THE CHARACTERISTICS OF OVERBANK DEPOSITS ASSOCIATED WITH A MAJOR FLOOD EVENT IN THE CATCHMENT OF THE RIVER OUSE, YORKSHIRE, UK (VOL 31, PG 53, 1997)

Overbank floodplain deposits associated with a major flood which occur red in 1995 were collected shortly after the event from transects at 1 4 locations within the catchment of the River Ouse, Yorkshire, UK. At most sites, the sediment deposited nearest to the channel consisted pr imarily of sand-sized material, and the absolute particle size composi tion of the mineral fraction of the deposits evidenced fining with inc reasing distance from the channel. Most of the sand-sized material was deposited within 20 to 40 m of the channel, although at some sites, s and was present at distances > 100 m from the channels. There was no o bvious downstream trend in the texture of the sediment deposited on th e floodplains. In most places, the overbank sediment was considerably coarser than the suspended sediment transported in the study rivers, a lthough at several sites, the d(50) of the latter was similar to that of overbank sediment deposited furthest from the channel. Although the C:N ratio of the organic fraction of the overbank sediment vias appro ximately constant across the width of the floodplain, the organic carb on and Cs-137 content of the deposited sediment increased with distanc e from the channel, and both properties were positively related to the magnitude of the < 63 mu m fraction. The texture of sediment in cores collected from two of the sites in 1994 was generally finer than that of the overbank deposits from the 1995 flood at the same locations, c onfirming the extreme nature of the 1995 flood event. (C) 1998 Elsevie r Science B.V. All rights reserved.