Water Sources - What is Best Option for the Community and Environment

Water for our cities and towns comes from a wide variety of sources, including rivers, dams, aquifers, tanks, recycling and more recently desalination plants.  Each of these sources can provide clean water however the cost-effectiveness of each source is different. The cost per litre and the cost to the community differ significantly. These issues have been hotly debated and there is no real common ground on what is the best water source in terms of the overall best outcome for the community.

The traditional sources of water for towns and cities have been from the river systems, which had storage dams built on them to ensure water year around. Water from rivers and dams typically has been cheaper than other sources because of the lower cost in terms of infrastructure. The ability to grow this form of water supply has become far more restrictive due to more rigid environmental requirements, along with the fact the easier and more accessible dam sites have now been used. The costs of building dams have risen significantly in recent years resulting in higher cost per litre for this water.

Ground water is used extensively in areas that have large volumes of water in aquifers which are readily available. Cites such as Perth obtain a large amount of their domestic water from groundwater. The issue that must be remembered is aquifer water is effectively large storage dam that is underground and it is a finite resource. There is only so much water that can be extracted from the groundwater system without having a negative impact on it.

Recycling is an excellent way to make better use of water by using it more than once before it goes back into the river system or ocean. Recycling systems can be large scale or can go down to a small system on a residential house. Because we are using water that maybe carrying harmful bacteria or chemicals the system must be well designed and maintenance is critical to ensure all water going through the recycling equipment is up to standard. The other drawback is recycling can be expensive compared to other sources of water.

A number of desalination plants have been built over the last few years with most major capital cities in Australia now having a plant. The appeal of turning sea water, which is in abundance in coastal areas into drinking water, is attractive on the surface. The downside is that this is an energy intensive process and even though there maybe wind farms built to supply energy, they will contribute significantly to the overall energy demand of the nation.  More recently there has been some controversy about the cleanliness of water coming from desalination plants because of their proximity to sewage plants and ocean outfalls.

Rainwater tanks have been around for many years and have had periods of popularity and other times when government have not supported their use. The benefit of rain water tanks is that they catch water that would otherwise go into the storm water system and be lost to the household. Water caught is owned by the home and can be used in the garden or washing the car, even in periods of water restrictions. It is a totally renewable resource and can reduce the demand on public infrastructure from both a storm water and water supply perspective. Once the tank is installed the cost is minimal. Water tanks also provide water where mains water is not available.

There are a range of sources of water and the important issue for government and the community as a whole is to ensure that water is sourced from places that provide clean water reliably and minimise the impact on the environment. Bushmans assessment is that rainwater tanks are an essential part of the water supply system and should be used in conjunction with other sources such as dams, rivers and recycling.