WATER?always running down?across landscapes, through the eons and the ages, carving creases and wrinkles on the face of ancient continents. Life-giving, the essential resource for survival of Earth as a Living Planet?yet running down, degrading, under our selfish human stewardship ... In Australia, the driest vegetated continent, water is the most precious resource and how we manage it will determine the future prospects of the nation. RUNNING DOWN Water in a Changing Land gives a deep-time perspective to the story of the co-evolution of water resources, the environment and the animal and plant life it supports. It sets the scene for an understanding of the geological history of the continent, the past history and the modern status of its water systems, and the impact of European land use and activities on our two main life-support systems?water and soil. Sustainable management of our land and water resources can only be achieved if the ancient history of the continent is taken into account and the limitations set by this unique land itself are recognised, RUNNING DOWN is thus a companion volume to Listen Our Land is Crying; complementing it and expanding the big picture, explaining modern water-related problems against the prehistoric background. Exploration of the subject confirms that Australia is unique and that this ancient land has some of the oldest landscapes preserved anywhere on Earth as well as some of the most ancient drainage patterns. What comprises a river system in Australia is usually far removed from the accepted concept of a river in Europe. Many of our rivers occupy ancient valleys, incised by their ancestors multi-millions of years ago or are superimposed on palaeoriver systems. Flat, poorly drained landscapes and an inwardly-draining centre of the continent have led to a vast accumulation of sediments and of salt, and much of Australia comprises floodplains spread by ancestral rivers, The floodplains of our modern rivers are as essentially part of the river systems as are the channels and banks, While the ancient history through geological time provides a background necessary for the understanding of the modern hydrology of the continent, the modern information gleaned from writings of explorers and pioneers on the status of rivers and landscapes at the time of European settlement establishes a benchmark against which changes due to human activities can he measured. It is surprising to find just how much change has in fact occurred, Changes resulting from our land-use practices and use of water resources have turned many rivers into drains. (A river is a living ecosystem, a drain is simply a conduit which carries water through a landscape.) Deep incision of stream beds; loss of chains of ponds or swamps in headwaters; loss of reedbeds; siltation and widening of channels; degradation of reaches downstream of dams and weirs; salination of riverwater; pollution with agricultural chemicals, sewage, industrial waste; increased nutrients promoting algal blooms; over-exploitation for irrigation?an endless list of changes result from human activities. Many rivers, including the Darling, are slowly dying. Groundwaters have been wantonly exploited without regard for the future, and in many cases it is fossil water which is being exploited. Unless the past history of the continent and the evolution of its hydrology are understood and taken into account there is no hope of curing today?s problems and achieving a situation which approaches sustainability of Australia?s precious water resources.
Publication Date: 1/1/2000