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Harris, J. H., G. Thorncraft and P. Wem (1998). Evaluation of rock-ramp fishways in Australia. Pages 331-347 in M. Jungwirth, S. Schmutz and S. Weiss, eds. Fish Migration and Fish Bypasses, Fishing News Books, Vienna (Austria).

Most of Australia's freshwater fish species are considered migratory, and all have some requirement for movement within streams. Many fish in coastal drainages are catadromous, while inland-drainage species are commonly potamodromous. Declining populations have been linked with fish-passage obstruction through water-supply development, with thousands of instream barriers. Attempts to restore fish passage are inhibited by the large numbers of barriers, and by the high cost of established technical fishways. The need for low-cost fishways has led to a test of rock-ramps, which use large rocks in transverse ridges, creating pools and small falls, to mimic stream riffles. Twelve rockramps have been built, generally sloping at 1:20. Some occupy only part of the width of the stream channel, but most are built full-width. Problems encountered included structural movement in unsupported ramps, excessive head losses, and fish missing the entrance of partial-width ramps. To assess the effectiveness of four rock-ramps of up to 1.5 m head loss, we compared species representation and length frequencies among fish arriving at the base of the ramps with those caught at the upstream exit. Preliminary results show rockramp fishways can be cheaper than technical fishways, and can provide passage for the species and sizes of native fish examined.