High magnitude flood deposits of the Kuiseb: an analysis of driftwood deposition on an ephemeral river. Fluvial deposits are not merely limited to inorganic sediments. The high energy events such as large floods can rip out living trees or carry away dead ones during flow. The impact on the ecosystem may be devastating, but the deposits left behind can be very informative and help to infer past, present or future flood flows. The desert environment of the Kuiseb river, Namibia, provides and incongruous setting for the study of high magnitude floods and deposition of large tree parts. However, driftwood left behind by this river is widespread and can be impressive in size of logs and number found in a small area. The aims of this study were to investigate whether there was a pattern in the distribution of the driftwood, to explain the distribution with reference to four hypotheses and to draw tentative conclusions as to the causes of the distribution. The hypotheses were that channel constrictions, channel widenings, bends or partial damming by linear dunes caused the deposition. The principal methods of investigating these aims involved surveying a 15k reach of river by a transect method and recording the location of logs exceeding an arbitrary 4cm diameter cut-off point. Location was recorded from surveying and pacing data. These results were used to create a contour plot of wood intensity for total, and 'large' wood, a stylised map of the deposition along the channel. The influence of channel widenings was researched by a combination of measuring channel width in the field, measurements from maps and aerial photographs, and surveying to 100m either side of the channel, to create a contour plot of morphology, this gave an impression of channel widenings at a flood stage. Keywords: Namibia, Namib Desert, Kuiseb River, ephemeral river, sediment transfer, fluvial basins, fluvial deposit, high magnitude floods, tree deposition, flooding, geomorphology, geohydrology. ACCESSION NUMBER: 551.4'688 HEW.