Learning to live with water

Access to water is one of the greatest assets of humanity. Aside from obviously being necessary for survival, modern economies were and are built on the cog ships, tall ships and supertankers that ply the oceans. Yet in recent times, there has been a shift in how humans perceive the waters around us.

Prior to the 19th century, the sea was respected and even feared. Dwellings typically were built away from the shore, while port cities were found not on the coast, but further inland, up rivers. Today, however, the sea has become a romantic and alluring place. Cities reach to the water's edge, and developers create fake islands or extensions because oceanfront property is desirable.

As New Yorkers have learned, these development patterns can leave cities exposed to Mother Nature's watery wrath.

By 2015, 18 of the world's 21 megacities -- encompassing a population of about 250 million people -- will be found on the coasts. In fact, with cities such as New York, Shanghai, Mumbai or Vancouver growing rapidly, some projections estimate that by 2030, half the global population will live in coastal zones. As climate change and the likelihood of extreme weather events have become hot topics in the last decade, experts are now looking at ways to reduce the risk to urban areas.

In the Netherlands, where two-thirds of the population lives below sea level, developers have come up with a number of creative solutions, including the construction of amphibious homes. These houses have fixed foundations, but rise up on their docks and float during a deluge, remaining buoyed by the floodwaters.

More ambitiously, for years engineers have advocated the construction of barriers along the world's coastal cities to protect inhabitants from storms. Such infrastructure already exists in England and the Netherlands, and in 2009, a Dutch firm offered to build a 1.5-kilometre barrier, nine metres high, to protect New York Harbor.

Many municipalities may balk at the price -- the New York City project was pegged at $6.5 billion -- but with the cost of the damage caused by Hurricane Sandy's four-metre storm surge estimated at $20 billion, plus $10 billion to $30 billion in lost business, ultimately they may prove a worthwhile investment.

Alternatively, many experts believe a more sustainable solution would be to re-establish natural barriers between cities and the sea, incorporating wetlands, marshes or barrier islands along the coast. A one-acre wetland can store about one million gallons of water, providing a protective sponge when hurricanes wash sea water up on shore. Last year, designers proposed to create 80 acres of new parks and freshwater wetlands along Manhattan Island to act as a buffer against flooding. Cities could also scale back construction along the existing water's edge, although considering the huge demand for waterfront property, that may prove easier said than done.

As Manitobans well know, seeking solutions to serious flooding is not a problem confined to the coast. Researchers believe inundations in southern Manitoba could similarly be mitigated, in part, by wetland preservation. Wetlands retain water and release it in a controlled fashion, reducing drainage during the spring. Moreover, without wetlands acting as a buffer, decomposing plants send phosphorus into the water system that is then washed downstream. These chemical elements end up in Lake Winnipeg and contribute to the algal blooms plaguing the lake. In fact, scientists at Ducks Unlimited have found four decades of wetlands loss in Manitoba has increased the amount of land draining into Lake Winnipeg by 4,518 square kilometres, and the quantity of phosphorus reaching the lake by 167 tonnes a year.

Less seriously, perhaps Winnipeg could use Dutch ingenuity as inspiration in designing a floating river walk, not unlike a very long floating dock, to replace the existing walkway at The Forks that is so often submerged for much of the spring and even summer.

Waterways are integral for the modern economy, and coasts and rivers provide leisure opportunities for residents and add beauty to the cityscape. Yet, citizens must not forget that choosing to build cities in a way that embraces their shores leaves them vulnerable to storms blowing in from the sea.

As New York's recent experience makes clear, it is in everyone's best interest to consider how to protect cities from future weather events now, instead of leaving those decisions for a rainy day.

Benjamin Gillies is a political economy graduate from the University of Manitoba, where he focused on urban development and energy policy. He works as a consultant in Winnipeg.

Republished from the Winnipeg Free Press print edition November 13, 2012 A7