Developments in sedimentology. Vol 17. Sedimentary structures of ephemeral streams / Достижения в седиментологии. Том 17. Осадочные структуры кратковременных потоков

Ephemeral streams, dry washes, gullies, draws and arroyos are common names for a major element of Western landscapes. By definition ephemeral streams are characterized by short periods of flow, following local and intense rainfall, and alternating with long periods in which the channel is dry (Fig.] ,2). Most ephemeral streams probably experience several flows each year, ranging in magnitude from large, destructive flash floods (Fig.3,4) to trickles of water. Flood occurrences are erratic, but over a period of years flow frequencies are predictable. To date, most interest in ephemeral streams has centered on engineering problems and the destructive aspects of flash flooding. Our interests, however, are centered on the sedimentology of ephemeral streams.

The principal purpose of this book is to describe, illustrate and explain the sedimentary structures that are developed along ephemeral streams. The locale of the study is the Uinta Basin, northeastern Utah, where a wide variety of ephemeral streams are present (Fig.5). We also have studied similar streams in Wyoming and Colorado. Some of the specific variables of these streams are: channel size and discharge, channel shape and intrenchment, nature of load (amount of load, sediment qze, sorting, composition), regional slope, and drainage basin characteristics (Fig.6-11). <...>