The water network of Machong, a town at the center of the Pearl River Delta. From the government webite of Machong

On the Earth Observatory (EO) website of NASA I found an archive news comparing the satellite photo of 2003 with that of 1979, the year when the opening policy of China started, the pearl river delta being the testing field. The two photos prove the astonishing effect of urbanization on the morphology of landscape. Vegetation (in red) is vastly replaced by buildings and paved surfaces (in gray). The news addressed the climate change during this decade, but another change that can be felt by local residents is the elimination of the network in the cities.

Houses along the river. From biggeorge’s photostream

As a river delta region, the landscape southern Guangdong used to be characterized by dense interconnected network of water. Thousands of branches of the Pearl river extended inside the cities and villages. Houses were built along rivers; boats was one of the most common transport tools, while bridges were also seen everywhere. All children could swim because the water was clean. As the modernization proceeds, however, the network of water is gradually replaced by that of roads, plus some smelly moats.

One of the effect of this is the increased risk of flood disasters. The crosslinking between major rivers as well as the lakes being the nodes of the network play a vital role in absorbing extra flux in rainy seasons. We have painful lessons from the Yanzi River Delta where the same problem is more severe. After the notorious 1998 flood, worse floods happen every year like a promise. Similar trend is evidenced in Pearl River Delta these years.

I don’t know how to make a conclusion of this post. Things do not always end up with conclusions. The problems caused by changes now seem to be solved by, rather than undoing, more changes, which lead to more new problems.