The Campaign - Impact
What will be the impact of the Project?
See also Alliance submissions to ERMP
Vast Quantities of Seawater Required.
Straits Salts' proposal involves the extraction of huge quantities
of seawater via two or more massive intake pump stations. These
pumps would also remove vast numbers of weakly swimming prawn and
fish larvae and post larvae fish from the Gulf ecosystem and the
The proposal will involve the impoundment of enormous quantities
of toxic bitterns, the highly
concentrated by-product of solar salt product. This material could
then enter the Gulf ecosystem through seepage or wall failure, potentially
resulting in a major 'kill' event.
The excavated inland harbour and other infrastructure works may
expose significant areas of acid generating sulphides as well as
removing mangrove and algal mat habitat.
Introduction of marine pests.
The expected increase in marine international and domestic vessel
traffic poses a high risk for the introduction of marine pests.
Straits estimate 40-50 ships up to 100,000 tonnes will be loaded
annually at 3000 tonnes salt production and increasing to 120-150
ships at 10,000 tonnes salt production. Each ship loading requires
a number of barge loads from the production site which will necessitate
a large dredge to establish a barge channel from the new boat harbour.
From around the world and within Australia, there are many examples
of Invasive Marine Species (IMS) being introduced and or translocated
by a variety of vectors, including ballast water from international
commercial shipping, biofouling on a wide range of vessels especially
barges or dredges and natural vectors such as ocean current movements.
Northern Pacific Seastar, Pacific oyster, European Fan Worm to name
just a few. Specific threats to pearl oysters are the Asian Green
Mussel and the Black Stripe Mussel which have the ability to wipe
out the pearling industry if they take any hold due to the spectacular
growth rates and smothering tendencies of substrate including pearl
The establishment of an IMS in a new environment can threaten biodiversity
and aquatic health, as well as specific industries dependent on
The pearling and prawn industries depends on pristine water quality
conditions and the region between NW Cape and the WANT border (including
Exmouth Gulf) produce the most conducive environment for producing
the highest quality pearls in the world as well as world renowned
Large Panamax salt transport vessels and transfer/loading barges
introduce the main vector for IMS translocation into Exmouth Gulf
through ballast water and hull biofouling.
Shipping - the Industrialisation of Exmouth Gulf
The silty bottom of the eastern Gulf is likely to be mobilised
by repeated dredging operations smothering marine producer habitats.
The 300 metre long Panamax bulk carriers, barges and service vessels
are likely to increasingly disturb and disrupt the use of the area
by megafauna such as Humpback Whales, Dugongs and Sea-Turtles. The
international shipping may transport exotic marine pests from high-risk
regions such as the coast of China.
The significant dredging required for the boat harbour and barge
channel may also create changes in local drainage patterns, current
directions and water circulation.
300 meter Panamax ships are huge - check out the photo
of a Panamax bulker at Dampier port below. For a comparison the
minimum and maximum lengths of an AFL oval are 135 and 185 metres
respectively. For roundball afficionados, these ships are longer
than three soccer pitches end to end. Straits Salts' ERMP states
that there will be up to three of these anchored in the Gulf at
any one time - presumably this means up to four bulk carriers could
be at anchor or at sea in the Gulf at any one time. At anchor, each
ship will have swing circle two kilometers in diameter.
The Wikipedia website (http://en.wikipedia.org/wiki/Panamax)
gives a good summary of this class of shipping leviathans.
Panamaxs off Newcastle, NSW. Warp to the future - Exmouth Gulf under
Latest shipping news. MSC Napoli, a Panamax scale
container ship, founders in the sea off the Devon coast UK. See
here for details (new window).
There is NO reason
why this couldn't happen to a bulk carrier anchored in the Gulf,
at the mercy of a category five cyclone, with disastrous consequences
guaranteed from fuel oil spillages, as can be seen ...
......and for disaster afficionados - more shipping
The proposed building of the 70km long sea wall and modification
of landforms and creek flow as per Straits' ERMP will change the
nutrient regime in the area. The proposal is for redirection of
the natural run off through two creeks to either end side of the
70 km seawall which will decrease the nutrient content in the water
in the middle of the wall. The redirection of this natural run off
has been poorly considered in the ERMP.
Habitat modification will also occur for the inshore waters opposite
the seawall and the inland areas of the Exmouth Gulf behind the
seawall which are very important to fishing activities. The Straits
Project is likely to alter existing habitat formats through redirection
of important nutrients and the impact of bittern discharge or leakage.
The eastern side of Exmouth Gulf requires
flooding events which move a significant way inland and experience
evaporation and nutrients are then returned to the Gulf during the
next flooding event. The seawall proposal will greatly impact the
natural nutrient flow from this process and significantly alter
hydrology and salinity within the mangrove community thus altering
the drainage and sedimentation and reducing the flushing of mangroves.
It is expected the soil water table will rise causing water logging
of mangroves and possible death of mangroves situated above the
intertidal zone as has happened in Port Hedland.
Halt the Salt privately commissioned research (to be published shortly)
strongly indicates the great significance of uninterrupted nutrient
flows to the input and assimilation of nutrients to the Gulf is
of major concern to the marine Gulf environment. See right for a
graphic example of what constitutes 'uninterrupted nutrient flow'.
Then imagine how this image would appear if there was interposed
between the Yannarie delta and the Gulf, a five metre high continuous
seawall seventy to eighty kilometres in length!
That is, the research shows that it is highly likely that Straits
Salt's strategy of diverting sheet floodwaters away from more than
70km of coastline adjacent to their project footprint, to point
discharge sources to the north and south of their giant 410 square
kilometre footprint, will result
in an environmentally neutral outcome. To the contrary, environmental
disaster might well be an early result.
(20 Feb. 2006)
image available here