Water is fundamental to life - but access to it is diminishing. In the future, securing an adequate supply of safe, reliable water will become strategic determinant for communities, regions and nations worldwide – and it is imperative for our farmers to sustain production. We must be efficient in using the rainfall we get and manage it in an integrated way with our soil and vegetation resources.
We need to retain our rainfall within
Australia is the driest inhabited continent with highly variable rainfalls. Australia’s landscape used to be characterised by ‘in-soil’ reservoirs. Complex microbial ecologies maintained soft deep soils which allowed for infiltration and retention of rainfall into well-structured subsoils. These in-soil reservoirs then leached any salt to depth and slowly recharged and sustained what were typical reed covered billabongs, meandering waterways and fully functioning floodplains. As a result, most of Australia’s inland rivers did not discharge rainfalls to the sea, but recharged aquifers or created highly productive inland deltas and extensive wetlands and intermittent lakes.
Today, 1 million kilometres of Australia’s rivers and streams are mostly incised, wetlands are drained and the essential balance between functional vegetation and crop areas has been lost. Aquifers are being depleted with grave consequences for farming communities (read the sobering article Peak Water: What Happens When The Wells Go Dry?).
Australians are also some of the highest per capita consumers of water. We need to secure many times the actual water that is projected to be available under current practice. With rainfall patterns changing, how each drop received is conserved and used is critical. Overgrazing, overcropping and soil degradation have further reduced rainfall penetration. The structure of soil is imperative to maximise efficient infiltration and capture of water.
What happens to water when it falls on the landscape as rain has to be managed in such a way that every drop is utilised to the maximum advantage; whether in maximising its capacity to hydrate the soil; to replenish relevant aquifers or when saved through capture from rooftops, roads and storm water drains or recycled from waste; it all has to be properly managed. Water is only a renewable resource if the water cycle is functional - and to achieve this, healthy soils are essential.
To date, emphasis has generally been on the water levels in our major dams and rivers. This ‘end of pipe’ philosophy focuses on what is flowing into storage rather than focusing on better use and conservation of the rainfall where it lands, in the landscape – the ‘front of pipe’ - before it makes its way into our waterways.
Typically, 50% of our rainfall is wastefully and unnecessarily lost to evaporation - largely because it cannot infiltrate the soil.