Red River Floodway, built between 1962 and 1968 for a cost of $63 million, was one of the most effective and significant flood protection infrastructure in the Province of Manitoba, Canada (“Red river floodway,” 2011). Ever since it had been putting in use, it has prevented more than $40 billion (in 2011 dollars) in flood damage in Winnipeg (“Red river floodway,” 2011).
However, after 1997 “Flood of the Century,” the International Joint Commission analyzed the flood protection measures and concluded that, under situations similar to the flood in 1997, there would be a high risk of failure for Winnipeg’s flood protection infrastructure (“The need for,” ). As a result, the Commission recommended the government to take immediate actions to improve the flood protection system in the preservation of Winnipeg (“The need for,”, ). Right Afterwards, continuous modification has been done in the expansion of Red River Floodway (“Red river floodway,” 2011).
After thorough planning and public hearing, in 2005, Canada and the Province of Manitoba decided to invest $665 million in the further expansion of the Red River Floodway; and that project was what we call today the Red River Floodway Expansion Project (“Red river floodway,” 2011). (INTRO TO THE ESSAY) This article will first give an overview of the expansion project; then discuss the distribution, hazard risk identification, hazard risk mitigation strategy, costs and benefits, and the support and criticism regarding the Red River Expansion Project.
First, the geographic location of the Red River Basin and the vulnerabilities of local communities’ have demanded intensive protection strategies for the area. Figure 1 shows that Red River entered Winnipeg from south and runs all the way through north (“Floodway components,”). The original build of Red River Floodway was located on the north eastern side of Winnipeg, spanning southward along the eastern border and wraps around the southern side of the city.
The expansion project keeps most of the modification along the existing floodway, and extended the West Dike by 70km from the inlet control, located at the south of Winnipeg (“West dike,”). The geographic distribution of the expansion project is shown in Figure 1, as well as the improvement components at specific construction locations (“Floodway components,”). The communities affected by the expansion project contain more than 450,000 Manitobans, 140,000 homes, 8,000 businesses, in Winnipeg region, East St. Paul region, and West St.
Paul region (“Red river floodway,” 2014). Thus, the expansion project was in great demand around the region of Red River Basin in the protection of vulnerability factors in the local communities. Second, in Manitoba, the hazards and their risks triggered by riverine flood has required a more comprehensive flood protection infrastructure system in place for the preservation of the area. One of the most devastating natural hazard that the Red River Floodway is meant to mitigate is riverine flood (“History of flooding,” ).
Manitoba is one of the places in Canada that has the worst situations for riverine flooding ever since, at least, the 1800s (“History of flooding,” ). Starting from then, there have been some historical floods in the years 1950, 1997, 2009 and 2011, which has caused extensive damages mainly among Red River and Assiniboine River basins (“History of flooding,” ). In terms of the frequency of riverine flood based on the record from 1875 to 1998, there have been 117 years where rivers have been on maximum capacity; the statistics also shows that there were 123 flood events, including 3 historical floods (Burn & Goel, 2001).
The speed of onset is usually very fast for riverine flood; fortunately, its coming can be predicted (“Slow & rapid,” 2011). One thing worth mentioning is that, when riverine flood occurs as a primary hazard, secondary natural and technological hazards can often be generated such as dike failure, dam failure, drinking water pollution, critical infrastructure failure, energy supply emergency, hazardous materials release, transportation emergency, rising level of anxiety, human health emergency, agricultural and food emergency, etc. ; riverine flood can also cause human-caused hazards indirectly (Bracey, 2013).
Therefore, the Red River floodway and its expansion project had become a necessity in the mitigation of primary and secondary hazards and the preservation of local communities. In order to better mitigate with intensive riverine flood and its potential secondary hazards, together with the hazards that may incur due to the floodway expansion construction, certain modifications were designed for the project in terms of expansion of the West Dike, widening to the Floodway Channel, improvements to the Inlet control and Outlet control, replacement nd enhancement of 8 bridge crossings, and advancement to service and utilities (“What is floodway,”).
The primary and the most significant hazard that the expansion project was aiming to intervene is the intensive riverine flood. The operation rules of Red River Floodway shall be introduced to demonstrate how riverine flood hazards could be intervened. Under normal summer conditions, as shown in Figure 2, Floodway gates divert part of the Red River flow to the east side of Winnipeg through the floodway channel (“Red river floodway,” 2011).
During flooding time, as the river rises, the water spills over and then flows down the floodway channel; thus, the river water flows through two routes – through the red river in Winnipeg and through the floodway, and the south of floodway inlet would then drop below its natural level (“Red river floodway,” 2011). When the floodway gates are raised, as shown in Figure 3, the water level south of the inlet will drop down to its natural level, which allows more water to be spilled into the floodway (“Red river floodway,” 2011).
If the Red River’s water flows continue to increase, the gates will be further raised due to the water level south of inlet drops below natural (“Red river floodway,” 2011). During floods, the floodway operation ensures the river stayed below its natural level at south of Winnipeg (“Red river floodway,” 2011). As stated before, historical floods sometimes happen in Manitoba; especially in the recent decades (“History of flooding,”).
Under such circumstances, the water flow through Winnipeg is controlled by three spring floodway operating rules to ensure the risk of secondary hazards like dike system failure will be reduced (“Red river floodway,” 2011). The fourth floodway operating rule is in place. It is effective only when high water levels of Red River affect the storm sewer and combined sewer system in Winnipeg (“Red river floodway,” 2011).
In summer, a frequently appearing situation is the combination of intense rain storm and high water, which could potentially overwhelm the local sewer systems and cause basement flooding (“Red river floodway,” 2011). When this occurs, operation of the floodway ensures the water stays at natural levels, therefore reduces the property and economic damages and human health hazards caused by basement flooding (“Red river floodway,” 2011).
The floodway operation system had been working alright until the “700 year flood”; ever since that, the expansion project had been under planning and some modifications had been completed. The Red River Floodway Expansion Project officially started in 2005 after sophisticated planning and public hearing (Red river floodway,” 2011). How to increase the floodway capacity without triggering drinking water emergency and under groundwater pollution experienced by the communities in the vicinity of the constructions was the first issue faced by Manitoba Flood Authority.
In order to reach this goal, Manitoba Flood Authority decided to focus its efforts on widening the floodway channel rather than deepening it (“What is floodway,”). This plan has successfully maintained the designed capacity and resulted in an increased capacity from 1,700 (cubic metres of water per) second to 4,000 (cubic metres per second) (“What is floodway,”). The second set of improvements was made to floodway’s inlet and outlet control structures (“Inlet & outlet,”).
Upgrades for the inlet structure includes advancement for fire protection system, upgrades to hydraulic system, installation of rip-rap and other erosion control techniques to protect inlet structure embankments from hazards like dam failures incurred by flooding or construction failure (“Inlet & outlet,” ). The outlet structure near Selkirk, together with the floodway channel that releases the water back into the Red River has also been improved and widened (“Inlet & outlet,”). The enhancement for riverbank stability and erosion protection techniques north of the floodway outlet has also been implemented (“Inlet & outlet,”).