How Water Will Shape 21st Century Cities: Floating Cities, Wave Power, Coastal Protection


Last week, I covered a list of 20 items from The Futurist magazine’s Outlook 2010 (Nov-Dec 09 issue that will shape 21st c cities. I am adding other trends, ideas, and forecasts beyond their list. The first segment included The Great Urban Divide, Megacities, and Poly-Centric Regions. This article covers three ideas involving water and cities.

Dry Mouths, Wet Feet
Water makes a claim on people and cities that is both undeniable and paradoxical. Both people and the planet are largely composed of water, and while we need it to survive, we tend to either be dehydrated or flooded, sometimes simultaneously. In fact, 900 million people are without clean drinking water today with estimates that 1.8 billion will suffer by 2025 and 2/3rds of us will be under severe water stress. Water scarcity threatens not only the developing world but also parts of the United States in California and in the Colorado and Rio Grande river basins. Last year, Atlanta was on the brink of disaster. Furthermore, in the US, residential water costs have doubled in the past ten years, even as streets are flooding. It defies common sense.

A brilliant civil engineer told me that if you took the peak waterfall in an area, say 6-12 inches in a day which is an extraordinary amount of rain, and managed to hold it in place for a 24 hour period, you could solve the problems of urban flooding. Imagine a holding place on your property that could handle that run-off, use it for landscape or gray water, and you’ll save your city tremendous problems and lower your water bills as well.

For buildings, we are concerned with conservation and net zero water buildings (from the excellent Living Building Challenge). For cities the problem is more complex. Water is part of the infrastructure for both water in (to drink, irrigate, etc), and water out in the form of sanitary sewers and storm water systems, including many cities which unfortunately combine the two. Where ground water is depleted, subsidence affects many cities dramatically with sink holes increasingly common. Flooding and drought represent two other forms of disaster, witness the devastation of New Orleans and last month found Sydney in a red dust storm.

In short, we have over-engineered and misunderstood the magnitude and significance of water. With dryer, hotter climates and more people, sustainable water management needs to be built into our lives. To nourish 9 billion people, we will be modifying cities and learning new habits. Three exciting ideas may come into play: floating buildings, wave energy, and barriers to rising oceans.

1. Floating Structures
While floating houses have been common for decades if not longer, the thought of floating cities has intrigued designers with few successful installations. The Citadel floats on a polder which is part of the natural tidal plain of the Netherlands. New Orleans Arcology Habitat (NOAH), a mega-structure city, houses a population of 30,000 people on a pyramid-like form. The Lilypad by Vincent Callebaut is specifically planned for climate change disasters and would shelter 50,000 refugees. Smaller scale temporary architecture offers immediate inspiration with this elegant wooden hotel in Helsinki. Far-thinking visions of mid-century architects such as Bucky Fuller and Paolo Soleri are revived in these floating designs.

2. Wave Power
Wave farms could hug the coasts of major cities and supply energy for the massive populations. Numerous proposals consider how to harness tidal waves into electrical power; some are visually elegant. Last year, Portugal opened the first wave farm but it has already been closed. The Sea Snake is an invention of Scottish company Pelamis Wave Power. Biowave power is under consideration for the bay of San Francisco.

3. Protecting Coastal Cities
In coming decades, cities will grapple with rising oceans, threats of flooding, and increased storm events. Beyond emergency planning for storm events, cities must prepare for chronic high water. Change should occur gradually (not like those crazy disaster films) unless the city sits truly below sea level as is the case of New Orleans, which places a city at risk of levee failure. Options include raising the ground elevation, allowing submergence by waterproofing such as a pool or submarine, abandoning facilities, floating as in item 1, or barricading between sea and city. Most would prefer the last option because it represents maintaining normal life except at the perimeter. Consequently, an era of expensive, elaborate sea walls, dykes, levees, seagates, and so on is coming. The Rising Tide competition to save San Francisco from higher oceans illustrates the need for adaptation, invention, and resiliency. For Chicago, UrbanLab invented the eco-boulevard to grow water resources in a closed loop system.

Looking Ahead
Water represents so many possibilities and problems as we aim to use it, but not drowned in it, and leave it for next generations. We have seen water problems emerging since the Great Depression and they continue to spread and multiply. Amazing inventions have accomplished huge steps forward yet we have not solved anything entirely. Sustainable water management and net zero water exist today; therefore I placed them in my descriptions of the present conditions, not in the future. Yet most places have not adopted these practices and we remain at the mercy of poor, aging infrastructure.

As it’s said: the future is already here, it’s just unevenly distributed. (William Gibson)

Next I focus on two high tech areas that will shape 21st century cities: robotics and geo-engineering.