Ecological Assessment of Pleura and Waikana Streams

Client:  Gore District Council
Date:  2019

We were engaged in 2019 as environmental consultants for Gore District Council to undertake ecological assessments of Pleura and Waikana streams near Gore, Southland.  Ecological assessments were required to provide further information for the resource consent renewal of a community water supply.  The key objective of this investigation was to ascertain whether there were any ecological effects associated with water takes (and associated structures) from the two streams.

Field and desktop assessments indicated that both streams comprise high-value native fish communities, including the ‘Threatened – Nationally Vulnerable’ gollum galaxias (Galaxias gollumoides).  Generalised habitat modelling completed downstream of each water intake structure showed that instream habitat was largely maintained during annual low-flow conditions and that satisfactory levels of non-migratory galaxiid (i.e. gollum galaxias) habitat will be retained during proposed minimum flow conditions. 

Water intake structures were identified as potential barriers to upstream freshwater fish migration.  However, as indicated by gollum galaxias populations upstream of Pleura Dam, the disruption of upstream predatory fish (i.e. trout) migration has likely fostered conservation benefits.

Key Aspects:

  • Information review of relevant water quality and ecological values
  • Water quality sampling
  • Streamflow gauging
  • Freshwater fish sampling (electric fishing and trapping)
  • Fish passage assessment
  • Macroinvertebrate sampling
  • Habitat assessment
  • Instream habitat modelling

Client:  Gore District Council
Date:  2019


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