When a category five hurricane devastated New Orleans in 2005, Dutch teams consulted with New Orleans about potentially reconstructing their canals to avoid flooding events, and to mitigate future disasters. The Dutch had advised the city to create very slightly sloped canal walls down to channels with flat bottoms and gentle grass verges on top, creating more space and land areas for water to naturally sit and saturate. While the plan was politely received, it was determined to be too radical and culturally different from the shallow familiar canals and shelved in favour of adding in new pumping stations.
The Dutch flooding teams also visited Vancouver and spoke at a gathering sponsored by the Dutch consulate. I have already written about the fact Vancouver is a sponge city, riddled with underground creeks and water.
One of the first issues that came up in private conversation with the Dutch team was the work done dredging the Fraser River near the former Olympic Skating Oval site. That, said the engineering team was a problem, in that in their experience, river bottom compromise would lead to eventual undershoring and severe flooding events.
How do the Dutch know? Over 50 percent of their coastline has deep banks of undeveloped, untarnished dunes hugging the coastline. Twenty-five percent of the country is below sea level.
In 1953 a horrendous flood resulting from a storm surge along the North sea killed 1,800 people. From that disaster the country developed a comprehensive management system of “polders”, which are reclaimed land parcels that would normally be below the sea. Instead of physical man made dikes protected and bolstered dunes double as water protection for communities and wonderful natural bird habitat.
In fact The Netherlands has an ambitious “Room for the River” plan where 39 areas have been designated to be wetlands. As written by Naomi O’Leary in Politico “It’s a modern reversal of the centuries-old practice of land reclamation by the famously low-lying country”. Experts are modelling out ways to compensate for a potential 84 centimeters of sea rise by 2100. (Vancouver’s sea rise is predicted to be one meter by 2100.)
The Dutch have famously used dikes, storm berms and pumping systems. While sand can be piled on shores and dikes made higher, water can be pumped out but the salt of ocean waters will severely compromise Dutch food growing and food security.
There is even a plan to use storm barriers to block off water access, but that would also compromise shipping to Rotterdam which historically has been the country’s main shipping port.
Much of the Netherlands is also sinking, something that happens to all river deltas as construction and human occupancy dries out land and compresses and lowers water levels below the ground. Cities like Amsterdam, Rotterdam, The Hague and Utrecht are all impacted as low lying delta cities.
The Netherlands have regional “water boards” that are operate independently from government so that they can plan long term. They have existed for over 700 years, which shows how seriously the Dutch take land conservation and water management. There are four scenarios imagined with sea rise that are summed up as “protect open” “protect closed” which refer to sea barriers, and “Advance” and “Retreat” referring to reclaiming land to build islands, and to abandoning land.
Here are two videos that describe the Dutch approach to water management. The first one features Ingwer de Boer describing the 2.3 Billion Euro “Room for the River Project” and how it works.
The second video is a TED video describing the unique engineering behind the Netherland’s delta works, and what the implications are for delta management in New Orleans and other delta areas, like Metro Vancouver.