East Trinity – a returning and flourishing wetland is real reason not to spend over $400M on Capital Dredge
Peter Senior’s opinion piece (2 May, 2015) is very misleading. He states controversially that ‘the (East Trinity) area is highly degraded costing $500,000 for annual maintenance that has failed to fix the degradation.” He then goes on to argue that it would be a suitable place to dump dredge spoil from Trinity Inlet. Both points require a serious rebuttal.
Since the State Government purchase of the East Trinity property in 2000, and gazettal in 2006 as a Reserve for Environmental Purposes, the degraded and acidified environment has been, or is being, returned to a functioning tidal wetland system. Mangroves are recolonising with all of the implications for fish nurseries. There has been a proliferation of marine and terrestrial biota. Bird species alone have now reached more than 150 with jabiru and great-billed heron regular visitors.
Soil and water quality indicators have returned to levels consistent with natural, undisturbed systems. The success of the East Trinity acid sulfate program has been praised as a world first for a remediation project of this scale. That is why ABC’s Catalyst chose to do a program about it .http://www.abc.net.au/catalyst/stories/3221659.htm
Daily, controlled, tidal exchange, with added hydrated lime, will continue at East Trinity in the areas surrounding the Firewood Creek catchment. It is clear that any placement of dredge spoil in areas where the treatment is happening would inhibit or compromise the progress of the remediation. The placement of spoil material over the active remediation areas and their surrounds has the potential to significantly reduce surface and subsurface water flow which is crucial to acid sulfate soil (ASS) remediation under a tidal regime.
The placement of spoil would also compromise the widely recognised progress that has been achieved over the last 14 years in returning the site to a functioning tidal wetland habitat, clearly evident by the return of diverse and widespread mangrove habitat. (See adjoining then and now images). Active remediation has finished in the Hills Creek area, so that only passive remediation (without added lime) continues under a managed daily tidal regime.
ASS management along Hills and Firewood Creeks has resulted in the re-colonisation of mangroves although Magazine and George Creeks still require significant management efforts. Dredge spoil dumping would severely jeopardise this progress and would be detrimental to the possible future use of the site for fish habitat, eco-tourism, eco-education, research, Indigenous culture and nature based recreational facilities.
Since I became involved in the East Trinity debate more than 20 years ago, the majority of the population has consistently supported maintenance and protection of this magnificent green backdrop to our city. It defies common sense after all that has happened through these long, tough years to talk about using the site as a dumping ground for potentially toxic spoils with all of the attendant problems that might arise. Far from being a highly degraded site, the East Trinity site is a largely rehabilitated wetlands; further, as a Wetland Reserve it is being actively managed with a sophisticated water treatment process in place, Indigenous field staff active on site and a bright future as a protected area.
Thankfully, the State Government response to the Cairns Shipping Development Environmental Impact Statement (EIS) recognises the environmental and economic cost of dredge spoil dumping on this precious wetland and put a stop to it. The community must remain vigilant that the idea never surfaces again.
Peter Hitchcock AM
Consultant, Environment and Heritage
(Formerly Executive Director of WTMA, Member, World Commission on Protected Areas (WCPA) and member of Cairns Wetlands Park Committee)