We estimated water ages in the upper critical zone with a soil physical model (SWIS) and found that the age of water stored in the soil, as well as of water leaving the soil via evaporation, transpiration or recharge was younger the higher soil water storage (inverse storage effect). We conceptualized the subsurface into a fast and slow flow domain and the water was usually half as young in the fast than in the slow flow domain. Hide

Socio-hydrological space (SHS) is a concept that enriches the study of socio-hydrology because it helps understand the detailed human-water interactions in a specific location. The concept suggests that the interactions between society and water are place bound because of differences in social processes and river dynamics. This would be useful for developing interventions under disaster management, but also other development goals. SHS provides a new way of looking at socio-hydrological systems. Hide

Phosphorus (P) is important to global food security. Thus it is concerning that natural P-reserves are predicted to deplete within the century. Here we explore the potential of P-recovery from wastewater (WW) at global scale. We identify high production and demand sites to determine optimal market prices and tradeflows. We show that 22 % of the agricultural demand can be met. However, only 4 % can be met economically. Nevertheless, recovery stimulates circular economic development in WW treatment. Hide

This paper presents a brief review and classification of sensitivity analysis (SA) methods. Six different global SA methods: Sobol, FAST, Morris, LH-OAT, RSA and PAWN are tested on the three conceptual rainfall-runoff models with varying complexity: (GR4J, Hymod and HBV), with respect to effectiveness, efficiency and convergence. Practical framework of selecting and using the SA methods is presented, which may be of assistance for practitioners assessing reliability of their models. Hide

This technical note derives the additional specific energy of evaporation, beyond the latent heat of vaporization, as the work done against ambient pressure when water expands from the liquid to the gas phase. The derivation yields a simple function of the virtual temperature, and corrects for a systematic 3–4 % underestimation of the energy required to evaporate water into the Earth's atmosphere. Hide

Rainfall time series are disaggregated from daily to hourly values to be used for rainfall-runoff modeling of meso-scale catchments. Spatial rainfall consistence is implemented afterwards using simulated annealing. With the applied calibration process, observed runoff statistics (e.g. summer and winter peak flows) are well represented. However, rainfall data sets with under- or overestimation of spatial consistence lead to similar results, so the need for a good representation can be questioned. Hide

Recently, deep learning (DL) has emerged as a revolutionary and versatile tool transforming industry and scientific disciplines. We argue that DL can offer a complementary avenue toward advancing water sciences because it can efficiently learn from all data and generate new data. New methods are being developed to interpret the knowledge learned by deep networks. We argue open competitions, more data sharing, data collection from citizen scientists will be helpful in incubating advances. Hide

For precipitation, an increasing tendency in precipitation for the southeastern monsoon region and a decreasing tendency for the northeastern monsoon region (the drier region) were observed. Strong increasing tendencies for air temperature and downward long wave radiation, were observed in the northeastern monsoon region and the western area of Qinghai-Tibetan Plateau. Due to changes in precipitation and air temperature and downward long wave radiation, the scarcity of water resources. Hide

At larger scales, the flow of rivers can often be described by a relatively simple, exponential decay, and it is unclear how such simple behaviour can be explained given that river basins show such vast complexity. Here, we use a highly idealised model to show that such simple behaviour can be explained by viewing it as the emergent consequence of the groundwater system (which feeds river flow) minimising its energy dissipation. Hide