Upscaling point-scale soil hydraulic properties for application in a catchment model using Bayesian calibration: An application in two agricultural regions of New Zealand

Hydrological modeling for landscape and catchment scale applications requires upscaling of soil hydraulic parameters which are generally only available at point scale. We present a case study where hourly root zone water content drainage observations from nine flat, pastoral sites (Waikato Canterbury regions in New Zealand) were used to develop an approach parameterize the balance module TopNet model, based on scaling multi-layer profile information national data base, S-map, single-layer TopNet. Using Bayesian calibration approach, behavioral TopNet's identified. Of eleven considered three found be insensitive (stress point, unsaturated conductivity infiltration rate); correlated could determined specific (wilting field capacity drainable water); five combined (drainage rate, saturated profile, effective depth, holding wetting front suction). Based eight parameters, functions then developed derive suitable model S-map-hydro each site. The validity was verified this research can other similar locations, also provides transferable framework catchment-scale hydrology models point-scale available.