The Study of Hydraulic Properties of Quarter-Circular Crested Stepped Spillway

Document Type : Research Paper


1 Former PhD candidate of Hydro-Structure Engineering, Water Engineering Department, Lorestan University and Assistant Professor of Shahid Chamran University of Ahvaz. Iran.

2 Professor, Water Engineering Department, Lorestan University, Khorramabad, Iran.

3 Associate Professor, Soil Conservation and Watershed Management Institute, Tehran, Iran.

4 Assistant Professor, Water Engineering Department, Lorestan University, Khorramabad, Iran.


In this paper, the quarter-circular crested stepped spillway (QCSS) is introduced and its hydraulic properties including the discharge coefficient (Cd) and energy dissipation of flow are investigated. The QCSS consists of a quarter-circular as the crest and a stepped chute. The Cd of QCSS variates between 0.9 and 1.4 considering the range of relative upstream head (hup/R) between 0.1 and 1.0, but at the same range of hup/R, the Cd of the broad crested stepped spillway (BCSS) changes between 0.9 and 1.0. The ratio of energy dissipation changes between 30% and 98% for both hydraulic models. Comparing the performance of QCSS and BCSS shows that in the skimming flow condition, the Cd of QCSS is about 30%more than the BCSS. Whereas, in the same flow regime, the energy dissipation of the flow on QCSS is a bit less than the BCSS about 10%.


Main Subjects

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Volume 43, Issue 4
March 2021
Pages 23-32
  • Receive Date: 29 December 2020
  • Revise Date: 01 February 2021
  • Accept Date: 06 February 2021
  • First Publish Date: 06 February 2021