How a hybrid solution could help you mitigate the next big flood

By Michelle Letourneau M.Sc. and Shelley Hazen, M.A., B. Envs.

2021 brought historic flooding to the province of British Columbia, causing highway washouts, landslides, and power outages that killed six people and 1.3 million animals, and evacuated more than 15,000 residents. The frequency of this kind of catastrophic flooding should be a wakeup call as our climate continues to change.

Given the magnitude and range of potential impacts associated with climate trends, such as rising temperatures, changes in precipitation patterns, and the increased frequency and severity of extreme weather events like flooding, it is essential for us to create, protect, and restore natural features that offer ecosystem advantages while also mitigating the effects of climate change.

Experience has taught us that it’s better to look at solutions that are nature-based and resilient – that is, something that can withstand and bounce back from the next flood. Historically, solutions for flooding have been largely composed of “grey” infrastructure, or things that are built by people, such as dams, levees, treatment plants, floodwalls, and reservoirs. Thankfully, we are seeing a shift in the interest and application of “green” solutions – those that support the natural environment as well as provide improved watershed management. Solutions like green roofs, rain gardens, wetlands, and animal habitats. In the past barriers to implementing these kinds of green solutions have included everything from hesitation to use unfamiliar designs, to ignorance of the environmental impacts, to the simple fact that resilience was not a priority. Things are changing. But that doesn’t mean we can do without those traditional “grey” types of infrastructure. Green vs. grey does not have to be all black and white. In most cases the best resolution is to seek out a “hybrid” model – a shared balance between green and grey solutions.

So how do we do this? First and foremost, we must make efforts to change our current way of thinking. Instead of building floodwalls (a grey solution), we change our focus to protection, resiliency, restoration, and improved land management. Get started by asking questions like:

“What does the system currently entail?”

“What are some natural solutions we could use?”

In most cases the best resolution is to seek out a “hybrid” model – a shared balance between green and grey solutions – to help prevent flooding.

Rather than engineering changes to the natural system, we can determine how to work with nature and within our current communities to find better solutions.

For example, we can use or mimic features that are already in our communities to serve the dual purpose of holding water – features like swim ponds, sports fields, green spaces, and even farms. Using dual-purpose areas can have immense flood protection benefits, and they can also strengthen our environment by providing habitat for animals or green spaces for people to use. Building a simple floodwall achieves neither.  The best hybrid solutions may include some engineered elements as support, but nature has valuable tools that we need to work with in tandem.

Take the Olympic Village in the city of Vancouver: Its design implements a hybrid solution within Vancouver’s Rain City Strategy. As one of the rainiest cities in Canada, it’s essential that Vancouver use rainwater as a valuable resource and design the city to be rain sensitive. The Olympic Village features green rainwater infrastructure, including green roofs, permeable pavers, and bioswales that capture and clean rainwater and provide greenspace for communities and wildlife. Within the Village is Hinge Park, a constructed wetland that collects and manages 2/3 of the rainwater that runs off the roadways, plazas, and other public lands in Olympic Village. It uses native plants and healthy bacteria to filter water, cleaning out pollutants before is the water returns to False Creek. The wetland also provides important habitat for wildlife including a family of beavers. In hybrid solutions like these, green rainwater infrastructure practices enhance the city’s resilience to climate change not only by reducing flooding, but also by cooling the air and improving the adaptability of natural and urban environments.

How can you get started on a hybrid solution to manage flood risk? It’s important to complete a risk assessment early to identify solutions for your project. Consult an expert who can identify risk points and key climate threats in order to find nature-based solutions that are right for your project and your community.

To learn more about finding a nature-based solution for your project, contact Shelley Hazen at 647-638-4042 or Michelle Letourneau at 226-979-6056.


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