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Aquatic Life

In order to ascertain the environmental effects of the diversion of water from the lower Parapara Gorge and in the vicinity of the Richmond Flat dam, a Fisheries Survey of the Parapara River was undertaken by Neil Deans of Fish and Game New Zealand.

In all, eight species of fish were identified and two invertebrates, koura and fresh water shrimp. Only three fish species were identified in the upper catchment; koaro (mountain trout), and long and short-finned eels. Below the lower gorge along with these three species were added a single brown trout, torrentfish, redfinned bully, inanga, banded kokopu and the invertebrate species.

None of these species are regarded by the Department of Conservation as endangered although koaro and banded kokopu are classed as threatened. Kokopu do not appear to find the Parapara River a suitable habitat (cf. Washbourne Creek nearby) and koaro are abundant in all parts of the catchment surveyed.

As the major aquatic impact of this proposal is on the lower gorge of the Parapara River. The data indicates the lower gorge is not a productive fisheries habitat as would be expected from the steep 7% gradients, many cascades and large flood flows but rather provides access for species to the habitats of the Parapara headwaters. The riffle and cascade fish habitat in the upper reaches of the gorge above Dam Creek will be reduced as water is diverted. There is evidence that this habitat is currently poorly exploited within the gorge reach.

Some mitigation of limitation of riffle and cascade habitats in the Gorge is possible from the re-addition of the wetland habitat through the re-raising of the water levels at Richmond Flat by the repair of the Dam crest. The provision of a fish pass at the Dam may provide the opportunity for species which are currently unable to transit this obstacle to gain access to Richmond Flat and beyond if such species are present in the upper section of the gorge. Such access may also be utilised by Brown Trout currently absent from above Richmond Flat.

A fisheries survey of the Parapara River is attached as Appendix #4.

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