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Beumer, J. P. (1984). Lerderderg River fish-ladder. Aqua. 23:16-17.

A study was undertaken to examine the movement of fish through a fish ladder installed in a diversion weir on the Lerderderg River. The River is a 60 km long tributary forming part of the Werribee River coastal drainage. The Merrimu Reservoir Project providing a domestic water supply for Melton and Bacchus Marsh involved construction of diversion weirs on Goodman Creek and the Lerderderg River. The ladder incorporates 42 steps with a trap bay at step 36. It has a slope of 1:10. A Nylex plastic screen covering the ladder prevents fish escaping and reduces the amount of leaf-litter and other debris falling into the ladder. A two way trap covered by a fine mesh was installed in the trap bay to monitor fish usage of the ladder. Monitoring of the trap and electrofishing were carried out on a weekly basis for 21 weeks. A total of 69 specimens were taken in the trap during the monitoring period, about half in each trap section. While the fish ladder design was suitable for the larger river blackfish and larger brown trout, few smaller specimens of these two species were caught in the trap. The other three species, short-finned eel, roach and Australian smelt, were poorly represented in trap catches suggesting that they could not cope with the fish-ladder in its then existing design. A number of design modifications to the ladder and alterations to the flow pattern downstream of the spillway should improve the efficiency of the ladder.