A natural storm-water system at Nanaimo’s Buttertubs Marsh is worth millions, a new study has found.
Buttertubs Marsh, a 40-hectare wetland that’s storing water and controlling floods, is providing a system the City of Nanaimo would have to pay millions to replicate, according to a pilot study that’s helping to change the way communities see natural infrastructure.
Nanaimo was chosen in 2016 as one of five Canadian communities to participate in the Municipal Natural Capital Initiative pilot study, organized by the David Suzuki Foundation, Town of Gibsons and other partners. The idea was to calculate the financial value of natural infrastructure like wetlands and the costs that can be saved by protecting and maintaining nature.
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For anyone looking at a wetland or watercourse, the value is clear but it’s also subjective, said city environmental planner Rob Lawrance, who notes the study put the marsh in the context of a physical utility asset and a language city financial planners speak.
The study hasn’t been released yet, but Lawrance told the News Bulletin it shows even in areas of the marsh without any control structures or weirs, water is still being retained and that as climate change progresses and storm events become more severe, the value of what the marsh does doubles. The natural system is able to handle increased pressure and has resiliency, he said, adding it has more value than he thought.
A hydrological model considered what it would cost to build an engineered system matching what Buttertubs does and found the replacement cost would be anywhere from $4.7 million to $8.3 million.
“Doing that just kind of underscores the point that the city does not have to pay that kind of money to have that kind of service provided to the community,” Lawrance said. “That was the main point of the exercise and the pilot study is to prove there’s real financial value that wetlands like this provide the community.”
The Town of Gibsons has already created a natural asset management strategy, and it’s that work that’s being replicated across the country.
Emanuel Machado, chief administrative officer and strategic advisor for the study, said the benefits of valuing natural assets is “tremendous.” Natural areas are resilient to climate change, he said, adding creeks can flex and compress as needed much more than a pipe with defined capacity. There’s also no up-front or replacement costs for natural systems, no depreciation and natural assets can last into perpetuity.
Gibsons has a watershed, for example, with ponds, creeks and a forest, that treats a lot of the community’s storm water, but a development prompted the need to upgrade those services.
The town priced out an engineered option, which would cost $4.5 million, and then looked at building upon the natural system and found by expanding some of the ponds and planting more trees, it could get the same service for $300,000, according to Machado.
It’s a good example of the importance of understanding what services nature provides in the community and the value of those services, he said.
Lawrance believes the information from the pilot will help when the city looks at how to improve or enhance the value of the marsh with further restoration or building upon the habitat. There are things that degrade the environment, like invasive species, and there are also opportunities to enhance the tree canopy or wetland around riparian areas.
“Maybe those are costs we should be looking at to kind of factor in to help maintain and enhance the value of places like this and perhaps this is something that gets blended into storm water utility at some point in the future,” Lawrance said.
He doesn’t believe the city has the full picture for whether it’s possible to put a dollar value on natural capital in the same way as engineered assets, but said it’s a tool for having a discussion with financial staff.
“Before, they wouldn’t even let me in the room,” he said with a laugh. “It’s just not conventionally considered as part of financing or accounting practice but there are other communities that are starting to look at this now.”
The city plans to build on the study with a further assessment of community wetlands. The pilot study is also expected to be publicly available once complete.