NIWA is currently carrying out a study for Auckland Council and Waikato Regional Council collating and analysing data on suspended sediment yields across the Northland, Auckland and Waikato regions. The aim of this study is to develop a predictor model of catchment suspended sediment yields based on various catchment characteristics. As an additional task in this study Auckland Council has commissioned NIWA to assess the Weiti Stream suspended sediment dataset for evidence of a trend or change in sediment loads that can be related to forestry harvesting activities. The data support analysis that looks for temporal change in the ‘rating’ relationship between suspended sediment yield (SSY) and event peak discharge (Qpeak). We are interested in whether the rating relationship between SSY and Qpeak for the period prior to forestry harvesting (2008-2012) still adequately predicts SSY for the period during (2013) and following (2014) forestry harvesting. The data analysis is summarised in plots that show: The rating relationship between event suspended sediment yield (SSY) and event peak discharge (Qpeak) for the pre-harvesting period. The during- and post-harvest data are also included on the plot, but the rating is based on the pre-Harvest data only. The during- and post-harvest period data all plot above the rating trendline, but are within the bounds of the preharvest data. A further two plots show the relationships between the residuals derived from the previous plot and time over the pre-Harvest period and time over the full data period respectively. It is the gradient of the trendlines in these two plots that we test to see if each is statistically different from zero.