Emergency Works Ecological Impact Assessment

Following a large land slip, Morphum Environmental was engaged by Watercare to prepare an Ecological Impact Assessment (EcIA) to support works to remediate a broken wastewater line within Rangatira Reserve.

Following the emergency works, a consent application was lodged for the emergency work and the planned completion of the pipe repair and site stabilisation. For this application, Morphum assessed the ecology for both the emergency work and proposed works.

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Morphum’s assessment followed the Environmental Institute of Australia and New Zealand’s Ecological Impact Assessment Guidelines (EcIAG) (EIANZ, 2018), which utilises a standard framework and matrix approach providing a consistent and transparent assessment of effects. While the framework for assessment provides structure to quantify the level of ecological effects, it also needs to incorporate sound ecological judgement to be meaningful.

The ecological values of the site were assessed for bats, avifauna, terrestrial vegetation, herpetofauna, native freshwater fish, and stream ecological values. The magnitude of effects ranges from Negligible to Moderate, with the highest impacts on native freshwater fish, terrestrial vegetation, and stream ecological values, leading to management and offset measures.

Management measures implemented include lizard management to salvage native lizards, vegetation removal outside the bird nesting season, and erosion and sediment controls which focussed on minimising sediment entering Kahika stream. Proposed measures for reinstatement and replanting to replace removed vegetation, and offsetting residual adverse effects. In addition to a formal streamworks design to stabilize the stream bank, work was done to improve fish passage and enhance wastewater network’s resilience.

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Using the Biodiversity Compensation Model, combined reinstatement and offsetting efforts will result in a 10.4% increase in ecological value over 15 years, restoring the area to pre-construction ecological values.

Morphum was able to provide formal recommendations that not only restores, but enhances the ecological and infrastructure value of Rangatira Reserve.

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