Reproducible construction of a high-resolution national variable-density groundwater salinity model for the Netherlands

Abstract

Freshwater availability in the coastal zone is threatened by overexploitation, seawater intrusion and global change. Recent advances in parallel computing of coupled variable-density groundwater flow and salt transport models enable the construction of large-scale high-resolution models, key to support sound policy making. Here, we present the construction of a nationwide coupled variable-density groundwater flow and salt transport model for the Netherlands, derived from the existing nationwide groundwater flow model. Construction of the model is fully scripted in a reproducible and transparent version-controlled workflow, aiding regular updating and stakeholder trust in model results. A 3D groundwater salinity distribution was interpolated from over 2M available measurements using Multiple Indicator Kriging as a starting condition in the model. Calculation of a high-end sea-level rise scenario shows the added benefit of large-scale groundwater salinity modelling for policy making. The presented approach is generally applicable to groundwater flow models of coastal aquifers.