/cost ratio is an indicator of economic efficiency that is calculated by dividing the net present value of the benefits over the net present value of the costs. When the economic benefits exceed the costs the ratio is greater than 1.0, and where the economic benefits are less than the costs the ratio is less than 1.0. The benefit/cost ratio does not take into account social costs or environmental impact. The following table is from the Projects Decisions Fact Sheet referenced above.

Flood Damage Reduction

Given the large size of these reports there will be three separate blog posts following this one to capture your thoughts and comments on all three proposed projects. We expect to post all three over the course of the next few days:

• Springbank Off-stream Reservoir
• McLean Creek Dry Dam
• Glenmore Reservoir Diversion (aka Calgary Tunnel)

Request for Feedback

Once again, a request is being made for community feedback on these new reports.

The reports released by the Government of Alberta are based off of preliminary engineering designs. The costs will change as the engineering designs are refined and additional environmental assessments are completed. Additional costs have already been identified by the McLean Creek Dry Dam Environmental Review. What are your thoughts on the benefit/cost analysis and environmental review?

Please contact the Alberta WaterPortal by email, or through the comments below. Feedback is accepted until March 31^st. All feedback will be summarized and provided back on the WaterPortal and to the Government of Alberta.