Please take the time to become a better-informed advocate for responsible flood mitigation solutions.
Groundwater, Flow Rates, Reservoir Management Dr. Cathryn Ryan, Department of Geoscience, University of Calgary, describes what happens with groundwater during flooding events. Flooded basements are on the insurance companies’ radar after the 2013 southern Alberta floods. While overland flow is one contributor to basement flooding, the groundwater component is not well understood. Calgary’s alluvial aquifers are both susceptible to pollution from suburban development and to basement flooding. Watertables respond quickly in the highly permeable alluvial aquifers to high flood levels in the river. Dr. Ryan describes two surveys of residents after the 2005 flood in the Rideau-Roxboro subdivision and in the Tsuu T’ina First Nation’s Redwood Meadows subdivision after the 2013 Elbow River flood. Paleochannel aquifers also transmit high watertables from flood levels. Homes built on alluvial aquifers whose basements are below the watertable level at flood stage are likely to flood. The watertable pressure can overwhelm even well sealed basements. Sump pump and basement foundation failures are common. Sewer backup may actually be watertable basement flooding. Dr. Ryan’s presentation was part of the Canadian Water Resources Association’s (Alberta Chapter) conference on the 2013 Alberta Floods, The Rains, Response, Recovery & Resiliency, March 23-25, 2014 in Calgary, Alberta.
Synopsis from abstract from YouTube:
Watch this video and understand why there is opposition to the proposed community barriers in Bowness.
Groundwater flooding has been a major contributor to flood damages in Calgary. A 2014 survey of Elbow River communities revealed that during the 2013 flood 88% of homes were flooded by groundwater first, with 12% of those homes flooded by groundwater alone. Like the Elbow River communities, Bowness is also built upon a “river-connected alluvial aquifer” and therefore subject to the same groundwater flooding risks. This short video explains how groundwater contributes to flooding.
This video shows the prevalence and challenges of groundwater in the NW community of Bowness located in Calgary, Alberta. During construction of a new home on Bow Crescent NW the builder had to pump for three days to keep the water out of the excavation for bringing water and sewer services to the new building.
In deciding to conceptualize a flood barrier in Bowness, the City of Calgary hired an external consultant (Associated Engineering) to evaluate the barrier for different flooding scenarios (Permanent Flood Barrier Assessment, April 2018). Of particular interest in the report are two different barrier concepts. One concept has the barrier extend to bedrock deep below the surface. This design prevents flooding of residents by not allowing water to go under the barrier, and is being implemented in Sunnyside. However, the cost of this solution was very high for Bowness as the gravel layer in Bowness is very deep. The second concept is a barrier, which minimally goes below surface. This design allows for water to go under the barrier and flood properties. The City has currently indicated the latter design fulfills their requirements for a barrier in Bowness. In the July/August 2019 issue of the Bowest’ner, BRFM explains the report.
Flowrate is the volume of water passing a given point in a set period of time. For example, the 2005 Bow River peak flow rate approached 800 cubic meters/sec (cms) and in 2013 it was 1783 cms. Dams reduce flowrates downstream by holding back water, and releasing it slowly, later when the flood event is over. Fast flowrates over an extended period contribute to groundwater flooding. You are encouraged to read the article to understand the importance of keeping flowrates through Bowness to below 800 cms.
Description from AEP website: The agreement allows the Province of Alberta to set elevations on the Ghost Reservoir during the period of May 16 to July 7, which is typically the highest storm risk period of the year. By keeping the reservoir lower during this period there is more space to store flood events thereby lowering peak flows downstream of the dam or, at the very least, delaying those peaks.
Environment
To objectively assess the potential environmental impact of the City’s proposed flood berm in Bowness, Bowness Responsible Flood Mitigation Society (BRFM) conducted a tree census. From May to November 2018, BRFM volunteers walked the conceptual alignment of the Bowness flood berm to record the number of trees that occupy a 30-foot wide footprint (this is the stated average from the City) from Shouldice Bridge in the east to the CP tracks in the west (3-4 km in length). The results were staggering!
Residents of Bowness submitted photos of wildlife seen in the area, to BRFM and they have been categorized and saved to the BRFM Wildlife Photo Gallery for general viewing. BRFM will receive your wildlife photos. Please send with a description to info@bownessrfm.ca.
The inquiry document was submitted to the City of Calgary Bowness Barrier Project Team (“City Project Team”) on May 1, 2019 The document organizes points for discussion between the City of Calgary Bowness Barrier Project Team (“City Project Team”) and BRFM. As of November 19, 2019 BRFM has not yet received a written response to our inquiries. The document includes the results of a tree census that was completed by BRFM in November 2018 and a wildlife inventory that documents wildlife sightings by Bowness residents who live along the Bow River.
Bow River Reservoir Options
Following the recommendations made in a May 2017 report by the Bow River Working Group (BRWG) the Province of Alberta is assessing options to mitigate the impacts of both flood and drought on the Bow River. In November 2018, AEP selected Wood Canada Limited to conduct a conceptual assessment on three runs of the Bow River: A letter to stakeholders (September 11, 2019) states that “the intent of the conceptual assessment is to develop conceptual designs for reservoir options on the Bow River upstream of Calgary that consider engineering, environment, social, economic, cultural and traditional land use factors, including information gathered through engagement with First Nation Communities, Métis associations, stakeholders and the public. The results of the Conceptual Assessment will provide context for consideration to determine if any of the mitigation options might move forward to a Feasibility Study.” This project website provides background to the study and information about the current conceptual assessment including interactive presentations with animations for the Glenbow East and Relocated Ghost Dam options.
Visit AEP’s online engagement page to view past submissions and feedback on Albertan’s thoughts on Bow River Water Management.
Flood Mitigation Studies Commissioned by the Government of Alberta
This report is the result of the Bow River Water Management Project, that was announced in October 2015 by Alberta Environment and Parks (AEP) and jointly chaired with the City of Calgary and is one of many water management projects and investments initiated in the Bow River Basin since the floods in 2013. The report summarizes the findings of the project and offers it as advice to the Minister of Alberta Environment and Parks in developing a strategic plan for water management in the Bow River Basin, from the headwaters to the confluence with the Oldman River and continuing through Medicine Hat. This advice focuses on screening structural flood and drought mitigation opportunities in the basin, assessing the resulting flow impacts downstream through the entire basin, and considering the associated effects on watershed health.
Land Owner Rights, Expropriation and Land Compensation
This brief was written for Bowness riverside land owners for the purposes of providing a general summary of how expropriation and compensation works in Alberta. There is a difference in expropriation of an easement versus an expropriation of the land. Expropriation of the land changes the title such that it is divided into two titles with the City owning the portion of land that is expropriated and the land owner owing the remaining portion. Expropriation of the land gives the City authority to do as they please with their land for public use or benefit. An expropriation of an easement gives the City the right to cross or otherwise use someone else’s land for a specified purpose as documented in the easement agreement. Given the differences in the rights to the land, it can be expected that the amount compensated to a property owner for an expropriation of an easement (right to use land) would be less that that compensated for expropriated land (ownership of land). This document’s purpose is to summarize in a non-legal, general nature expropriation and compensation cases that are as close as possible to the proposed barrier situation in Bowness.
This document was created to provide a summary of what has been researched on berms created by the City in Inglewood circa 2007 prior to this document’s issue date. It will be updated as information becomes known. The City constructed flood barriers in Inglewood circa 2007 on 16 properties, of which the City owned or acquired at least 1. The City proposed this barrier as saving 724 other Inglewood properties. Since the City is proposing barriers for Bowness, some Bownesians thought it would be useful to canvas Inglewood homeowners regarding their experiences with the construction process and the results. Inglewood residents enjoy riparian rights as we do in Bowness.
This document was created to provide a summary of what has been researched on berms created by the City in Inglewood circa 2007 prior to this document’s issue date. It will be updated as information becomes known. It is an extended version of the short report listed above.
The brochure is intended to provide a basic introduction to easements and rights-of-way.
(https://www.alsa.ab.ca/Portals/0/PDF/Public/Easements/Understanding_Easements_and_Rights-of-Way_2010.pdf?ver=2012-09-06-182700-000)
Bodies of water are bounded by natural boundaries which can shift over time and affect the area of the adjoining lands. On this AEP website page you can read about “ownership of beds and shores”, “legal bank” and “public access”.
Flood Mitigation Studies Commissioned by the City of Calgary
Body of the report: (https://www.bownessrfm.ca/AE_RiverFloodConceptualDesignReport.pdf). The appendices, including “refined designs”, detailed cost benefit analysis, flood inundation maps, etc. are available from the City of Calgary Website for download.
(https://www.calgary.ca/UEP/Water/Pages/construction-projects/Construction-projects-and-upgrades/Community-Flood-Barrier-Related-studies-and-reports.aspx).
Available for download from City Online: This is the full report. The City of Calgary made available an executive summary (see below). It contains a detailed cost/benefit analysis of various flood mitigation options, including upstream, community level, property level and land use regulations.
(https://cityonline.calgary.ca/Pages/Product.aspx?category=Unlisted&cat=CITYonlineDefault&id=8092-12527-14294-00002-P).
Other Resources