Mapping Freshwater Contaminants

How can the research be used? Ka pēhea e whai take ai te rangahau?

• This research will produce a National Landscape Classification for Freshwater Management, including contaminant flow-paths and attenuation coefficients; national maps of groundwater redox and denitrification potential; and national maps of attenuation coefficients for nitrogen and phosphorus species, sediment, and microbial contamination.
• The work will identify uncertainties, limitations and data gaps, and will make recommendations of where to prioritise new monitoring and modelling to help predict contaminant flow-paths (N and P species, suspended sediment, E. coli) and their potential attenuation.
• This research will provide the Ministry for the Environment with better landscape biogeochemical information in relation to contaminant risks, for use in policy option assessments. Local government will also benefit from this information, for use in NPS-FM implementation, for example as inputs to catchment models.
• This research will provide information about the achievable accuracy and precision of analyses that simulate the impacts of land use and management on contaminant levels in freshwater receiving environments.

• Understanding nitrogen and phosphorus attenuation uncertainty is of critical importance, because it underpins policy makers’ and land managers’ confidence in predicting water quality changes from land use or management changes. Understanding uncertainty in the attenuation estimates strongly determines the accuracy and precision with which any land management regime variable can be specified, including contaminant accounts, allocations and expected water quality outcomes. Not understanding the achievable accuracy and precision associated with catchment models can create false confidence in any predicted outcomes or decisions that will not be achievable.