A Budyko-type model for human water consumption

Budyko-type models in hydrology are simple but efficient descriptions of the vegetation-mediated hydrologic cycle in catchments. Based on hypothesized similarities between vegetation and human water consumption interactions in terms of water demand, constraints, and system functioning as well as catchment processes and outcomes, a corresponding Budyko-type framework is proposed here for human water consumption at the catchment scale. To validate this framework, socioeconomic data (human water consumption and economic and agricultural structure data), as well as hydrometeorological data, for 51 human-impacted catchments located in 10 major river basins in China were assembled. The results demonstrate (1) similar observed patterns to the traditional Budyko curves, with two limits and a monotonous increase shape; (2) the same functional form and mathematical features of the derived Budyko-type equation. Parameters of the new Budyko-type model for human consumption are estimated and analyzed based on the concept of water productivity. This study suggests that the functioning of both social and hydrologic subsystems within catchment systems can be explored within a common conceptual framework, thus providing a unified socio-hydrologic basis for the study of human–water systems.