Increasing Water Demand Research Articles

Public Acceptance of Utilization of Water Reuse in Community-Based Sanitation Infrastructure (Case Study: Bandung City)

The difficulty of sustainable development is hampered by water scarcity and increased water demands, particularly in urban areas. Domestic wastewater discharges contaminate surface water bodies, such as the Citarum River. These difficulties, which disproportionately affect low-income populations, contribute to health consequences like diarrhoea and stunting. The Reinvented Toilet Project, a community-based sanitation programme, was put into place in Pasirluyu Village, Bandung, to combat water pollution. In order to lower water demand and sewage generation, it includes water reuse, reusing processed wastewater for other applications. This study assesses Pasirluyu Village infrastructure users' attitudes towards social water reuse. Surveys gathered data on demographics, views on water recycling, and information about sanitary facilities. Spearman correlation tests and descriptive analysis were carried out. The outcomes show that infrastructure users have a positive impression of water reuse. However, some people are hesitant to use reclaimed water for activities that require close personal touch. The relationship between public acceptability of water reuse for flushing toilets and acceptance for other purposes raises the possibility of a cascading expansion of water reuse practises. Keywords: community-based infrastructure, households, water reuse, water reuse aceptance

Climate-induced shifts in irrigation water demand and supply during sensitive crop growth phases in South Asia

This study investigated the shifts in irrigation water demand and supply of the major staple and water-intensive crops (wheat and rice) in the Indus, Ganges and Brahmaputra (IGB) river basins of South Asia under the combined impacts of climate change and socio-economic development during the period 1981–2100. It explores irrigation water usage during climate-sensitive crop growth phases (i.e. vegetative and reproductive which required ~ 60% of the total seasonal (sowing to harvest) water demand), which is supposed to be crucial for long-term integrated crop water management. A hydrology vegetation model Lund Potsdam Jena Managed Land is forced with an ensemble of eight downscaled (5 arc-min) global climate model’s using the RCP (Representative concentration pathways) -SSP (Shared socio-economic pathways) framework, i.e. RCP4.5-SSP1 and RCP8.5-SSP3. To investigate phase-specific crop water projections, trend analysis is performed. It shows a significant (p<0.001) increase in irrigation water demand during the vegetative phase of wheat (6 mm) and reproductive phase of rice (26 mm) and a decrease during the reproductive phase of wheat (13 mm) and vegetative phase of rice (11 mm) in selected study sites. The large decrease in projected irrigation demand for wheat can be explained by a shortening of the growing season length as a result of rising temperatures and increased precipitation. Whereas, an increase in irrigation demand for rice is a combined effect of higher temperatures and less precipitation during the reproductive phase in the region. At the same time, irrigation supply by surface water and groundwater is likely to change in future due to warmer and drier growing periods, causing a significant increase in groundwater irrigation, mainly for rice. Our major research findings show the importance of crop water assessments during the sensitive crop growth phases of wheat and rice which vary in space and time. Including crop phase-specific, climate impact assessments of regional and global projection will help improve the region’s existing crop-water management strategies and adaptation practices.

Simulation of population size and economic scale supportable by available freshwater in China in 2030

AbstractLimited water availability, population growth, and increasing water demand have resulted in freshwater crises in many countries, including China. In this paper, the water resource‐carrying capacity (WRCC) model simulated the trajectory of China's various systems, representing interactions among humans, water resources, and economics, among others. The results indicated that, at the national level, 700 billion m3 of available freshwater could support population sizes of 2.12, 1.96, and 1.85 billion, along with economic sizes of $40.65, $34.08, and $29.21 trillion, under high‐, moderate‐, and low‐development scenarios, respectively. And it also showed the population and economic size of each province across China under high‐, moderate‐, and low‐development scenarios. This study's WRCC‐based simulations can provide guidance for future policies related to water, population, and economics. Overall, contributions of this study include (1) a quantitative model related to freshwater security and water policies; (2) the model narratives that paint a better picture of China's future water security and socioeconomic development; (3) the conclusion that it is conducive to adjust water use rigid constraints with water policies; (4) an understanding that it is more intuitive to use population size and economic scale instead of dimensionless scores to characterize the state of WRCC. The WRCC model is instructive for the other counties or regions.

Analyzing the Drivers of Agricultural Irrigation Water Demand in Water-Scarce Areas: A Comparative Study of Two Regions with Different Levels of Irrigated Agricultural Development

Both the demand for agricultural irrigation and the level of water-saving technology in water-scarce regions have met food demand with technological progress and economic growth. There are differences in irrigation water demand drivers in regions with different levels of irrigated agricultural development. However, the relationship between related drivers in response to regional irrigation water demand is not fully understood. This study quantified the driving influence of six indicators, including technological progress, planting structure, water conservation management, economic development, planting scale, and consumption intensity, on agricultural irrigation water demand in JC (Jinchang) and WW (Wuwei), two cities in the Shiyang River Basin, from 2011 to 2020. The results shows that economic development is the main driver of the increase in irrigation water demand, with 29% and 43% driving contributions in JC and WW, respectively. Consumption intensity contributes the most to the decrease in irrigation water demand, with 31% and 23% of driving contribution in JC and WW, respectively. Cropping size has a greater positive drive on irrigation water demand in non-agricultural areas relative to agricultural areas. Planting structure has a more pronounced negative drive on irrigation water demand in agricultural areas relative to non-agricultural areas. In particular, relative to irrigated areas, the proportion of water-saving irrigated areas to the sown areas has a greater impact on changes in irrigation water demand, with a significant rebound effect when it exceeds 80%, so that blindly expanding water-saving irrigated areas will drive an increase in irrigation water demand. The results of this study can provide useful suggestions for agricultural water management in water-scarce areas with different levels of water-saving irrigation development, and realize the sustainable development of agriculture in water-scarce areas.

Irrigation alters biogeochemical processes to increase both inorganic and organic carbon in arid-calcic cropland soils

Irrigation in arid croplands is necessary to sustain crop growth, but with increasing water scarcity and population growth in drylands, irrigation systems may need to shift from flooding to dripping techniques to cope with increased water demand. Therefore, it is important to understand how irrigation drives organic and inorganic carbon dynamics in arid-calcic soils. This study on arid-calcic cropland soils assessed the influence of flood and subsurface drip irrigation on soil organic carbon (SOC) and soil inorganic carbon (SIC) formation as influenced by soil chemical properties and bacterial and fungal biomass. As well, these dynamics were assessed in an unmanaged/unirrigated desert soil. Under drip irrigation, SOC was significantly greater than under flood irrigation, but flood stored more SIC than drip irrigation and no irrigation. The observed SOC–SIC patterns were likely driven by calcium binding. Flood irrigation adds significantly more calcium and bicarbonate to the system, while leaching dissolved organic carbon (DOC). Under flood, calcium is likely more preferentially bound as calcium carbonate. Under drip irrigation, less water was added, calcium and SOC were maintained in the rooting zone where SOC may be stabilized via cation-mediated bridging. Despite higher SOC under drip, more total, and bacterial biomass were detected under flood than drip irrigation, which promoted fungal biomass. Bacterial biomass under flood irrigation may be contributing to microbial carbonate precipitation, supported by the greater presence of common bacterial groups known to contribute to this process, and significant positive relationships with calcium. This research emphasizes the importance of examining SOC and SIC dynamics from abiotic and biotic and particularly microbial perspectives; to optimize soil carbon storage in arid croplands.

Critical Examination of the Scope and Methodology of Water Resources Economics, Accounting and Auditing

The paper is central on accounting for water use and productivity water to improve water savings from accountability to sustainability. It critically examination of the scope and methodology of water resources economics, accounting and auditing. This paper presents a conceptual framework for water accounting and provides generic terminologies and procedures to describe the status of water resource use and consequences of water resources related actions. The exploratory study involves Water resources economics, water scarcity in economic theory, water accounting frameworks, water accounts, water consumption and water use, water valuation, water accounting and ‘water budgets’, water balance approach, water accounting plus (Wa+) and water accounting using remote sensing. Water accounting is a method of organising and presenting information relating to the physical volumes of water in the environment and economy as well as the economic aspects of water supply and use. The framework applies to water resource use at three levels of analysis: a use level such as an irrigated field or household, a service level such as an irrigation or water supply system, and a water basin level that may include several uses. An increase in water demands, exacerbated by climate change and the tightening of environmental requirements, leads to a reduction in available water resources for economic uses. This situation poses challenges for water resource planning and management. Water accounting has emerged as an appropriate tool to improve transparency and control in water management. There are multiple water accounting approaches, but they generally involve a very exhaustive list of accounted concepts.

TRANSFORMAÇÕES DAS PAISAGENS E DO TERRITÓRIO DA CHAPADA DIAMANTINA PELA INSERÇÃO DO PIVÔ CENTRAL COMO IRRIGAÇÃO

Objective: This research analyzes the changes in landscapes and territory in Chapada Diamantina, with emphasis on the municipalities of Ibicoara-BA and Mucugê-BA, caused by the implementation of central pivot irrigation systems and the appropriation of these spaces by agribusiness. Theoretical framework: This study was conducted based on theoretical reflections on environmental issues, the relationship between society and nature and theories on space and territory. Water use issues, granting policies and the procedures that bodies in the environmental sector used to monitor access to water and its multiple uses. Method: It is based on the use of data collection with thematic mapping, use of satellite images and theoretical discussion. The data were obtained from the Brazilian Institute of Geography and Statistics (IBGE), the National Water Agency (ANA), the Brazilian Agricultural Company - Embrapa and the Institute of the Environment and Water Resources (INEMA). Results and conclusion: The results demonstrate strong growth in agribusiness in Chapada Diamantina and a high impact on environmental resources, especially due to the removal of vegetation cover from the surfaces of Gerais and an increase in demand for water. Implications of the research: The environmental and territorial approach of the research questions the development model implemented in the region, pointing out intra-regional inequalities, and the environmental problems arising from the massive land and water in the area with high environmental fragility. Originality/value: This research has social, economic, scientific and environmental value with the data analyzed and the originality of the discussions presented.

Assessment of the influence of an Australian native eucalypt, Corymbia maculata, on soil desiccation in a temperate climate

AbstractExpansive soils undergo significant moisture change under prevailing climate conditions, resulting in shrinkage and swelling in dry and wet months. Such seasonal movements of expansive soils can greatly affect the serviceability and performance of lightweight structures founded on shallow footing systems. The extent of movement may be exacerbated if trees are present since large amounts of water can be absorbed by the root system of trees, leading to localized settlement due to soil shrinkage. This study established a well-instrumented site that included a row of Australian native eucalypts located in an eastern suburb of Melbourne, Australia. A tree from this row was chosen for the monitoring of soil movements, soil moisture and suction over a period of 44 months. A sap flow instrument was used to monitor the transpiration and water uptake by the tree. The results showed that noticeable shrinkage settlement occurred at a radial distance of 7.8 m from the trunk of the tree, attributable in part to the increased water demand of the tree. This study promotes a better understanding of the process of expansive soil–tree root interaction. The field data presented can assist geotechnical engineers and practitioners with footing design in the presence of trees.

Mechanisms influencing changes in water cycle processes in the changing environment of the Songnen Plain, China

The process of the land-surface water cycle has undergone substantial changes as a result of climate change and human activities. Disclosing the evolution of the water cycle and its mechanisms in a changing environment is a challenging and hot issue in hydrological science research, which is essential for regional ecological protection and sustainable development. Based on the MIKE SHE/MIKE 11 model, multi-source data are used to simulate the water cycle change process in the Songnen Plain from 1980 to 2020. The study indicates that groundwater data inverted by GRACE and GLDAS data is relatively accurate, which effectively reflects the process of groundwater storage change in particular regions. Moreover, the surface-groundwater coupling model employs strongly correlated inverse groundwater data to simulate the water cycle change process in the Songnen Plain, yielding highly accurate simulation results. In terms of the impact of climate change and human activities on the water cycle process, climate change is the primary cause of changes in the regional water cycle, with contributions to actual evapotranspiration, surface runoff, and groundwater level of 77.04 %, 70.88 %, and 67.86 %, respectively. Nonetheless, as human activities intensify, their impact on the water cycle process progressively increases. From the perspective of the mechanism of water cycle change, the decrease in wetland area, the expansion of urban areas, and the increase in urban water demand are the primary causes of regional water cycle change between 1995 and 2010. The establishment of water conservation facilities and the dramatic increase in paddy field area are the primary causes of the water cycle change between 2011 and 2020. This study combines multi-source remote sensing data with hydrological models to simulate medium- and large-scale water cycle processes, providing new concepts and methods for examining water cycle processes in water-scarce areas.

Urban green spaces and their relationship with groundwater quality: the case of a shallow aquifer in the south of Mexico City

Water supply security is a top priority for decision-makers in cities. Urban population growth increases water demand from aquifers, while urban expansion reduces water infiltration and boosts water pollution sources. Urban green spaces are a few of the remaining infiltration areas. Therefore, they are essential for water supply and urban hydric resilience. The urban dynamic directly influences shallow aquifers, but they usually are unappreciated. This work illustrates the relationship between urban green spaces and city water quality by evaluating the influence of urban green space, Reserva Ecológica del Pedregal de San Angel (REPSA), on a shallow aquifer in Mexico City. Five springs were sampled: two upstream of REPSA, a spring within REPSA, and two downstream. Because the study area is mainly residential but with an industrial history, water quality was tested based on microbiological pathogens, nutrients, pharmaceutical drugs, and heavy metals. Results showed an enhancement of water quality of the shallow aquifer in the sampling points downstream of REPSA for some of the pollutants. These results illustrate how urban green spaces can help to dilute pollutants present in the water of shallow aquifers, increasing water quality in cities.

Insights of dam site selection for rainwater harvesting using GIS: A case study in the Al- Qalamoun Basin, Syria

Today's world is plagued with water shortages, especially in developing countries. The problem is made worse by increasing water demands and decreasing rainfall occurrences in arid and semi-arid areas. Rainwater harvesting (RWH) has the potential to be a viable solution for this issue, as it can augment existing water supplies in the long term. This study aimed to identify suitable areas for RWH using a multi-criteria decision analysis (MCDA) based on the analytic hierarchy process (AHP) method, combined with geographic information system (GIS) and remote sensing (RS) techniques. This study has been carried out in the Al-Qalamoun Basin, the western part of Syria, which has not been studied for rainwater harvesting before. To fill this gap, a potential RWH map was created in the Al-Qalamoun Basin using nine factors, which are land use and land cover (LULC), soil texture, slope, rainfall, curve number (CN), stream order, distance to faults, distance to roads, and distance to residential areas. All thematic layers were allocated appropriate weights and combined using the weighted Overlay process (WOP) in ArcGIS 10.8 to produce a RWH map of the study area. The findings indicated that about 18.1% of the total study area was classified as most suitable and suitable for RWH. Validation of the RWH map with the existing dams indicated that the methodology adopted in this study had a high capacity to identify sites suitable for RWH. The study presents a useful and inexpensive tool for decision-makers to avoid unsuitable sites and focus on the most suitable sites for constructing dams.

Pseudomonas aeruginosa biofilm formers in drinking water

Currently there has been an increase in demand for bottled water, this is due to the population’s dissatisfaction with the quality of water provided by public agencies. The present study sought to evaluate the presence of biofilm-forming P. aeruginosa in bottled drinking water. Thirty-five typical bottled water samples were selected to identify the presence of P. aeruginosa and its ability to form bacterial biofilm. The methodology used to verify the presence of P. aeruginosa followed the multiple tube technique and the evaluation of biofilm forming capacity followed the microdilution technique, with the optical capacity read by spectrophotometry at 620 nm. The presence of P. aeruginosa was detected in 26% of the samples analyzed, representing nine of the 35 samples tested. Of these, 55% had the ability to form biofilm. The present study shows that the presence of P. aeruginosa, which is capable of forming biofilms, is a risk factor for public health because of the widespread commercialisation of bottled water.

Water Balance Assessment, Land Use Land Cover Change and Increasing Water Demand in Three Major Watersheds in Jember, East Java, Indonesia

Jember Regency is the third largest agricultural area in East Java Province. Expansion of built-up and agricultural areas occurred and significantly changed the landscape. Moreover, increasing both types of land cover will increase water consumption. Therefore, there may be changes in the condition of the water balance in the Jember Regency area. This area has three major watersheds: Bedadung, Mayang, and Tanggul. This study evaluated the water balance condition at the three major watersheds in Jember, East Java, Indonesia. The WEAP (Water Evaluation and Planning) model calculated the water balance. Research procedures include (1) inventory of spatial and non-spatial data; (2) setup of the WEAP scheme; (3) Calibration; (4) Validation; and (5) Simulation of water balance model in scenario increasing water demand and land-use change). From 1997 to 2020, the water balance was evaluated using a 10-day interval. The results show that from the November 1st to August 2nd periods, the watershed can supply all demand sites with 100% coverage. However, from August 2nd t to October 3rd periods, the watershed’s ability to supply the water needs decreased. This deficit is due mainly to the uneven rainfall distribution between rainy and dry seasons. Variation in annual rainfall received from 1997 to 2020 also affects the water balance’s surplus and deficit. The fluctuation of land-use change contributed to the surplus and shortage of water balance.&#x0D; &#x0D; Keywords : Supply; Demand; Water Balance; WEAP; Jember; East Java&#x0D; Copyright (c) 2023 Geosfera Indonesia and Department of Geography Education, University of Jember&#x0D; This work is licensed under a Creative Commons Attribution-Share A like 4.0 International License

The deterioration and restoration of dried soil layers: New evidence from a precipitation manipulation experiment in an artificial forest

Ongoing climate change alters the amount and frequency of precipitation, deteriorating the water status of soils and the ecosystem services that they provide. The decline of soil water formed the dried soil layers (DSLs), which is particularly relevant for dryland ecosystems like the forests planted on the Chinese Loess Plateau (CLP), because there is an increased water demand for vegetation transpiration. To assess the impacts of precipitation changes on DSLs, we conducted a large throughfall manipulation experiment comprising seven precipitation gradients, ranging from 30%, 50%, and 65% precipitation interception treatments (PIT) to the ambient condition and then to 30%, 50% and 65% precipitation accession treatments (PAT), under a Robinia pseudoacacia planting forest on the CLP. We measured changes in soil water content (SWC) and examined the development of DSLs for over a year. We found that: (1) mean SWC in the 0–2100 cm soil profile and in DSLs decreased by 0.44%–0.77% and 0.13%–0.36% under the PIT, respectively, while increasing by 0.13%–0.36% and 0.16%–0.92% under the PAT, respectively; (2) DSLs were observed c. 100 cm and c. 100–180 cm below the soil surface under the PIT and PAT, respectively; (3) DSLs varied seasonally, with the largest reduction occurring during the transition period between the dry and rainy seasons, while the reduction developed more rapidly under the PAT than the PIT; (4) the incremental rate of SWC in DSLs increased linearly (p < 0.05) with increasing precipitation, while the increase was faster when precipitation was above (PAT) than below the ambient conditions (PIT), indicating greater precipitation sensitivity of DSLs under enriched than limited water supply. These changes in DSLs provide experimental evidence for the effects of climate change on soil water, and may have strong effect on the sustainable development management of drylands.

Integrated Hydrogeological Modelling for Sustainable Management of the Brindisi Plain Aquifer (Southern Italy)

Nowadays, changes in precipitation patterns together with the increasing water demand impose a sustainable management where the budget between water availability and demand is positively closed. A parsimonious hydrogeological modelling approach coupled with a soil water balance is developed and applied in order to quantify the hydrological and hydrogeological dynamics in a semi-arid region of the Mediterranean basin. In particular, the present work focuses on the hydrogeological dynamics of the catchment areas of Siedi, Foggia di Rau, Pigonati, and the Palmarini channels located in the Brindisi Plain, Southern Italy. In the last decades, in the Brindisi Plain the anthropization processes as well as the industrial and agricultural development have generated an intensive exploitation of both shallow and deep groundwater resources as well as their qualitative deterioration. A dry hydrologic year (2019–2020) caused a recharge deficit, resulting in a lowering of the groundwater level of the shallow aquifer compared to the expected seasonal value. The results evidence a sensitive natural system, where the variability of the rainfall regime combined with water withdrawal leads to a system that is very vulnerable to climate change impacts, such as the presence of erratic rainfall patterns affecting aquifer recharge. This study represents the first approach to couple a soil moisture balance model and groundwater flow model to assess the impact of changes in rainfall patterns on groundwater recharge for the Brindisi Plain aquifer. The developed integrated hydrogeological model can be applied to other sites with similar hydrogeological features and represents an important tool in order to evaluate the effectiveness of cost-effective sustainable actions for the management of the groundwater resources with respect to land-use practices and socio-economic aspects.

Advancements in saline water treatment: a review

Abstract The growing population and increasing water demand necessitate exploring alternative sources of water, including saline water. Saline water treatment technologies have undergone significant advancements in recent years, enabling the production of potable water from seawater and brackish water. This review provides an overview of the current state of saline water treatment technologies, including desalination and membrane-based processes. The advantages and limitations of each technology and their suitability for different applications are discussed. Recent advancements in materials and techniques that have led to improvements in energy efficiency, productivity, and cost-effectiveness of these technologies are highlighted. Finally, the future directions and challenges in the field of saline water treatment are outlined.

Evaluating Hydrological Drought Risk in Lithuania

Hydrological drought poses a major global challenge, exacerbated by climate change and increasing water demand, leading to water scarcity, environmental degradation, and socioeconomic impacts. Thereby, there is a need for comprehensive methods to assess and predict hydrological droughts. The methodology part was based on the calculation of hydrological drought risk components—hazard and vulnerability—according to the equal weight scale of each variable. The spatial distribution of point values was performed by the inverse distance weighting interpolation method. To calculate indices, the spatial layer overlapping of variables was performed using the Raster Calculator tool. Statistical tools were used to estimate drought risk in river catchments. As a result, three main maps were prepared: The hydrological drought hazard index, the hydrological drought vulnerability index, and the hydrological drought risk. These maps highlight regional variations in drought hazards, vulnerability, and risk. Hazard and risk index values are higher in the northern part of Lithuania and lower in the south. The central region exhibits the highest percentage of areas at high and very high risk; the western region shows less risk due to a maritime climate; and the Southeastern region demonstrates the lowest susceptibility to hydrological drought due to physical-geographical factors.

Calculating the Quantity and Cost of Distilled Water Produced by Solar Plants to Desalinate Drain Water and use it in Irrigation

Abstract Industrial and agricultural growth, population explosion, as well as climate change all over the world have led to a significant increase in demand for fresh water, so obtaining it in the simplest, cheapest and most appropriate way has become a challenge for many countries, including Iraq. The aim of the study is to invest free solar energy through the use of solar stills to desalinate water and use it in agricultural production through mixing and drip techniques. The results showed the possibility of obtaining arable water through the construction of a network of virtual solar stills, and through the process of mixing distilled water with an equal amount of drainage water and using drip irrigation, it was found that the cost of one liter of water used in agriculture is (1.077 IQD) (0.0007 $, i.e. 0.0007 $ Less than one cent) within 20 years (the lifespan of the project), where a group of agricultural crops can be grown according to the amount of water produced and according to the default design of the distillers and the amount of salt in produced water, such as chickpeas, cabbage and lentils.

A Study on Irrigation Water Productivity under Different Irrigation Environments of Tamil Nadu, India

The world is attempting to increase water efficiency in all activities, especially in irrigation, which consumes three-fourths of total available water. Concerning the near future food demand and sustainability issues, views are directed to reduce the usage of water or increase the efficiency of water use. India is a major contributor to the agricultural production and food supply to many countries. Irrigated agriculture is being followed by the many farmers in India which consumes huge amounts of water. Considering the monsoon failure and increased water demand, one must find solutions for retaining water in an available manner. The focus is on finding major water-consuming crops and irrigation methods under different irrigation environments of Tamil Nadu. Pudukottai, Salem and Erode are the districts of Tamil Nadu state selected as a study area. In each district, blocks, villages and respondents are selected through multi-stage random sampling. This study is entirely based on primary data which is collected using a well-structured interview schedule. The collected data is used to estimate the Physical Water Productivity (PWP) and Economic Water Productivity (EWP). The results show that PWP and EWP are variable across crops under different irrigation environments. In a tank environment, the alternate drying and wetting method of irrigation in paddy is effective and saves around 39 per cent of water compared to the conventional method by flooding. For Groundnut crops, drip irrigation is more effective than check basins which are better than the flood irrigation method. We can conclude that the farmers should follow water-saving irrigation methods/technologies and cultivate crops that show less demand for water during the season when the water is scarce and turn to cultivation of crops like sugarcane and banana in water surplus season.

Climate Change Impacts on the Côa Basin (Portugal) and Potential Impacts on Agricultural Irrigation

The increasing gap between water demands and availability is a significant challenge for sustainable water management, particularly in the context of growing irrigation needs driven by climate change. In the Côa region (inner-north Portugal), agriculture plays a vital role in the local economy, ensuring food security and contributing to the conservation of natural resources, though also threatened by climate change. The present study assesses how streamflow in the Côa River can be affected by climate change. The HSPF (Hydrological Simulation Program-FORTRAN) hydrological model was coupled with three global–regional climate model chains to simulate historical monthly and annual streamflow (1986–2015), and to predict future (2040–2099) streamflow under RCP8.5. Irrigation scenarios were subsequently developed considering a potential future increase from 10% to 50% per decade. The evaluation of HSPF performance during the historical period revealed good agreement (R2 &gt; 0.79) between simulated and observed flows. A general decrease in streamflow is found in the future, particularly in 2070–2099, with annual mean streamflow projected to decrease by −30% until 2099. Interannual variability is also expected to increase. Generally, the simulations indicated higher future flows in winter/early spring, whilst they are expected to decrease over the rest of the year, suggesting drought intensification. An increase in water demands for irrigation, potentially rising from 46 hm3·yr−1 (baseline scenario) up to 184 hm3·yr−1 (50% increase per decade) may lead to unsustainable irrigation. Managing these opposite trends poses significant challenges, requiring a comprehensive and integrated approach from stakeholders and policymakers. Strategies should focus on both demand-side and supply-side measures to optimize water use, improve water efficiency, and preserve water availability.