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Future water security will be determined by climate change along with socio-economic changes, driving water availability, water demands and catchment conditions. Over recent decades, hydrological models have evolved to incorporate the effect of anthropic activities that allow them to explore the main challenges and opportunities regarding global water security. These advances have been underpinned by progress in high-resolution and large-scale data availability, as well as in computational and data storage capabilities. Hydrologists are currently capable of developing high-resolution large-scale hydrological models designed to represent and study the global hydrological cycle, and even to zoom-in on specific regions essentially removing the barriers between global and regional models. However, the use of these modelling approaches is often seen with suspicion by end-users, be it regional water managers or water users, who may consider that their personal knowledge and understanding of the catchments where they carry out their activities is disregarded in favour of novel technologies. Indeed, despite their growing sophistication, the current generation of LHMs is not yet exempt of limitations in their ability to represent dynamic trade-offs in the water-food-energy-environment nexus, and water competition between upstream and downstream users in complex water resources systems. These limitations hinder the ability of LHMs to provide reliable insights at the regional or local levels, leaving the task of incorporating human water management activities within these models as one of the grand challenges for the hydrologic research community. The inclusion of this local knowledge into LHMs’ modelling process can, therefore, increase their capacity to support rigorous nexus analyses to inform water policy and management decisions. Unfortunately, the access to these data may be limited by several inconveniences such as overprotective water authorities, language access barriers, or simply not existing at all. This work explores to what extent the inclusion of local knowledge can improve the performance of globally formulated models as well as their reliability to support decision making on the ground. We discuss what type of data might be more relevant and what should be the priorities in data acquisition to maximise the output of modellers efforts. To demonstrate this, we built a CWatM model of the Ebro River catchment in Spain using large-scale datasets to later substitute or enhance such datasets with data obtained from local and regional specific datasets available from local authorities and water users. The additional data/enhancements were included in separate and cumulative steps. The model improvements were assessed comparing the model results against gauged flows, reservoir storage, water demand and supply, and the system’s drought indicator. The findings of this study will assist in the transition of globally formulated models to being applied locally by identifying the priorities in data gathering and advances in modelling capabilities, ensuring that they provide reliable outputs to inform decision making.

Sistemas de compartilhamento de veículos são uma realidade há décadas na Europa, no entanto ainda estão pouco presentes em países em desenvolvimento como o Brasil. Este trabalho aborda a perspectiva do compartilhamento de veículos sob a ótica da sustentabilidade, nas dimensões ambiental, econômica e social. É feita a descrição de componentes importantes do modelo de negócio desenvolvido, como clientes, recursos, estrutura de custos e a rede de valor envolvida no compartilhamento de veículos. São também destacadas as contribuições de um modelo de negócio de compartilhamento de veículos para os Objetivos do Desenvolvimento Sustentável propostos pela Organização das Nações Unidas. Sob a perspectiva ambiental, um ponto importante é relacionado à extensão do ciclo de vida da bateria do veículo elétrico, que além do alto custo, também gera alto impacto ambiental e social na produção. Como contribuições sociais, o veículo elétrico é considerado seguro e pode substituir o transporte utilizando motocicletas- que estão relacionadas com altos índices de acidentes de trânsito e por sua vez gastos governamentais relacionados a esses acidentes.

Over recent decades major advances have been made in global hydrological modelling underpinned by progress in high-resolution data availability, as well as in computational and data storage capabilities. These advances have provided hydrologists with opportunities to develop high-resolution large-scale hydrological models (LHMs) designed to represent and study the global hydrological cycle. However, with the aim of answering relevant questions for water resources policy and management, LHMs have recently been used in a number of regional applications. This has been enabled by their increasing spatial resolution which makes it possible to zoom-in on specific regions, essentially removing the barriers between global and regional models.Notwithstanding their growing sophistication, the current generation of LHMs still fall short in their ability to represent dynamic trade-offs in the water-food-energy-environment nexus, and water competition between upstream and downstream users. These limitations hinder the ability of LHMs to provide reliable insights at any scale other than the global, leaving the task of incorporating human water management activities within these models as one of the grand challenges for the hydrologic research community.Catchment-scale water management models (CWMMs) adopt a holistic systems approach to comprehensively address water availability, use, infrastructure, and policy aspects within multi-sectoral water allocation. The coupling of these models with LHMs can enhance their representation of human interventions in the natural water cycle (e.g., management of reservoirs, intra- and inter-basin water transfers) and improve the accuracy of water demand estimations such as irrigation requirements by including irrigation schemes. The inclusion of this local knowledge into LHMs’ modelling process can, therefore, increase their capacity to support rigorous nexus analyses to inform water policy and management decisions.This work represents the preliminary outcome of a project with the overall research objective of developing and providing a “proof-of-concept” to explore and design an approach for integrating CWMMs with LHMs, and to assess its potential and limitations to enhance the quality of information LHMs provide at regional scale. This work will present the initial efforts to compare the outcomes of LHMs from the Inter-Sectoral Impact Model Intercomparison Project and the CWMM AQUATOOL in the Ebro River basin, a heavily managed catchment in Spain with multiple competing water uses. This comparison will provide an estimate of the capacity of LHMs to provide useful information for decision making, as well as to identify knowledge gaps to be filled with management models.

Erosion and the impacts of the redistribution of sediment are a serious threat to the quality of water resources. They cause losses and/or additional expenses in many areas, such as water treatment, biodiversity or fisheries. The implementation of catchment management measures, aimed at preventing the transfer of sediment to rivers, can be a cost-beneficial way to address the problem. In order to select the measures and appropriate locations for erosion control, the spatially distributed soil erosion and sediment delivery model WaTEM-SEDEM was used. The model was calibrated against total suspended solids data at the outlet of the Wey catchment, South-east England, yielding satisfactory results. Different scenarios of catchment management were modelled to reduce the amount of sediment transported to the river. Scenarios introducing 24 retention ponds, 50-m-wide buffer strips and cover crops in areas with the largest erosion and sediment delivery were tested. The largest decrease in both sediment production and sediment export was obtained using cover crops, with reductions of 13.4% and 14.1%, respectively. A cost-benefit analysis considering multiple ecosystem services (e.g. control of erosion rates, attenuation of mass flow, pest control, wildlife and its outputs) identified the cover crops as the most cost-beneficial measure and a possible funding scheme based on payments for ecosystem services was developed as a way to enable its implementation.

This work was supported by the Global Challenges Research Fund through quality-related funding (QR GCRF) and the UK Natural Environment Research Council (Grant number NE/N015541/1). J. Krishnaswamy acknowledges support from the Climate Change and Disaster Risk Mitigation component of the National Mission on Biodiversity and Human Well-being supported by the Office of the Principal Scientific Adviser to the Government of India and Google Research (Google Grant for AI on Social Good). In India’s Indo-Gangetic plains, river flows are strongly altered by dams, barrages and water diversions for irrigation, urban supply, hydropower production and flood control. Human demands for freshwater are likely to intensify with climatic and socio-economic changes, exacerbating trade-offs between different sustainable development goals (SDGs) dependent on freshwater (e.g. SDG2, SDG6, SDG7, SDG11 and SDG15). Freshwater ecosystems and endangered aquatic species are not explicitly addressed in the SDGs, but only nested as targets within SDG6 and SDG15. Thus, there is high risk that decisions to advance other SDGs may overlook impacts on them. In this study, we link a water resource systems model and a forecast extinction risk model to analyze how alternative conservation strategies in the regulated Beas River (India) affect the likelihood of survival of the only remaining population of endangered Indus River Dolphins (IRD) in India in the face of climate change-induced impacts on river hydrology and human water demands, explicitly accounting for potential trade-offs between related SDGs. We find that the frequency of low flow released from the main reservoir may increase under some climate change scenarios, significantly affecting the IRD population. The strongest trade-offs exist between the persistence of IRD, urban water supply and hydropower generation. The establishment of ecologically informed reservoir releases combined with IRD population supplementation enhances the probability of survival of the IRD and is compatible with improving the status of relevant SDGs. This will require water managers, conservation scientists, and other stakeholders to continue collaborating to develop holistic water management strategies. Publisher PDF

Holistic water management approaches are essential under future climate and socio-economic changes, especially while trying to achieve inter-disciplinary societal goals such as the Sustainable Development Goals (SDGs) of clean water, hunger eradication, clean energy and life on land. Assessing water resources within a water-food-energy-environment nexus approach enables the relationships between water-related sectors to be untangled while incorporating impacts of societal changes. We use a systems modelling approach to explore global change impacts on the nexus in the mid-21st century in a complexwestern Himalayanwater resource system in India, considering a range of climate change and alternative socio-economic development scenarios. Results show that future socio-economic changes will have a much stronger impact on the nexus compared to climate change. Hydropower generation and environmental protection represent the major opportunities and limitations for adaptation in the studied system and should, thereby, be the focus for actions and systemic transformations in pursue of the SDGs. The emergence of scenario-specific synergies and trade-offs between nexus component indicators demonstrates the benefits that water resource systems models canmake to designing better responses to the complex nexus challenges associated with future global change. (c) 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license

Satellite Remote Sensing, with both optical and SAR instruments, can provide distributed observations of snow cover over extended and inaccessible areas. Both instruments are complementary, but there have been limited attempts at combining their measurements. We describe a novel approach to produce monthly maps of dry and wet snow areas through application of data fusion techniques to MODIS fractional snow cover and Sentinel-1 wet snow mask, facilitated by Google Earth Engine. The method is demonstrated in a 55,000 km2 river basin in the Indian Himalayan region over a period of ∼2.5 years, although it can be applied to any areas of the world where Sentinel-1 data are routinely available. The typical underestimation of wet snow area by SAR is corrected using a digital elevation model to estimate the average melting altitude. We also present an empirical model to derive the fractional cover of wet snow from Sentinel-1. Finally, we demonstrate that Sentinel-1 effectively complements MODIS as it highlights a snowmelt phase which occurs with a decrease in snow depth but no/little decrease in snowpack area. Further developments are now needed to incorporate these high resolution observations of snow areas as inputs to hydrological models for better runoff analysis and improved management of water resources and flood risk.

The Himalayan region has a large hydropower potential due to the natural topographic gradient and abundance of water resource from rainfall, snow and glacier melt. However, future water availability in the Himalayan streams is likely to be altered due to climatic conditions, which necessitates an assessment of hydropower investments, especially for small run-of-the-river projects. Here, we study the future glacio-hydrological changes in a small catchment located in the Upper Beas basin, in Western Himalaya in India, and their impacts on the operation of two small hydropower projects with contrasting hydrological requirements. The Water Evaluation and Planning (WEAP) model is used to integrate and analyse changes in cryosphere, hydrology and hydropower production in the middle and end of the 21st century using multiple climate models representing different types of future scenarios under RCP 4.5 and 8.5. In response to projected climate, the snow and glacier melt contribution to annual discharge declines from 34% in the baseline to 16.5% (RCP4.5) and 13.8% (RCP8.5) by the end of the century. The total streamflow shows broad uncertainty in magnitude and direction of change but shows a noticeable seasonal shift in the hydrological cycle. Of the two hydropower projects, the plant that utilizes high flows with low hydraulic head shows a behaviour similar to streamflow projections resulting in 13% (RCP45) and 19.7% (RCP85) increase in annual power generation by the end of the century arising from the increased hydropower potential of low flows and the rise in precipitation. The second power project that relies on lesser flows with high head maintains its designed power production consistently throughout the century in all the climate change scenarios. The differing sensitivity of the power projects to climate change is influenced by future changes in the runoff as well as by their design. Thus, this study provides insights into the climate-adaptive development and planning of small hydropower projects in the Himalayan region.

The vast majority (~70%) of tropical glaciers in the world are located in the Peruvian Andes. The Santa River Basin, in the Ancash region of Peru, is bound by two parallel mountain ranges; the Cordillera Blanca to the east and the Cordillera Negra to the west. The main water sources in the Cordillera Blanca are rivers and lakes originated from glacier melt, while the Cordillera Negra has no glaciers and depends on seasonal rainfall. In the last decades, water resources have decreased due to climate change, while demand has increased due to population growth and intensification of agricultural and industrial activities. Moreover, higher water levels in glacial lakes due to accelerated glacier melt has reduced their flood attenuation capacity that, along with other triggers of outburst floods, can have catastrophic consequences. One of the strategies adopted by the regional government is the construction of dams, floodgates and siphon drainage systems to reduce the risk of outburst floods. The lowering of lake water levels to provide flood attenuation conflicts with the need for increasing water regulation in the basin (to compensate glacier mass loss) and alters the natural downstream flow regime.This study responds to the need for long-term planning of the major glacial lakes in the Santa River Basin to satisfy all water uses, including environmental ones, and contributing to flood reduction under alternative future climate change scenarios. We adopt a systems analysis approach with the support of the Water Evaluation and Planning system (WEAP) coupled with the hydro-glaciological model TOPographic Kinematic APproximation and Integration (TOPKAPI). They are driven by high-resolution climate projections from the Weather Research and Forecast (WRF) model for future emission scenarios and global climate models available in the CMIP5, for the period 2022-2050. The integration of these models allows representing the complex hydrology of the catchment, explicitly accounting for glacier mass change, and water resources management including the main lakes and water demands. A large spectrum of climate change and lake management scenarios are analysed with a no-regret approach using criteria related to the reliability of water supply for human demands and environmental flows, along with flood abatement and water scarcity. The results of this study that interface hydrology, water demands and infrastructures support local decision-making and exchange with stakeholders in the Santa River Basin, which will strengthen water security across water uses, fostering development and economic growth in the region.

Study Region Allain catchment, a sub-basin of Beas basin, Western Himalaya. Study Focus This study aims to assess future glacio-hydrological changes in a small basin and their impacts on the operation of two Small Hydropower Projects (SHP) with contrasting hydrological requirements. The Water Evaluation and Planning (WEAP) model is used to integrate cryosphere, hydrology and hydropower production modelling in the 21st century using climate changes projected by the ensembles of five global climate models under RCP 4.5 and 8.5. New Hydrological Insights for the Region The total streamflow in the future is projected to have widespread uncertainty in the magnitude but shows noticeable changes in the seasonality. Of the two SHPs, the one utilizing high flows with low hydraulic head shows a power generation behaviour similar to streamflow projections. Its annual hydropower production is projected to change by 2 to 21% (RCP4.5) and -5 to 40% (RCP8.5) by the end of the century. The other plant that uses lesser flows but high head maintains its designed power production consistently throughout the century. The study indicates that the design of hydropower plants strongly influences their sensitivity to future climate and thus provides important insights into the climate-adaptive designs and planning of future hydropower projects in Himalaya.

Lake Ziway, the only freshwater lake in Ethiopia’s Central Rift Valley basin, has been the source for irrigation, floriculture, fish farming and domestic water supply in the region for the last few decades. This study examined the impacts of the planned future agricultural developments and climate change on the lake water balance by an integrated application of the Soil Water Assessment Tool and Water Evaluation and Planning models. The future projections of precipitation and temperature from the Coordinated Regional Downscaling Experiment, CORDEX-AFRICA, under the Representative Concentration Pathways 4.5 and 8.5 were used for the climate change impact assessment. Nine irrigation development and climate change scenarios were developed and simulated to examine the separate and combined impacts on the lake water balance and supply coverages. The study showed that the planned future agricultural developments could result in a mean annual lake water level decline by about 0.15 m, with a considerable reduction (27% to 32%) in the outflow to the downstream Bulbula River. Climate change could increase evaporation losses from the shallow lake resulting in a drastic decrease in the lake water level, especially during the dry season. It could also significantly reduce (by about 74%) the amount of water flowing out of the lake. The combined impacts of future development and climate change are likely to reduce the supply coverages of most of the competing demands. Approaches need to be studied to minimize the lake water evaporation losses and explore water demand/supply management options.

International audience; Climate change in the Indian Himalayan region is being manifested in the loss of glaciers and altered patterns of monsoon rainfall. Simultaneously, rapid population growth together with economic development are increasing sectoral water demands and changing land use patterns. This study investigated the impact of this complex interplay on water resources in the Beas-Sutlej water resources system. The GFDL-CM3 model was used to describe RCP8.5 future meteorological conditions throughout the 21st century. Population and land use changes were projected under the Shared Socioeconomic Pathway-1 (SSP1). The water evaluation and planning (WEAP) system was applied for assessing sectoral water demands. The results showed increasing runoff during the premonsoon and monsoon seasons due to increased glaciers melting and more rainfall, respectively. It also emerged that irrigation water demand decreased moderately in Punjab (8%–13%) and Haryana (1%–9%); however, the situation was reversed in Rajasthan where it increased by 14%. Adaptation strategies were proposed including increased water allocation to Rajasthan and converting lands to cultivating more staple crops in Punjab and Haryana.

Future climate change will likely impact the multiple freshwater ecosystem services (fES) provided by catchments through their landscapes and river systems. However, there is high spatio-temporal uncertainty on those impacts linked to climate change uncertainty and the natural and anthropogenic interdependencies of water management systems. This study identifies current and future spatial patterns of fES production in a highly managed water resource system in northern India to inform the design and assessment of plausible adaptation measures to enhance fES production in the catchment under uncertain climate change. A water resource systems modelling approach is used to evaluate fES across the full range of plausible future scenarios, to identify the (worst-case) climate change scenarios triggering the greatest impacts and assess the capacity of adaptation to enhance fES. Results indicate that the current and future states of the fES depend on the spatial patterns of climate change and the impacts of infrastructure management on river flows. Natural zones deliver more regulating and cultural services than anthropized areas, although they are more climate-sensitive. The implementation of a plausible adaptation strategy only manages to slightly enhance fES in the system with respect to no adaptation. These results demonstrate that water resource systems models are powerful tools to capture complex system dependencies and inform the design of robust catchment management measures. They also highlight that mitigation and more ambitious adaptation strategies are needed to offset climate change impacts in highly climate-sensitive catchments.

The need to provide accurate estimates of precipitation over catchments in the Hindu Kush, Karakoram, and Himalaya mountain ranges for hydrological and water resource systems assessments is widely recognized, as is identifying precipitation extremes for assessing hydro-meteorological hazards. Here, we investigate the ability of bias-corrected Weather Research and Forecasting model output at 5-km grid spacing to reproduce the spatiotemporal variability of precipitation for the Beas and Sutlej river basins in the Himalaya, measured by 44 stations spread over the period 1980 to 2012. For the Sutlej basin, we find that the raw (uncorrected) model output generally underestimated annual, monthly, and (particularly low-intensity) daily precipitation amounts. For the Beas basin, the model performance was better, although biases still existed. It is speculated that the cause of the dry bias over the Sutlej basin is a failure of the model to represent an early-morning maximum in precipitation during the monsoon period, which is related to excessive precipitation falling upwind. However, applying a nonlinear bias-correction method to the model output resulted in much better results, which were superior to precipitation estimates from reanalysis and two gridded datasets. These findings highlight the difficulty in using current gridded datasets as input for hydrological modeling in Himalayan catchments, suggesting that bias-corrected high-resolution regional climate model output is in fact necessary. Moreover, precipitation extremes over the Beas and Sutlej basins were considerably underrepresented in the gridded datasets, suggesting that bias-corrected regional climate model output is also necessary for hydro-meteorological risk assessments in Himalayan catchments. © 2019. The Authors.