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River Derwent Catchment Pollution

Dr Rosalie Woodruff MP

Dr Rosalie Woodruff MP  -  Thursday, 1 August 2019

Tags: Derwent River, Algal Blooms

Dr WOODRUFF (Franklin) - Mr Deputy Speaker, I rise tonight to draw attention to severe pollution that is being discharged into the pristine headwater streams of the River Derwent catchment.

This pollution is being spewed into the Derwent and Florentine rivers from two large salmon hatcheries that have been hidden away in the Tasmanian wilderness. Today, Environment Tasmania has released some documentary film footage which shows the difference between the upstream and downstream of these industrial farms, and I have seen the footage and it is very stark. There is beautiful clear water that is prized for trout fishing upstream, and a slimy, stinking, green mess downstream.

Mr Deputy Speaker, clearly the visual imagery is not enough to have any weight, so Environment Tasmania, in conjunction with Dr Christine Coughanowr who, until recently, was the CEO of the Derwent Estuary Program. She is an experienced water quality scientist. Dr Christine Coughanowr undertook some monitoring of water quality in the two rivers on 24 March 2019 at sites upstream and downstream of the hatchery and smolt production facilities at Wayatinah and Florentine. She took samples from outfalls at the two facilities and at the point at which those outfalls entered the river. She tested for dissolved nutrients including ammonium plus ammonia nitrogen, nitrate plus nitrite oxygen, and dissolved reactive phosphorous. She also looked for samples of coliform E-coli bacteria.

The results that she found were shocking. It indicates very high nutrient levels in both the outfalls and the downstream rivers, ranging from five to more than 128 times the upstream levels of the nutrients and bacteria that I have mentioned. She found significant levels of fouling on the rocks and riverbed downstream.

The results for Wayatinah Hatchery showed excellent water quality in the Derwent River directly above the hatchery and showed that nutrient levels below the hatchery ranged from 18 to more than 40 times the upstream levels for dissolved phosphorous and nitrogen.

The results for the Florentine Hatchery showed excellent water quality in the Florentine River above the hatchery and in the downstream river of the hatchery dissolved phosphorous and nitrogen levels were five to more than 128 times the upstream levels. Very concerningly, coliform and Ecoli bacteria levels in the outfall were very high and there was a very strong odour and a visible slick in the area.

With regard to the E-coli count in that area, she recorded a count of 886 parts MPN per 100mls, which is astoundingly high. It is not clear why that is the case, because that is normally associated with warm-blooded animals. Alert levels for E-coli in recreational waters are in the range of 126 to 260.

What this indicates is disturbing because these waterways flow into the hydro lakes of Wayatinah and Catagunya and there is serious concern about the risk of nuisance or toxic algal blooms in the drinking water supplies and recreational waters that flow from those lakes.

She notes high nutrient levels also have been documented recently by the monitoring of the Derwent Estuary Program, so that is clearly an ongoing problem.

This is a dirty secret about our waterways being polluted. That has been happening for over two decades. We have heard numbers of observational comments about this, but this is hard evidence that we now have that salmon hatcheries located at the headwaters of the Florentine and Derwent rivers are pouring thousands of tonnes of fish effluent into the rivers every year.

This is an environmental crime that really cannot be tolerated in this current era. It is up to the fish farm companies to have a zero-pollution plan for those factories immediately. The Environment Protection Authority clearly is incapable of undertaking the work that needs to be done to detect these outrageous levels and to do something about it. Where is the action from the EPA? Why has there been such silence on this matter?

It would not be surprising that the fish farm industry in Tasmania gets constant cover from this Government and from the Labor Party as well, all in the name of bigger is better and let us just expand without any question about the environmental consequences.

Not only is this causing environmental damage downstream, it is impacting the water quality of the Derwent River Estuary and Hobart's drinking water supply. How is it acceptable for this to continue? Clearly, it is not. How much is it costing TasWater to clean this pollution out of the water? We want the Environment minister to launch an immediate action into these two stinky hatcheries to prevent the pollution reaching the water and the river below, to investigate why it has gone on for so long and why is was not picked up and acted on by the EPA. We call on the Environment minister to do that work. I strongly recommend that people who are interested in looking at the video go to the Environment Tasmania website and see what has been allowed in the name of industry expansion in Tasmania.