Very few studies investigated the geomorphological and sedimen-tological processes of modern very coarse-grained, ephemeral streams. A field study on such topics is carried out on the Golina river, a sandy boulder-bed ephemeral stream of the Kobo basin in northern Ethiopia, subjected to intermittent flow generated by isolated, high intensity rainfall. The main gemorphological characteristics of the study reach channels are only apparently similar to those of perennial counterparts, in fact, a detailed analysis shows macroforms such as bars, riffles and pools and their sedimentary structures resuls from very different depo-sitional/erosion processes. A conceptual model based on the superimposition of coarse-grained bedload sheets, with the characteristics described by Whiting et al. (1988), and subsequent dissection during the receding flood flow is proposed. This model was found to well explain the morphological and sedimentological features of the study river reach.
Sediment Dynamics and Morphology of a Boulder-Bed Ephemeral Stream
BILLI, Paolo
2015
Abstract
Very few studies investigated the geomorphological and sedimen-tological processes of modern very coarse-grained, ephemeral streams. A field study on such topics is carried out on the Golina river, a sandy boulder-bed ephemeral stream of the Kobo basin in northern Ethiopia, subjected to intermittent flow generated by isolated, high intensity rainfall. The main gemorphological characteristics of the study reach channels are only apparently similar to those of perennial counterparts, in fact, a detailed analysis shows macroforms such as bars, riffles and pools and their sedimentary structures resuls from very different depo-sitional/erosion processes. A conceptual model based on the superimposition of coarse-grained bedload sheets, with the characteristics described by Whiting et al. (1988), and subsequent dissection during the receding flood flow is proposed. This model was found to well explain the morphological and sedimentological features of the study river reach.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
