In the US the term watershed is equivalent to the expression water catchment used in Australia and elsewhere. Watershed is also a term used metaphorically or figuratively to indicate a dividing line - a watershed issue - a line of division.
The word watershed came into use around the beginning of the 19th century. Then it represented the boundary between two river systems. It also referred to the surrounding hills and ridges and indicated the side of the hill or ridge where the rain fell and the water flowed. But in the US it has a wider meaning and refers to the wider river catchment, or river valley, that 'catches' the water drawing it towards the river.
Political editor from the Australian Newspaper, Dennis Shanahan(2006), put the issue quite differently when speaking about Australia's water crisis and water shortage.
'...at the heart of this crisis of water management is a complex web of conflicting and warring political and governmental interests, where states such as South Australia suffer at the mouth of the Murray while Queensland allows huge water harvesting for cotton at the head of the Darling system, and the Federal Government funds water initiatives without any power to force action.'
Water sources have become a political and ecological watershed.
Using the term watershed in its figurative sense, let's look at the watershed issue of logging the water catch-ments. The water or hydrological cycle is very clear, especially in the drawings of the cycle from primary school science classes. The rain is shown as falling onto the side of the hill which is treed or forested. The trees and land catch the water, channelling it to the ground water and eventually to the creeks, tributaries and flowing water.
A New Zealand report by Haikai Tane (2004) states that: 'Australia and New Zealand are caught in an intractable cultural dilemma.' The report declares that the continued industrialisation of water catchments for timber as well as surrounding development has 'led local communities in watershed catchments ... to believe that the long term degradation of watershed catchments is normal and natural. The degradation of watershed catchments in Australia and New Zealand will continue unabated so long as communities impose activities and infrastructure that destroys ecostructure.'
The issue is one of division and values, economic versus ecological, aesthetic versus industrial, spiritual versus profitability and resource use. Tane write 'that key cosmic roles have reversed, for industrial society sets goals like Gods, and Nature becomes its maid and servant.' This is so reminiscent of the issues raised in Carolyn Merchant's 1980 ground-breaking work, The Death of Nature as well as Val Plumwood's Feminism and the Mastery of Nature (1993).
Leading Australian water researcher Professor Peter Cullen makes the issue clear: 'Catchment land use is an important driver of river health, and river health seems commonly to be impaired when agricultural activities cover more than 30 per cent of a catchment area; although distance from the river and the health of the riparian vegetation can mediate these effects. The removal of native vegetation can markedly alter the hydrologic behaviour of a catchment.'
'As trees are removed, runoff commonly increases, as does the amount of water flowing below the root zone and entering groundwater, and this may lead to consequent waterlogging and salinity, although there may be a lag of 20 to 50 years before these impacts are obvious.'
'River and wetland health is assisted if the connections between a river channel and its floodplain and wetlands are maintained, allowing recovery from stress events. Deeper pools and wetlands may be important refuges that allow organisms to survive extreme high or low flow events. This is called resilience: the capacity to recover. The riparian zone has a profound impact on stream ecosystem processes.'
Re-making wetlands and deep pools, developing programs aimed at ecological resilience, regeneration of riparian zones, removal of noxious weed species and revitalization of native plant species - it seems all these things can help on the eco-front, but on the socio-political front, Haikai Tane declares we need a deeper understanding and a regeneration and revitalization of awareness, values and actions.
'What post-industrial society urgently needs is a new paradigm for understanding watershed catchments based on the integrity and connectivity of catchment habitats and landscape ecosystems.'
References
Cullen P, 2007, The Ecological Challenge of Water Reform, ATSE Focus, 145, http://www.atse.org.au/index.php?sectionid=1007
Merchant C, 1980, The Death of Nature: Women, Ecology, and the Scientific Revolution, San Francisco, Haper and Row.
Plumwood V, 1993, Feminism and the Mastery of Nature, New York: Routledge.
Shanahan D, 2006, A Watershed on the Water Front, The Australian, Sept 26, 2006.
Tane H, 2004, Catchment Habitats and Landscape Ecosystems, Watershed Systems Ltd,Center for Catchment Ecology, http://watershed.net.nz/fpeandwm.htm
