The perennial environmental concern over dredging for ship channels has again erupted regarding a planned upgrade of the Townsville Harbour. And, as usual, the standard platoon of know-nothing suspects is at the fore of this latest effort to crimp prosperity in the name of a notional “threat” to the environment.
The inshore waters of the Great Barrier Reef lagoon have been a natural sediment trap for land runoff over the past 10,000-plus years, ever since the sea rose to near current levels at the end of the last glacial period. This is a windy coast and the inshore waters are characterised by high levels of natural turbidity from re-suspension of accumulated bottom sediments through wave action. The nearshore reefs are comprised of a specialised suite of silt-resistant corals adapted to these conditions.
These inshore reefs are a fringe environment for corals and are subject to repeated devastation from storms, floods and extremes of temperature, both hot and cold. Their condition fluctuates widely and most of the time they are in a state of recovery from their most recent disaster. Long term monitoring of the closest reefs to the Townsville ship channel display this pattern, with no indication of any correlation to previous dredging.
The high level of coastal sediments has required dredging at every port to provide channels of sufficient depth for ships to enter as frequent strong winds and storms slowly shift sediment back into the channels, thus re-dredging every few decades is needed to maintain them.
Shipping access is essential to the economy of the region for imports of fuel, manufactured goods and various materials as well as the export of primary produce which is the economic backbone of the region. Without dredging shipping would soon cease and, with no outlet for the mines and agriculture, the area would become an economic backwater littered with largely abandoned towns and suburbs. For those who may find it difficult to imagine this, a visit to Detroit is recommended to see what happens when the economic base of a wealthy city disappears.
Those opposing the dredging appear to eager to accept that result if it means the end of coal. As Greens candidate and dredging foe Wendy Tubman told the Townsville Bulletin, “You can’t have a massive expansion of the coal industry and protect the reef from climate change.”
A costly, well conducted environmental impact statement has been prepared for the proposed port expansion. Section 6, dealing with marine water quality, is available online. It comprises the most comprehensive scientific assessment of the likely effects of the planned dredging and finds no expectation for anything beyond low level temporary effects on the nearest reef areas. This is entirely consistent with the now considerable body of experience with previous dredging both in Townsville and at other ports in the region.
The concerns being expressed are not based on any sound evidence but are simply the same discredited hypothetical possibilities repeated for every proposed dredging — and repeatedly proven to be non-existent when the dredging was eventually done. The only noticeable effect of the previous dredging in the Townsville channel has been the creation of one of the better places for recreational fishing in the general area. The eventual decision on this one is another no-brainer.
Lengthy delays and expensive surveys every time a shipping channel needs re-dredging, as if it were something that has never been done before, has become a ludicrous and expensive eco-charade. It is also ultimately pointless as the option of abandoning the ports is not going to happen despite the most fervent demands of the eco-saviours. It is probably not just coincidence that their ranks seem to comprise few persons from the productive sector of society.
However, those who don’t work for a living, but only vote for one, are abundantly represented in the eco-cadres. How many of these the productive sector can continue to both support as well as pander to is going to be interesting to observe. Or alternatively, is this perhaps just a precursor to every farmer having to conduct an impact assessment before ploughing a field?
Walter Starck is one of Australia’s most experienced marine biologists, much of whose professional career has been devoted to the study of coral reef and fishery ecosystems