Environment Canterbury Reports

The Healthy Estuary and Rivers of the City page on the Environment Canterbury website contains technical reports covering the water quality and ecosystem health monitoring programme of Ihutai. The reports cover aspects of water quality, sediment and biota of the Avon-Heathcote Estuary/Ihutai and rivers, as well as heavy metals in fish in shellfish. This valuable resource begun in 2007 and continues to the present day.

View Healthy Estuary and Rivers of the City reports on the Environment Canterbury website

The sediments and biota within the Estuary of the Heathcote and Avon Rivers Ihutai 2007-2013


Other Technical Reports

Ulva /Graciliaria surveys in the Avon-Heathcote Estuary 2014-15

The marine macroalgae Ulva sp. and Graciliaria sp. are regarded as nuisance weeds in the Avon-Heathcote Estuary due to their excessive biomass negatively impacting on aesthetic, recreational and ecological values. Proliferations of these species are often associated with increased nutrient loading, in particular nitrogen, and historic discharge of treated wastewater into the Avon-Heathcote Estuary was considered to be a main driver of excessive biomass in the estuary.

Author: Donna Sutherland, November 2015

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Broad scale mapping of the Estuary of the Heathcote and Avon Rivers/Ihutai

Broad scale habitat mapping is a method that is used to document the key habitats within an estuary. This mapping also provides data that allow for an assessment of sedimentation, eutrophication and habitat loss of an estuary. The mapping of the Estuary of the Heathcote and Avon Rivers/Ihutai was carried out as part of an Environment Canterbury project.

Authors: Jessica Hollever and Lesley Bolton-Ritchie, July 2016

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Water Quality in the Estuary of the Heathcote and Avon Rivers/Ihutai

A presentation to The Avon-Heathcote Estuary Ihutai Trust by Lesley Bolton-Ritchie from Environment Canterbury.

Author: Lesley Bolton-Ritchie, February 2016

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Terrestrial invertebrates from the salt marshes of the Avon-Heathcote Estuary/Ihutai and Pegasus Bay

This report was commissioned to investigate terrestrial invertebrates (insects, spiders and mites) of tidal and estuary margin vegetation of the Avon-Heathcote Estuary/Ihutai and Pegasus Bay, Canterbury.

Author: R Macfarlane, August 2012
Edited: Denise Ford, 20 June, 2014

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The Avon-Heathcote Estuary as a Recorder of Coseismic Vertical Deformation

This report documents the effects of land deformation following the 22nd February 2011 Christchurch Earthquake on saltmarsh plants and sediment around the Avon-Heathcote Estuary/Ihutai.

GNS Science Consultancy Report 2014/128
UA Cochran, CM Reid, KJ Clark, NJ Litchfield, I Marsden, W Ries

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