Tasmania, fires and water catchment issues

via Dr Alison Bleaney
THE article below is from the ABC, about lessons learnt from the Victorian fires and water catchment issues.
So, how does this article relate to the Tasmanian catchment issues for ‘burns’ after clear felling, napalm firing, prior to re-planting plantations?

Are the issues not disturbingly similar?

Is this included in the risk assesment of a plantation coupe when the Forest Practices Plan – abiding by the Forest Practices Code – is produced if a ‘burn’ is to be ‘used’?

Who assesses this risk and how are other water users advised of the risks to the water quality and quantity that they use as years pass and the weather patterns change?
Are these risks being openly discussed with downstream farmers who produce our necessary food?

Is this not a matter for DPIW, DEnv, DHHS, FPA, and EPA, and which will be the lead agency?

Are farmers, community groups and consumers of drinking water involved in these dicussions re catchment management or will FPA just enforce the FPC and turn a blind eye to these issues?

And will the Premier then stand bye and continue to watch this happening?

Where is the holistic approach to management of water and catchments in Tasmania, and why do we not even have a plan let alone have one in action?
Dr Alison Bleaney 20-3-09

The Article:
Bushfire risk to water quality ‘could last years’

By Anna Salleh for ABC Science Online

Posted Tue Mar 17, 2009 2:38pm AEDT

Related Story: Authorities monitor waterways in wake of fires Water catchments affected by Australia’s most deadly bushfire disaster could be at risk from pollution for several years, experts say.

Forest hydrologist Patrick Lane of the University of Melbourne says the evidence comes from recent studies into the impact of earlier fires on catchments.

Forested areas usually have very high water quality because vegetation intercepts rain and reduces run-off and soil erosion, says Dr Lane, who is also an author of a new Land and Water Australia report into the impacts of fire on water catchments.

He says the water that emerges from such areas normally percolates through the soil and is slowly released into water storage areas.

But he says that after a fire, the lack of vegetation to protect the soil can lead to massive erosion, and even “debris flows” that form instant gullies.

“You get this blast of high intensity rainfall that gouges out large gullies,” Dr Lane says.

“They’ll dump a lot of sediment and nutrients and rocks and all sorts of stuff into streams.”

He says a debris flow was responsible for the only death – that of a firefighter – in the 2003 Victorian fires.

Sediment and algal blooms

Dr Lane says sediment in run-off causes turbidity in water supplies and nutrients in the sediment later lead to algal blooms in lakes and dams.

He says severely burnt areas are especially vulnerable to erosion triggered by rainfall.

“Areas are the most vulnerable in the first few months after a fire because there’s very little regrowth,” Dr Lane says.

“One, two, three, four years is the danger period. Normally you would expect the first year to be the worst but we have had some instances where a year after the fire, with quite good vegetation recovery, we had the worst erosion events.”

Dr Lane says immediately after the Black Saturday fires earlier this year, Melbourne water authorities transferred water from burnt catchments into unaffected reservoirs before rain fell.

“In this case Melbourne has probably got off fairly lightly, although there is still some potential,” he says.

But he says some of the regional areas badly affected by the fire, including Kilmore and Marysville, remain at the mercy of rain that may trigger pollution of water supplies.

“Their water supply would be in some jeopardy,” Dr Lane says.

He says it is hard to predict the exact impact because it will depend on the site and the amount and intensity of the rainfall.

Dr Lane and other experts are advising water authorities on how best to protect catchments in the future by considering storage dams to catch sediment, filtration plants or alternative water sources.

Water yield affected

Dr Lane says a further problem is the impact of bushfires on catchment yield, especially in mountain ash forests.

He says research shows water supplies can increase in the first five years after a fire in such catchments, because there is less water being pumped into the atmosphere by trees.

But this extra water will be carrying more sediment and can even lead to floods if rainfall is too intense, Dr Lane says.

And in the long term, yield can fall as much as 25 per cent as a growing forest soaks up more water than a mature forest.

Dr Lane says one option to reduce the impact on yield could be to thin vegetation as it is growing, but there is a lack of evidence on what the long-term effects of this might be.

Some concern has been expressed about the impact of fire retardants on water quality but Dr Lane says the studies he has been involved in did not study that impact.

And,

Integrated solutions needed for water, climate and food crises

In a new report, the Institute for Agriculture and Trade Policy (IATP) argues the convergence of multiple crises — climate, food and water — requires a global shift from the industrial model of agriculture to more sustainable practices. Integrated Solutions to the Water, Agriculture and Climate Crises (PDF) traces the role of industrial agriculture in contributing to greenhouse gas emissions, water use and pollution, and global hunger. The paper outlines the effects industrial agriculture has had on driving irrigated agriculture, massive water infrastructure projects and water withdrawals. “We can no longer afford to tackle these crises separately,” said IATP’s Shiney Varghese. “We must take a comprehensive approach that supports sustainable practices in agriculture that are good for people and the planet, protect our water resources and provide enough food for everyone.” In addition to pointing out key opportunities for change in the coming year, the report offers a series of recommendations to governments: an international rights-based approach that ensures water availability for ecosystems and people; support for agro-ecological practices including investments in the climate change-mitigating potential of agriculture; harmonization of policy approaches to water, agriculture and climate; recognition of women’s involvement in farming, food production and water management; and inclusion of small-scale farmers in reforming policy. These recommendations are consistent with findings of the recently published UN International Assessment of Agriculture (IAASTD), to which both IATP and Pesticide Action Network North America contributed as lead authors.