The sea is going to rise; that’s almost certain, though by how much and when are both unknown. And if the sea rises, we have options as to the actions we can take in coastal towns. We can build seawalls and levees. We can abandon developed land and buildings and surrender them to the new tidal reach. We can set our town afloat.
The floating option is being developed by the Dutch, who have established a nation based on compromises between water and land. Yes, they continue to work on strengthening and extending dikes and manmade offshore islands. But they understand that a higher sea level is going to intrude in some areas, causing at least occasional flooding. And so they are building arks.
There is a string of 37 houses located along the Maas River in Holland that were designed and built by Dura Vermeer. Such houses can rise 16 feet without problems and contain flexible pipes, electrical, and sewer lines.
The foundation of the sits on the river bottom. If you were to drill a hole through the basement floor, water would come in (so this is not recommended).
When the river floods, the house becomes buoyant. Unlike a boat or an ark, two broad steel posts driven deep into solid ground hold the house in place.
“In the other village we have lived, there was always the water,” said Mariana Smits, a floating homeowner in Maasbommel. “I was very scared. Two times, we have evacuated to leave our old house. This was very scary for us. And we got the opportunity to buy this house. It’s a safe place.”
We’ve got quite a large colony of houseboats nearby in Sausalito. They’re not prepared yet for substantial sea level rise, but float, they do. Here’s the view looking down the Issiquah houseboat dock.