View of a dike
Highwood River Peak Flow Rates
Anatomy of a dike
Flood Mitigation and Protection
High River is now one of the most well protected towns in Canada from flooding. To date, over $200 million has been invested in flood mitigation and protection for the community. This includes:
- The construction of permanent and interim dikes throughout town
- Returning two neighbourhoods to an undeveloped state to allow more room for the Highwood River to flow
- Installation of backup emergency notification systems
- Continued training for Town of High River staff
The permanent dikes have been built to protect against the river flows experienced during the 2013 flood, plus an additional vertical metre of protection.
More detail on the Town’s flood mitigation program can be found below.
Over seven kilometers of permanent dikes have been constructed along the Highwood River. These have been built to protect against an upstream river flow rate of 1820 cubic metres per second, plus an additional vertical metre of free board protection. This includes the raising of 498 Avenue by the MD of Foothills to protect the eastern portion of town.
As a comparison, the 2013 flood produced an upstream river flow rate of approximately 1820 cubic metres per second, which was the largest ever recorded in the last 100 years.
Currently the southern parts of town along 12 Avenue S.W. are being protected by interim diking measures that have been built to provide protection to river flow rates of 1200 cubic metres per second, which is well above all other flood events in the last 100 years, with the exception of 2013. These interim measures will remain in place until permanent measures are approved and constructed.
The Government of Alberta has received a report from its consultant, Deltares, in regards to the diversion of the Highwood River. The recommendation is to not divert the river, nor was the consultant supportive of the Little Bow floodway enhancement project south of High River.
The Town is working with the Government of Alberta to design the Southwest Dike to replace the interim measures in the southwest.
The Town of High River is in the design stage of the Southwest Dike that will be located south of 12 Avenue S.W.
On November 2, 2015 the Government of Alberta announced $30 million of funding to go towards completing essential mitigation projects including the Southwest Dike and Fifth Street Dike.
In February of 2016 the Town submitted an application for regulatory approval to the Government of Alberta and is currently awaiting response.
The interim flood mitigation measures along 12 Avenue S.W. will remain in place until a permanent solution has been approved and constructed. Read more here
5 Street Dike
Construction on the 5 Street Dike was completed in 2018 and will enhance the natural flood mitigation protection in this area.
The Highwood River’s capacity has been increased through the removal of the CP Rail Bridge and more than 60,000 cubic metres of rock and flood debris that was removed from the river in 2013.
The areas around the proposed dikes shown on the map provide natural flood mitigation protection to High River. Dikes to enhance the natural level of protection to the 2013 flood level plus one metre vertical free board will be constructed pending funding, regulatory approval and landowner negotiations.
Centre Street Flood Gate
As part of the Town of High River’s ongoing flood mitigation strategy, infrastructure improvements have been made to the Centre Street Bridge. A flood gate was constructed on the south side of the bridge starting and was completed in November 2018.
Permanent dikes have been constructed on either side of the Centre Street Bridge that protect the level of river flows seen in the 2013 flood, plus one additional metre. To provide this same level of protection throughout town, it was necessary to construct a flood gate across Centre Street immediately south of the Highwood River bridge that can be closed in the event of a future flood.
A variety of different design options were considered and evaluated. Two options were presented at the May 23, 2017 regular meeting of council and the decision was made to move forward with a sliding gate option that is concealed within the dikes when not in use.
The project is fully funded through the Alberta Community Resilience Program (ACRP) from the Government of Alberta and Long Term Recovery Support (LTRS).
Funding for these flood mitigation programs has come from a number of Government of Alberta sources including a GOA Flood Mitigation Grant, an Alberta Environment and Parks grant, a Flood Recovery Erosion Control program grant, the Disaster Recovery Program, GOA/Tervita contract, as well as from the Town of High River.