Australia is the driest continent on earth, yet farming is at the core of Australian life. The question of how is this possible in such a dry environment is fair.
The city sider rarely thinks about the source of water, or that is finite. On the other hand, how to conserve water is top of mind of the farmer, and people living in rural areas, every day. For most rural people the only way to secure water supply is trying to collect each and every single drop of rain water. This is called rainwater harvesting, and it is the essence of rural Australian homes. For many of us this may come as a surprise. Or it may seem like an unnecessarily cumbersome exercise to get water. The reality is, rainwater harvesting is the third largest source of water in Australia, after surface water (dams) and groundwater. Rainwater harvesting is supplying 109 billion litres of water, or 63 percent, of residential water outside urban areas, to our parched country.
The primary and most efficient component of water supply management for rural and regional Australia is, therefore, rainwater harvesting. Rainwater falls on roofs of houses, sheds and other farm buildings. This means that the water can be collected locally and where it is needed. The quality of rainwater is typically superior most other sources of water, such as dams, bores and local waterways. This is good news for the farmer as well as the rural dwellers, because rainwater can meet local water demand for domestic use. Also, rainwater harvesting in rural areas is used across a range of applications such as stock, spraying and fire water storage.
Water security in rural areas is pivotal to rural life. To ensure that water is available when needed, roof catchment is used, together with correct tank storage (multiple large tanks are frequently used). Some people living in the rural areas of Australia, particularly those with large machinery sheds, use multiple tanks with 260,000 or even as high as 300,000 litres of rain water storage.
How does rainwater harvesting work?
The use of rainwater harvesting is not a novel invention but rather a well-established practice used in rural areas. Farmers have used this method for many generations and have developed a deep understanding and appreciation of how it works. In addition to securing water, rainwater harvesting is cost effective. The harvesting system includes the interacting elements of rain, roof and collection, tank, pump and rainwater use, and has some useful features:
- Rainheads or leaf diverters have proven to be highly effective at maintaining water quality throughout the system, reducing organic material in charged pipes, reducing sludge and assisting pumps to operate correctly.
- Using efficient water use appliances (such as front-loading clothes washers, low flow showers and low flush toilets) within the house will reduce the capital and operating costs of the system.
- Correctly installed rainwater harvesting systems develop a natural treatment train that addresses many of the potential contamination issues that may be associated with a roof catchment. As such, the risk of becoming ill from rainwater harvested water is low. Two million Australians rely entirely on rainwater and there is no evidence of widespread negative health impacts.
- In very dry conditions a normal soil catchment will soak up water rather than allow it to runoff. In contrast, a roof is an impervious surface and will generate runoff from even small rain events in a drought, right when you most need it.
How do farmers use water?
Many farmers apply several approaches to water management, where rainwater is one important part. This was revealed through research conducted by the Independent Water Council regarding how Australians use independent water . The term ‘independent water’ relates to all water provided to households that are separate, or independent, of government and utility services. This includes rainwater tanks, recycled water, water from waterways, bottled water and bore water for homes in both urban and rural areas.
An example of how farmers apply a multitude of water management approaches is Sandy Stump of Burren Junction. He uses bore water, rainwater and creek water as water supplies for different uses. His domestic water use is supplied by a combination of bore water and rainwater, his cattle drink bore water, the garden is supplied from a dam storage off the creek and Sandy uses rainwater for chemical spraying and domestic top-ups. In this example, more than 4 million litres of water is used annually and Sandy has 700,000 litres of rainwater tank storages.
What is the future of rainwater harvesting?
Rainwater harvesting is not limited to rural life. A considerable growth in rainwater harvesting can be seen in the urban fringe. This interesting fact emerged through consultation with rainwater harvesting suppliers carried out by the Independent Water Council. The urban fringe, or the semi-rural development, is typically within half an hour’s drive of towns in regional areas in Australia. The reason for this development is generally because housing approved without mains water supply will be required by the local council to have rainwater harvesting along with septic tanks or water treatment systems for water supply and waste water management. There is a significant cost effective aspect in this arrangement as rainwater harvesting is a more cost effective option rather than attempting to provide mains water and sewerage services in semi-rural areas.
The cost efficiency of adopting this approach is in fact so significant, according to some research, that it should be investigated to reduce the demand for water in urban areas as well. As an example, if this approach was rolled out the system-wide savings from a rainwater harvesting system on every house would save South East Queensland 160 billion litres of mains water by 2050. To apply rainwater harvesting in rural area is an important argument for rural areas as some urban areas are seeking to buy rural river water to meet future demand. Therefore, the prediction is that rainwater harvesting will be a major water policy issue in Australia in the 21st century.