Puhinui Stream – Offset Investigation Report

Client:  Auckland Council (Healthy Waters Department)
Date:  2019

PDP was engaged in 2019 as environmental consultants by Auckland Council (AC) (Healthy Waters Department), to undertake a Stream Ecological Valuation (SEV) assessment of the Puhinui Stream. A key objective of the assessment was to determine the ecological potential for restoration of the watercourse, to then inform stream restoration conceptual design. This assessment formed part of a wider project to increase the ecological and amenity value of the Puhinui Stream, and to offset the loss of ecological values from development and/or the provision of infrastructure elsewhere in the region.

SEV scores of 0.2 and 0.25 were calculated from field survey results, indicating that the assessed Puhinui Stream sites had ‘poor’ ecological value based on key ecological functions. However, with modelled enhancements to riparian, channel, and in-stream habitat features, as well as the removal of a fish passage barrier, potential SEV scores increased to 0.65 and 0.6, respectively.

Key Aspects:

  • SEV assessment and comparison of current versus potential scores
  • Additional qualitative habitat assessment
  • Benthic macroinvertebrate and fish survey
  • Assessment of potential stream enhancement options, high level cost assessment, geotechnical assessment and planning assessment
  • Consideration for the wider design of the stream benefits for the community, i.e. designing the stream such that the amenity and aesthetic value of the stream is given higher regard

Client:  Auckland Council (Healthy Waters Department)
Date:  2019

 

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