Flash floods in desert rivers: studying the unexpected

Abstract

[eng] Flash floods in desert ephemeral streams are unpredictable, infrequent, and shortlived. Although some observations of flood bores have been reported [e.g., Hassan, 1990], there is little quantitative data on the hydraulic and sediment transport dynamics of desert flash floods, despite the fact that desert streams pose many problems for river and reservoir management [Tolouie et al., 19937rsqb;. Furthermore, it has been suspected for some time that rates of sediment transfer might differ markedly in ephemeral and perennial rivers [e.g., Reid and Frostick, 1987; Schick et al., 1987]. Today, because of concern over prospective climate change, water resource issues are the subject of lively debate. Since current understanding and models of sediment dynamics derived from perennial streams may not be readily applicable to ephemeral flows, there is an urgent need for improved understanding of the dynamics of dryland rivers.