Reimagining flood management

Photo courtesy GHD.

Floods are among the world’s most devastating natural disasters, causing enormous property damage and loss of life. With the increasing frequency and intensity of these events due to climate change, it is crucial to rethink our approach to flood management and work with communities to get them more involved in building resilient urban environments.

Learning from history

GHD’s research suggests floods that wash out highways, damage buildings and affect power grids could cost Canada’s economy $139 billion over the next 30 years.

Calgary’s catastrophic flood in 2013 serves as a stark reminder of their destructive nature; with five lives lost, 110,000 people evacuated and $6 billion in property damage, it stands as one of the costliest natural disasters in Canada’s history. And it highlighted the inadequacy of traditional flood defences, like embankments and levees.

More recently, in 2021, floods in British Columbia cut off rail and highway links between Canada’s biggest port in Vancouver and the rest of the country and stressed supply chains already hampered by COVID-19 pandemic response. The effects of the floods included an increase in consumer good prices, reduced production in factories that could not acquire supplies and empty shelves in grocery stores.

The most intelligently designed infrastructure will not protect against future floods if we forget these past events. It is essential to integrate historical flood data into modern planning to avoid repeating past mistakes.

The role of natural floodplains and public infrastructure

One of the core concepts in modern flood management is giving rivers and waterways space to flood naturally. It is crucial to shift away from merely managing floods to instead avoiding them altogether by preserving natural floodplains.

Natural hazards can never be fully mitigated by building dams, levees and walls. Allowing rivers to reclaim portions of their natural floodplains can prevent damage to human infrastructure and promote ecological balance.

Public spaces also play an important role in enhancing a community’s resilience to floods. Initiatives like the Netherlands’ Ruimte voor de Rivier (‘Room for the River’) design project, which ran from 2006 to 2015, have demonstrated how integrating flood management with public spaces can provide many benefits.

Flood parks, permeable infrastructure and submersible structures are examples of how urban planning can incorporate flood resilience. Such spaces not only reduce flood risk, but also offer esthetic and recreational value, fostering a closer connection between communities and their environment.

In the U.S., the Federal Emergency Management Agency’s (FEMA’s) High Water Mark (HWM) Initiative—part of the National Flood Insurance Program—encourages communities to host high-profile signage to increase local awareness of flood risk and motivate action toward mitigation. In Boulder, Colo., the Boulder Flood Mural serves a similar purpose, indicating the different flood levels the city may experience every two, five, 10, 25, 50 and 100 years, particularly highlighting its historic September 2013 flood.

Collaboration and citizen engagement

Effective flood management requires active collaboration between governments, experts and the public. Comprehensive flood risk maps are crucial for identifying zones where flood-proofing measures are needed and directing new development away from high-risk areas. Resistance driven by concerns over real estate values poses a significant challenge, however. In fact, it is not uncommon in Canada to see flood or wetland mapping withdrawn or modified because of public pressure.

Fostering collective, long-term thinking about climate change is essential to overcome this resistance. Engaging citizens in the process and educating them about the benefits of accurate flood risk maps can lead to more resilient communities.

A holistic approach

As climate change continues to exacerbate the frequency and severity of floods, it is imperative to adopt a holistic approach to flood management. Integrating natural floodplains, using public spaces, engaging communities and commemorating past events are key strategies in building flood-resilient urban environments.

By learning from history, embracing natural solutions and fostering collaboration, we can build a resilient future that not only mitigates flood risks, but also enhances the quality of life for urban residents.

Jonathan Heinz is an emergency management specialist for GHD, based in Calgary.