Thermal Enhancement

Thermal enhancement is the beneficial advantage gained from lower water temperatures which result from water being drawn from the lower levels of impoundments. Colder temperatures provide special benefits of oxygen rich environments generating healthy populations of sub aquatic macro invertebrates. Vigorous growth in cold water tail waters below dams and impoundments are regarded world wide as highly valuable assets providing clean, clear oxygen rich water. Rivers are regenerated, reinvigorated and desilted by weirs. Low level discharges increase water velocities recharging the water with air and nutrients. Turbulent environments with lower temperature enhancements provide large areas of habitat where substrates are scoured free and loose providing interstices for sub aquatic insect life. Large populations of native birds and animals are attracted to these special environments. Platypus populations thrive in the cold water and with staggering numbers of them present in this altered river. Eighty seven pairs of platypus were logged in a fifteen kilometre stretch of the Goulburn between Eildon and Thornton. Platypus and native water rat being furred animals can control the lower ranges of temperatures. Subsequently the platypus thrive in tailwaters like the Goulburn.

European Carp, the most virulent pest of our waterways, pose the single most dangerous threat to the native fish stocks of our rivers and streams. Carp avoid cold temperatures and are driven into the lower stretches of the tailwaters because they seek warmer water temperatures where their eggs and young are incubated in incredible numbers.

In warm water environments carp overwhelm the native fish population by their sheer weight of numbers. In the colder tailwaters the carp are eliminated by high, cold summer flows that supply large volumes of water for summer irrigation of the dairy farms and fruit growing areas of the lower flood plains of our major rivers. Where carp thrive in low flow, high temperature situations they utilise their barbels to locate food items, muddying the stream bottom in the process. Using their mouths to agitate the mud and weed they siphon the macro invertebrates, stirring up clouds of mud and silt that eliminate sunlight, stifling the growth of weeds that support and sustain native fish. Soon all evidence of the natural habitat is destroyed and the carp have permanently altered the natural habitat of native fish.

Only in the tailwaters where the water remains clear, cool and unaffected by carp are there the remaining sanctuaries of natural aquatic vegetation and populations of macro invertebrates. Repopulation and regeneration would quickly occur downstream of these pristine trout environments if carp control methods began to take effect. Currently there is no effective carp control method or policy action. Native fish populations can never effectively recover until this is achieved. Carp have become the most successful warm water species in Australia, dominating the waterways and the natural population.

The key to the restoration of our native fish populations is to solve the problem of noxious European Carp in the warm water sections of our rivers. Only then will any progress be made towards the restoration of our native fish stocks. Environmental flows replicating spring floods that trigger the breeding cycles of many of our native species only serve to spread carp throughout the system which was once the breeding ground of the native fishes. The Barmah forest is a case in point. Once a haven for native fish it is now a massive breeding factory for European Carp, the warm shallow waters infested and expelling huge numbers of Carp into all areas of the Murray Darling system. Recent studies have shown Carp travelling six hundred kilometres from the Barmah forest breeding grounds.

None of this has any relationship to the temperature enhanced Tailwaters. The only areas where carp have not advanced in large numbers are the cooler parts of the tailwaters. Evidence the sidewaters and lagoons connected to the Goulburn. In the lagoons the water is polluted and turbid as massive schools of Carp destroy the habitat. The Carp have retreated to these shallow warm water havens. The main river is cold and clear with high flows of rich oxygenated water and largely devoid of carp.

Carp have been in the waterways for over thirty years polluting, infesting, degrading and destroying the habitat of our native fish. Fisheries departments in all states have engaged in hand wringing excuse making, but have failed to produce any action that successfully combats the problem. To hear that a fisheries biologist from N.S.W suggests that cold water from impoundments is a form of pollution beggars belief. To also suggest that carp are a cold water species in Australia tells us that the author is entirely ignorant and is in fact seriously deficient in deductive logic.

The truth is probably that the person is a product of their own environment where logic, empirical reasoning and accurate scientific process has been lost. These people inhabit a dark nether world created by a feedback loop of self justification. Fisheries departments in N.S.W and Victoria have developed a form of competitive zealotry where each tries to behave as better eco-terrorists than the other.

This is only a diversion from the knowledge of their failure to recognise and respond to the greatest imminent danger to the waterways of Australia and the single cause of the demise of native fish and native fish habitat.

Thermal enhancement on the other hand has provided an enormous tourism industry. Attracted by the pristine waters of the Victorian tailwater fisheries, vast numbers of recreational anglers seek out the pleasure provided by the salmonid fishery that has existed for nearly 150 years in Victoria.

The recreational angling economy generates 1.037 billion, much of it in regional Victoria. In north east Victoria $188 million circulates in the valleys around Lake Eildon. All of this comes as the state's single most valuable renewable asset. Fisheries such as these are the icons of North America and Europe. Similar fisheries exist in the southern hemisphere in New Zealand, Tasmania, Chile, Argentina and South Africa to name but a few. These highly prized national assets that generate vast wealth for their economies are considered to be the jewel in the crown of fisheries departments around the world. What a sad indictment that Victorian and NSW fisheries departments have become so captive to eco-terrorists that they have become irrelevant to the tourism industry, recreational anglers, regional economies and politicians who represent these constituencies.

It is my view that the proponents of this terminology and their managers should be made accountable for these destructive proposals, before they hide behind outrageous blame shifting by inventing nonsense terms like the emotive phrase 'Thermal Pollution'.

Of greater amazement to me is the poor deluded fisheries staff who, when recruited, had to demonstrate their fanatical zeal that precluded any serious scientific credentials. In order to meet the condition that they form a self replicating system incapable of thinking outside the feedback loop or else employment would be denied.

The alliance between fisheries, Parks Victoria and NRE staff means this closed feedback loop is self fulfilling and reinforced until a rational view is precluded.

In my opinion the environmental radicals that propose such vandalism should be made to account for the situation that has been allowed to decline into such farce. The politicians should be asking their department heads account for the lack of leadership and direction that has resulted in money being spent on such absurd areas of investigation when they have failed to address the critical dangers that currently exist.

The term thermal pollution has been used to describe high temperature waste water from nuclear power stations in Europe and North America. It refers to the raised temperatures from cooling towers. Raised temperatures create the types of problems such as blue green algae outbreaks, carp infestations and the like. Is it erroneous to describe lower temperatures as thermal pollution, as it is in fact the reverse. Thermal enhancement describes the beneficial effects of lowered temperatures and the subsequent improvements in aquatic environments, water quality and wildlife. The benefits of thermal enhancement are manifold and the notion that this should be changed for no workable benefit is absurd.

The natural habitat of native fish is below the tailwaters. Until the native fish lobby can produce the sort of money required to remove, restructure and compensate all the regional economies that rely on stored irrigation water, tourism, flood mitigation and control and all the benefits of water control and storage, then they need to recognise that their primary goal should be to concentrate on the possible. That is, restoration of the native fish habitats that are currently available but degraded by the problems of erosion, carp infestations, land use and management problems associated with tree clearing etc.

If the sorts of proposals we have heard recently are to properly costed and analysed with how cost benefit outcomes form part of the economy, and are assessed on their merits, then they must stand or fall on the logical outcomes. I would recommend that they should all read a small book called 'The Price of Preservation' (Chisolm and Moran) and then take a cold shower and have a good lie down.

~ Geoff Hall email: geoff@theflyshop.com.au