Water Resources of South Africa, 2012 Study (WR2012) SALMOD: salinity modelling of the Upper Vaal, Middle Vaal and Lower Vaal sub-water management areas (new Vaal water management area) Water Resources of South Africa, 2012 Study (WR2012) SALMOD: salinity modelling of the Upper Vaal, Middle Vaal and Lower Vaal sub-water management areas (new Vaal water management area) Posted in .