Future Water Availability Research Articles

Integrating Water Evaluation and Planning Modeling into Integrated Water Resource Management: Assessing Climate Change Impacts on Future Surface Water Supply in the Irawan Watershed of Puerto Princesa, Philippines

The Irawan Watershed in Puerto Princesa, Philippines, is an important resource that supports domestic, agricultural, and industrial water needs. This study applies the Water Evaluation and Planning (WEAP) model to project the impacts of climate change on future surface water availability, integrating the findings into an Integrated Water Resource Management (IWRM) framework. Using bias-corrected General Circulation Models (GCMs) under four shared socioeconomic pathways (SSPs), this study examines scenarios from low to high emissions (SSP126, SSP245, SSP370, and SSP585) for the assessment of potential variations in water supply. The results indicate a significant vulnerability to water availability, especially under SSP370 and SSP585, where climate warming is pronounced, leading to significant reductions in streamflow. Conversely, SSP126 suggests relatively stable conditions with less pronounced hydrological changes. The study also explores the socioeconomic drivers that affect water demand, including population growth and land use changes that influence agricultural water needs. The findings underscore the urgency of using adaptive management strategies to conserve water resources in the face of these anticipated challenges. Key recommendations include optimizing water use efficiency in all sectors, establishing protective zones around natural ecosystems, implementing climate-resilient infrastructure, and promoting community engagement in water management. These measures are critical for enhancing water security and promoting sustainable development within the watershed, contributing to the broader goals of Sustainable Development Goal (SDG) 6. This study offers decision-makers and resource managers an evidence-based framework for integrating hydrological modeling into IWRM, providing valuable insights to navigate the complexities of climate change and ensure the long- term sustainability of water resources in the Philippines.

Hydropower potential of the Marsyangdi River and Bheri River basins of Nepal and their sensitivity to climate variables

Abstract. Understanding the hydrology of the Himalayan region and its response to current and future climate scenarios is crucial for identifying the region's future water availability for infrastructural development. For this, the hydropower potential and the impact of future change on the hydrology of the Bheri River basin (BRb) and the Marsyangdi River basin (MRb) were analysed. The Glacio-hydrological Degree-Day Model version 2.0 (GDM V2.0), developed in the PCRaster dynamic modelling framework, was used to simulate the river runoff. Geospatial tools and different criteria were used to assess topographic features, identify suitable places for run-of-river (ROR) hydropower development, and estimate power potential. Eight scenarios with various combinations of temperature and precipitation changes were used to assess the hydropower potential. Increases in temperature by 0.5 and 1 °C (assumed for the near-term and mid-term future) and changes in precipitation of ±10 % and ±20 %, respectively, are used to conduct a sensitivity analysis for the hydropower potential. A total of 116 and 83 suitable sites were identified, and 4242 and 2823 MW power potentials were estimated in the BRb and the MRb, respectively. All the sensitivity scenarios show an increase in hydropower production, except for one with a drier scenario and less precipitation. The integration of a geographic information system (GIS) and a hydrological model helps us to understand the hydrological response to climate variables and its impact on hydropower in the Himalayan region.

Assessing the impact of climate change on spring discharge using hydrological modelling in Musanze District, Rwanda

Climate change has far-reaching impacts on water availability globally, with changing precipitation patterns and global warming contributing to increasing scarcity and unreliability of spring water in many regions. Despite this understanding, the implication of climate change on the hydrological system remains limited in certain areas, including the district of Musanze, Rwanda. This study investigates the effects of climate change on the discharge of 14 springs in Musanze using the hydrological model V2Karst. CORDEX data from two global climate models of CMIP5 are used to simulate the future spring discharges over the period 2021–2100. The results reveal significantly higher annual discharges in the RCP2.6 scenario compared to the RCP8.5 for all springs from 2021 to 2100. Nevertheless, no significant long-term trend in spring discharge is observed between the early (2021–2050) and late (2071–2100) periods. However, the intra-annual temporal discharge patterns are changing with a significant increase in the seasonality index for the RCP8.5 scenario towards the end of the twenty-first century. Additionally, for both RCPs, there is a notable increase in the number of days with discharges below 40% of the mean of annual discharges during the baseline period. The overall findings of this study suggest that climate change significantly impacts the future evolution of spring discharges in Musanze, indicating potential risks to the future availability of water in the region.

Visual MODFLOW, solute transport modeling, and remote sensing techniques for adapting aquifer potentiality under reclamation and climate change impacts in coastal aquifer

Global environmental changes, such as climate change and reclamation alterations, significantly influence hydrological processes, leading to hydrologic nonstationarity and challenges in managing water availability and distribution. This study introduces a conceptual underpinning for the rational development and sustainability of groundwater resources. As one of the areas intended for the development projects within the Egyptian national plan for the reclamation of one and a half million acres; hundreds of pumping wells were constructed in the Moghra area to fulfill the reclamation demand. This study investigates the long-term impacts of exploiting the drilled pumping wells under climate change. The approach is to monitor the groundwater levels and the salinity values in the Moghra aquifer with various operational strategies and present proposed sustainable development scenarios. The impact of global warming and climate change is estimated for a prediction period of 30 years by using satellite data, time series geographical analysis, and statistical modeling. Using MODFLOW and Solute Transport (MT3DMS) modules of Visual MODFLOW USGS 2005 software, a three-dimensional (3D) finite-difference model is created to simulate groundwater flow and salinity distribution in the Moghra aquifer with the input of forecast downscaling (2020–2050) of main climatic parameters (PPT, ET, and Temp). The optimal adaptation-integrated scenario to cope with long-term groundwater withdrawal and climate change impacts is achieved when the Ministry of Irrigation and Water Resources (MWRI) recommends that the maximum drawdown shouldn’t be more significant than 1.0 m/ year. In this scenario, 1,500 pumping wells are distributed with an equal space of 500 m, a pumping rate of 1,200 m3/day and input the forecast of the most significant climatic parameters after 30 years. The output results of this scenario revealed a drawdown level of 42 m and a groundwater salinity value of 16,000 mg/l. Climate change has an evident impact on groundwater quantity and quality, particularly in the unconfined coastal aquifer, which is vulnerable to saltwater intrusion and pollution of drinking water resources. The relationship between climate change and the hydrologic cycle is crucial for predicting future water availability and addressing water-related issues.

Effectiveness of wetlands as reservoirs for integrated water resource management in the Ruzizi plain based on water evaluation and planning (WEAP) approach for a climate-resilient future in eastern D.R. Congo

It is widely predicted that climate change’s adverse effects will intensify in the future, and along with inadequate agricultural practices, settlement development, and other anthropic activities, could contribute to rapid wetland degradation and thus exert significant negative effects on local communities. This study sought to develop an approach based on the Integrated Water Resource Management (IWRM) in the Ruzizi Plain, eastern Democratic Republic of Congo (DRC), where adverse effects of the climate change are increasingly recurrent. Initially, we analyzed the trends of climate data for the last three decades (1990–2022). Subsequently, the Water Evaluation and Planning (WEAP) approach was employed on two contrasting watersheds to estimate current and future water demands in the region and how local wetlands could serve as reservoirs to meeting water demands. Results indicate that the Ruzizi Plain is facing escalating water challenges owing to climate change, rapid population growth, and evolving land-use patterns. These factors are expected to affect water quality and quantity, and thus, increase pressure on wetland ecosystems. The analysis of past data shows recurrence of dry years (SPI ≤ − 1.5), reduced daily low-intensity rainfall (Pmm < 10 mm), and a significant increase in extreme rainfall events (Pmm ≥ 25 mm). The WEAP outcomes revealed significant variations in future water availability, demand, and potential stressors across watersheds. Cropland and livestock are the main water consumers in rural wetlands, while households, cropland (at a lesser extent), and other urban uses exert significant water demands on wetlands located in urban environments. Of three test scenarios, the one presenting wetlands as water reservoirs seemed promising than those considered optimal (based on policies regulating water use) and rational (stationary inputs but with a decrease in daily allocation). These findings highlight the impact of climate change in the Ruzizi plain, emphasizing the urgency of implementing adaptive measures. This study advocates for the necessity of the IWRM approach to enhance water resilience, fostering sustainable development and wetland preservation under changing climate.

Future Agricultural Water Availability in Mediterranean Countries under Climate Change: A Systematic Review

Warming and drying trends in the Mediterranean Basin exacerbate regional water scarcity and threaten agricultural production, putting global food security at risk. This study aimed to review the most significant research on future water availability for the Mediterranean agricultural sector under climate change (CC) scenarios published during 2009–2024. Two searches were performed in the Scopus and Web of Science databases, to which previously identified significant studies from different periods were also added. By applying a methodology duly protocoled in the PRISMA2020-based guideline, a final number of 44 particularly relevant studies was selected for review. A bibliometric analysis has shown that most of the published research was focused on Southwestern European countries (i.e., Spain, Italy, Portugal) and grapevine and olive tree crops. Overall, the reviewed studies state that future Mediterranean water reserves may not meet agricultural water demands, due to reduced reservoir inflows and higher irrigation demands under future CC and socioeconomic scenarios. Regarding adaptation measures to improve water-use management in agriculture, the majority of the reviewed studies indicate that the use of integrated modelling platforms and decision–support systems can significantly contribute to the development and implementation of improved water/land-management practices.

Will there be water? Climate change, housing needs, and future water demand in California

Climate change in California is expected to alter future water availability, impacting water supplies needed to support future housing growth and agriculture demand. In groundwater-dependent regions like California's Central Coast, new land-use related water demand and decreasing recharge is already stressing depleted groundwater basins. We developed a spatially explicit state-and-transition simulation model that integrates climate, land-use change, water demand, and groundwater gain-loss to examine the impact of future climate and land use change on groundwater balance and water demand in five counties along the Central Coast from 2010 to 2060. The model incorporated downscaled groundwater recharge projections based on a Warm/Wet and a Hot/Dry climate future from a spatially explicit hydrological process-based model. Two urbanization projections from a parcel-based, regional urban growth model representing 1) recent historical and 2) state-mandated housing growth projections were used as alternative spatial targets for future urban growth. Agricultural projections were based on recent historical trends from remote sensing data. Annual projected changes in groundwater balance were calculated as the difference between land-use related water demand, based on historical estimates, and climate-driven recharge plus agriculture return flows. Results indicate that future changes in climate-driven groundwater recharge, coupled with cumulative increases in agricultural water demand, result in overall declines in future groundwater balance, with a Hot/Dry future resulting in cumulative groundwater decline in all but Santa Cruz County. Cumulative declines by 2060 are especially prominent in San Luis Obispo (−2.9 to −5.1 Bm3) and Monterey counties (−6.5 to −8.7 Bm3), despite limited changes in agricultural water demand over the model period. These two counties show declining groundwater reserves in a Warm/Wet future as well, while San Benito and Santa Barbara County barely reach equilibrium. These results suggest future groundwater supplies may not be able to keep pace with regional demand and declining climate-driven recharge, resulting in a potential reduction in water security in the region. However, our county-scale projections showed new housing and associated water demand does not conflict with California's groundwater sustainability goals. Rather, future climate coupled with increasing agricultural groundwater demand may reduce water security in some counties, potentially limiting available groundwater supplies for new housing.

Impact of reservoir evaporation on future water availability in north-eastern Brazil: a multi-scenario assessment

Impact of reservoir evaporation on future water availability in north-eastern Brazil: a multi-scenario assessment

High-resolution estimates of water availability for the Iberian Peninsula under climate scenarios

Water availability is of paramount importance for sustainable development and environmental planning, specifically in regions such as the Iberian Peninsula, renowned for diverse landscapes and varying climatic conditions. Due to climate change, understanding the potential impacts on water resources becomes essential for effective water management strategies. This research effort aims to assess future potential water availability for the Iberian Peninsula in different climate scenarios, employing cutting-edge water resource modelling techniques integrated within a geographic information system (GIS) framework. In this study, potential water availability is defined as the annual demand for water that can be satisfied at a specific point in the fluvial network with certain reliability. An ensemble of state-of-the-art climate models is utilised to project runoff for the Iberian Peninsula during the mid- and late-twenty-first century periods. These climate projections were subsequently processed using the GIS-based water resource management model, WAAPA, to derive potential water availability under a range of realistic hypotheses. The results indicate that anticipated shifts in precipitation patterns will lead to alterations in hydrological regimes across the region, significantly impacting future water availability. By using GIS-based methodologies, we can facilitate the identification of vulnerable areas susceptible to changes in water availability, offering spatially explicit information along the main rivers of the Iberian Peninsula for decision-makers and stakeholders. High-resolution spatial outputs from this research and detailed water availability estimates serve as valuable input for integrated water resource management and climate change adaptation planning. By combining advanced GIS-based hydrological modelling with climate scenarios, this research presents a robust framework for assessing water resources amidst a changing climate, applicable to other regions struggling with analogous challenges. Ultimately, our study provides vital insights for policymakers and stakeholders, empowering them to make informed decisions and devise adaptive measures to ensure sustainable use of water resources despite uncertain future climatic conditions.

Crop and Economical Water Productivity of Wheat at Perennial and Non-Perennial Canals in Sindh

The freshwater resources are under immense pressure to provide water and food security. New climate change projections for current and future water availability suggest that farmers and policymakers must move from traditional per-acre crop yield measurement to crop and economics water productivity. This research aimed to assess wheat-crop CWP and EWP at perennial and non-perennial canals. The Nara and Rice canals were selected, and both canals were off-take at Sukkur Barrage from Indus. Two distributaries were selected from each canal with the location of the head and tail. A survey tool was designed to collect data. In total, 431 farmers were randomly selected. The collected data was analyzed by using CWP, EWP, Vw, Cobb-Douglas production function, and DEA techniques. Results show that the tail of the Rice canal, CWP, EWP, and Vw was higher than the head. But at the head of the Nara canal, CWP, EWP, and VW were higher than at the tail. The Cobb-Douglas results show the significant impact of irrigation, fertilizer, and watercourse position on production. Further, in DEA results, the tail reaches of both canals were more efficient. Similarly, higher water-saving potential is observed at the head of both canals.

Climate and vegetation change impacts on future conterminous United States water yield

Future water availability is influenced by both climate and associated vegetation dynamics. This study coupled vegetation projections from a dynamic global vegetation model (MC2) with an ecohydrological model, Water Supply Stress Index (WaSSI), to predict water yield at the 8-digit Hydrologic Unit Code (HUC8) watershed level for the conterminous United States (CONUS) for the 21st century. We considered two contrasting warming scenarios (Representative Concentration Pathways 8.5 and 4.5) and accounted for simulation uncertainty by using a large ensemble of climate model outputs. The coupled model projects a decrease in water yield across much of CONUS, especially towards end-century (2080–2099) under RCP 8.5 (warmer scenario), reaching up to −30% at the regional level, relative to the 2008–2027 baseline period. Overall, the projected water yield reduction under RCP 8.5 is roughly twice as high as under RCP 4.5. Substantial changes in water yield for watersheds in the central and southeastern United States are expected by mid-century (2040–2059), reaching up to −40% (RCP 4.5) and −75% (RCP 8.5) at at the century’s end (2080–2099), relative to 2008–2027, respectively. Climate change, rather than vegetation change, strongly dominates the projected future changes in water yield, with contributions typically one order of magnitude higher. For a small number of watersheds, the effects of vegetation change can mitigate or exacerbate the effects of climate change on water yield. Our simulation results suggest a widespread increase in aridity and evaporative indices and a decrease in soil moisture, especially under RCP 8.5. Our integrated modeling results can inform policy makers and resource development planners quantitative information of future water availability.

Projection of future water availability in the Amu Darya Basin

AbstractWater scarcity is a major challenge facing many regions worldwide, especially arid and semi‐arid areas that are increasingly vulnerable to climate change. This study aimed to project water availability in the Amu Darya Basin (ADB) of Central Asia under four Shared Socioeconomic Pathways (SSPs) from the Coupled Model Intercomparison Project Phase Six (CMIP6) during two upcoming periods (2020–2059 and 2060–2099). The study used a robust machine learning approach, namely a Random Forest (RF) model, to simulate Gravity Recovery and Climate Experiment (GRACE) Terrestrial Water Storage (TWS) data from precipitation and maximum and minimum temperatures (Tmax and Tmin). It then incorporated precipitation, Tmax and Tmin from four selected CMIP6 GCMs, into a water storage model to project spatiotemporal changes in water availability across the basin. The study also evaluated the relative impacts of land use and population on TWS. Results indicate an increase in TWS by approximately 4 cm in the basin's eastern, northwestern and southwestern regions in both future periods, while a decrease by approximately −4 cm in the remaining areas. These projections suggest that TWS will decline in densely populated regions and increase in certain intensively cultivated areas. The most pronounced increase in TWS is anticipated in the snow‐covered Tundra climate zone of the basin. This is attributed to the melting of glaciers, which contributes to runoff in the tributaries of the Amu River. The findings highlight the importance of considering climate change and socioeconomic factors when projecting water availability in arid and semi‐arid regions. The projected changes in TWS have important implications for water resources management in the ADB, particularly in densely populated and intensively cultivated areas.

Sustainable treatment scheme for in-situ remediation of contaminated drains using engineered natural systems

Ensuring water security in resource-constrained, densely populated regions is a significant challenge globally. Due to insufficient treatment infrastructure, untreated sewage discharge into drainage channels is prevalent, especially in developing countries. This leads to the pollution of already dwindling water bodies and threatens future water availability. In this context, in-situ treatment within drains using nature-based systems is an attractive option. This study evaluates microbial bioremediation and phytoremediation as engineered natural solutions for in-stream treatment of municipal wastewater. A three-stage treatment system consisting of anoxic biofilm, aerobic biofilm, and hydroponic floating wetlands was adopted. Each stage was optimized for operational parameters through batch and continuous flow studies. The anoxic biofilm system using autoclaved aerated concrete (AAC) as the attachment media, at an optimized hydraulic retention time (HRT) of 2 h, showed the best performance with respect to COD removal. Comparable COD removal was observed in both externally aerated and non-aerated aerobic biofilm systems with coir fibre at 6 h HRT. However, aerated system outperformed non-aerated system at low HRTs. The hydroponic system with Canna indica effectively removed residual ammonia-N with an HRT of 2 h. The sequential continuous flow studies employing the optimized conditions showed significant removals of COD (86%) and ammonia-N (97.6%). The results highlight that locally available materials having a high specific surface area can be used as biofilm supports for COD removal, and floating wetlands employing indigenous macrophytes can be an ideal choice for in-situ nutrient removal. The Life Cycle Assessment (LCA) showed that the developed system did not have direct significant impacts on freshwater eco-toxicity and eutrophication. The proposed hybrid treatment system can be implemented as modular units without major drainage modifications or energy-intensive operations. The study, therefore, finds potential application in densely populated settlements in low-income countries where systematic sewage treatment options remain inadequate.

A multi-objective optimization-based framework for extending reservoir service life in a changing world

Reservoirs are an essential component of water resources systems, improving water supply reliability and security. With long-term climate and water demand changes, the performance of reservoirs may deteriorate, necessitating interventions such as infrastructure upgrades and/or water demand management. These interventions often require substantial financial investment, have long implementation time or impede economic development. Therefore, a more cost-effective and less disruptive alternative is needed to extend the service life of existing reservoir systems. Adapting reservoir operation policies to cater for future changes is such an alternative. By adapting reservoir operation policies to future water availability and demand changes, the capacity of existing systems can be fully utilized to avoid or postpone more expensive and disruptive interventions. However, there is a lack of an integrated framework for estimating the potential of service life extension by re-optimizing operation policies to cater to uncertain changes in future conditions. In this study, we develop a multi-objective optimization-based framework to allow operation policies to adapt to uncertain future changes in water availability and demand by optimizing operation policies for a range of plausible future conditions, thus enabling the service life of existing reservoir systems to be maximized albeit uncertainty in future changes. The developed framework is demonstrated using a reservoir system in Northern Australia. Results show that the service life of the reservoir can be extended by up to 40 years considering uncertain future water availability and demand. In addition, significant changes in operation policies and system responses with time are identified, providing valuable information for developing long-term reservoir planning strategies.

Illuminating Snow Droughts: The Future of Western United States Snowpack in the SPEAR Large Ensemble

AbstractSeasonal snowpack in the Western United States (WUS) is vital for meeting summer hydrological demands, reducing the intensity and frequency of wildfires, and supporting snow‐tourism economies. While the frequency and severity of snow droughts (SD), that is, anomalously low snowpacks, are expected to increase under continued global warming, the uncertainty from internal climate variability remains challenging to quantify with observations alone. Using a 30‐member large ensemble from a state‐of‐the‐art global climate model, the Seamless System for Prediction and EArth System Research (SPEAR), and an observations‐based data set, we find WUS SD changes are already significant. By 2100, SPEAR projects SDs to be nearly 9 times more frequent under shared socioeconomic pathway 5‐8.5 (SSP5‐8.5) and 5 times more frequent under SSP2‐4.5, compared to a 1921–2011 average. By investigating the influence of the two primary drivers of SD, temperature and precipitation amount, we find the average WUS SD will become warmer and wetter. To assess how these changes affect future summer water availability, we track late winter and spring snowpack across WUS watersheds, finding differences in the onset time of a “no‐snow” threshold between regions and large internal variability within the ensemble that are both on the order of decades. We attribute the inter‐regional variability to differences in the regions' mean winter temperature and the intra‐regional variability to irreducible internal climate variability which is not well‐explained by temperature variations alone. Despite strong scenario forcing, internal climate variability will continue to drive variations in SD and no‐snow conditions through 2100.

Adaptation to climate change in the mountain regions of Central Asia: A systematic literature review

AbstractThe mountains of Central Asia support many environmental functions and ecosystem services. The mountain environments and their services are affected by climate change and climate change adaptation (CCA) actions are required to increase resilience of regional communities. This paper is a systematic review of the English and Russian‐language literature published between 2013 (IPCC AR5) and May 2021 (IPCC AR6) focusing on CCA in the Central Asian mountains. In all, 52 publications have been reviewed. Criteria defining incremental and transformative adaptation were established and the reviewed studies were assigned to one of these approaches. The relatively low number of publications shows that the extent of CCA knowledge represented in academic literature is limited in comparison to other mountainous regions. There is a disparity between the growing body of publications addressing climate change and limited and decreasing number of academic publications focusing on adaptation in the region. Only 11 publications reported transformative adaptation actions. Most of the reviewed papers (55%) focus on water resources and future water availability; 15% focus on land degradation, 10% on changes in vertical zonation of plant species, 7% on loss of plant species, 3% on impacts of hazardous events, and 10% on multiple impacts of climate change. The awareness of the importance of CCA among the regional actors should be improved through closer collaboration between researchers, international organizations focusing on sustainable development and adaptation which have recently become more active in the region, practitioners, and local communities and co‐production of knowledge on the development and implementation of CCA.This article is categorized under: Trans‐Disciplinary Perspectives &gt; Humanities and the Creative Arts Trans‐Disciplinary Perspectives &gt; Humanities and the Creative Arts Vulnerability and Adaptation to Climate Change &gt; Institutions for Adaptation Assessing Impacts of Climate Change &gt; Observed Impacts of Climate Change

Assessing future intra-basin water availability in madagascar: Accounting for climate change, population growth, and land use change

The Major River Basins in Madagascar (MRBM) play a crucial role in providing water to the Malagasy population as well as the ecosystem. Little is known about the impact of climate change on these basins, and it is not clear what factors have the most significant impact on them. There are two central objectives of this study: 1. To assess the future potential water available for daily life and agriculture use across the MRBM. 2. To compare the projected change within the MRBM with the historical trends analysis and identify the water-stressed basins. In this paper, a new method for assessing the future available Intra-basin water resources combined with the impacts of climate change, land use, and population is proposed. Three imbalance indicators are introduced to quantify the spatial availability (indicator N°1), distribution (indicator N°2), and variability (indicator N°3) of the Potential Water Resources (PWR) available and have been applied to the MRBM. Under the SSP2–4.5 scenario, results showed a decreasing trend of the PWR in most of the basins by 2050 with a rise in evapotranspiration and a decline in precipitation. The increasing trend and uneven distribution of the population and agricultural land upstream/downstream are found to cause the reduction of the PWR available per capita (by 37 %) and agriculture area (by 69 %) across the MRBM. This study predicts water scarcity for most of the basins by 2050, especially in the Mangoro and Onilahy Basins. Upstream populations are expected to grow in Mahajamba, Mahavavy, Betsiboka, Manambolo, Tsiribihina, Mangoro, Onilahy, Mananara, and Mandrare basins, along with an expansion of the downstream agricultural land in Sofia, Betsiboka, Manambolo, Mangoky, and Mandrare basins. These findings enhance the cause-effect relationship between climate change, land use change, population growth, and water scarcity in the MRBM. Urgent action is therefore needed for an efficient and sustainable management of these water-stressed basins.

Future projection of water resources based on digitalisation and open data in a water-rich region: a case study of the city of Klagenfurt

ABSTRACT Implementation of different strategies on the demand and supply side to deal with potential water scarcity is based on a comparison of future water demand and availability of water resources based on different scenarios of climate change and population growth. Especially, the Alpine region is characterised by many small and medium water supply systems (WSSs) having neither human resources nor time for advanced planning, requiring simple methods for estimating future development. Therefore, the aim of this work is to provide future projections of water demand, resource availability, and drinking water quality for an Alpine area based on simple approaches with minimal data requirements. As the results of the case study show, linear and polynomial regression with precipitation and temperature data can illustrate the temporal variation of system input and drinking water temperature with sufficient accuracy and is suitable for an estimation of future development. The groundwater modelling, however, requires the consideration of a non-linear term depending on the depth to obtain reasonable results. Due to the usage of open-access data and the easy approaches developed and applied, a good transferability to other case studies is expected which can provide stakeholders a first assessment of the future need for action.

Persistent neural calibration for discharges modelling in drought-stressed catchments

Cross-sector coordination between all water uses and the environmental flows is an essential target for achieving sustainable management in any hydrographic region. In this framework, a novel neural approach was developed and implemented, by the software ANNPI 1.0, to characterise and infer of the discharges regime in a specific basin using only a few attributes as independent variables. The calibration procedure is controlled by the Persistence Index (PI), which is function of a determined estimation lead-time, to facilitate the dynamic character of these simulations. A model validation was carried out in the Lower Guadiana Transboundary Basin, in the Southwest Iberian Peninsula, characterised by moderate and severe drought cyclical events. The best neural approaches included as input variable, between others, the Standardized Precipitation Index at a twelve-month scale SPI(12) that is indicator of hydrological drought, obtaining results statistically very good with determination coefficients higher to 0.77, Nash-Sutcliffe Efficiency coefficients higher to 0.75, Kling-Gupta Efficiency coefficients higher to 0.87 and Persistence Indexes higher to 0.60 in three of the four reservoirs analysed. These accuracy measures showed the ability of the software ANNPI 1.0 to reduce the naïve effect in the forecasting of streamflows time series and could therefore facilitate the development of decision-support systems to make reliable reservoir water balance simulations which will allow to assess future water availability to ensure the main ecosystem services.

Quantifying the effects of future environmental changes on water supply and hydropower generation benefits of cascade reservoirs in the Yellow River Basin within the framework of reservoir water supply and demand uncertainty

Inflow and water demand prediction plays an important role in reservoir operation rulemaking. Uncertainties in meteorological and hydrological modeling increase the complexity of inflow and water demand prediction, which are not sufficiently considered in conventional inflow and water demand prediction. Thus, this study took cascade reservoirs as the research object. These cascade reservoirs were located in the mainstream of the Yellow River Basin (YRB). A three-step framework was proposed: (1) developing a distributed Soil & Water Assessment Tool (SWAT) model to determine historical and future water availability in the reservoirs; (2) constructing the AquaCrop agricultural irrigation water demand model to predict future water demand of water users at 264 nodes (reservoirs and hydrological stations) in the YRB; (3) developing an optimal regulation model of cascade reservoirs in the YRB mainstream to quantitively determine the influence of future environmental changes on hydropower generation and water supply benefits of cascade reservoirs. The results indicate that the inflow of cascade reservoirs increased in the flood season and decreased significantly during the non-flood season compared with that in the historical period (1970–2016). However, there was a slight increase in the agricultural irrigation water demand, and the contradiction became more prominent between water resource supply and demand. During the future period (2020–2050), the guaranteed rate of hydropower generation and water supply in the YRB’s lower reaches will increase significantly. Uncertainties in climate models greatly impact hydropower generation benefits and reservoir water supply, especially in the flood season. These findings can facilitate the understanding of the complexity of hydropower management and production of cascade reservoirs under future environmental changes (inflow and demand) and encourage the use of regulation models for impact assessment studies and adaptive reservoir management to mitigate climate change.