River‐Channel Changes in England and Wales

Abstract

ABSTRACT An investigation of the literature on river‐channel changes in the UK reveals that the rate and extent of changes is much higher than was previously thought. In order to assess how widespread these changes are, and whether the rates and types of changes are typical, an historical survey has been carried out of the streams which drain the upland areas of England and Wales. This survey involved the comparison of Ordnance Survey 1:10,560 maps from approximately 1870 and 1950, and revealed that almost 35% of the rivers draining upland England have shown some pattern instability during this period. Great variety exists both in the types of channel planform changes and their extent: several rivers possess short isolated reaches of change separated by stable sections. This suggests the operation of thresholds of channel stability, and further research aims to identify these in terms of specific factors and conditions.