Noise Modelling Reveals Impact of Proposed LNG Platform Chinese white dolphin and finless porpoise put in danger | WWF Hong Kong

Noise Modelling Reveals Impact of Proposed LNG Platform Chinese white dolphin and finless porpoise put in danger

Posted
07 September 2018


Noise generated from the percussive and vibratory piling from proposed construction of CLP’s proposed Liquefied Natural Gas (LNG) platform will have direct impact on Chinese white dolphin and finless porpoise in the area, affecting their numbers in Hong Kong. Noise from the project site can travel in a 4 kilometre radius, even with mitigation measures in place, according to results of a sound propagation modelling study conducted by Dr Matthew Pine from Ocean Acoustics Limited.

Dr Pine’s study shows that piling work could reduce the listening space of the Chinese white dolphin and finless porpoise by up to 80% when they are within 800-2000 metres of the work (depending on the season), hindering their communication, social interaction, foraging and navigation. The modelling tested how far the noise from each strike of piling will travel using acoustic propagation algorithms and incorporating environmental data, including bathymetry, sediment properties, water chemistry and the existing ambient sound levels.

The Environmental Impact Assessment (EIA) report submitted by CLP lacks any sort of underwater noise propagation modelling. WWF-Hong Kong urges the Director of the EPD and members of ACE to put the EIA on hold.  Samantha Lee, WWF-Hong Kong’s Assistant Director of Oceans Conservation, said, “The modelling can help us to quantify the impact of the underwater noise, assess the effectiveness of the mitigation method proposed and suggest the size of exclusion zone needed in order to protect the Chinese white dolphins and finless porpoise. 

“It’s a grave concern that CLP has skipped this important procedure in the EIA study, which is clearly flawed. Critical information, such as the number of strikes required to drive one pile and how much time is needed to complete one pile, are all missing. The actual impact from cumulative noise energy could be much larger than we expect,” said Samantha.

The survival of Hong Kong’s iconic dolphins doesn’t need to be threatened by underwater noise. WWF-Hong Kong findings show the use of noise reduction “air-bubble curtains” will not be effective. The zone of influence with noise over 160dB is extensive and overlaps with the proposed South Lantau Marine Park, especially during summer period (June-October). These high energy sounds could cause temporary or permanent change in the hearing of marine mammals. 

“We are deeply concerned that the proposal will destroy the area’s biodiversity and be in total conflict with the setting up of the marine park. WWF-Hong Kong considers it is imperative to now protect dolphin and finless porpoise populations to stabilize and recover in their core habitat. For those reasons the proposal and its flawed EIA should be deferred,” said Peter Cornthwaite, CEO of WWF-Hong Kong.