Guangzhou’s watery future

Yesterday at Observation Society, I was describing the Waterways of the Illawarra project to Anthony, Trevor and Hanting. At home, the seepage from the escarpment is a major part of the “character” of the region. It’s what creates the more than 50 creeks which make their way through the landscape into the sea.

It wasn’t something I had considered before I arrived, but a major part of the “character” of Guangzhou and the Guangdong region is the Pearl River Delta. In the delta, waterways flow in a crisscrossing matrix wherever you find yourself. Maps of the delta are beautiful and confounding – they don’t look like “normal” rivers which have a clear directionality:

pearl river delta
This map also shows the massive urban development in the Pearl River Delta over the last 30 years.

So – one thing that’s been haunting me recently is the future rise of sea levels. In the Illawarra, it seems clear that sea level rises will immediately affect the areas surrounding creeks, since these are the lowest parts of the landscape. Like in the big floods of 1998 (when the extra water came from the sky), houses with creeks running through their yards will have to think about how to protect themselves from serious land erosion and property damage.

Here’s a map I saw of Brisbane a few years ago, where the future sea level rise totally transforms the city’s useable spaces:

brisbane sea level rise
This is the first image I saw which showed future projections of the impact of sea level rises on low-lying cities, and I imagine we’ll be seeing these maps with ever more frequency now.

So what about Guangzhou?

Anthony, Trevor and Hanting didn’t know what the future prospects of the city will be. So I googled it.

Uh oh. Of all the cities in the entire world, Guangzhou is listed at number one. The most likely to be caused massive damage due to sea level rises:

In terms of the overall cost of damage, the cities at the greatest risk are: 1) Guangzhou, 2) Miami, 3) New York, 4) New Orleans, 5) Mumbai, 6) Nagoya, 7) Tampa, 8) Boston, 9) Shenzen, and 10) Osaka. The top four cities alone account for 43% of the forecast total global losses.

OK. So, what can be done about this?

In a rudimentary search, I couldn’t find much specific about Guangzhou’s plan for the future of sea level rises, but hopefully something will turn up. Meantime, here’s some research from 13 years ago: a paper called “Coastal Inundation due to Sea Level Rise in the Pearl River Delta, China” in a journal called Natural Hazards, by geographers ZHENGUO HUANG, YONGQIANG ZONG, and WEIQIANG ZHANG, from 2003. The authors mention 193 flooding events in the last 40 years (that’s about 5 per year!) and make some calculations based on the idea of a 30cm rise by 2030. Their conclusion:

The potential rise in sea level during the 21st century will pose a severe threat to the communities in the deltaic area. In order for the current and future investments and communities to be protected from potential threat of marine inundation, preventive policies need to be formulated and implemented as soon as possible.

And here’s something from 2005, where plans were mooted to upgrade the Pearl River Delta’s flood defences (no mention of climate change though in that article).

Here’s a more recent article which describes the threat to GZ from Climate Change, but without any mention of what measures could be taken to mitigate it.

This article seems to tackle the heart of the matter, and it’s more recent (2013): “A Review of Assessment and Adaptation Strategy to Climate Change Impacts on the Coastal Areas in South China“. The strategies discussed include:

  • improving the monitoring and early warning systems;
  • fortifying coastal protection engineering;
  • working on ecological restoration to buffer the effects of climate change on biodiversity;
  • and strengthening salt tide prevention to ensure the water resource security.

This last factor was one I hadn’t considered. With rising sea levels, salty water will start to infiltrate areas where fresh water had been drawn for drinking.

This jaunty piece discusses the threat to Guangzhou in connection with China’s apparent turnabout on Climate Change policy.

Even though these articles present some practical ideas, they still seems to be operating at the level of generalised recommendations.

Surely work is already underway? Surely?

It seems to me that the options for adapting to the future for GZ are the following:

  • build defenses against flood events (sea walls? dykes? will these work in the future??);
  • smarten up evacuation plans (how do you evacuate a city with more than 15 million people?);
  • begin radically re-designing the city with higher water levels in mind (what, like lift it up on stilts? what other ideas are there?);
  • start relocating the city to higher ground based on future sea level projections (abandon current Guangzhou and move it inland??);
  • Stop burning coal and oil.

Similar ideas (and some nice maps) are generated in this project which was presented in the 2011 Shenzhen and Hong Kong Bi-City Biennale of Architecture and Urbanism.

What have I not considered here?

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