Norfolk Island soil water holding capacity DSM attributes

Soil water holding capacity modelled for 0-60 cm, 0-100 cm and 0-150 cm are three of nine soil attributes analysed as one component of a digital soil mapping exercise undertaken as part of the Norfolk Island Water Resource Assessment (NIWRA). It was selected due to its importance to groundwater recharge, surface water storage and managed aquifer recharge. Soil water holding capacity is the total amount of water a soil can hold at field capacity (after excess water has drained away by gravity) and is water that is held in the ‘unsaturated’ zone of the soil (i.e. above the groundwater table) and does not contribute to groundwater or streamflow. These raster data represent modelled datasets of soil water holding capacity and are derived from field measured site data and environmental covariates. Data values are expressed in mm of water to the respective soil depth. Companion datasets presenting reliability of these data is also provided and can be found described in the lineage section of this metadata record. Processing was carried out in the ranger package inside R and attributes were modelled using a Random Forest approach. Further soil water holding capacity information can be found in the NIWRA technical report (Petheram et al., 2020). The DSM process is described in Appendix E of the NIWRA technical report.