What is a healthy river?
The concept of ‘river health’ means different things to different people.
The Murray-Darling Basin Commission’s Sustainable Rivers Audit describes it thus:
‘The idea of ‘river health’ requires us to think of a river as an ecological system, not merely a channel that conveys water from the uplands to the sea. The ‘ecosystem’ includes the flora and fauna and their habitats, linkages between the river and its catchment, the dynamics of water flow and the transport and transformation of nutrients…
A system is ‘healthy’ when its character, biodiversity and functions are sustained over time.
It demonstrates good health by being resilient in the face of environmental changes, including changes in climate, resource exploitation or other impacts of human activity. It implies a long-term balance whereby the integrity of the natural system is preserved while meeting human needs.
An ‘unhealthy’ system is one where such a balance does not exist.
It may be changed from its healthy state by losing species, or gaining new ones, it may be affected by salinisation or other environmental changes, or its resources may be intensively exploited….
Rivers transport, store, decompose and reconstitute the resources on which plant and animal communities depend. They are intimately linked to the surrounding landscape, and their ties with the floodplain are especially close. Just as wetlands and woodlands depend on the river for water, and as a corridor for dispersal of plants and animals, the channel depends on the floodplain as a refuge for biodiversity. Rivers and their floodplains are ecologically inseparable.
For human communities, rivers are a source of water for drinking and other household needs. They underwrite food production by the irrigation and pastoral industries, and they supply water for all forms of industry. They are used to transport waste, including domestic, agricultural and industrial effluents. They also provide for recreational activities, destinations for tourists and form a ‘common stream’ through the lives of families, towns and the histories of entire regions. An unhealthy river is one whose capacity to supply these resources and services is prejudiced’. (5)
References
(5) Sustainable Rivers Audit Murray-Darling Basin Rivers: Ecosystem Health Check, 2004-07. MDBC, June 2008, p2
