The figure describes the iAqueduct framework of methodologies and approaches. It includes six closely connected working packages (WPs). WP1 deals with the scaling from global satellite water cycle products to field-scale water states, which includes both the surface and profile information on soil water states. Specifically, WP1 will advance the space-time characterization of soil moisture and evapotranspiration processes through the combined use of field, UAS, and satellite observations. In particular, the combined use of high-resolution soil characteristics and satellite data will increase our capabilities to describe soil moisture and evapotranspiration processes with high-level detail.

It has been demonstrated that soil hydraulic and thermal properties (SHP/STP) play a critical role in determining soil water and heat flow at field/plot scales, while such information is rarely available at such detailed scales. WP2 will apply pedotransfer functions to derive local field specific SHP/STP properties for the modelling of soil water and heat dynamics at field-scale precision. It will bridge soil spectral information that can be obtained at a high resolution by satellites and UAS and the needed soil properties that are traditionally obtained at limited locations by in situ sample collections.

Using the information obtained from the two previous WPs, WP3 attempts to retrieve field- and grid-specific relationship functions between soil properties, soil moisture, and evapotranspiration. Such a relationship function is expected to advance the current hydrological modelling concepts, in which the actual evapotranspiration is parameterized on the availability of soil moisture using untested (linear) assumptions. Field-specific functions will be developed on the basis of downscaled satellite observation of soil moisture and evapotranspiration, and their combined analysis with in situ measurements and UAS observations.

WP4 is expected to advance ecohydrological modelling by intercomparing models with different levels of complexity, in terms of the soil–water–vegetation–atmosphere transfer processes involved. It sets to explore the advantages and disadvantages of these different models, while aiming at reducing the reliance on in situ observations for model parameterization and taking full advantage of UAS, airborne, and satellite observations. It focuses on the parameterization of the minimalist soil moisture models, coupled soil and plant models, and crop growth models.

WP5 will then demonstrate the benefits in closing water cycle gaps from the global to local scale, in terms of how to effectively handle spatiotemporal data (from in situ, UAS, and satellites), regarding ecohydrological model calibrations and accuracy evaluations of simulated spatial patterns of ecohydrological variables. Particularly, numerical experiments will be conducted for the calibration of a parsimonious-distributed ecohydrological daily model in ungauged basins using exclusively spatiotemporal information obtained from WP1, WP2, and WP3, to link the scales from plant to plot, sub-catchment, and catchment/basin.

WP6 is about disseminating and communicating generated knowledge, data, and tools to water managers, companies, and farmers for actual sustainable water management of their responsible domains. Particularly, to address stakeholders’ requirements, iAqueduct will develop an integrative information system (an open source iAqueduct toolbox), which will integrate models, soil parameters, forcing and field-scale observation, and gridded water states and fluxes to support the translation of science knowledge into water productivity information for the smart management of water resources. The goal is to develop potentially effective approaches connecting science to the society, thus influencing citizens towards desirable behavior in water management.