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Ward 1 News: Bowness Flood Protection - Q and A

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Bowness Flood Barrier
 
Being so close to the Bowness River means that there is always a risk of flooding, and there is a 12% chance of one happening in the community each year.
 
In 2016, The City hired external consultants to update the Provincial Flood Damage Assessment study for Calgary, and to assess and recommend future resiliency and mitigation measures. The resulting document, the Flood Mitigation Measures Assessment (FMMA) report, was approved by Council in spring of 2017. Recommendations include a combination of watershed-, community- and property-level mitigation solutions to create a flexible and adaptable flood risk management program. The Bowness flood barrier project was one of the recommendations from this study.
 
Project Details
 
This project is still in the early preliminary design stage. Once a design consultant has been hired, it will be their role to gather detailed information about each property, and consult with homeowners and community members to develop recommendations for exactly what the barriers could look like.
The City is proposing building permanent flood barriers that will extend from the CP Rail tracks to the Shouldice Bridge.

Conceptual work has been completed, however, detailed design has not yet started. Input from citizens is an important piece of the detailed design process. Engagement with residents began in early 2018 and will be ongoing through to the completion of the project.
 
Frequently Asked Q & A
 
The following are frequently asked questions regarding the Bowness flood protection measures and the proposed flood barriers.


What is a flood mitigation strategy?
A flood mitigation strategy represents The City’s overall approach to ensuring that our city has the right measures in place to reduce our risk of flooding.  A flood mitigation strategy brings together research, technical studies, citizen perspectives and expert advice to develop the right mix of elements in the right areas.  Our strategy guides our actions and the future projects we pursue.  
 
How did The City develop its river flood mitigation strategy? 
The 2013 flood caused $400 million in damages to public infrastructure and about $1 billion in damages to private property and businesses.  After the flood, The City invested in a comprehensive Flood Mitigation Measures Assessment, several technical studies, a social-economic-environmental assessment and captured input from citizens to develop a solution for reducing Calgary’s flood risk.   

Options for reducing flood damages can include physical infrastructure (such as reservoirs, flood barriers, canals, tunnels), as well as things like education and policies or bylaws that can help reduce the risk of damage during a flood.  Many of these options were investigated for Calgary, such as dredging the reservoirs and rivers, a tunnel to take flood water from the Elbow River to the Bow River, the feasibility of upstream reservoirs, and new bylaws regulating development in flood prone areas.

The City enlisted an external consultant, the IBI Group, to create a list of options that would be feasible in Calgary, and then assess combinations of options. They compiled 13 scenarios using a combination of watershed level, community level, and property level mitigation, as well as some non-structural measures. 
 
All the scenarios were then compared against the existing level of flood risk, which accounts for existing flood protection projects that were already underway, to see how effective they would be at reducing flood risk. The scenarios were also subjected to a comprehensive sustainability analysis that considered environmental, social and economic factors, and citizens were engaged to provide feedback on the scenarios. 
 
The final recommendations approved by Council reflect the technical assessment’s cost-benefit results, sustainability analysis ranking, and citizen feedback, to form The City’s flood mitigation strategy. 
 
What options did the Flood Mitigation Measures Assessment (FMMA) report identify for the Bow River?
The report indicated that a  combination of options were required for the Bow River.  These included a new upstream reservoir, modified operations of the Ghost reservoir, and flood barriers in the neighbourhoods of Bowness, Sunnyside, and Pearce Estates Park in Inglewood. These pieces would work together to to reduce flood risk to citizens, private property, businesses, critical infrastructure, public property, and community services. 
 
Was the public consulted as part of the strategy development process?
Yes. The City sought input from the public when developing the flood mitigation strategy. Citizen feedback was gathered through several methods: 

  • Community Advisory Group (CAG): A 19 member citizen group was formed to review mitigation measures, examine the trade-offs and provide input into optimizing solutions to meet community needs. The CAG was not a decision-making group nor was it expected to reach a consensus on solutions. The input from the CAG was used to help The City confirm, modify or enhance the assessment of flood mitigation options.  
  • Telephone Survey:  A telephone survey was conducted by IPSOS Public Affairs in April of 2016 to gauge citizens’ opinions on the value of the river to our community and flood mitigation. A survey sample of 300 citizens from the general population and an additional 200 citizens from flood-affected communities was used. 
  • Community Events and Online Engagement: The City held community events and online engagement to gather input from citizens on proposed flood mitigation concepts. Input was gathered between 2016 October and 2016 November at:
    • Six community workshops,
    • Two open houses, 
    • Online engagement  
  • Feedback was gathered on how the proposed flood mitigation measures would:
    • Affect the way their communities would look, feel, and move
    • Reduce damages from river flood and impact personal property, business operation, and Public safety
    • Impact the amenities and services in communities
    • Protect Calgary’s economic core
    • Affect the city as a whole. 

Over 3400 comments were received from 1000 citizens through the worskhops, open houses and online engagement participants. 
When the river flood mitigation strategy was presented at Council in spring 2017, several citizens attended and delivered their thoughts. This feedback is incorporated into ongoing work planning and communication.  
 
Why does the strategy include a flood barrier in Bowness? 
The report proposed several recommendations that would work together to support flood protection efforts on the Bow River.  These include a new upstream reservoir, modified operations of the TransAlta reservoir, and flood barriers in the neighbourhoods of Bowness, Sunnyside, and Pearce Estates Park in Inglewood. Each piece of the strategy provides great benefits independently, but together, they ensure the most effective flood protection strategy.
 
Without a new reservoir, the barrier serves to protect the community from smaller floods that are more likely to occur every year. The river banks in Bowness begin to overtop when the river flows at about 600 m3/s. The flood barrier will protect buildings, streets and infrastructure up to flow rates of 1200 m3/s. There is a 5 per cent (or 1 in 20) chance that such floods will occur in any year. 
Once Bowness is protected by the barrier so that flows of 1200 m3/s can pass through Bowness without damage, the upstream reservoirs (including the existing Ghost Reservoir) can be operated to provide better flood mitigation for all downstream communities. In combination, upstream reservoirs with the Bowness flood barrier can mitigate much larger floods than the reservoirs could alone. 
 
How will the strategy, and specifically a barrier, help Bowness with groundwater and basement flooding?
The land in Calgary’s river valleys is generally composed of gravel, with patches and layers of silt, clay, or sand. When water levels in the river rise, this also causes water levels in the groud to rise, with the water moving through the spaces between the soil and rocks. Where there are cracks in foundations or basement walls, window wells, etc., high groundwater can seep into basements. 
Groundwater seepage can be reduced by using a sump pump. It is a good idea to have a back up power source to run the sump pump when power is shut off to a flooded community. 
Basement flooding can also be caused water backing up storm and sanitary sewer systems. This is often a result of  river water entering manholes and catchbasins (street drains) which forces water backwards into the storm and sanitary system. Sewer backup into basements can be reduced by installing backflow preventer valves in sewer pipes on your property or in your basement. 
 
Groundwater was modelled during the development of the barrier concepts. This was a high-level study based on generalized soil types. During detailed design, the soil types and groundwater will be investigated in more detail. The barrier design will incorporate consideration of groundwater to ensure structural stability of the barrier and nearby structures.  The barrier is not intended to completely prevent high groundwater during a flood, but may have modest influence on local groundwater conditions. This will be characterized and addressed as part of the design. By preventing overland flooding for river flows up to 1200 m3/s, the barrier will help reduce basement flooding due to sewer backup, as floodwater will not be entering manholes and catchbasins.  

Why aren’t we just pursuing an upstream reservoir?
Through studies and analysis, it has been determined that there isn’t one single project that will provide adequate flood protection on its own on the Bow River.  Each piece of the strategy provides great benefits independently, but together, they ensure the most effective flood protection strategy. 
An upstream reservoir is a very important piece of the strategy, but further work is required before a reservoir is approved and funded.  In the meantime, the barriers proposed in the strategy and the TransAlta agreement will provide some mitigation against Bow River flooding.  Once a reservoir is built, the barriers would allow the upstream reservoirs to be operated in a way that has a greater flood mitigation potential.  
 
What is this I heard about a new upstream reservoir?
The Province of Alberta created the Bow River Working Group (BRWG) to explore ways to improve flood resilience and manage water in the Bow River basin.  The BRWG is comprised of  municipalities, First Nations, Irrigation Districts, watershed stewardship groups, and other key stakeholders to reach the best possible solutions.
The BRWG’s report, released in August 2017, assessed the feasibility of a new upstream reservoir on the Bow, among other actions that can increase the flood and drought resiliency on the Bow River. The construction of an upstream reservoir is a provincial initiative, so please visit aep.alberta.ca for a copy of the Bow River Working Group’s report, visit. 
 
What will The City do if upstream mitigation efforts don’t happen on the Bow?
The City’s current strategy is designed to be flexible and adaptable to future Provincial decisions and will be reassessed as new information from the Province and Federal government becomes available. 
 
What is the TransAlta agreement, and how effective is it?
The Province has an  agreement with TransAlta to draw down the water in the Ghost  Reservoir every spring to create room for flood water, should a flood occur. The agreement provides significant flood mitigation on the Bow River by reducing the risk of flood damages on the Bow by as much as 20-40 per cent, depending on the size of the event.  
 
The TransAlta agreement will help most significantly for smaller floods that have the potential to happen more frequently. The original agreement is in place for 2016-2020. The City considers an ongoing agreement a key component of flood resiliency in Calgary.  
 
How is the barrier project being funded?
To date, the Province has committed $150 million over ten years through the Alberta Community Resiliency Program (ACRP) for flood mitigation projects within the city. 
 
The City has included flood protection projects in Bowness, the downtown core, Sunnyside and Pearce Estates Park as part of its 2018 funding application through this program. The City is required to match a portion of the funding that is acquired through the program. The application was submitted September 2017. 
 
Has The City’s flood risk been reduced since 2013?
Yes. The FMMA determined that Calgary’s flood risk, if no mitigation were in place, is about $170M per year. Mitigation that has been previously completed and currently underway will reduce Calgary’s flood risk to $115M.  This does not include any of the future flood protection work that will happen in Bowness, Sunnyside or Pearce Estates Park, which will lower our city’s flood risk even further. 
 
The following completed or underway projects have made Calgary more resilient to flooding: Glenmore Dam Improvements (gates on the crest of the dam) Permanent flood barriers: 
  • Heritage Drive, Centre Street bridge;
  • Bonnybrook Wastewater Treatment Plant,
  • West Eau Claire Park 
  • Memorial Drive at 19th Street NW,  
  • Deane House 
  • Calgary Zoo 
  • Stormwater system upgrades 
Bowness Project-Specific Questions
 
What is the Bowness Flood Barrier project?
The Bow River is an integral part of the Bowness community. Being so close to the river means there will always be a risk of flooding. In Bowness, flooding can happen when the flow rate is approximately 850 cubic metres per second (m3/s), which has a 12 per cent chance of occurring each year. For context, the ‘normal’ spring flow rate ranges from 70 - 400 m3/s. 
In 2016, The City hired external consultants to update the Provincial Flood Damage Assessment study for Calgary, and to assess and recommend future resiliency and mitigation measures. The resulting document, the Flood Mitigation Measures Assessment (FMMA) report, was approved by Council in spring of 2017. Recommendations include a combination of watershed-, community- and property-level mitigation solutions to create a flexible and adaptable flood risk management program. 
 
The Bowness flood barrier project was one of the recommendations from this study.
 
Much of the riverfront property is privately owned in Bowness and The City will work with individual property owners to gather their input, and discuss their concerns and ideas as the detailed design work gets underway.  
 
Why does the strategy include a flood barrier in Bowness? 
The report proposed several recommendations that would work together to support flood protection efforts on the Bow River.  These include a new upstream reservoir, modified operations of the Ghost reservoir, and flood barriers in the neighbourhoods of Bowness, Sunnyside, and Pearce Estates Park in Inglewood. 
 
The river banks in Bowness begin to overtop when the river flows at about 600 m3/s. The flood barrier will protect buildings, streets and infrastructure up to flow rates of 1200 m3/s. There is a 5 per cent (or 1 in 20) chance that such floods will occur in any year. 
 
Once Bowness is protected by the barrier so that flows of 1200 m3/s can pass through Bowness without damage, the upstream reservoirs (including the existing Ghost Reservoir) can be operated to provide better flood mitigation for all downstream communities. In combination, upstream reservoirs with the Bowness flood barrier can mitigate much larger floods than the reservoirs could alone. 
 
What stage is the project currently in?
A barrier concept was developed to assess the viability, costs and benefits of the project. Currently, a Request for Proposals (RFP) to select a consultant to do the detailed, technical design work has been issued. The RFP closes May 4, 2018.
 
After the consultant is selected, they will do studies to verify geotechnical and groundwater conditions, site drainage, and other technical information that will be incorporated into the barrier design. The City would like to work with property owners to create a solution that will protect the community, while maintaining the well-being of property owners. A consultant to to lead community engagement work is also being hired. 
 
How is the project being funded?
A detailed project plan is in the process of being developed, but it looks like the project will be funded 70/30 between the Province and City, respectively.
 
The City is also actively working to determine Federal funding opportunities to support any flood mitigation work, which would have similar cost share obligations for The City. 
 
Is a barrier a cost-effective solution?
The completed conceptual design work included a high-level cost-benefit calculation. Estimates of the economic benefits of the barrier were calculated based on the amount of flood damages that will be prevented once the barrier is in place. 
As we proceed through the detailed design stage, the cost-benefit will be refined and confirmed. The final cost-benefit of the project will depend on complexity of the final design (e.g., location, extent and type of barrier), property easement agreements, and construction costs.  
 
What studies have been done on groundwater? 
Groundwater was modelled during the development of the barrier concepts. This was a high-level study based on generalized soil types. During detailed design, the soil types and groundwater will be investigated in more detail. The barrier design will incorporate consideration of groundwater to ensure structural stability of the barrier and nearby structures.  
 
The barrier is not intended to completely prevent high groundwater during a flood, but may have modest influence on local groundwater conditions. This will be characterized and addressed as part of the design. By preventing overland flooding for river flows up to 1200 m3/s, the barrier will help reduce basement flooding due to sewer backup, as floodwater will not be entering manholes and catchbasins.  
 
How will the barrier deal with local and private lot drainage?
Study of local lot drainage will be conducted as part of the technical design process and the barrier will be designed with detailed consideration of local topography.  
 
What level of protection is the project trying to achieve?
The river banks in Bowness begin to overtop when the river flows at about 600 m3/s. The flood barrier will protect buildings, streets and infrastructure up to flow rates of 1200 m3/s. There is a 5 per cent (or 1 in 20) chance that such floods will occur in any year. 
 
Once Bowness is protected by the barrier so that flows of 1200 m3/s can pass through Bowness without damage, the upstream reservoirs (including the existing Ghost Reservoir) can be operated to provide better flood mitigation for all downstream communities. In combination, upstream reservoirs with the Bowness flood barrier can mitigate much larger floods than the reservoirs could alone.
 
With the three part plan in place, Bowness would be protected from flood events up to the 200 year return period flood event.  
 
If the detailed design work hasn’t been completed how do you know that barriers are the right choice?
Technical studies have shown that even with a potential new upstream dam, local flood protection is also required to protect Bowness. The location, type and extent of the final structure will be determined during the detailed design. 
 
Once a design consultant has been hired it will be their role to gather detailed information about each property, consult with home owners and community members, conduct geotechnical and groundwater studies, and provide their recommendation in terms of what the best flood barrier for Bowness will look like. 
 
Does The City really need to build all of the planned barriers? Can’t it just build some?
Although the detailed, technical design work has not yet been completed, we know that the final solution will need to be fully constructed in order to provide adequate flood protection for Bowness.   
 
When will I know where and how my property will be impacted?
It is too early to provide details about specific properties with any certainty. We have not yet entered the detailed design phase, so while we have an idea of which properties will be affected, we don’t understand the full extent to which they would be affected. 
 
How many homes will be affected by this project?
The work that has been completed to date identified 94 riverfront properties within the proposed barrier alignment. That said, because the technical design work has not yet been completed, this number could  change. 
 
What is the proposed height of the barriers?
From then conceptual design, we have an idea of potential barrier heights. However, the unique elevation (height) of the riverbank is a key factor in determining the height and location of the barrier for each property and this be refined during the technical design phase. 
 
Our initial conceptual work reflected that barriers may range anywhere from 0.5 metres (1.5 feet) in height in some areas to 2.0 metres (6.5 feet) in height in other areas. The average barrier height over the length of the project is 0.8m (2.62 feet). 
 
What will the barrier look like?
The City’s conceptual work looked at earthen berm barriers as well as floodwalls. Once we enter the detailed design phase, we will analyze where those barriers should be placed, how they function, how tall they are, and aesthetics.
 
It’s important to note that because much of the riverfront property in Bowness is privately owned, The City will work with individual property owners to gather their input, and discuss their concerns and ideas as the detailed design work gets underway.     
 
How do I find out if a barrier is planned for my property? 
The flood protection work in Bowness focuses on the area along the river’s edge, roughly between the CP Rail tracks and the Shouldice Bridge. 
 
Once detailed design work has begun, The City will be reaching out to private property owners to have conversations and explore potential flood protection opportunities.  
 
Citizen and community engagement is going to be a critical piece of this project.  We realize the potential impacts and are committed to working with you to ensure that you have the information you need and the right channels for sharing your thoughts, concerns and ideas.  
 
What process does The City use to engage with property owners?
The City had an initial information session with citizens in January 2018 to inform them about the project.  Moving forward,The City will be seeking input from property owners and the community on a regular basis, as the detailed, technical design portion of the project gets underway. 
 
A plan of how to gather property owner input and address their concerns is currently being developed. The City would like to work with private property owners to create a solution that will protect the community, while meeting the needs of private property owners. 
 
Will the process be the same as it was for the Inglewood Flood Barrier?
The Inglewood Flood Barrier project occurred between, approximately, 1998 and 2011. It protects the community of Inglewood from river flooding. The barrier is located on public land and 12 private properties. As the local context, geography, design requirements, community, land owners and economic context are all different, this project will draw on lessons learned from the Inglewood project, but will not be the same.  
 
Would a barrier on my property reduce my privacy?
The purpose of a barrier is to provide flood protection. Unlike barriers on public property that might be suitable for recreational access, The City recognizes that privacy is of concern to property owners along the river. Therefore, public access in Bowness is not being considered.  We will work to maintain privacy and security on private property as part of the design process. 
 
Would a barrier incorporate public access for recreation along the riverbank?
The City has no plans to create public access or encourage recreation along the barrier or riverbank in front of private property in Bowness. 
 
How do I find out if my property is at risk of flooding?
There are a number of maps that are available on The City’s website that can help citizens determine their flood risk. For more information, visit Calgary.ca/floodinfo and click on the ‘Mapping’ section to view maps that can show you whether your property is at risk.  
 
What if I am planning on selling my property?
What can I tell prospective buyers who ask about the Bowness barrier project? Homeowners are free to discuss the project with potential buyers, using The City’s website as a resource. Since the project is still in the early stages of planning, the website will be the best resource for up-to-date project information.   
 
Why is The City not buying out the properties at risk of flooding?
From a financial perspective, it was deemed impossible to purchase all properties in the current flood hazard area. The buy-out costs have been estimated to be up to several times greater than the cost of developing new upstream mitigation. 
 
The costs that would be associated with building demolition, conversion of properties to parkland, and incentives to assist homeowners to relocate make this too costly an option. Property buy-outs are also very disruptive to communities and have significant impacts on property owners. 
 
Would barrier design include river bank erosion protection? 
Erosion potential of the adjacent bank would be assessed during the barrier design. Where required to create a stable barrier, erosion protection will be incorporated into the design. 
 
Would a barrier increase flood levels on the opposite bank or in downstream communities?
Part of the design process includes verifying the impact that any potential flood protection measures could have on flood levels both upstream and downstream. Studies to date show that the impacts of a barrier would be negligible.  
 
How would barriers affect riparian areas or aquatic habitats?
Protecting the riparian habitat in all of our rivers and streams is important to The City.  The City has a Riparian Action Program, which aims to protect riparian habitat. The impact to the riparian areas of all projects are carefully considered and where possible, riparian restoration is undertaken.   
 
With the exception of 2013 and 2005, Bowness hasn’t flooded in a long time. How great is our risk to flood again?
It’s true that Calgary had several decades without a flood event, however, with a changing and warming climate, extreme rainfall and floods are expected to happen more frequently.  
 
What do I do if I need more information?
For more information or specific questions about the project, call 311 or email BownessBarrier@calgary.ca. You can also visit the Bowness Flood Barrier Project engage page, for updated engagement information and a more detailed project timeline. 
 
General Flooding-Related Questions 
 
What can citizens do to protect their property?
Flooding can happen at any time in Calgary. The period between May 15 and July 15 is when we are most likely to experience flooding since historically this is when we receive the most rainfall. 
 
To make sure you and your family are as prepared as possible in the event a flood occurs, follow the steps below:
  • Read The City’s Flood Readiness Guide
  • Create a 72 hour kit
  • Get the latest alerts and notices from Alberta Emergency Alert and Alberta Rivers apps
  • Create an evacuation plan
  • Visit Calgary.ca/floodinfo for more information. 

The City is also able to provide recommended flood elevations for your property if you are constructing flood proofing measures or rebuilding. 
 
What is the City doing to educate home owners about flood readiness and being prepared for flood season?
The City holds an annual Flood Readiness Campaign between May 15 and July 15 to help citizens, property managers and businesses to prepare for a flood event.  There are a number of resources for citizens can use to prepare for flood season and to stay aware of potential flooding:

What other measures is The City taking to protect citizens from flooding?
A variety of additional non-structural flood mitigation measures are currently being reviewed to evaluate which are the most effective and make the most sense for our city. Options being investigated include education, policy, land use, building regulations for undeveloped, developed or re-development areas.  
 
What other mitigation options were considered? 
The following measures have previously been researched and ruled out as they were not technically, economically, environmentally, or socially practical: o Dredging of the Glenmore Reservoir, Elbow River or Bow River. o Full barrier fortification of the Elbow and Bow Rivers. o Temporary barriers along the Bow and Elbow Rivers 
 
Why do we have dams? Aren’t they being decommissioned elsewhere? 
In addition to controlling the flow of water through the city during a flood, a dam offers storage capacity as an adaptive means of addressing the need for water as our population, along with the risk of drought,  increases in the future. 
 
Why don’t we build higher barriers now?
Community barriers are intended to work together with upstream mitigation to achieve protection from a 2013-level flood event on the Bow River. The upstream mitigation is a critical piece for the long-term watershed protection for our community, potentially providing flood and drought mitigation.
 
Stakeholder engagement on The City’s flood mitigation strategy identified that many residents were against high barriers throughout Calgary that could provide flood protection to a level equal to what a reservoir could provide . They cited community disruption, restricted views and access to the river as key reasons for not wanting higher barriers.  
 
How will residents be protected until barriers and upstream mitigation is in place?
The City has been consistently working on flood protection projects since 2013. Studies determined that Calgary’s flood risk, if no mitigation were in place, is about $170M per year. Mitigation that has been completed and currently underway will reduce Calgary’s flood risk to $115M per year.   
 
Until mitigation is constructed in Bowness, The City continues to refine its emergency response measures to maximize safety during a flood event, including our flood forecasting and warning systems.  
 
What about the remaining risk?
There will always be a risk of flooding in Calgary. We cannot prevent flooding entirely but we are working to reduce its impact. 
The City is doing what it can to address risks to the best of its ability and resilience to flooding is a shared responsibility. As part of The City’s flood mitigation strategy, it is recommending further investigation of some non-structural policy measures to help further reduce risk. 
 
Should I be inquiring about flood insurance?
The Flood Mitigation Measures Assessment noted that insurance may be helpful to repair flood damages, however, insurance does not reduce the risk of a flood occurring and should not be relied upon as a form of flood mitigation. The availability, amount of coverage and costs of insurance varies  considerably. Contact your Insurance provider for more information.

For project details, please visit calgary.ca/BownessFloodBarrier
 
Other Important Resources
 
Please visit calgary.ca/floodinfo for more information, sign up for our e-newsletter and download our Flood Readiness Guide.
 
We invite you to this upcoming event to learn more:
 
Flood Preparedness Open House for Bow River Communities
Tuesday, May 15, 2018 
Start time: 7:00 p.m.
Foothills Academy
745 37th Street N.W.

This content represents the personal views and opinions of the Councillor and should not be taken as a statement of policy of The City of Calgary. The inclusion of any external content does not imply endorsement by The City of Calgary.

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