An ambitious Australian project intended to restore a watershed to its pre-agricultural functioning, while supporting modern agriculture, has attracted the attention of the United Nations.
The Mulloon Community Landscape Rehydration Project involves 20 landholders, 23,000 ha of land and about 40 kilometres of waterway in the ranges east of Canberra. It is using the ideas developed by Peter Andrews about pre-European water movement in the Australian landscape to reshape how water moves through the catchment.
The project has been selected as one of five models of sustainability supported by the United Nations Sustainable Development Solutions Network. The UN network was formed in 2012 to develop sustainability projects that cam scale from local to national level.
Peter Andrews’s ideas are controversial because they involve interference in watercourses that sometimes butt against legal restrictions. However, the validity of his ideas has been demonstrated at a number of sites, notably Mulloon Creek Natural Farms, a farm aggregation at the head of the Mulloon catchment.
The farms are owned by businessman-philanthropist Tony Coote, who has made the aggregation available for sustainable agriculture research and education through the not-for-profit Mulloon Institute.
One of the first projects undertaken on the farms was the reshaping of part of Mulloon Creek by Peter Andrews in 2007. From the beginning, the work has been monitored by Australian National University researchers.
Mr Andrews put in place several rock-and-reed “leaky weirs”, which raised the level of the creek with little impact on its flow. Mr Coote said that only 0.2 of one per cent of the creek’s flow fails to travel downstream as a result of the works.
The leaky weirs have visibly raised the level of the creek in its bed, but Mr Coote said the important thing is that lift in water level has also occurred under the creek’s floodplain - his paddocks.
He reports that the productivity of his grazing enterprise has lifted 60 per cent on the floodplain as a result of the natural irrigation provided by the raised water table.
As well as providing some drought-proofing, the impact of floods down the creek has been neutralised because the water spreads, rather than being contained in the creek channel.
Meanwhile, researchers have monitored rising levels of biodiversity, including more fish species than occur in an untouched chain of ponds nearby.
The Mulloon Community Landscape Rehydration Project will examine whether the positive results demonstrated on Mr Coote’s farms can be replicated across a whole catchment.
Some 90 structures will be built through the catchment’s watercourses to lift stream levels without sapping long-term flows, alogn with swales, mulch banks and strategic tree planting.
Ultimately, Mr Coote hopes the project will deliver enough proof-of-concept to rewrite current laws limiting in-stream works, and to be a model for the “healing and rehabilitation of all watersheds in NSW and Australia”.
The physical outcomes of the Mulloon Community Landscape Rehydration Project will be important, but Stephen Dovers thinks other aspects are just as important.
The Director of Australian National University’s Fenner School for Environment and Society says that an environmental project that involves 20 landholders across 23,000 hectares of land has a scale and a level of community buy-in that makes it of international significance.
The project will measure changes to hydrology and natural indicators, like changes in plant composition; but importantly for its wider relevance, it will also document changes in farm productivity.
“The financial production returns of this sort of work haven’t been terribly well documented,” Prof. Dovers said.
“The other aspect is how landholders, scientists and policy makers can collaborate at this sort of scale.”
“The unique part of this is that the Mulloon Institute advisory board is drawn not just from Australian National University, but the University of Woolongong, and we’ve got student groups doing training in the field. It’s a big field experiment.”
Prof. Dovers is chairman of the Mulloon Institute Science Advisory Council.
The broad hypothesis to be tested in the project is that attenuating stream flows will allow more water to be stored in the soil profile, to support farm productivity, lessen the impact of dry periods, and boost biodiversity.