I - Impact of vadose zone media (DRASTIC)

I layer is calculated by direct assignment of vadose zone material to I index values according to DRASTIC methodology, raning from 1 to 10. In areas covered by subsoil deposits, the vadose zone media classification (the ‘I’-rating) was based on soil and subsoil type. In areas of exposed bedrock and subcrop or areas with < 3 m of subsoil coverage, the characteristics of the vadose zone was taken from the aquifer characteristics.