ABSTRACTSedimentary processes and recent sediments are described from the lower course of the Sachs River, Banks Island and from adjacent sandflats. The river is characterised by a short period, annual spring flood which deposits a hierarchy of superimposed bedforms in the high-stage river channel. In the early part of the melt season ephemeral stream action also occurs on the sandflats adjacent to the river. The fluvial deposits of the ephemeral streams and the channel are subject to aeolian modification during the subsequent arid summer months such that interbedded fluvio-aeolian sediments accumulate.The presence of permafrost restricts the depth of aeolian reworking so that ripples and climbing adhesion structures are the typical aeolian bedforms whilst laterally persistent, planar deflation surfaces are ubiquitous in sections through the sandflats.These observations have been integrated to produce a local model of fluvio-aeolian sedimentation which is characterised by channel fills and sediments deposited as aeolian sandsheets which are truncated by deflation surfaces.