Water is an integral part of the ecosystem. It is a natural resource as well as a social and economic good. Freshwater resources form an intrinsic part of the earth's hydrological cycle and are an indispensable part of all ecosystems. Aquatic ecosystems provide many of the natural ecological functions that underpin much of our social and economic well being. The condition of a river system is a direct reflection of land use activities within the catchment and has a major influence on downstream estuarine and coastal environments. Safeguarding freshwater ecosystems is therefore essential to the protection of a range of ecological processes and economic prosperity which, in turn, are essential to the welfare and well being of future generations.
Water is essential for life. There are no substitutes for water. Water is not distributed equally across the globe. Only 2.5% of the world's water is fresh, and two-thirds of that is locked up in ice caps and glaciers. Of the remaining amount, some 20% is in areas too remote for human access and a further 60% comes at the wrong time and place – in monsoons and floods – and is not captured for use by people. Only 0.08% of the total water on the planet is accessible for human consumption [UNEP 2000:4]. Freshwater is a finite and scarce resource and in many parts of the world is coming under increasing pressure as a result of degradation of resources and growth in population. Worldwide, freshwater consumption rose sixfold between 1900 and 1995 – more than twice the rate of population growth [UNEP 2000:1]. At present, approximately one-third of the world's people live in countries with moderate to high water stress, and more than 5 million people die every year as a result of poor water quality [Töpfer in UNEP 2000:1-2].
Freshwater ecosystems provide economic and environmental services crucial to all life and well being in Australia, both now and in the future. Water, delivered at appropriate times and of suitable quality and quantity, is vital to the ecological health of aquatic, riparian, and terrestrial ecosystems. It is also vital to our towns and cities, and is an essential, non-renewable economic resource that underpins much of Australia's economic development.
Assessing the condition of our aquatic ecosystems is vital to maintaining them. Accurate and timely assessments of extent and condition allow water resource managers and the community to better conserve and protect this vital resource.
