Energy Dissipation and Drop Structures in Ancient Times: The Roman Dropshafts

Chanson, Hubert (1999). Energy Dissipation and Drop Structures in Ancient Times: The Roman Dropshafts. In: Water 99 Joint Congress, 25th Hydrology & Water Resources Symposium and 2nd International Conference on Water Resources & Environmental Research, Brisbane, Australia, (987-992). 6-8 July 1999.

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Author Chanson, Hubert
Title of paper Energy Dissipation and Drop Structures in Ancient Times: The Roman Dropshafts
Conference name Water 99 Joint Congress, 25th Hydrology & Water Resources Symposium and 2nd International Conference on Water Resources & Environmental Research
Conference location Brisbane, Australia
Conference dates 6-8 July 1999
Publication Year 1999
Sub-type Fully published paper
Volume 2
Start page 987
End page 992
Abstract/Summary Drop structures and stepped cascades have been used for over 3,000 years. In particular, Roman engineers designed successfully dropshafts in Tunisia, Algeria, France and Italy. There is however little information available on their hydraulic performances. In the present study, the writer investigates the operation of Roman dropshaft. A new re-analysis of Roman dropshaft hydraulics, associated with physical model tests performed at the University of Queensland, demonstrates that the vertical dropshafts were very efficient energy dissipator and re-oxygenation structures. Most aqueducts were covered along their entire length, limiting the gas transfer at the free-surface and the downstream waters were low in DO content, unless re-oxygenation dropshafts were installed. It is interesting to compare the Roman dropshaft design with current designs. Today vortex dropshafts are common design to minimise scouring effects and, to some extent, air entrapment. In contrast, the Roman dropshafts were equipped with deep water pools which acted as a cushion to prevent scour. And air bubble entrainment (by plunging jet) was substantial at the free-falling nappe impact, contributing successfully to an enhancement of the DO content.
Subjects 290799 Resources Engineering not elsewhere classified
260500 Hydrology
291199 Environmental Engineering not elsewhere classified
290899 Civil Engineering not elsewhere classified
290800 Civil Engineering
260502 Surfacewater Hydrology
290000 Engineering and Technology
291100 Environmental Engineering
290700 Resources Engineering
260000 Earth Sciences
300100 Soil and Water Sciences
260501 Groundwater Hydrology
299901 Agricultural Engineering
300000 Agricultural, Veterinary and Environmental Sciences
299900 Other Engineering and Technology
290802 Water and Sanitary Engineering
300105 Applied Hydrology (Drainage, Flooding, Irrigation, Quality, etc.)
260599 Hydrology not elsewhere classified
Keyword dropshaft hydraulics
hydraulic structures
Roman aqueducts
energy dissipation
drop structures
physical modelling
engineering heritage
Q-Index Code E1
Q-Index Status Provisional Code
Institutional Status Unknown
Additional Notes CHANSON, H. (1999). "Energy Dissipation and Drop Structures in Ancient Times : the Roman Dropshafts." Proc. Water 99 Joint Congress, 25th Hydrology & Water Res. Symp. and 2nd Intl Conf. Water Res. & Environ. Research, Brisbane, Australia, Vol. 2, pp. 987-992 (ISBN 185 825 7165).

Document type: Conference Paper
Collection: School of Civil Engineering Publications
 
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Created: Wed, 26 Oct 2005, 10:00:00 EST by Hubert Chanson