HZMB – engineering masterpiece or ecological risk?

The world’s longest sea bridge between Hong Kong and mainland China is now open, but what is its impact on marine life?

A section of HZMB transitioning from bridge to tunnel

On 23rd October 2018 Chinese President Xi Jinping opened the Hong Kong – Zhuhai – Macau Bridge (HZMB) a 55km sea crossing that has become the longest road link on the Planet. It took 9 years, 400,000 tonnes of steel and around £15.3 billion to build the bridge/tunnel system that connects the independent territories of Hong Kong and Macau to the Chinese city of Zhuhai. It crosses the Pearl river delta which is an important shipping area for the local economy and so a 6.7km section of the link is in a seafloor tunnel that keep the shipping lanes open above. For this 2 artificial islands had to be created to allow the road to be diverted downward. As well as this the entire structure was designed to withstand earthquakes and typhoons which are common in the region. There is no doubt that the HZMB project is an impressive example of human ingenuity and engineering, but is it also an example of human caused environmental impacts?

Why was it built?

The primary reason for the construction of HZMB is China’s plan to create a Greater Bay Area connecting Hong Kong to Macau and 9 Chinese cities including Zhuhai. It is believed that increasing the ease at which people and valuable goods can be transported across the area will boost the economy and create new jobs. Whereas it would previously take 4 hours to travel between Hong Kong and Zhuhai by boat, the drive now takes as little as 30 minutes. Over 68 million people live in this proposed area, however only around 50,000 people have been given initial permits to be able to drive on the link. This is likely to increase and bus services are running across, but some economists believe the bridge may never recoup the costs it took to build it.

Construction impacts

The Pearl river delta is a region high in biodiversity and is important for many species of marine life. Construction of such a huge structure has inevitably impacted on some of these animals in a negative way. The most significant impact is on the population of Chinese white dolphins whose population in the area is one of only a handful in China. As early as 2009 when construction began the Hong Kong branch of WWF has been warning about the impacts the bridge could have on these endangered creatures. They are now reporting that the number of dolphins in Hong Kong waters has dropped from 148 to just 47 over the last 10 years. The dolphins like most other cetaceans are very vulnerable to underwater noise pollution which damages their hearing and disrupts vital behaviours. Samantha Lee of the WWF Hong Kong has said “I am worried that the number will never rise again”.

A Chinese white dolphin in Pearl river delta

Other species highlighted as being threatened by HZMB include Finless porpoises, Horseshoe crabs, Greasy-back shrimp and several species of sea grass and corals. An Environmental Impact Assessment was carried out by HZMB officials but the report is unnecessarily complicated, hard to read and offers little useful information. The construction workers did put up silt curtains to try and minimize the disturbance in the water column but this did nothing to reduce noise levels. The Chinese government also opened up new marine parks to protect dolphins but there was little to no evidence that these areas ever contained any dolphins in the first place. As a result they are likely to have no real effect.

It is also not just wildlife that has been effected, officials say 18 people have died during construction. However conflicting reports indicate that total is higher and that hundreds of others were injured. As a result the local media has nicknamed the project ‘the bridge of death’.

Potential future impacts

There are several aspects of HZMB that will also become a problem in the future as well as other issues that scientists haven’t even yet considered. Firstly the traffic will cause increased levels of pollution including CO2, light and noise all of which can negatively affect the areas ecology.  Secondly the decline of keystone species such as Chinese white dolphins as well as plants such as seagrass will create knock on effects in the food chain upsetting the delicate ecosystem of the Pearl river delta. Finally, although the bridge is designed to withstand natural disasters, if it were to collapse due to some unforeseen circumstance the damage to the area would be severe.

It is not just the HZMB that will have negative impacts going into the future. It is just the first step in China’s plan to develop the Greater Bay Area. Liu Xiaodong a major designer of HZMB told Chinese media that there will be 5 crossings including HZMB every 20km by 2035. This would be an unprecedented level of development and there is no way of predicting how much damage the construction would cause. Although it would be a good guess that Chinese white dolphins and other species would be completely eliminated from the area.

To sum up

The HZMB is undoubtedly an impressive engineering accomplishment and will remain as an iconic sight in the Pearl river delta for years to come. However it is also clear it has impacted the marine environment in a negative way. Nicknamed ‘the bridge of death’ due to the workers that have died during construction, the project has also been deadly to Chinese white dolphins and other marine wildlife in the area. It is perhaps the most recent symbol of how human ambition is encroaching on the natural world and making permanent ecological changes. It is also likely that more impacts will be discovered in the future.





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