The Research Report CE158 may be downloaded in two parts :
http://www.uq.edu.au/~e2hchans/reprints/ce158_1.pdf    [Part I]
http://www.uq.edu.au/~e2hchans/reprints/ce158_2.pdf    [Part I]

Reference
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, 74 pages (ISBN 1 864995297).