To assess the water stress level in the respective region (catchment), water withdrawals from surface water or from groundwater (so-called "blue water") for households, industry and livestock were considered, in addition to irrigation water. Water withdrawals were set in relation to water availability in the respective region ("withdrawal-to-availability" relation = wta):*
If wta is less than 0.2, no water stress is present,
if wta is between 0.2 and 0.4, a medium water stress situation is assumed,
and if wta is equal to or greater than 0.4 (i.e. 40% of available water or more is withdrawn), high water stress must be assumed.