EPA launches into new era of land-clearing surveillance

Researchers from EPA Victoria and Melbourne University have devised a method to quickly and cheaply detect land clearing from space, giving the regulator a crucial head start in the race to protect streams and rivers from sediment pollution.

The tool, developed by a team including Melbourne University Waterway Ecosystem Research Fellow Dr Kathryn Russell and EPA freshwater scientist Tim Coggan, analyses satellite images to detect changes in land cover.

It is designed to detect changes in areas as small as 800 square metres – the size of a large suburban block. Images are received around every two weeks, meaning changes can be rapidly identified.

That’s especially important in Victoria, where many of our soils are “dispersive”, meaning they easily break down into fine particles in water. When exposed by land-clearing, these soils are highly prone to erosion if not managed properly. And if the eroded soil is washed into a waterway, it quickly becomes cloudy, or turbid.

Dr Hannah Mikkonen, EPA Principal Contaminated Land and Landfill Scientist, says high turbidity can create many potential problems.

“When the water is cloudy, it reduces the amount of sunlight that can get through,” she said. “This limits plant growth and leads to lower oxygen levels and the potential loss of habitat. The fine particles can also clog fish gills, smother plants, fish eggs and insect larvae.

“Even when sediment does not reach waterways, erosion can lead to the destabilisation of slopes and infrastructure, block drains, and strip topsoil needed for plant growth.”

Dr Mikkonen said there could be long lag times between developers receiving a permit and starting work, so it wasn’t always clear when land-clearing would begin. The satellite imaging would help close that knowledge gap.

“The quicker we can detect land clearing, the quicker we can check that the developer is implementing the appropriate controls to minimise impacts to the environment,” she said.

“The best way to protect our rivers from sediment is to make sure management measures are in place before and during land development. About one in 10 complaints about construction projects relate to water impacts, so clearly there’s room for improvement. When it comes to managing erosion, prevention is key.”

For more information about managing erosion, go to EPA’s Civil construction, building and demolition guide(opens in a new window) or visit the International Erosion Control Association best practice guide(opens in a new window).

To report sediment or other pollution to EPA, call our 24-hour hotline on 1300 372 842 or go to our reporting pollution web page(opens in a new window).