Storm chasing - understanding sediment generation and transport
NIWA scientists have been out in the rain, monitoring the impact of storms on sediment erosion and transport. Data collected will be used to help integrate a series of models which simulate the ‘source-to-sea’ generation, transfer, and dispersal of fine sediment from a range of sources following storms.
Scientist Lucy McKergow explains: “To date, models of river and coastal processes have tended to evolve separately, because of the lack of integrated research. We want to link existing catchment, stream, and estuarine models, to create a seamless story of sediment movement.” This integration has been held back in the past by lack of detailed information on storm flow generation and transport of sediments from hills to harbours.
The Waitetuna catchment, near Raglan, was the focus for the research. Fifteen monitoring sites were established throughout the catchment; these were in small catchments with different land covers, the main river, and the estuary. At each site factors such as water flows, turbidity, and suspended sediment were measured during a large storm.“Ultimately we aim to develop tools to guide land managers, so as to minimise the risk of fine sediment ending up in streams and estuaries, where it has the potential to smother life and cause a lot of ecological damage,” says Lucy.