Determination of Discharge Coefficient in Ogee Spillways and Investigation the Effects of Submergence, Upstream Slope and Apron Elevation on Its Variations

Document Type : Research Article


1 University of Tabriz, Tabriz, Iran

2 Associated Professor, Department of Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz-Iran


Discharge over the ogee spillway is related to the length of crest, upstream total head, and discharge coefficient. Also, the discharge coefficient is influenced by several factors. In this study, some parameters that are affecting the discharge coefficient in ogee weir are investigated. These are ogee spillway upstream slope, apron elevation, and downstream submergence. In this regard, some ogee spillway physical models were fabricated. These models include (1) ogee spillway with vertical upstream face, (2) ogee spillway with inclined upstream face (18, 33, and 45 degrees), (3) ogee spillways with downstream apron elevations (3, 5, 7, and 10 cm thickness) in free flow, and (4) ogee spillway with the vertical upstream slope in submerged flow condition. Results showed that in all the ogee weirs, the discharge coefficient (C) increases with increasing (P/He) and then remain constant. The value of the discharge coefficient decreased from 2.25 (in free flow) to 2.15 (in submerged flow). For a constant value of head over ogee spillways (He), the discharge coefficient decreased with increasing downstream apron elevation and submergence. The relative discharge coefficient had a constant trend at the beginning with parameter (hd/He), then it had a decreasing trend. The threshold value for submergence (hd/He), was 0.75 in the ogee spillway in this study. With increasing relative submergence (hd/He) from 0.75 to 1, the relative discharge coefficient (Cs/C0) decreased from 0.88 to 0.24.  


Main Subjects

[1] T. Eshrati, R. Fazloula, M. Sanei, A. Emadi, Laboratory Study of Hydraulic Performance of Ogee Spillway and Downstream Canal with Axial Arc, Journal of Water and Soil, 9(4) Sept.-Oct (2015) 874-885.
[2] M. Karimi, Simulation of Flow over Ogee Spillway by VOF Method, Thesis is approved for the Degree of     Master of Science, in Hydraulic Structure,Department of Water Engineering, Faculty ofAgriculture Shahid Bahonar University of Kerman (2013).     
[3] M. Mahmoudian Shooshtari, Principles of flow in open channels. Shahid Chamran University of Ahvaz   Publications. First Edition. (2009). Volume II 508 pages.
[4] W. Boiten, Environmental Research Instruments. Venturi gate, Adjustable gate for discharge measurement and fish migration, Elsevier, 13(6) (2002) 203-207.
[5] M.G. Bos, Discharge measurement structures, third revised edition. International institute for land reclamation and improvement, (1989) 121-151.
[6] P.N. Kanyabujinja, CFD Modelling of Ogee Spillway Hydraulics and Comparison with Physical Tests, Master of Engineering Thesis, Stellenbosch University, Stellenbosch, Western Cape, South Africa, 42 (2015).
[7] F. Salmasi, Effect of downstream apron elevation and downstream submergence in discharge coefficient of ogee weir. ISH Journal of Hydraulic Engineering. (2018).
[8] J. Sheikh Kazemi, and M. Saneie, The Effect of Approach Channels on the Discharge of Ogee Spillway in the Axial Arc Condition with Convergent Sidewalls, Journal of Middle East Applied Science and Technology (JMEAST), 22(2) (2014) 119-123.
[9] B.P. Tullis, Behavior of Submerged Ogee Crest Weir Discharge Coefficients, Journal of irrigation and Drainage Engineering, ASCE, 137(10) (2011) 677-681.
[10] B.P. Tullis, and J. Neilson, Performance of Submerged Ogee-Crest Weir Head-Discharge Relationships, Journal of Hydraulic Engineering, ASCE, 134(4) (2008) 486-491.
[11] US Bureau of Reclamation (USBR), Design of small dams, Washington, USA, (1987) 365-375.
[12] Z. Shamsi, A. Parsaie and A.H. Haghiabi, Optimum hydraulic design of cylindrical weirs. ISH Journal of Hydraulic Engineering: 1-5. Doi: 10.1080/09715010.2019.1683474 (2019).
[13] A. Parsaie and A.H. Haghiabi, Inception Point of Flow Aeration on Quarter-Circular Crested Stepped Spillway. Flow Measurement and Instrumentation 101618 (2019).
[14] A. Parsaie and A.H. Haghiabi, The Hydraulic Investigation of Circular Crested Stepped Spillway. Flow Measurement and Instrumentation. 101624 (2019).
[15] A. Parsaie, H.M. Azamathulla and A.H. Haghiabi.  Prediction of discharge coefficient of cylindrical weir–gate using GMDH-PSO. ISH Journal of Hydraulic Engineering 24 (2):116-123. (2017).
[16] A.H. Haghiabi, J. Mohammadzade-Habibi and A. Parsaie. Development of an evaluation method for velocity distribution over cylindrical weirs using doublet concept. Flow Measurement and Instrumentation 61:79-83. (2018).
[17] S. Dehdar-behbahani and A. Parsaie. Numerical Modeling of Flow Pattern in Spillway Approach Channel. Jordan Journal of Civil Engineering 12 (1):1-9 (2016).