River restoration in developed economies
G.E. Petts, R. Sparks and I. Campbell
‘The geometrical precision of an aqueduct
signifies the engineer’s vision of water flow, a
bounded channel form that has become the
common conception of how even a natural river
should appear (Cosgrove, 1990).’
Tamed rivers were once a symbol of advanced civilizations. The ‘training’ of river channels for navigation and flood control, ‘reclamation’ of floodplains for productive farmland, ‘conservation’ of water by using large storage reservoirs to prevent ‘wasting’ run-off to the sea, the use of high dams to ‘harvest’ the energy from flowing water, and the largescale transfer of water to make deserts bloom, came to symbolize social advancement and technological prowess (Scarpino, 1985; Reisner, 1986; Cosgrove and Petts, 1990; White, 1995). In all long-settled regions of the world subject to large-scale administration, the modernist vision of development has involved megaprojects of land and water management designed to extract wealth from rural areas for dispersal through cities. The 1990s have witnessed a major change in social philosophy, with global recognition of the need for sustainable environmental management and the protection of biodiversity; in developed countries, attention has turned to environmental restoration. This chapter discusses the restoration of river corridors in developed economies by reference to experience in the UK, USA and Australia.
In the UK, the creation of the modern cultural landscape began quite suddenly with the onset of the Neolithic period about 6000 BP (Rackham, 1997). The natural vegetation cover is forest with only small areas of moorland and grassland (Rackham, 1997). Lime, hazel, oak and elm would dominate southern areas, with birch and pine in the north, and alder around pools and fens. Most of the uplands had been deforested by 4000 BP and floodplain woods were cleared by about 2500 BP. By the Roman period (AD 40–410) much of the lowlands had experienced a long history of cultivation. More than 5000 water-mills with weirs to control river levels are recorded in the Domesday Book of 1086. In 1665 an Act was passed ‘for making divers rivers navigable’ – most rivers were channelized by 1880. The long history of change in the UK (Table 23.1) contrasts with the more recent environmental changes in the USA (Table 23.2) and Australia (Table 23.3) that are largely confined to the past 200 years of European settlement. Australia’s population of 16 million is small in relation to the area of the continent, but the aridity of the country and the concentration of the population in the higher rainfall areas, along the east coast and southwest, has resulted in a disproportionately large impact on Australian rivers.
From the early 19th century, the ‘taming’ of rivers was led by the popular pioneering vision of the human struggle to tame nature, and entrepreneurs motivated by the desire for economic growth. In 1853, Charles Ellet wrote:
‘The banks of the Ohio and Mississippi, now
broken by the current and lined with fallen