This report, prepared by NIWA, evaluates the deposited fine sediment (DFS) attribute within the National Policy Statement for Freshwater Management. It assesses the clarity, consistency and practical implementation of the DFS policy and associated guidance, drawing on scientific literature and feedback from regional and unitary councils across New Zealand.

The review highlights concern among councils about the ecological impacts of fine sediment on river health, particularly on macroinvertebrate communities, and identifies key challenges in applying the DFS attribute such as limitations of the SAM2 monitoring method, uncertainty in classifying riverbeds, and narrow threshold bands.

The report concludes that while DFS is widely recognised as a significant stressor, improvements in policy guidance, monitoring protocols, and decision-making support are needed to enhance freshwater management outcomes.