The interprovincial green water flow in China and its tele-connected effects on socio-economy

Abstract. Green water (terrestrial evapotranspiration), flowing from source regions and precipitates downwind via moisture recycling, generates surface water resources and sustains socio-economy in sink regions. However, unlike blue water, there has been limited assessment of green water flows and their tele-connected effects on socio-economy. This study used the moisture tracking dataset of 2008–2017 to quantify interprovincial green water flows in China and their socio-economic contributions. Results reveal a complex flow network where green water of each province reciprocally exchanges with each other. Despite self-recycling, green water from source provinces mainly forms precipitation in neighboring provinces, with average interprovincial flow directions from west to east and south to north. About 56 % of total green water exported from 31 provinces retains at home and contributes 43 % of precipitation in China. Our assessments show that green water from source provinces embodies substantial socio-economic values for downwind provinces with regionally varying importance. Western provinces are the largest contributors to surface water resources while southwestern and central provinces embody the highest GDP, population, and food production. About 40 % surface water resources, 45 % GDP, 46 % population, and 50 % food production of China are supported by green water from 31 provinces. There is an overall increase in embodied socio-economic value of green water flow from source to sink provinces, suggesting that less developed provinces effectively support the higher socio-economic status of developed provinces through green water supply. The results emphasize the substantial tele-connected socio-economic values of green water and the need to incorporate it for a more comprehensive and effective water resources management.