Embankment overflow stepped spillways,
Earth dam spillways with precast concrete blocks & Gabion stepped weirs
by Hubert CHANSON (h.chanson@uq.edu.au)
M.E., ENSHM Grenoble, INSTN, PhD (Cant.), DEng (Qld), Eur.Ing., MIEAust., MIAHR , 13th Arthur Ippen awardee
School of Civil Engrg., Univ. of Queensland, Brisbane QLD 4072, Autralia

In recent years, the design floods of a number of dams were re-evaluated and the revised flows were often larger than those used for the original designs. In many cases, occurrence of the revised design floods would result in dam overtopping because of the insufficient storage and spillway capacity of the existing reservoir. A number of overtopping protection systems were developed for embankments and earthfill dams. These include concrete overtopping protection systems (Photo No. 1, No. 10, No. 11),  timber cribs, sheet-piles, riprap and gabions, reinforced earth, Minimum Energy Loss weirs (Photo No. 2), and the precast concrete block protection systems developed by the Russian engineers (Photo No. 3).

Soviet engineers were among the first to propose a stepped concrete chute design on the downstream face of embankment dams under the leadership of P.I. GORDIENKO. The choice of a stepped structure allows the use of individual blocks interlocked with the next elements and the design assists in the energy dissipation (CHANSON 1995, CHANSON 2001, Photo No. 3). For new dams, a stepped spillway made of concrete blocks may be considered as the primary flood release structure of the embankment. The design concept was more recently tested in USA and UK (Photo No. 4 and 5), although it did not prove cost-effective there.

An interesting feature of the concrete block system is the flexibility of the stepped channel bed allowing differential settlements of the embankment. Individual blocks do not need to be connected to adjacent blocks. Another advantage is the short construction time on site. In a typical design, the blocks lay on a filter and erosion protection layer. The layer has the functions to filter the seepage flow out of the subsoil and to protect the subsoil layer from erosion by flow in the drainage layer. Further the protection layer reduces or eliminates the uplift pressures acting on the concrete blocks. Usually a geotextile membrane is laid on the embankment before the placing of the layer, and another covers the protection layer before the installation of the blocks. Suction of the fluid from underneath the concrete steps can be produced by the pressure differential created by the high velocity flow over the vertical face of the step. Drains placed in areas of sub-atmospheric pressure will function to relieve uplift pressures (Photo No. 5).

Hydraulic calculations
The overflow embankment protection system is designed to operate in a skimming flow regime. The steps contribute to a substantial flow resistance and most of the energy dissipation takes place as a form drag process (CHANSON et al. 2000,2002, GONZALEZ 2005).
On the stepped chute, both the flow acceleration and boundary layer development affect the flow properties significantly. The complete flow calculations can be tedious and most backwater calculations are not suitable. CHANSON (1999,2001) proposed a pre-design calculation method which provides a general trend to be used for a preliminary design (Photo No. 6). Ideally, the maximum velocity at the downstream chute end is Vmax. In practice the downstream flow velocity V is smaller than the theoretical velocity Vmax because of friction losses. In Photo No. 6, the mean flow velocity is plotted as V/Vmax versus H1/dc where H1 is the upstream total head and dc is the critical depth. Both developing flow calculations and uniform equilibrium flow calculations are shown. Fitting curves must be plotted to connect these lines.
In skimming flow, free-surface aeration is always significant (Photo No. 7). It occurs downstream of the inception point of air entrainment, defined as the point of apparition of 'white waters'. It is generally accepted that the inception point occurs when the outer edge of the turbulent boundary layer reaches the surface. Downstream of the point of inception, a layer containing a mixture of both air and water extends gradually through the fluid. The rate of growth of the layer is small and the air concentration distribution varies gradually with distance (CHANSON 1997, 2001). Full details are presented at {http://www.uq.edu.au/~e2hchans/self_aer.html}.

Design considerations
There are two fundamental design rules for precast concrete block systems : a skimming flow in a straight prismatic chute. The step block system was developed for a skimming flow regime : maximum block stability can only be achieved in skimming flows (e.g. BAKER 2000). All but one Russian applications were designed for relatively small discharge capacity : q ~ 3 m2/s. PRAVDIVETS urged that "the alignment of the spillway should be straight from the crest to the toe. Any curvature of the spillway in plan, or change in cross-section, will cause an uneven distribution of flows within the spillway which, in general, should be avoided" (e.g. Photo No. 3).
Usually the channel sidewalls are flat inclined slopes (i.e. trapezoidal spillway cross-section). The slopes of the sidewalls can be designed as inclined stepped surfaces (in the flow direction) and may use the same concrete block system as the main channel (Photo No. 3). Typical sidewall slopes are about 1V:3H (i.e. 18º). A known construction weakness is the joint between the chute invert and the sidewalls. At Brushes Clough, two longitudinal concrete guides were built to facilitate the installation of the blocks and the connection with the stone-pitched sidewalls. At the downstream end, the residual energy of the flow must be dissipated with a small flip bucket arrangement and a conventional concrete pool. Laboratory tests showed high risks of block uplift and failure under a hydraulic jump (BAKER 2000).
The Russian experience with overflow earth dam spillways (chute slope = 9.4 to 26.6º) showed the potential of the concept and highlighted that the quality of the drainage layer is uppermost important. Failure cases were caused by improper drainage revetment. If the drainage requirements are fulfilled, the stepped spillway can sustain large floods and discharges even ice debris. In Siberia, the Magadan experimental dam has resisted for over 15 years without accident. Additional information on design criteria can be found in CHANSON (2001) and BAKER (2000).
GONZALEZ and CHANSON (2007) presented a complete design procedure for embamkment dam stepped spillways.

Salado10
Discussion on earth dam with precast concrete stepped spillway
Embankment overflow stepped spillways have common features with stepped storm water systems and sabo channel systems (Photo No. 9), which differ significantly from concrete dam stepped spillways. Namely the channel has often a trapezoidal cross-section, the bed slope is moderate (i.e. less than 30 deg.) and the step height ranges from about 0.05 to 0.3 m. Futher strong interactions may occur between seepage and overflow (e.g. CHANSON and TOOMBES 2001, pp. 41-50). Therefore steep stepped chute results cannot be applied (CHANSON and TOMBES 2001, GONZALEZ and CHANSON 2004a,b). CHANSON and TOOMBES (2001, pp. 46-50) further discussed a number of key issues, including the design of the downstream energy disispator. GONZALEZ and CHANSON (2007) developed the particular case of small dams.

Practical considerations
In one case (Brushes Clough dam spillway, Photo No. 4 and 5) numerous acts of vandalism were reported, including destruction of concrete blocks. In practice it is recommended to use concrete blocks heavy enough to avoid their displacement by individuals and to enhance their strength against acts of vandalism. At the limit another construction technique (e.g. RCC overlays) should be selected if man-made destruction cannot be prevented.
In Russia, the cheapest construction method uses precast concrete slabs which are made for the building industry. The slabs are rectangular (3-m long, 1.5-m wide and 0.160-m thick typically) and they are installed in an overlapping arrangement with mild steel spacers. A long-term issue would be the corrosion of the spacers.

Gabion stepped weirs

Gabion stepped weirs are commonly used for embankment protection, river training and flood control; the stepped design enhances the rate of energy dissipation in the channel, and it is particularly well-suited to the construction of gabion stepped weirs (WUTHRICH and CHANSON 2014). For very-low flow, a porous seepage flow regime may take place, when the water seeps through the gabion materials and there is no overflow past the step edges. At larger flow rates, strong air-water exchanges between seepage and stepped cavity flows are observed, with a complex bubbly seepage motion in the gabions, leading to a modification of the step cavity recirculation and lesser flow resistance (ZHANG and CHANSON 2016). The discharge properties of capped gabion stepped weirs are typically intermediate between the flat impervious and un-capped gabion stepped chute flow properties (WUTHRICH and CHANSON 2015).


Detailed photographs

Energy Dissipation in Hydraulic StructuresPhoto No. 1 : An overflow embankment dam : Melton dam (VIC, Australia). Completed in 1916, the dam was heightened twice because of the rapid reservoir siltation. During the last refurbishment in 1994, the overflow stepped spillway was added.

Photo No. 2 : Chinchilla weir (Chinchilla QLD, Australia 1973) on 8 Nov. 1997 during low overflow. Designed with the assistance of Professor Gordon McKAY. Weir height: 14 m, Crest length: 410m, Spillway capacity: 850 m3/s, Condamine river. The Chinchilla weir is listed as a "large dam" by the International Commission on Large Dams (1984). For further techncial data, see CHANSON, Butteworth-Heinemann 1999, pp. 417-421 & 316. More information at : {http://www.uq.edu.au/~e2hchans/mel_weir.html}.

Photo No. 3 : Zaraysk dam (also called Laraisky), Russia (Courtesy of Prof. Y. PRAVDIVETS). Overflow embankment spillway made of precast concrete blocks.

Photo No. 4 : Brushes Clough dam (1859-1991). 26-m high embankment dam refurbished with a new overflow spillway system in 1991. General view (Courtesy of Mr GARDINER, NWW).

Photo No. 5 : Brushes Clough dam (1859-1991). Details of the precast blocks (120 kg each) and of the drainage holes (Courtesy of Mr GARDINER, NWW).

Photo No. 6 : Relationship between the flow velocity at the end of the chute V, the ideal fluid flow velocity Vmax (at end of chute), the total head above spillway toe H1 and the critical flow depth dc for a stepped chute (f = 0.2) (after CHANSON 1999,2001 - see also http://www.uq.edu.au/~e2hchans/reprints/errata.htm).

Photo No. 7 : Air entrainment in skimming flow down a 22 degree slope (1V:2.5H) for dc/h = 1.1 (h = 100 mm). Research experiments at the Hydraulics/Fluid Mechanics Laboratory of the University of Queensland.

Photo No. 8 : Nappe flow down a 16 degree slope (1V:3.5H) for dc/h = 0.64 (h = 100 mm). Research experiments at the Hydraulics/Fluid Mechanics Laboratory of the University of Queensland.

Photo No. 9 : Stepped storm waterway East of Okazaki city, Aichi prefecture (Japan) in the middle of a residential area. Photograph taken on 10 Nov. 2001. 

Photo No. 10 : Salado 10 embankment dam and secondary stepped spillway (Courtesy of Craig SAVELA and USDA, Natural Resources Conservation Service; National Design, Construction and Soil Mechanics Center, Fort Worth, Texas).

Photo No. 11 : Choctaw 8A embankment dam and secondary stepped spillway (Courtesy of Craig SAVELA and USDA, Natural Resources Conservation Service; National Design, Construction and Soil Mechanics Center, Fort Worth, Texas).

Photo No. 12 and 13 :  Melton dam overflow stepped spillway (Melton VIC, Australia 1916). The Melton dam is an earthfill structure. Completed in 1916, the dam was heightened twice because of the rapid reservoir siltation. During the last refurbishment in 1994, an overflow stepped spillway was added. The overflow stepped spillway is considered to be the world's largest embankment overflow stepped spillway in terms of total discharge capacity (CHANSON 2001). Photo No. 12 : general view (30 Jan. 2000). Photo No. 13 : details of the dam overflow spillway (30 Jan. 2000).  More about Extreme reservoir siltation ...

Photo No. 14 and 15 : Pedrogao dam, Moura (Portugal, 2006). Completed in March 2006, the Pedrogao dam is a RCC gravity dam (H = 43 m, L = 473 m) with an uncontrolled overflow stepped spillway (h = 0.6 m, 1V:0.75H). The dam is equipped also witha  fish lock/lift. The reservoir is located immediately downstream of the Alqueva dam which is multipurpose reservoir for irrigation (326 km of open channels, 9 main pump stations) and hydropower (2 * 130 MW pump-turbines). Photo No. 14 : view from right bank on 4 Seopt. 2006. Photo No. 15 : view from left bank on 4 Sept. 2006.

Photo No.16 to 18: Joe Sippel weir (Murgon QLD, Australia) - Completed in 1984, the 6.5-m high stepped weir is used for irrigation and water regulation purposes. The structure was built of steel sheet piles and concrete slabs. It is located upstream of the Silverleaf weir. Photo No. 1: in November 1997. Photo No. 2:  on 5 March 2013. Photo No. 3: details of the plung point on 5 March 2013.

Brushes Clough References

  BAKER, R. (2000). "The CIRIA Guide for the Design of Stepped-Block Spillways." Intl Workshop on Hydraulics of Stepped Spillways, Zürich, Switzerland, H.E. MINOR & W.H. HAGER Editors, Balkema Publ., pp. 155-161.
  CHANSON, H. (1995). "Hydraulic Design of Stepped Cascades, Channels, Weirs and Spillways." Pergamon, Oxford, UK, Jan., 292 pages (ISBN 0-08-041918-6).
  CHANSON, H. (1997). "Air Bubble Entrainment in Free-Surface Turbulent Shear Flows." Academic Press, London, UK, 401 pages (ISBN 0-12-168110-6).
  CHANSON, H. (1999). "The Hydraulics of Open Channel Flow : An Introduction." Butterworth-Heinemann, London, UK, 512 pages.
  CHANSON, H. (2001). "The Hydraulics of Stepped Chutes and Spillways." Balkema, Lisse, The Netherlands (ISBN 90 5809 352 2).
  CHANSON, H. (2001). "Hydraulic Design of Stepped Spillways and Downstream Energy Dissipators." Dam Engineering, Vol. 11, No. 4, pp. 205-242 (ISSN 0 617 00563 X).  (Download PDF File)
  CHANSON, H., and GONZALEZ, C.A. (2004). "Recent Advances in Stepped Spillway Design: Air-Water Flow on Stepped Chutes, Embankment Dam Stepped Spillway and Other Considerations." in "Fluvial, Environmental & Coastal Developments in Hydraulic Engineering", Balkema, Leiden, The Netherlands, Proc. International Workshop on State-of-the-Art Hydraulic Engineering, 16-19 Feb. 2004, Bari, Italy, M. MOSSA, Y. YASUDA and H. CHANSON Ed., pp. 81-97 (ISBN 04 1535 899 X). (PDF Version at EprintsUQ) (Leaflet and Order Form
  CHANSON, H., and TOOMBES, L. (2001). "Experimental Investigations of Air Entrainment in Transition and Skimming Flows down a Stepped Chute. Application to Embankment Overflow Stepped Spillways." Research Report No. CE158, Dept. of Civil Engineering, The University of Queensland, Brisbane, Australia, July (ISBN 1 864995297). (Download PDF files : Part 1 and Part 2) (Alternate PDF file at EprintsUQ)
  CHANSON, H., and TOOMBES, L. (2002). "Air-Water Flows down Stepped chutes : Turbulence and Flow Structure Observations." Intl Jl of Multiphase Flow, Vol. 27, No. 11, pp. 1737-1761 (ISSN 0301-9322). (Download PDF File)
  CHANSON, H., YASUDA,Y., and OHTSU, I.(2000). "Flow Resistance in Skimming Flow : a Critical Review." Intl Workshop on Hydraulics of Stepped Spillways, Zürich, Switzerland, H.E. MINOR & W.H. HAGER Editors, Balkema Publ., pp. 95-102 (ISBN 90 5809 135X). (download PDF file)
  CHANSON, H., YASUDA, Y., and OHTSU, I. (2002). "Flow Resistance in Skimming Flows and its Modelling." Can Jl of Civ. Eng., Vol. 29, No. 6, pp. 809-819 (ISSN 0315-1468). (Download PDF File)
  GONZALEZ, C.A. (2005). "An Experimental Study of Free-Surface Aeration on Embankment Stepped Chutes." Ph.D. thesis, Department of Civil Engineering, The University of Queensland, Brisbane, Australia. (PDF version at EprintsUQ)
  GONZALEZ, C.A., and CHANSON, H. (2004a). "Interactions between Cavity Flow and Main Stream Skimming Flows: an Experimental Study." Can Jl of Civ. Eng., Vol. 31, No. 1, pp. 33-44 (ISSN 0315-1468). (Download PDF file)
  GONZALEZ, C., and CHANSON, H. (2004b). "Effects of Turbulence Manipulation in Skimming Flows: An Experimental Study." Proceedings 15th Australasian Fluid Mechanics Conference, AFMC, Sydney, Australia, M. BEHNIA, W. LIN & G.D. McBAIN Ed., Paper AFMC00104, 4 pages (CD-ROM) (ISBN 1-864-87695-6). (Download PDF file)
  GONZALEZ, C.A., and CHANSON, H. (2007). "Hydraulic Design of Stepped Spillways and Downstream Energy Dissipators for Embankment Dams." Dam Engineering, Vol. 17, No. 4, pp. 223-244 (ISSN 0 617 00563 X). (PDF file at UQeSpace)
 WUTHRICH, D, and CHANSON, H. (2014). "Hydraulics, Air Entrainment and Energy Dissipation on Gabion Stepped Weir." Journal of Hydraulic Engineering, ASCE, Vol. 140, No. 9, Paper 04014046, 10 pages (DOI: 10.1061/(ASCE)HY.1943-7900.0000919) (ISSN 0733-9429). (Postprint at UQeSpace) (PDF file)
 WUTHRICH, D, and CHANSON, H. (2015). "Aeration Performances of a Gabion Stepped Weir with and without Capping." Environmental Fluid Mechanics, Vol. 15, No. 4, pp. 711-730 and 5 video movies (DOI: 10.1007/s10652-014-9377-9) (ISSN 1567-7419 [Print] 1573-1510 [Online]). (PDF file) (Postprint at UQeSpace) (Videos movies at UQeSpace)
 ZHANG, G., and CHANSON, H. (2016). "Gabion Stepped Spillway: Interactions between Free-Surface, Cavity, and Seepage Flows." Journal of Hydraulic Engineering, ASCE, Vol. 142, No. 5, Paper 06016002, 5 pages (DOI: 10.1061/(ASCE)HY.1943-7900.0001120) (ISSN 0733-9429). (PDF file) (Preprint at UQeSpace with colour figures)

Additional bibliography

AMADOR, A., SANCHEZ-JUNY, M., DOLZ, J., SANCHEZ-TEMBLEQUE, F., and PUERTAS, J. (2004). "Velocity and Pressure Measurements in Skimming Flow in Stepped Spillways." Proc. Intl Conf. on Hydraulics of Dams and River Structures, Tehran, Iran, Balkema Publ., The Netherlands, pp. 279-285.
ANDRE, S., BOILLAT, J.L., SCHLEISS, A.J., and MATOS, J. (2004). "Energy Dissipation and Hydrodynamic Forces of Aerated Flow over Macro-Roughness Linings for Overtopped Embankment Dams." Proc. Intl Conf. on Hydraulics of Dams and River Structures, Tehran, Iran, Balkema Publ., The Netherlands, pp. 189-196.
AROSQUIPA NINA, Y., WÜTHRICH, D., and CHANSON, H. (2020). "Air-Water Flows on Stepped Spillways with Inclined Steps." Proceedings of 22nd Australasian Fluid Mechanics Conference AFMC2020, Brisbane, Australia, 7-10 December, Published by The University of Queensland, Editors H. CHANSON and R. BROWN, Paper 14, 4 pages (DOI: 10.14264/27b1c79) (ISBN 978-1-74272-341-9). (Deposit at UQeSpace)
AROSQUIPA NINA, Y., SHI, R., WÜTHRICH, D., and CHANSON, H. (2021). "Intrusive and Non-Intrusive Air-Water Measurements on Stepped Spillways with inclined steps: a Physical Study on Air Entrainment and Energy Dissipation." Hydraulic Model Report No. CH121/21, School of Civil Engineering, The University of Queensland, Brisbane, Australia, 258 pages & 8 video movies (DOI: 10.14264/e3f4d48) (ISBN 978-1-74272-348-8). (Deposit at UQeSpace) (Movies at UQeSpace)
AROSQUIPA NINA, Y, SHI, R., WÜTHRICH, D., and CHANSON, H. (2022). " Air–Water Flows and Head Losses on Stepped Spillways with Inclined Steps." Journal of Irrigation and Drainage Engineering, ASCE, Vol. 148, No. 11, Paper 04022037, 15 pages (DOI: 10.1061/(ASCE)IR.1943-4774.0001701) (ISSN 0733-9437 [Print]; ISSN: 1943-4774 [online]). (PDF file) (Preprint at UQeSpace)
BOES, R.M. (2000). "Zweiphasenstroömung und Energieumsetzung an Grosskaskaden." Ph.D. thesis, VAW-ETH, Zürich, Switzerland (in German). (also  Mitteilungen der Versuchsanstalt fur Wasserbau, Hydrologie und Glaziologie, ETH-Zurich, Switzerland, No. 166).
CAROSI, G., and CHANSON, H. (2006). "Air-Water Time and Length Scales in Skimming Flows on a Stepped Spillway. Application to the Spray Characterisation." Report No. CH59/06, Div. of Civil Engineering, The University of Queensland, Brisbane, Australia, July, 142 pages (ISBN 1864998601). (PDF version at EprintsUQ)
 CHANSON, H. (1995). "History of Stepped Channels and Spillways : a Rediscovery of the 'Wheel'." Can Jl of Civ. Eng., Vol. 22, No. 2, April, pp. 247-259 (ISSN 0315-1468).  (Download PDF file)
CHANSON, H. (1998). "Review of Studies on Stepped Channel Flows." Hydraulic Characteristics of Stepped Channel Flows, Workshop on Flow Characteristics around Hydraulic Structures and River Environment, Nihon University, Tokyo, Japan, November, Invited keynote lecture, 25 pages. (PDF Version at EprintsUQ)
CHANSON, H. (1998). "Utilisation of Stepped Channels and Study of Stepped Channel Flows in Australia." Hydraulic Characteristics of Stepped Channel Flows, Workshop on Flow Characteristics around hydraulic Structures and River Environment, Nihon University, Tokyo, Japan, November, Invited keynote lecture, 21 pages. (PDF Version at EprintsUQ
CHANSON, H. (2000). "A Review of Accidents and Failures of Stepped Spillways and Weirs." Proc. Instn Civ. Engrs Water and Maritime Engrg, UK, Vol. 142, Dec., pp. 177-188 (ISSN 0965-0946). (Download PDF file)
CHANSON, H. (2004). "Drag Reduction in Skimming Flow on Stepped Spillways by Aeration." Jl of Hyd. Research, IAHR, Vol. 42, No. 3 , pp. 316-322 (ISSN 0022-1686). (Download PDF file)
CHANSON, H. (2006). "Hydraulics of Skimming Flows on Stepped Chutes: the Effects of Inflow Conditions?" Jl of Hyd. Res., IAHR, Vol. 44, No. 1, pp. 51-60 (ISSN 0022-1686). (Download PDF file) (PDF version at UQeSpace)
CHANSON, H. (2008). "Physical Modelling, Scale Effects and Self-Similarity of Stepped Spillway Flows." Proc. World Environmental and Water Resources Congress 2008 Ahupua'a, ASCE-EWRI, 13-16 May, Hawaii, R.W. BADCOCK Jr and R. WALTON Eds., Paper 658, 10 pages (ISBN: 978-0-7844-0976-3). (PDF file at UQeSpace)
CHANSON, H. (2009). "Embankment Overtopping Protections System and Earth Dam Spillways." in "Dams: Impact, Stability and Design", Nova Science Publishers, Hauppauge NY, USA, Ed. W.P. HAYES and M.C. BARNES, Chapter 4, pp. 101-132 (ISBN 978-1-60692-618-5). (PDF file at UQeSpace)
CHANSON, H. (2013). "Interactions between a Developing Boundary Layer and the Free-Surface on a Stepped Spillway: Hinze Dam Spillway Operation in January 2013." Proc. 8th International Conference on Multiphase Flow ICMF 2013, Jeju, Korea, 26-31 May, Gallery Session ICMF2013-005 (Video duration: 2:15). (Description) (Record at UQeSpace) (Video movie at UQeSpace) (Video movie on YouTube)
CHANSON, H. (2013). "Hydraulics of Aerated Flows: Qui Pro Quo?" Journal of Hydraulic Research, IAHR, Invited Vision paper, Vol. 51, No. 3, pp. 223-243 (DOI: 10.1080/00221686.2013.795917) (ISSN 0022-1686). (Postprint at UQeSpace) (PDF file)
CHANSON, H. (2014). "Embankment Dam Spillways and Energy Dissipators." in "Labyrinth and Piano Key Weirs II - PKW 2013." Proceedings of 2nd International Workshop on Labyrinth and Piano Key Weirs - PKW 2013, 20-22 Nov., Paris-Chatou, France, CRC Press, Taylor & Francis, Leiden, the Netherlands, Editors S. ERPICUM, F. LAUGIER, M. PFISTER, M. PIROTTON, G.M. CICERO, and A.J. SCHLEISS, Invited keynote, lecture, pp. 23-37 (ISBN 978-1-138-00085-8). (PDF file) (Record at UQeSpace)
CHANSON, H. (2021). "Stepped Spillway Prototype Operation, Spillway Flow and Air Entrainment: the Hinze Dam, Australia." Hydraulic Model Report No. CH123/21, School of Civil Engineering, The University of Queensland, Brisbane, Australia, 183 pages (DOI: 10.14264/c8d5280) (ISBN 978-1-74272-354-9 [Print]; 978-1-74272-355-6 [Electronic]). (Deposit at UQeSpace)
CHANSON, H. (2021). "Hydraulics and Energy Dissipation on Stepped Spillways - Prototype and Laboratory Experiences." Proceedings of the 2nd International Symposium of Advances in Water Disaster Mitigation and Water Environment Regulation WDWE2021, July 7-9, Chengdu, China, Sichuan University Press, P. LIN and J ZHANG Editors, Invited Plenary Keynote Paper, pp. 1-15 (ISBN 978-7-5690-4817-9). (Plenary Keynote Lecture on YouTube) (Published paper) (Postprint with colour figures) (Postprint at UQeSpace)
CHANSON, H. (2022). "Energy dissipation on stepped spillways and hydraulic challenges - Prototype and laboratory experiences." Journal of Hydrodynamics, Vol. 34, No. 1, pp. 52-62 (DOI: 10.1007/s42241-022-0005-8) (ISSN 1001-6058). (PDF file) (Postprint at UQeSpace)
CHANSON, H. (2022). "Stepped Spillway Prototype Operation and Air Entrainment: Toward a Better Understanding of the Mechanisms Leading to Air Entrainment in Skimming Flows." Journal of Hydraulic Engineering, ASCE, Vol. 148, No. 11, Paper 05022004, 17 pages (DOI: 10.1061/(ASCE)HY.1943-7900.0002015) (ISSN 0733-9429). (PDF file) (Preprint at UQeSpace)
CHANSON, H., BUNG, D., and MATOS, J. (2015). "Stepped spillways and cascades." in "Energy Dissipation in Hydraulic Structures." IAHR Monograph, CRC Press, Taylor & Francis Group, Leiden, The Netherlands, H. CHANSON Editor, pp. 45-64 (ISBN 978-1-138-02755-8). (PDF file) (Record at UQeSpace)
CHANSON, H., and CAROSI, G. (2007). "Turbulent Time and Length Scale Measurements in High-Velocity Open Channel Flows." Experiments in Fluids, Vol. 42, No. 3, pp. 385-401 (DOI 10.1007/s00348-006-0246-2) (ISSN 0723-4864). (PDF File) (PDF file at UQeSpace)
CHANSON, H., and GONZALEZ, C.A. (2004). "Stepped Spillways for Embankment dams: Review, Progress and Development in Overflow Hydraulics." Proc. Intl Conf. on Hydraulics of Dams and River Structures, Tehran, Iran, Balkema Publ., The Netherlands, pp. 287-294 (ISBN 90 5809 632 7). (Also CD-ROM, Taylor & Francis, ISBN 90 5809 683 4.). (download PDF file)
CHANSON, H., and GONZALEZ, C.A. (2005). "Physical Modelling and Scale Effects of Air-Water Flows on Stepped Spillways." Journal of Zhejiang University SCIENCE, Vol. 6A, No. 3, March, pp. 243-250 (ISSN 1009-3095). (Download PDF file)
CHANSON, H., and TOOMBES, L. (1997). "Flow Aeration at Stepped cascades." Research Report No. CE155, Dept. of Civil Engineering, University of Queensland, Australia, June, 110 pages (ISBN 0 86776 730 8). (PDF version at EprintsUQ)
CHANSON, H., and TOOMBES, L. (2002). "Experimental Study of Gas-Liquid Interfacial Properties in a Stepped Cascade Flow." Environmental Fluid Mechanics, Vol. 2, No. 3, pp. 241-263 (ISSN 1567-7419). (Download PDF File)
CHANSON, H., and TOOMBES, L. (2002). "Experimental Investigations of Air Entrainment in Transition and Skimming Flows down a Stepped Chute." Can. Jl of Civil Eng., Vol. 29, No. 1, pp. 145-156. (ISSN 0315-1468). (Download PDF File)
CHANSON, H., and TOOMBES, L. (2004). "Hydraulics of Stepped Chutes: the Transition Flow." Jl of Hyd. Res., IAHR, Vol. 42, No. 1, pp. 43-54 (ISSN 0022-1686).  (Download PDF file)
CHANSON, H., and WHITMORE, R.L. (1996). "Investigation of the Gold Creek Dam Spillway, Australia." Research Report No. CE153, Dept. of Civil Engineering, University of Queensland, Australia, 60 pages (ISBN 0 86776 667 0). (PDF version at EprintsUQ)
FELDER, S., and CHANSON, H. (2008). "Turbulence and Turbulent Length and Time Scales in Skimming Flows on a Stepped Spillway. Dynamic Similarity, Physical Modelling and Scale Effects." Report No. CH64/07, Hydraulic Model Report CH series, Division of Civil Engineering, The University of Queensland, Brisbane, Australia, March, 217 pages (ISBN 9781864998870). (PDF file at UQeSpace)
FELDER, S., and CHANSON, H. (2009). "Turbulence, Dynamic Similarity and Scale Effects in High-Velocity Free-Surface Flows above a Stepped Chute." Experiments in Fluids, Vol. 47, No. 1, pp. 1-18 (DOI: 10.1007/s00348-009-0628-3) (ISSN 0723-4864). (PDF file at UQeSpace)
FELDER, S., and CHANSON, H. (2011). "Energy Dissipation down a Stepped Spillway with Non-Uniform Step Heights." Journal of Hydraulic Engineering, ASCE, Vol. 137, No. 11, pp. 1543-1548 (DOI 10.1061/(ASCE)HY.1943-7900.0000455) (ISSN 0733-9429). (PDF file) (Postprint at UQeSpace)
FELDER, S., and CHANSON, H. (2013). "Air Entrainment and Energy Dissipation on Porous Pooled Stepped Spillways." Proceedings of International Workshop on Hydraulic Design of Low-Head Structures, IAHR, 20-22 Feb., Aachen, Germany, D. BUNG and S. PAGLIARA Editors, Bundesanstalt für Wasserbau (BAW, Karlsruhe), pp. 87-97 (ISBN 978-3-939230-04-5). (PDF file)
FELDER, S., and CHANSON, H. (2015). "Aeration and Air–Water Mass Transfer on Stepped Chutes with Embankment Dam Slopes." Environmental Fluid Mechanics, Vol. 15, No. 4, pp. 695–710 (DOI: 10.1007/s10652-014-9376-x) (ISSN 1567-7419 [Print] 1573-1510 [Online]). (PDF file) (Postprint at UQeSpace)
FELDER, S., and CHANSON, H. (2016). "Simple Design Criterion for Residual Energy on Embankment Dam Stepped Spillways." Journal of Hydraulic Engineering, ASCE, Vol. 142, No. 4, Paper 04015062, 11 pages (DOI: 10.1061/(ASCE)HY.1943-7900.0001107) (ISSN 0733-9429). (PDF file) (Preprint at UQeSpace)
GONZALEZ, C.A. (2005). "An Experimental Study of Free-Surface Aeration on Embankment Stepped Chutes." Ph.D. thesis, Department of Civil Engineering, The University of Queensland, Brisbane, Australia. (PDF version at EprintsUQ)
GONZALEZ, C.A., and CHANSON, H. (2006). "Air Entrainment and Energy Dissipation on Embankment Stepped Spillways." Proc. International Symposium on Hydraulic Structures, IAHR, Ciudad Guayana, Venezuela, Recent Developments on Hydraulic Structures, from Hybrid Modeling to Operation and Repairs, A. MARCANO and A. MARTINEZ Ed., pp. 487-497 (ISBN 980 12 2177 1). (PDF version at EprintsUQ)
GONZALEZ, C.A., and CHANSON, H. (2008). "Turbulence and Cavity Recirculation in Air-Water Skimming Flows on a Stepped Spillway."  Journal of Hydraulic Research, IAHR, Vol. 46, No. 1, pp. 65-72 (ISSN 0022-1686). (PDF file at UQeSpace)
GONZALEZ, C.A., and CHANSON, H. (2008). "Turbulence Manipulation in Embankment Stepped Chute Flows: an Experimental Study." European Journal of Mechanics B/Fluids, Vol. 27, No. 4, pp. 388-408 (DOI: 10.1016/j.euromechflu.2007.09.003) (ISSN 0997-7546). (PDF file at UQeSpace)
GONZALEZ, C.A., TAKAHASHI, M., and CHANSON, H. (2005). "Effects of Step Roughness in Skimming Flows: an Experimental Study." Research Report No. CE160, Dept. of Civil  Engineering, The University of Queensland, Brisbane, Australia, July, 149 pages (ISBN 1864998105). (Download PDF File) (PDF Version at EprintsUQ)
GONZALEZ, C.A., TAKAHASHI, M., and CHANSON, H. (2008). "An Experimental Study of Effects of Step Roughness in Skimming Flows on Stepped Chutes." Journal of Hydraulic Research, IAHR, Vol. 46, No. Extra Issue 1, pp. 24-35 (ISSN 0022-1686). (PDF file at UQeSpace)
GUENTHER, P., FELDER, S., and CHANSON, H. (2013). "Flat and Pooled Stepped Spillways for Overflow Weirs and Embankments: Cavity Flow Processes, Flow Aeration and Energy Dissipation." Proceedings of International Workshop on Hydraulic Design of Low-Head Structures, IAHR, 20-22 Feb., Aachen, Germany, D. BUNG and S. PAGLIARA Editors, Bundesanstalt für Wasserbau (BAW, Karlsruhe), pp. 77-86 (ISBN 978-3-939230-04-5). (PDF file)
MATOS, J., SÁNCHEZ, M., QUINTELA, A., and DOLZ, J. (1999). "Characteristic Depth and Pressure Profiles in Skimming Flow over Stepped Spillways." Proc. 28th IAHR Congress, Graz, Austria, Session B14, 6 pages.
MURZYN, F., and CHANSON, H. (2008). "Experimental Assessment of Scale Effects Affecting Two-Phase Flow Properties in Hydraulic Jumps." Experiments in Fluids, Vol. 45, No. 3, pp. 513-521 (DOI: 10.1007/s00348-008-0494-4) (ISSN 0723-4864). (PDF file at UQeSpace)
OHTSU, I., and YASUDA, Y. (1997). "Characteristics of Flow Conditions on Stepped Channels." Proc. 27th IAHR Biennal Congress, San Francisco, USA, Theme D, pp. 583-588.
OHTSU, I., YASUDA, Y., and TAKAHASHI, M. (2004). "Flow Characteristics of Skimming Flows in Stepped Channels." Jl of Hyd. Engrg., ASCE, Vol. 130, No. 9, pp. 860-869.
SUN, S., and CHANSON, H. (2013). "Characteristics of Clustered Particles in Skimming Flows on a Stepped Spillway." Environmental Fluid Mechanics, Vol. 13, No. 1, pp. 73-87 (DOI: 10.1007/s10652-012-9255-2) (ISSN 1567-7419 [Print] 1573-1510 [Online]). (Postprint at UQeSpace) (PDF file)
TAKAHASHI, M., GONZALEZ, C.A., and CHANSON, H. (2006). "Self-Aeration and Turbulence in a Stepped Channel: Influence of Cavity Surface Roughness." International Journal of Multiphase Flow, Vol. 32, pp. 1370-1385 (DOI:10.1016/j.ijmultiphaseflow.2006.07.001) (ISSN 0301-9322). (PDF file at EprintsUQ)
TOOMBES, L. (2002). "Experimental Study of Air-Water Flow Properties on Low-Gradient Stepped Cascades." Ph.D. thesis, Dept of Civil Engineering, The University of Queensland. (PDF version at EprintsUQ)
TOOMBES, L., and CHANSON, H. (2005). "Air-Water Mass Transfer on a Stepped Waterway." Jl of Environ. Engrg., ASCE, Vol. 131, No. 10, pp. 1377-1386 (ISSN 0733-9372). (Download PDF file)
TOOMBES, L., and CHANSON, H. (2008). "Flow Patterns in Nappe Flow Regime down Low Gradient Stepped Chutes." Journal of Hydraulic Research, IAHR, Vol. 46, No. 1, pp. 4-14 (ISSN 0022-1686). (PDF file at UQeSpace)
WANG, H., FELDER, S., and CHANSON, H. (2014). "An Experimental Study of Turbulent Two-Phase Flow in Hydraulic Jumps and Application of a Triple Decomposition Technique." Experiments in Fluids, Vol. 55, No. 7, Paper 1775, 18 pages & 2 video movies (DOI: 10.1007/s00348-014-1775-8) (ISSN 0723-4864). (Postprint at UQeSpace) (PDF file) (Video movies at UQeSpace)
WUTHRICH, D., and CHANSON, H. (2014). "Aeration and Energy Dissipation over Stepped Gabion Spillways: a Physical Study." Hydraulic Model Report No. CH92/13, School of Civil Engineering, The University of Queensland, Brisbane, Australia, 171 pages and 5 video movies (ISBN 9781742720944). (PDF at UQeSpace) (Video movies at UQeSpace)
YASUDA, Y., and OHTSU, I. (2000). "Characteristics of Plunging Flows in Stepped Channel Chutes." Intl Workshop on Hydraulics of Stepped Spillways, Zürich, Switzerland, Balkema Publ., pp. 147-152.
WANG, H., LENG, X., and CHANSON, H. (2017). "Bores and Hydraulic Jumps. Environmental and Geophysical Applications." Engineering and Computational Mechanics, Proceedings of the Institution of Civil Engineers, UK, Vol. 170, No. EM1, pp. 25-42 (DOI: 10.1680/jencm.16.00025) (ISSN 1755-0777). (PDF file) (Reprint at UQeSpace)
ZHANG, G. (2017). "Free-Surface Aeration, Turbulence, and Energy Dissipation on Stepped Chutes with Triangular Steps, Chamfered Steps, and Partially Blocked Step Cavities." Ph.D. thesis, The University of Queensland, School of Civil Engineering, 361 pages (DOI: 10.14264/uql.2017.906). (PDF at UQeSpace)
ZHANG, G., and CHANSON, H. (2016). "Hydraulics of the Developing Flow Region of Stepped Spillways. I: Physical Modeling and Boundary Layer Development." Journal of Hydraulic Engineering, ASCE, Vol. 142, No. 7, 8 pages (DOI: 10.1061/(ASCE)HY.1943-7900.0001138) (ISSN 0733-9429). (Preprint with colour figures) (PDF file)
ZHANG, G., and CHANSON, H. (2016). "Hydraulics of the Developing Flow Region of Stepped Spillways. II: Pressure and Velocity Fields." Journal of Hydraulic Engineering, ASCE, Vol. 142, No. 7, 9 pages (DOI:10.1061/(ASCE)HY.1943-7900.0001136) (ISSN 0733-9429). (Preprint with colour figures) (PDF file)
ZHANG, G., and CHANSON, H. (2018). "Air-water Flow Properties in Stepped chutes with Modified Step and Cavity Geometries." International Journal of Multiphase Flow, Vol. 99, pp. 423-436 (DOI: 10.1016/j.ijmultiphaseflow.2017.11.009) (ISSN 0301-9322). (PDF file) (Record at UQeSpace)
ZHANG, G., and CHANSON, H. (2018). "Effects of Step and Cavity Shapes on Aeration and Energy Dissipation Performances of Stepped Chutes." Journal of Hydraulic Engineering, ASCE, Vol. 144, No. 9, Paper 04018060, 12 pages (DOI: 10.1061/(ASCE)HY.1943-7900.0001505) (ISSN 0733-9429). (PDF file) (Preprint at UQeSpace)
ZHANG, G., and CHANSON, H. (2019). "Application of Optical Flow Methods to Aerated Skimming Flows above Triangular and Trapezoidal Step Cavities." Journal of Hydraulic Research, IAHR, Vol. Vol. 57, No. 4 (2019), pp. 488-497 (DOI: 10.1080/00221686.2018.1489900) (ISSN 0022-1686). (PDF file) (Deposit at UQeSpace)

Internet links

Air entrainment on chute and stepped spillways ... {http://www.uq.edu.au/~e2hchans/self_aer.html}
Current expertise and experience on stepped channel flows {http://www.uq.edu.au/~e2hchans/dpri/topic_2.html}
Minimum Energy Loss (MEL) weir design: an overflow earthfill embankment dam {http://www.uq.edu.au/~e2hchans/mel_weir.html}
Photographs of stepped spillways {http://www.uq.edu.au/~e2hchans/photo.html#Step_spillways}
Sabo check dams {http://www.uq.edu.au/~e2hchans/sabo.html}
Timber crib weirs ... {http://www.uq.edu.au/~e2hchans/tim_weir.html}

CIRIA {http://www.ciria.org.uk/about.htm} CIRIA Report : http://www.ciria.org.uk/publications/pubscat/sp142.htm
USBR Concrete Step Overtopping  Protection{http://www.usbr.gov/wrrl/steps/}

Video movie on YouTube
Stepped Spillway Research - {https://youtu.be/j_AsUXD4D3M}

 

Acknowledgments

The author thanks also the following people in providing some information : Dr R. BAKER (formerly Salford University, UK); Mr K.D. GARDINER (NWW, UK); Professor Y. PRAVDIVETS (Moscow Institute of Civil Engineers, Russia); Mr Craig SAVELA (USDA-NRCS).

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Hubert CHANSON is a Professor in Civil Engineering, Hydraulic Engineering and Environmental Fluid Mechanics at the University of Queensland, Australia. His research interests include design of hydraulic structures, experimental investigations of two-phase flows, applied hydrodynamics, hydraulic engineering, water quality modelling, environmental fluid mechanics, estuarine processes and natural resources. He has been an active consultant for both governmental agencies and private organisations. His publication record includes over1200 international refereed papers and his work was cited over 7,500 times (WoS) to 25,500 times (Google Scholar) since 1990. His h-index is 45 (WoS), 51 (Scopus) and 79 (Google Scholar), and he is ranked among the 150 most cited researchers in civil engineering in Shanghai’s Global Ranking of Academics. Hubert Chanson is the author of twenty books, including "Hydraulic Design of Stepped Cascades, Channels, Weirs and Spillways" (Pergamon, 1995), "Air Bubble Entrainment in Free-Surface Turbulent Shear Flows" (Academic Press, 1997), "The Hydraulics of Open Channel Flow: An Introduction" (Butterworth-Heinemann, 1st edition 1999, 2nd editon 2004), "The Hydraulics of Stepped Chutes and Spillways" (Balkema, 2001), "Environmental Hydraulics of Open Channel Flows" (Butterworth-Heinemann, 2004), "Tidal Bores, Aegir, Eagre, Mascaret, Pororoca: Theory And Observations" (World Scientific, 2011), "Applied Hydrodynamics: an Introduction" (CRC Press, 2014). He co-authored three further books "Fluid Mechanics for Ecologists" (IPC Press, 2002), "Fluid Mechanics for Ecologists. Student Edition" (IPC, 2006) and "Fish Swimming in Turbulent Waters. Hydraulics Guidelines to assist Upstream Fish Passage in Box Culverts" (CRC Press 2021). His textbook "The Hydraulics of Open Channel Flows: An Introduction" has already been translated into Spanish (McGraw-Hill Interamericana) and Chinese (Hydrology Bureau of Yellow River Conservancy Committee), and the second edition was published in 2004. In 2003, the IAHR presented him with the 13th Arthur Ippen Award for outstanding achievements in hydraulic engineering. The American Society of Civil Engineers, Environmental and Water Resources Institute (ASCE-EWRI) presented him with the 2004 award for the Best Practice paper in the Journal of Irrigation and Drainage Engineering ("Energy Dissipation and Air Entrainment in Stepped Storm Waterway" by Chanson and Toombes 2002) and the 2018 Honorable Mention Paper Award for  "Minimum Specific Energy and Transcritical Flow in Unsteady Open-Channel Flow" by Castro-Orgaz and Chanson (2016) in the ASCE Journal of Irrigation and Drainage Engineering. The Institution of Civil Engineers (UK) presented him the 2018 Baker Medal. In 2018, he was inducted a Fellow of the Australasian Fluid Mechanics Society. Hubert Chanson edited further several books : "Fluvial, Environmental and Coastal Developments in Hydraulic Engineering" (Mossa, Yasuda & Chanson 2004, Balkema), "Hydraulics. The Next Wave" (Chanson & Macintosh 2004, Engineers Australia), "Hydraulic Structures: a Challenge to Engineers and Researchers" (Matos & Chanson 2006, The University of Queensland), "Experiences and Challenges in Sewers: Measurements and Hydrodynamics" (Larrate & Chanson 2008, The University of Queensland), "Hydraulic Structures: Useful Water Harvesting Systems or Relics?" (Janssen & Chanson 2010, The University of Queensland), "Balance and Uncertainty: Water in a Changing World" (Valentine et al. 2011, Engineers Australia), "Hydraulic Structures and Society – Engineering Challenges and Extremes" (Chanson and Toombes 2014, University of Queensland), "Energy Dissipation in Hydraulic Structures" (Chanson 2015, IAHR Monograph, CRC Press). He chaired the Organisation of the 34th IAHR World Congress held in Brisbane, Australia between 26 June and 1 July 2011. He chaired the Scientific Committee of the 5th IAHR International Symposium on Hydraulic Structures held in Brisbane in June 2014. He co-chaired the Organisation of the 22nd Australasian Fluid Mechanics Conference held as a hybrid format in Brisbane, Australia on 6-10 December 2020.
 His Internet home page is http://www.uq.edu.au/~e2hchans. He also developed a gallery of photographs website {http://www.uq.edu.au/~e2hchans/photo.html} that received more than 2,000 hits per month since inception.

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Energy Dissipation in Hydraulic Structures Applied Hydrodynamics: An Introduction 2014 Tidal boresApplied HydrodynamicsThe Hydraulics of Open Channel Flow: an IntroductionEnvironmental hydraulics of open channel flow The Hydraulics of Stepped Chutes and SpillwaysThe Hydraulics of Open Channel Flow: an IntroductionAir bubble entrainment in turbulent shear flowsHydraulic design of stepped cascades, channels, weirs and spillways
 McGraw-Hill Interamericana 13th Ippen award (IAHR)