Bushfire impact on water yields

January 22, 2008
Bushfire impact on water yields
Aerial photograph of spot fires. Image credit – CSIRO

While forest fires can often result in an initial increase in water runoff from catchments, it’s the forests and bush growing back that could cause future problems for water supplies by reducing stream flows.

In the summer of 2002-03, bushfires burnt through 700,000 ha of forests in northeast Victoria. This region supplies 38 per cent of the water that flows into the Murray-Darling River, the main source of water supply for much of Australia’s irrigated agriculture, the city of Adelaide and many towns along the river.

In a country where wildfires are prevalent and water supplies are at a premium, understanding the impact of wildfires on the water catchments is vital. A study by CSIRO Forest Biosciences has helped shed light on how impacts of fires might be more accurately estimated in future.

“Understanding the long-term impact of fires on water yield from major catchments is critical to understanding the long-term security of water supplies to cities, farms and the environment,” says Dr Richard Benyon of CSIRO Forest Biosciences.

“The study demonstrated a promising technique for catchment managers to more accurately predict changes in stream flow following wildfire, not only in northeast Victoria, but elsewhere in Australia.”

CSIRO remote sensing specialists analysed Landsat satellite images from before and after the 2003 fires to accurately map changes in the forest cover from which changes in water availability were predicted.

Initially, the loss of vegetation as a result of the fires meant the burnt areas used less water so there was more entering streams because it was not being used by the trees, however, this short-term effect does not last. As the forest grows back and the young trees consume more water, substantial reductions in water yield from the catchment can be expected over coming decades.

Victoria’s North East Catchment Management Authority Chief Executive John Riddiford says the research provides a real capacity to predict the impact of forest fire on water yield over large areas for the first time.

“With the potential impacts of climate change, including the lower rainfall and increased risk of wildfire, it is important for catchment authorities to understand these possible impacts and to plan accordingly,” he says.

Dr Benyon says long-term impacts of wildfires on water yield is dependent on the type and condition of the forest before fires, the intensity of fires and the subsequent type, density and vigour of forest recovery.

Source: CSIRO

Explore further: Increase in red spruce growth tied to the Clean Air Act

Related Stories

Increase in red spruce growth tied to the Clean Air Act

September 1, 2015

The Clean Air Act, implemented in 1990, has been heralded as an economic and environmental success story that has led to cuts in ground-level ozone by more than 25% since 1980, a reduction in mercury emissions by 45%, and ...

Preventing floods and erosion

August 19, 2015

California is on fire—again. About 130,000 acres have been scorched in more than 20 major fires actively burning in the state, according to the California Department of Forestry and Fire Protection. But the flames are not ...

Recommended for you

Climate ups odds of 'grey swan' superstorms

August 31, 2015

Climate change will boost the odds up to 14-fold for extremely rare, hard-to-predict tropical cyclones for parts of Australia, the United States and Dubai by 2100, researchers said Monday.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.