New York is still reeling from Hurricane Sandy, one of the worst storms the city has ever encountered. Days later, Venice lay submerged in water after torrential rains led to one of the worst floods in its long history. Unfortunately, these are not isolated events: the number of storms and cases of extreme flooding is reported to have increased more than fourfold worldwide in the past four decades, with more than 100 “intense disasters” recorded each year.
Regardless of one’s belief of the root causes of this rise, the reality is that the world’s coastal cities have to face up to the realities of the decades ahead, which is likely to be characterised by increased volatility and uncertainty in global weather patterns, with more frequent, and often more intense, storms and flooding as part of the mix (others, meanwhile, will deal with more intense, and frequent, drought – another challenge altogether).
The good news though is city leaders are not unaware of the risks ahead. Around the world, many forward-thinking municipalities have taken steps to prepare for the problems faced. Following are a few of the approaches that various cities have taken, or are busy planning:
- Six years of intensive study on London’s flood challenges led to the creation of the Thames Estuary Project in 2002. The project incorporates a long-term flood management plan and administration of the Thames Barrier, the world’s second largest movable flood barrier. The mayor’s office has also launched a project titled Drain London, which is designed to deal with the more potent threat of flooding from surface water. According to the London.gov.uk website, climate change is leading to more intense storms, raising peak rainfall rates by up to 40% for the city. This project hopes to establish a Surface Water Management plan that will contain a Preliminary Flood Risk Assessment and a Flood Risk Management Plan for all local boroughs.
- In Boston, in the UK’s Lincolnshire region, sensors are being used to detect changes below the ground in temperature, moisture and movement to help detect instability issues in flood defences. This is part of the European Commission-funded UrbanFlood project which uses sensors within flood embankments to support an online early warning system, real time emergency management and routine asset management.
- City officials and urban planners would do well to take lessons from the Dutch when it comes to effective flood prevention techniques. The low-lying region has the majority of its population living below sea-level, including cities such as Amsterdam, Rotterdam and The Hague. But the Delta Works system, an extensive network of dams, levees, and surge barriers, is model engineering for the rest of the world coastal cities.
- One close rendition of the Dutch innovation is the Mose construction project, started in 2003, and designed to eliminate flooding in Venice. The project involves the construction of a series of huge, submerged gates that upon high tide or storm warning would rise out of the water and block it from entering the lagoon and flooding the city.
But while the above projects enjoy the backing and security of the developed world, it is the megacities in Asia and Africa that are at greater risk of severe consequences from extreme flooding. Nigeria’s monsoon season has been one of its worst. The country’s National Emergency Management Agency noted that 363 people died over three months of flooding across the West African nation and another 2.1 million others were displaced. Ibadan, one of the worst hit cities is taking matters into their own hands. The local government is launching campaigns to deal with floods. Efforts include erection of structures in flood plains and obstruction of natural paths of rain water, which are the lead factors of flooding.
Elsewhere, a report from the Asian Development Bank aptly points out that it is the unplanned yet rapidly expanding cities in Asia that face the highest risk as storms and disasters grow in numbers. In fact, 13 of the top 20 cities identified as most vulnerable to climate change extremes in another article, are Asian. Cities such as Mumbai, Jakarta, and Shanghai have received funding and got certain projects underway to address flood problems. Unfortunately, though, relatively few get finalised, in part due to a lack of involvement from local governments. Local citizens better stock up on their sandbags.