Hydraulics of stepped spillways : current status

H. CHANSON Department of Civil Engineering, The University of Queensland, Brisbane QLD 4072, Australia Email : h.chanson@mailbox.uq.edu.au Stepped-channel spillways, staircase waste waterways, stepped spillways, or stepped chutes have been used for more than 3,000 years (Fig. 1). In recent years they are experiencing renewed attention. The present forum article discusses briefly the current status of stepped spillways, and it draws attention to a recent workshop on the subject. A significant number of dams were built with overflow stepped spillways during the 19th century and early 20th century, before such spillways became outdated by progresses in hydraulic jump stilling basins (Fig. 2). Recent advances in technology (e.g. RCC, polymer-coated gabion wire) have however triggered a regain of interest for stepped spillways. Unfortunately, though, much expertise had been lost in the past 60 years. Research on stepped spillway hydraulics has been active for the past ten years (Fig. 3). During the period 1985-2000, the international database Science Citation Index (The Web of Science) lists fourteen papers and twenty-one discussions and closures on stepped spillway, or stepped chute, hydraulics, all but two were published between 1990 and 2000. A 1985 paper (