Climate change impacts on suspended sediment loads in New Zealand


This dataset provides modelled median baseline and future changes in net accumulated mean annual suspended sediment load and local suspended sediment yield for REC2 watersheds by mid- and end-century (2040 and 2090) for four greenhouse gas emissions pathways from the IPCC 5th assessment report.


Date: April 2023 Version: v1

Owner: Manaaki Whenua - Landcare Research

Contact: Dr Hugh G. Smith, Manaaki Whenua - Landcare Research


Link to report / paper

Climate change impacts on erosion and suspended sediment loads in New Zealand


Preview Image


Dataset attributes

Spatial extent New Zealand
Spatial resolution REC2 watersheds
Temporal extent 1995 - 2090
Temporal resolution Multi-decadal annual average
Evaluation method (Validation) NZeem model calibrated with instream data (see Dymond et al., 2010). Dymond, J. R., Betts, H. D., & Schierlitz, C. S. (2010). An erosion model for evaluating regional land-use scenarios. Environmental Modelling & Software, 25(3), 289-298.
Evaluation result (Numeric) None
Evaluation result (Categorical) None
Uncertainty method
Uncertainty data format (Numeric) None
Uncertainty data format (Categorical) None



In response, we have developed a framework for estimating erosion and suspended sediment loads under climate change for use with existing national models. The new framework improves on previous national-scale erosion and sediment load modelling (e.g. Neverman et al. 2019; Monaghan et al. 2021) by:

  • partitioning hillslope-derived sediment loads into mass movement and surface erosion contributions for soft-rock hill-country terrain
  • representing the trapping and storage of sediment in lakes
  • replacing the use of a spatially uniform estimate of the proportional contribution from riverbank erosion to total loads (i.e. 18% of total load in every catchment) with a spatially variable estimate of bank-derived loads in lowlands


Fitness for purpose / limitations

This table indicates whether the dataset is suitable for different types of questions at different scales.

Note: Users should carefully consider their purpose as this dataset may not be suitable.

Operational Absolute Relative Screening/scoping
Block/farm No No Maybe Maybe
Multi-farms(5+) Maybe Maybe Maybe Maybe
Catchment Maybe Maybe Yes Yes
National/regional Yes Maybe Yes Yes
Caveat(s) These model outputs are designed for national-scale assessment of the relative differences in the impact of climate change on erosion and suspended sediment loads between regions. Caution should be taken when using the data at finer resolutions (i.e. catchment to individual REC2 watersheds) due to limitations in the ability of the model to represent erosion processes at this scale.

Data and Resources