Tin streaming and channel changes some preliminary observations from Dartmoor, England

Abstract

Summary The valley floor of the North Teign River on Dartmoor has been much modified by tin streaming activity, particularly during the nineteenth century. Field measurements of channel size at sample sites along the river were collected, to asses whether the tin streamed reaches had undergone observable channel changes. Close similarities in the relationships between channel size and drainage area for both natural and streamed sites suggest that no real channel changes are apparent at the present time, but differences in the relationships between channel size and total stream length for the natural and streamed sites show that the uppermost natural sites are considerably larger than the streamed sites at similar locations. Integration of the relationships between channel size and total stream length allows a comparison of estimated total network volumes for the streamed and natural sites, and the estimated volume for the streamed river is about 18 % smaller than that of the natural channel over the same reach. Channel change is believed to be related to changes in the size composition of sediment load in the stream, occasioned by the modified distribution of valley floor sediments brought about by the streaming activities.