---

In the last few decades, stepped spillways have got more attention because of their compatibility with the new innovative construction techniques especially RCC (roller compacted concrete) and gabions. Using these techniques leads to time and cost saving compared with conventional concrete spillways. This book aims to contribute in developing new designs for stepped spillways as well as study previous designs. The studied designs are: RCC-gabion (hybrid) stepped spillways, steps with porous and non-porous end sills, the conventional non-stepped and flat steps stepped spillways. Results of experimental work revealed better flow behavior and higher energy dissipation rate of gabion steps than flat and pooled steps in relatively low discharges. In high flow rates, little differences between the tested configurations were observed, the highest dissipation rate was for the pooled steps with and without porosity. Porous end sills give a better flow behavior and higher energy dissipation than non-porous end sills in relatively low discharges. Empirical equations for calculating the limits of flow regimes, energy dissipation and location of inception of air entrainment have been developed.

---

Salam Mohammad Ali, B.Sc in civil engineering (2008) and M.Sc in civil engineering-water resources engineering (2014) from University of Babylon, Iraq. His research interests include hydraulic structures with a focus on hydraulics of stepped spillway, gabion weirs and energy dissipators.

---