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Critical Pathways

Understanding water flow on catchment scale

Lincoln Agritech, New Zealand, is leading a five-year Critical Pathways Programme (CPP)  - a research programme funded by the Ministry of Business, Innovation and Employment (MBIE) in New Zealand. Responding to a well-recognised knowledge gap, it aims to elucidate the relatively shallow and short pathways operating at the sub-catchment scale, and to represent them in water flow and contaminant transfer models.

Two contrasting Waikato catchments, the Waiotapu Stream catchment (approx. 300 km2) and the Piako River headwater catchment (approx. 100 km2) were surveyed using SkyTEM. The survey took only seven flight days to complete. Using parallel flight paths (200 m apart) enabled us to get high-resolution data across the entire catchment areas. This starkly contrasts with the conventional approach that uses a limited number of point-scale lithology data (colour, texture, and composition) from the installation of groundwater bores.

The Hydrogeophysics group is a partner in the project and has assisted with optimal SkyTEM setup with respect to mapping the shallow subsurface environment. Furthermore HGG has assisted in the processing and interpretation of the big-data SkyTEM dataset. Researchesr from HGG and Lincoln Agritech will also collaborate closely on how to take all this big data and transform it into realistic modelling of the water and contaminant  flow on a catchment scale. The Critical pathways project should thus be seen as a "sister project" to Mapfield.