Flood Scoping Study for Highwood and Little Bow
Update July 18, 2019
Phase 2 of the Scoping Study
With funding provided by Alberta Environment and Parks, Foothills County has been able to complete Phase 2 of the Scoping Study. This work included hydraulic modelling and modelling support on both the Highwood and Little Bow Rivers.
On the Little Bow River: A bathymetric survey and modelling support were undertaken to incorporate design changes to the proposed South West Dike and improve low-flood accuracy of the Little Bow River two-dimensional (2D) hydraulic model. This model was developed to examine flood-related areas of concern on the Little Bow River upstream from the Twin Valley Reservoir subsequent to mitigation works being constructed to protect the Town of High River after the June 2013 flood event. The final report is provided below.
On the Highwood River: Additional modelling was undertaken to incorporate the design changes to the south west dike and to make refinements to areas of uncertainty in the previous hydraulic model of the Highwood River. The final results of the modelling can be found below:
It should be noted that the post mitigation condition for both studies was the 55A flood mitigated scenario. The Town of High River's application to the Province for the South West Dike was based on the 53A scenario. Both scenarios include the updated s-curve configuration for the south west dike. Following is an explanation of the difference between the two scenarios taken from Table 1 in Appendix 1 of the Bathymetry Survey and Modelling Support for the Little Bow River report:
Scenario 55A: Complete mitigation scenario that includes all mitigation measures included within Scenario 53A but with their representation within the model updated to reflect as built survey. This includes at minimum the inclusion of all topographic changes that have occurred on the unprotected side of the Town Levee System. In addition to model changes to better represent dikes further model upgrades were made to incorporate the as-constructed Centre Street upgrades, finished surface elevations associated across Wallaceville, and changes to channel bank elevations associated with completed scour protection measures.
Update November 20, 2018
As part of Phase 2 of the Scoping Study of Flood Related Areas of Concern on the Highwood River and Little Bow River, and with funding from Alberta Environment and Parks, the County has undertaken additional modelling of the Highwood River.
This modelling was done to address deficiencies in the previous modelling work and evaluate a potential mitigation option. The main goals of the modelling support were to:
- Improve and refine model around NE 32-19-28 W4;
- Assess impacts of Town of High River dikes on residence at NE 30-19-28 W4;
- Model the effects of lowering a segment of 72 St E near 34-18-29 W4.
The resulting report has been reviewed by Council and is now available to the public. To view Stage1 Phase 2 Modelling report click here.
Update July 11, 2018
As part of the study recommended by the Scoping Study of Flood Related Areas of Concern on the Highwood River and Little Bow River, and with funding from the Government of Alberta, the County has been able to undertake an evaluation of the 498th Avenue Bridge on the Highwood River.
The purpose of the evaluation was to understand the impacts on this bridge of the flood mitigation works constructed to protect the Town of High River.
A report was completed this spring and was accepted by Council. To view the study click below.
Update May 18, 2018
With funding provided by the Government of Alberta, the County is undertaking a bathymetric survey along the Little Bow River from the Town of High River to the Twin Valley Reservoir. This work is part of Phase 2 of the Scoping Study of Flood Related Areas of Concern on the Highwood River and Little Bow River and will enable refinements to the flood model of the entire Little Bow. Survey crews will be in the area through June. The following letter was sent to impacted landowners.
Update March 16, 2018
The Province of Alberta has recently approved the redirection of unused money that had been allotted for flood recovery in the County to facilitate a limited number of buy outs of the properties most at risk on the Little Bow River.
Eligible landowners have been contacted and a letter was sent out on March 8th to all landowners along the Little Bow River who had been impacted by flooding in 2013.
With respect to the Lower Highwood Flood Mitigation program, Foothills County submitted a revised proposal to the Province early this year for a program to offer buyouts or mitigation to landowners along the Highwood River downstream from High River. This proposal is still under review by Alberta Environment and Parks.
Should you have questions regarding the buy-outs on the Little Bow please contact Donna Fowler by using the email link provided or by phone at 403-652-2341.
Update October 3, 2017
As part of the flood mitigation study that was enabled by the November 2015 Government of Alberta funding announcement, the Foothills County commissioned IBI Group, to undertake a Flood Mitigation and Compensation Study.
Foothills County is seeking a fair solution to address the expected impacts of the flood mitigation works that have been constructed to protect the Town of High River. These mitigation works have resulted in a change in the flow split between the Highwood and Little Bow rivers and a reduction in flood storage capacity in the vicinity of the Town. The end result is that in future extreme flood events, landowners along the Highwood downstream from the Town are expected to see higher flood levels and faster water. It is also expected that they may flood more often.
The IBI report proposes a program of buyouts or compensation for landowners who are expected to have adverse impacts to their properties. The program that is suggested by the study is not to be interpreted as compensation for pre-existing flood risk or previous flooding, rather it is proposed as compensation for these landowners not being afforded the same protection given to others and for the use of their lands as part of an overall flood mitigation strategy for the Town.
This study was presented to Foothills County Council in September and Council gave direction to staff to release it to the public.
Some of the recommendations put forth in this study have been used by Foothills County staff to develop a proposal for a Lower Highwood Flood Mitigation Program for consideration by the Government of Alberta. A confidential draft version of the proposal for Phase One of a two part program is currently undergoing a preliminary review by Alberta Environment.
Update Sept 22, 2017
Foothills County has now received the updated river modeling studies for the Highwood and the Little Bow as well as the updated Scoping Study that includes the extension down the Little Bow River to the Twin Valley Reservoir.
These studies can be downloaded below:
Foothills County 2016 Year-end Update Regarding Flood Studies
Earlier this year, funding was requested for the following projects or studies:
- Reinforcement of the Hoeh Dike,
- Evaluation of the 498th Avenue Bridge in light of higher predicted flows on the Highwood,
- Additional modelling of sensitive or complex areas on the Highwood and Little Bow rivers, and
- A report on whether compensation is appropriate for properties where flood mitigation works constructed at High River will have a negative impact.
An application was made to fund some of the proposed study with money that was part of the Province’s November 2015 announcement of funding to undertake flood studies. If this application is approved, Foothills County will be able to proceed with this work early in the New Year.
Meanwhile, on the Little Bow River, work continues on the Scoping Study / Model Extension downstream from Foothills County through the M.D. of Willow Creek and Vulcan County to the Twin Valley Reservoir. The data collection and high water mark collection in this area is complete, the model has been developed and model calibration and sensitivity analysis are on-going.
Foothills County will continue to work with the Province through 2017 towards our Council’s goal of having residents of the County protected to the same level afforded residents of the Town of High River – that is a 2013 equivalent event plus a metre.
Draft Scoping Study of Flood Related Areas of Concern: Highwood River and Little Bow River within Foothills County.
Released May 2016
Click on map for larger pdf version
We would like to thank everyone who came to one of the two open houses that were recently held to share the draft results of the Flood Scoping Study. If you were not able to attend, you may view the information boards from the event by following the link below.
Your feedback is important to us and will assist us with determining the direction for future work. If you did not get a chance to submit a survey at one of the open houses you may still do so. Please fill out the Feedback Form and return as per the instructions below by June 30th , 2016.
Please fill in the Open House Feedback Form and return it via email, or print and deliver to the attention of:
Julie McLean, Senior Planner, Foothills County,
309 Macleod Trail, Box 5605, High river, AB T1V 1M7 | Fax: 403-652-7880 | Email
The purpose of the information sessions was to give an overview of the study and the results including the changes in the flow split between the Highwood and Little Bow Rivers as a result of mitigation completed in and around the Town of High River. Opportunities were provided to view maps showing the modelled flood hazard along both Rivers. There was also general information on the proposed next steps.
We understand that a number of our landowners have concerns related to the flood hazard on their property, the impact that mitigation projects (both completed and planned) within the Town of High River may have on that hazard and what help will be available to them to address the hazard. Landowners have the opportunity to sign up for individual meetings with representatives from the County to discuss their property in detail.
Residents may request an individual meeting by calling 403-603-6219 or emailing Flood Study
Please note these files are very large, 20 MB each
Hard copies of the Flood Scoping Study are available for purchase at Foothills County office for $40 to cover the cost of printing.
Subsequent to the 2013 flood, Foothills County, with support from the Province of Alberta retained the services of AMEC Foster Wheeler Environment and Infrastructure, and Advisian WorleyParsons Group to complete the Scoping Study of Flood Related Areas of Concern on the Highwood River and Little Bow River within Foothills County.
The purpose of the Flood Scoping Study is to:
- identify potential areas of concern along the Highwood River upstream from the Town of High River;
- gain a full understanding of the impacts of a 2013 equivalent flood event on landowners along the Highwood and Little Bow Rivers in Foothills County;
- determine how flood mitigation that is either planned or has already been completed in the High River Area may change those impacts; and
- complete a High Level cost benefit analysis comparing the 2013 flow conditions to the same flows in post mitigation conditions.