HISTORICAL CHANNEL-FLOODPLAIN DYNAMICS ALONG THE RIVER-TRENT - IMPLICATIONS FOR RIVER REHABILITATION

The geomorphological history of the River Trent, UK, is documented fro m historical (documentary and cartographic) information to establish t he character of the river along a 60-km reach in the seventeenth and e ighteenth centuries, prior to intensive regulation. Using aerial photo graphy, 28 former channels, as well as a number of growth bends charac terized by scroll meandering, could be identified. However, many of th ese features date from the early medieval period and some reaches are shown to have had an extremely stable history, with the river experien cing little or no planform change since at least enclosure times. Alon g the 60-km reach examined, 21 per cent of the length could be classed as being stable over the 400-year period. Unstable reaches were assoc iated with tributary confluences of the Dove, Derwent and Soar. While 79 per cent of the reach showed some evidence of channel mobility and reworking of floodplain sediments, in most reaches lateral mobility wa s restricted to a narrow (<200 m) corridor. It is recommended that: (1 ) channel dynamics and natural vegetation successions should be restor ed in habitat 'islands' at tributary confluences; (2) the geomorpholog ically active reaches of the upper sector, together with adjacent floo dlands, should be protected; (3) along the lower sector, floodlands sh ould be expanded, and (4) throughout the river corridor, specific floo dplain features, such as backwaters and woodlands, should be maintaine d and enhanced, including works to restore connectivity with the main channel and between patches. Copyright (C) 1996 Elsevier Science Ltd.