Periphyton in the Tairāwhiti Region
Client
Gisborne District Council
Experts
Dr Mark Heath (Traverse Environmental)
Gisborne District Council (GDC) sought advice on how to establish baseline attribute states for periphyton biomass at monitoring sites in the Tairāwhiti Region within Freshwater Management Units.
Guidance under the NPS-FM meant that periphyton sample collection – to determine baseline attribute states - needed to be taken monthly, rather than annually as had been occuring in Tairāwhiti until recently. In response to this requirement, GDC requested expert support in developing an approach to setting attribute states in the absence of historic monthly data.
Through A2E’s support, Dr Mark Heath (Traverse Environmental) reviewed the available data and guidance to help GDC develop suitable methodology. This factored in different lines of evidence and data to develop attribute states. Some of the data assessed included:
- all available biomass and periphyton visual cover
- river environment classifications and segment model estimates from nutrient outcome/criteria models
- data related to stream substrate, channel morphology characteristics and shading
- local knowledge of periphyton state.
Based on the expert support provided by A2E and Dr Mark Heath, GDC are able to make more informed decisions and provide greater certainty around the developed baseline attribute states.