A new plugin to estimate the level of water stress (SDG 6.4.2) by season and by sub-basin (Food and Agriculture Organization of the United Nations)

While at global level water stress does not seem to present a serious threat to the sustainability of freshwater withdrawal and use, the situation appears much grimmer if a closer look is given to the status of the freshwater resources at basin and sub-basin level. Hence, disaggregating water stress at basin and sub-basin level is fundamental to provide a finer view of both its causes and effects. When the water stress is disaggregated at sub-basin level, there is the possibility of counting twice or more the same amount of water as it flows from one sub-basin to the neighbouring ones. This causes an underestimation of water stress, and an overestimation of the water resources available for human use.

Considering the importance of disaggregating at a finer scale, FAO, as a partner of the UN-Water Integrated Monitoring Initiative for SDG 6 and custodian of the monitoring of the SDG 6.4 target, has started a collaboration with the Stockholm Environment Institute (SEI) to develop a new plugin in the Water Evaluation And Planning tool (WEAP) to assess the SDG indicator 6.4.2 at sub-basin scale. In this new tool, the double counting of the water resources was addressed by assessing the water supplies of each sub-basin considering the water demands of their neighbouring sub-basins. Calculating the water stress by sub-basin becomes factually an input to inform water management choices.