Cleveland Bay – current condition and cumulative impacts

Cleveland Bay
View over Railway Estate and the mouth of Ross River to the southern half of Cleveland Bay

The 2016 Additional Environmental Impact Statement (AEIS), which accompanied the proposal to expand the Port, and which added to and amended the 2013 Environmental Impact Statement (EIS), continues to claim that the current condition of Cleveland Bay is its natural state, exacerbated by natural disasters. This is in defiance of the facts. The literature demonstrates the ecological health of the Bay declines as a result of port activities, such as sea dumping of dredge spoil, as well as urbanisation and agricultural development in the catchment. The past and on-going impacts add up over time and have largely established the generally poor condition of the Bay in recent times.

The AEIS acknowledges that the bay is under stress, but refuses to recognise the critical role that still, clear days in the dry season play in ensuring that reefs and seagrass beds get sufficient light to recover. While cyclones and floods may cause larger impacts than dredging, turbidity due to the port activities maintains a major stress and threatens recovery.

The project outlined in the 2016 AEIS varied considerably from that outlined in the 2013 EIS (see The Port’s changing plans). The 2016 plan increases the amount of new (capital) dredging from 9.9 million to 11.4 million cubic metres.

These are big numbers – what do they look like? If one cubic metre boxes (like the one in the picture below) were stacked 3 high, Queensland could have its own 3m high wall around the full length of its land borders with NSW and the NT, from the capital dredge spoil alone! Alternatively, a one metre high wall would stretch from Townsville to Perth, back again and down to Brisbane. We are talking about HUGE amounts of seabed being removed!

What one cubic metre looks like    Photo: RMIT

For those who see things other ways. The amount of capital dredge spoil dug up from the bed of Cleveland Bay in the expansion would fill over seven (7.402) MCGs.

The MCG. Capital dredge spoil from the expansion would fill almost 7.5 of these! And annual maintenance dredge spoil would fill one in 3 years.

As a result of the capital dredging, annual maintenance dredging will increase from an already massive 400,000 cubic metres to 450,000 cubic metres.

Not surprisingly, maintenance dredge spoil does not stay where it is dumped (there’s no wall out there!). The sediment is picked up by waves and currents and transported far and wide. The CEO of the Great Barrier Reef Marine Park Authority told a 2014 Senate inquiry into the management of the Great Barrier Reef Marine Park that dredge spoil can move tens of kilometres. Scientists from James Cook University found that coal particles from east coast ports have reached as far as the outer reef. (See TropWATER report 13/23, Unrecognised Pollutant Risks to the Great Barrier Reef.)

The AEIS states that “the potential impacts of the revised design on marine ecosystems is considered to be conservative, recognising the … current poor condition and low resilience of coastal ecosystems in Cleveland Bay.” Most of the time, the cumulative impacts that have led to this poor condition largely relate to re-suspended sediment. Against established theory, the AEIS sees “cumulative impacts” as acting concurrently. The idea that turbidity from accumulated on-going port activities, and the impacts of re-suspension of historic and recent dredge spoil could accumulate over time to inhibit the recovery of seagrass and corals, escapes the attention of the authors of the AEIS.