Water is essential to the progress of human societies. It is required for a healthy environment and a thriving economy. Food production, electricity generation, and manufacturing, among other things, all depend on it. However, many decision-makers lack the technical expertise to fully understand hydrological information. In response to growing concerns from the private sector and other actors about water availability, water quality, climate change, and increasing demand, WRI applied the composite index approach as a robust communication tool to translate hydrological data into intuitive indicators of water-related risks. This technical note serves as the main reference for the updated Aqueduct™ water risk framework, in which we combine 13 water risk indicators-including quantity, quality, and reputational risks-into a composite overall water risk score. The main audience for this technical note includes users of the Aqueduct tool, for whom the short descriptions on the tool and in the metadata document are insufficient. This technical note lays out the design of the Aqueduct water risk framework, explains how various data sources are transformed into water risk indicators, and covers how the indicators are aggregated into composite scores. This document does not explore the differences with the previous version. The resulting database and online tools enable comparison of water-related risks across large geographies to identify regions or assets deserving of closer attention. Aqueduct 3.0 introduces an updated water risk framework and new and improved indicators. It also features different hydrological sub-basins. We introduce indicators based on a new hydrological model that now features (1) integrated water supply and demand, (2) surface water and groundwater modeling, (3) higher spatial resolution, and (4) a monthly time series that enables the provision of monthly scores for selected indicators. Key elements of Aqueduct, such as overall water risk, cannot be directly measured and therefore are not validated. Aqueduct remains primarily a prioritization tool and should be augmented by local and regional deep dives. Source: WRI. OVERALL WATER RISK Physical risk quantity Baseline water stress Baseline water depletion Interannual variability Seasonal variability Groundwater table decline Riverine flood risk Coastal flood Drought risk Untreated connected wastewater Coastal eutrophication potential Unimproved/no drinking water Unimproved/no sanitation Peak RepRisk country ESG risk index Physical risk quality Regulatory and reputational risk

The forecast of climate change effects on the groundwater system in coastal areas is of key importance for policy makers. The Dutch water system has been deeply studied because of its complex system of low-lying areas, dunes, land won to the sea and dikes, but nowadays large efforts are still being done to find out the best techniques to describe complex fresh-brackish-saline groundwater dynamic systems. In this paper, we describe a methodology consisting of high-resolution airborne electromagnetic (EM) measurements used in a 3-D variable-density transient groundwater model for a coastal area in the Netherlands. We used the airborne EM measurements in combination with borehole-logging data, electrical conductivity cone penetration tests and groundwater samples to create a 3-D fresh-brackish-saline groundwater distribution of the study area. The EM measurements proved to be an improvement compared to older techniques and provided quality input for the model. With the help of the built 3-D variable-density groundwater model, we removed the remaining inaccuracies of the 3-D chloride field and predicted the effects of three climate scenarios on the groundwater and surface water system. Results showed significant changes in the groundwater system, and gave direction for future water policy. Future research should provide more insight in the improvement of data collection for fresh-brackish-saline groundwater systems as it is of high importance to further improve the quality of the model

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The hydrologic regime of a river is one of the factors determining its ecological status. This paper tries to indicate the present hydrologic stress occurring across European rivers on the basis of model integration. This results in a pan-European assessment at the resolution of the functional elementary catchment (FEC), based on simulated daily time-series of river flows from the model PCR-GLOBWB. To estimate proxies of the present hydrologic stress, two datasets of river flow were simulated under the same climate, one from a hypothetic least disturbed condition scenario and the second from the anthropogenic scenario with the actual water management occurring. Indicators describing the rivers' hydrologic regime were calculated with the indicators of hydrologic alteration (IHA) software package and the river total mean flow and the relative baseflow magnitude over the total flow were used to express the deviations between the two scenarios as proxy metrics of rivers' hydrologic alteration or hydrologic stress. The alteration results on Europe's FEC-level background showed that Southern Europe is more hydrologically stressed than the rest of Europe, with greater potential for hydrology to be clearly associated with river segments of unreached good ecological status and high basin management needs.Water 2019, 11, 703 2 of 17 shapes the patterns of erosion and sedimentation, and influences the type and dynamics of the river channels, banks and floodplains [1]. The hydrologic regime affects water chemistry through processes of retention, dilution or concentration. By this, it constitutes the habitat template for the riverine biota. Hydrology is thus an indispensable component of riverine ecology, and anthropogenic alteration of the hydrologic regime entails ecological detriment [2].Riverine hydrology is altered by humans in various ways [3,4]. At the local to regional scale, water abstraction, water diversion, water drainage and channelization modify the flow regime for the benefit of domestic, industrial or agricultural supply. In particular, dams represent one of the major anthropogenic disturbances of the rivers' hydrologic regimes [5]. At the river basin scale, the water retention capacities are reduced by converting natural vegetation into land used for agriculture or urbanization. At the continental scale, patterns of precipitation and evaporation shift due to a changing climate, with important changes in climate extremes over time. These alterations impact on the riverine ecosystems and lead to changes in natural flows, including water scarcity or overabundance with implications for ecological status and ecosystem services [6,7].However, full understanding of the effects of hydrologic alteration is still not available [8]. On the one hand, this relates to the intricate features of riverine hydrology covering the elements of timing, magnitude, duration and frequency, all of which are integral components of the ecosystem [9]. On the other hand, this relates to the lack of comprehensive datasets, e.g., from strea...

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