This is the same virtual-water-trade model as the 3D globe view, redrawn as a flat top-down network map you can pan and zoom. Every kilogram of a farmed good embeds the water used to grow, process and dilute waste from it — its water footprint (Hoekstra & Chapagain / Water Footprint Network method), split into three components that always sum to 100%:
WF_total = WF_blue + WF_green + WF_grey
blue = surface + groundwater consumed (irrigation)
green = rainwater stored in the soil and used by the crop
grey = freshwater needed to dilute fertiliser/pesticide runoff
back to safe concentration
When a region exports a commodity, it exports the water embedded in it — this is virtual water trade. For an export volume V (kilotonnes/year):
Water exported (billion L/yr) = V × 10⁶ kg/kt × WF_per_kg (L/kg) / 10⁹
Because only the blue share draws down a region's actual rivers, lakes and aquifers, sustained exports of a blue-water-intensive good from an already water-stressed region push its Blue Water Scarcity Index (blue water withdrawn ÷ blue water available, weighted by sensitivity) higher — the same logic behind real concerns about water-stressed countries exporting thirsty crops like cotton or almonds:
BWSI = baseline withdrawal/availability + (blue water exported ÷ regional availability) × sensitivity
- Commodity — sets the blue/green/grey split and the litres-per-kilogram footprint (published global averages).
- Exporting region — sets the baseline water stress and how sensitive that region is to extra blue-water withdrawal.
- Export volume — scales how many droplet particles leave the source node per second and the live readouts.
- Droplets are colour-coded by which component of the footprint (blue/green/grey) they represent, and arc from the exporter to a randomly weighted importer along the map.
- Drag to pan the map, scroll / pinch to zoom.