Search Results (289)

Integrated hydrological modeling plays a crucial role in advancing sustainable water resource management, particularly in regions facing seasonal and extreme precipitation events. However, comprehensive studies that assess hydrological variability in temperate river basins remain limited. This study addresses this gap by evaluating the performance of the Soil and Water Assessment Tool (SWAT) in simulating streamflow, water balance, and seasonal hydrological dynamics in the Chikugo River Basin, Kyushu Island, Japan. The basin, originating from Mount Aso and draining into the Ariake Sea, is subject to frequent typhoons and intense rainfall, making it a critical case for sustainable water governance. Using the Sequential Uncertainty Fitting Version 2 (SUFI-2) approach, we calibrated the SWAT model over the period 2007–2021. Water balance analysis revealed that baseflow plays dominant roles in basin hydrology which is essential for agricultural and domestic water needs by providing a stable groundwater contribution despite increasing precipitation and varying water demand. These findings contribute to a deeper understanding of hydrological behavior in temperate catchments and offer a scientific foundation for sustainable water allocation, planning, and climate resilience strategies. Full article

The mean annual water balance is essential for evaluating water availability in a catchment and planning water resources. Climate change alters this balance by affecting precipitation, evapotranspiration, and overall water availability. This study analyses the impact of climate change on the mean annual water balance in the Catamayo catchment, a key water source for irrigation and hydropower in southern Ecuador and northern Peru. A Budyko-based approach was employed due to its conceptual simplicity and proven robustness for estimating long-term water balances under changing climatic conditions. Using outputs from 23 Global Circulation Models (GCMs) under CMIP6’s SSP2-4.5 and SSP8.5 scenarios, the results indicate increasing aridity, particularly in the lower and middle parts of the catchment, which correspond to arid and semi-arid zones. Water availability may decrease by 26.3 ± 12.3% to 33.3 ± 17% until 2080 due to negligible changes (statistically speaking) in average precipitation but rising evapotranspiration. However, historical precipitation analysis (1961–2020) reveals an increasing trend over this historical period which can be attributed to natural climatic variability associated to the El Nino-Southern Oscillation (ENSO), possibly enhanced by anthropogenic climate change. A novel hybrid method combining the statistics of historical precipitation deficits with GCM mean projections provides estimates of future precipitation deficits. These findings suggest potential reductions in crop yields and hydropower capacity, which (although not quantitatively assessed in this study) are inferred based on the projected decline in water availability. Such impacts could lead to higher energy costs, increased reliance on fossil fuels, and intensified competition for water. Mitigation measures, including water-saving strategies, energy diversification, and integrated water resource management, are recommended to address these challenges. Full article

The cocoa production in Ghana, largely reliant on rainfall and undertaken by smallholder farmers, is increasingly endangered by climate change-induced water scarcity. Although supplemental irrigation has been posited as an adaptive measure, its hydrological impacts remain understudied. This current study seeks to bridge this knowledge gap by employing the Soil and Water Assessment Tool (SWAT) to evaluate the hydrological and water resource implications of supplemental irrigation within the Upper Offin sub-basin of Ghana. High-resolution spatial data and field survey inputs were used to model dry period baseline and irrigation scenarios for cocoa farms with gentle slopes (2%). The results reveal that supplemental irrigation from the shallow aquifer can sustainably support irrigation for up to 5% of the cocoa area (4760 ha) without adversely affecting groundwater flow. Extending irrigation to 30% of the cocoa area (28,540 ha) is feasible with minimal reduction in catchment water yield. This study’s novelty lies in integrating high-resolution data with localized management practices to provide actionable insights for balancing cocoa productivity and water sustainability. The findings offer practical recommendations for policymakers, emphasizing that through solar-powered irrigation the shallow groundwater is a pathway to enhance climate resilience of cocoa productivity. Full article

Climate-induced extreme rainfall events are increasing the intensity and frequency of flash floods, highlighting the urgent need for advanced flood management systems in climate-resilient cities. This study introduces an Intelligent Flood Control Decision Support System (IFCDSS), a novel AI-driven solution for real-time flood forecasting and automated pump operations. The IFCDSS integrates multiple advanced tools: machine learning for rapid short-term water level forecasting, NSGA-III for multi-objective optimization, the TOPSIS for robust multi-criteria decision-making, and the ANFIS for real-time pump control. Implemented in the flood-prone Zhongshan Pumping Station catchment in Taipei, the IFCDSS leveraged real-time sensor data to deliver accurate water level forecasts within five seconds for the next 10–30 min, enabling proactive and informed operational responses. Performance evaluations confirm the system’s scientific soundness and practical utility. Specifically, the ANFIS achieved strong accuracy (R² = 0.81), with most of the prediction errors being limited to a single pump unit. While the conventional manual operations slightly outperformed the IFCDSS in minimizing flood peaks—due to their singular focus—the IFCDSS excelled in balancing multiple objectives: flood mitigation, energy efficiency, and operational reliability. By simultaneously addressing these dimensions, the IFCDSS provides a robust and adaptable framework for urban environments. This study highlights the transformative potential of intelligent flood control to enhance urban resilience and promote sustainable, climate-adaptive development. Full article

Inland saline wetlands in the Ebro Basin (Spain) are protected by international regulations but are also threatened by the expansion of animal farms. We studied the input–output budgets of N from animal farms in four catchments of wetlands in the central Ebro Basin designated as Nitrate Vulnerable Zones. We used the N produced in animal farms as inputs and the N extracted by the crops on which manures and slurries are applied as outputs in each catchment. The balances considered the regulations concerning the slope of land where animal excreta may be applied and the doses of application. At a detailed scale, we applied the Water Erosion Prediction Program (WEPP) to the Farnaca catchment to assess the runoff and nutrients arriving to its wetland. While the Bujaraloz-Sástago basin showed a high excess of N load, in the Gallocanta basin, N extraction by crops was significantly higher than the N produced by the animal farms. Despite this lack of surplus of N from animal excreta, the groundwaters in the Gallocanta catchment are polluted by nitrates. The emphasis on N from animal farms in plans to prevent water pollution is missing the role of mineral fertilizers as the sources of pollution in basins with small N loads from animal farms. Agricultural plots in the Farnaca catchment produce significant amounts of sediments and nutrients that eventually pollute the wetland. Modelling approaches at detailed scales are required to assess the flows of materials to individual wetlands. Full article

The Okavango River is a transboundary waterway that flows through Angola, Namibia, and Botswana, forming a significant alluvial fan in northwestern Botswana. This fan creates a Delta that plays a vital role in the country’s GDP through tourism. While research has primarily focused on the Delta, the river’s catchment area in the Angolan highlands—its main water source and critical for downstream flow—has been largely overlooked. The basin is under pressure from development, water abstraction, and population growth in the surrounding areas, which negatively affect the environment. These challenges are intensified by climate change, leading to increased water scarcity that necessitates improved management strategies. Currently, there is a lack of published research on the basin’s hydrology, leaving many hydrological parameters related to streamflow in the catchments inadequately understood. Most existing studies have employed single-site calibration methods, which fail to capture the diverse characteristics of the basin’s catchments. To address this, a SWAT model has been developed to simulate the hydrologic behaviour of the basin using sequential multisite calibration with data from five gauging stations, including the main river systems: Cubango and Cuito. The SUFI2 program was used for sensitivity analysis, calibration, and validation. The initial sensitivity analysis identified several key parameters: the Soil Evaporation Compensation Factor (ESCO), the SCS curve number under moisture condition II (CN2), Saturated Hydraulic Conductivity (SOL_K), and Moist Bulk Density (SOL_BD) as the most influential. The calibration and validation results were generally satisfactory, with a coefficient of determination ranging from 0.47 to 0.72. Analysis of the water balance and parameter sensitivities revealed the varied hydrologic responses of different sub-watersheds with distinct soil profiles. Average annual precipitation varies from 1116 mm upstream to 369 mm downstream, with an evapotranspiration-to-precipitation ratio ranging from 0.47 to 0.95 and a water yield ratio between 0.51 and 0.03, thereby revealing their spatial gradients, notably increasing evapotranspiration and decreasing water yield downstream. The SWAT model’s water balance components provided promising results, with soil moisture data aligned with the TerraClimate dataset, achieving a coefficient of determination of 0.63. Additionally, the model captured the influence of the El Niño–Southern Oscillation (ENSO) on local hydrology. However, limitations were noted in simulating peak and low flows due to sparse gauge coverage, data gaps (e.g., groundwater abstraction, point sources), and the use of coarse-resolution climate inputs. Full article

The hydrological cycle in the Tibetan Plateau is experiencing notable changes in recent decades under a changing climate. The hydrological changes, however, are not well investigated due to the limitations in the availability of ground-based observations. In this study, by incorporating satellite-based observations into a hydrological modeling framework, seasonal and inter-annual dynamics of water balance for lakes in the northwest Tibetan Plateau are examined systematically for the period of 1990 to 2022. Satellite-based observations, including lake water area and water level, have been used to calibrate the hydrological model and to estimate lake water storage. The hydrological model performs satisfactorily, with the Nash–Sutcliffe efficiency coefficient (NSE) exceeding 0.5 for all 15 studied lakes. It is found that inflow contributes over 70% of annual water gain for most lakes, while percolation accounts for a larger portion (>60%) of total water loss than evaporation. The studied lakes have expanded substantially, with regional average increasing rates in lake level and water storage of 0.38 m/a and 3.12 × 10⁸ m³/a, respectively. Some lakes transitioned from shrinking to expanding around 1999, and expansion in most lakes has further accelerated since around 2012, primarily because of increased precipitation over the lake catchments, leading to greater inflow to the lakes. These findings provide important insights into understanding and predicting responses of lake water balance to climate change as well as for developing adaptative strategies. Full article

At the global level, numerous reservoirs exhibit a pronounced water degradation. Inadequate land use and climate change effects contribute to freshwater degradation and disrupt the ecosystem balances. This study aimed to evaluate the temporal and spatial effects of the surrounding area on two Portuguese reservoirs: Rabagão and Aguieira. For each reservoir sub-watershed scale, the evolution of land use and soil occupation and the pressures reported over the past decade were analyzed. Additionally, official records of water quality parameters were collected, and water quality was assessed according to the Water Framework Directive (WFD). Both reservoirs show anthropogenic pressure, reflected in the water quality. Rabagão has good water quality, associated with undeveloped lands (47%), agriculture (26%), and one pressure on the aquaculture sector. Aguieira is characterized by high nutrient concentrations, low transparency, and phytoplankton. This is linked to various land uses, including forestry (75%), and agriculture (19%), as well as multiple environmental pressures. Key contributors include urban discharge (27 sites) and water catchments allocated for agricultural purposes (89 sites) and others. The long-term data showed an increase in chlorophyll a concentration, water temperature, and pH values, and a decrease in the concentration of total phosphorus, but higher than the reference value. Additionally, the usage of the surrounding area of the hydrographic basin shows that it is extremely important for water quality and should be included in the WFD. Addressing the problems in the surrounding areas reservoirs is essential to adopting measures that improve water quality, therefore guaranteeing the health of the environment as expected under the One Health concept. Full article

Understanding rainfall partitioning by shrub canopies is essential for assessing water balance and improving hydrological models in cold regions. From 2010 to 2012, field experiments were conducted in the Hulu catchment of the Qilian Mountains, focusing on Potentilla fruticosa and Caragana jubata during the growing season. Throughfall, stemflow, and interception loss were measured using rain gauges, stemflow collars, and a water balance approach. A total of 197 natural rainfall events were recorded, and precipitation partitioning characteristics were analyzed in relation to rainfall intensity, amount, and vegetation traits. One-way ANOVA and regression analyses were used to test differences and correlations. The results showed that the critical rainfall threshold for generating throughfall and stemflow was 1.9 mm. For P. fruticosa, throughfall, stemflow, and interception loss accounted for 66.96%, 3.51%, and 29.53% of gross rainfall, respectively; the corresponding values for C. jubata were 67.31%, 7.27%, and 25.42%. Significant differences (p < 0.05) in stemflow were observed between species. Partitioning components were positively correlated with rainfall amount and stabilized at ~4 mm h⁻¹ intensity. Interception loss percentage decreased with intensity and plateaued at 2 mm h⁻¹ for P. fruticosa and 5 mm h⁻¹ for C. jubata. These findings provide empirical evidence for modeling shrub canopy rainfall redistribution in alpine environments. Full article

The overuse of concrete in historical areas, currently observed in various urban watersheds in Poland, may pose a significant threat to the water balance of catchments, leading even to pluvial flooding. The distorted water balance may be, to some extent, restored by sustainable green architecture designs. This paper presents an attempt at the numerical assessment of changes in the water balance caused by revitalization in three main historical squares in cities in Lublin Voivodeship, Poland. A proposal for rain garden installation, allowing the partial restoration of the water balance, is also introduced. Numerical calculations of the runoff generation were performed in SWMM 5 software for real weather conditions recorded in Lublin during the period 1 June–31 August 2024. The performed simulations show that an increase in the imperviousness of the studied urban catchments results in a significant increase in runoff characteristics, with a 78.2–90.9% increase in volume and a 108–141.7% increase in peak flows. The introduction of the proposed rain gardens allows the partial reduction in the runoff volume and peak flows, down by 18.1–30.2% and 17.9–32.0%, respectively. Full article

The Australian Bureau of Meteorology provides flood forecasting and warning services across Australia for most major rivers in Australia, in cooperation with other government, local agencies and emergency services. As part of this service, the Bureau issues a flood watch product to provide early advice on a developing situation that may lead to flooding up to 4 days prior to an event. This service is based on (a) an ensemble of available Numerical Weather Prediction (NWP) rainfall forecasts, (b) antecedent soil moisture, stream and dam conditions, (c) hydrological forecasts using event-based models and (d) expert meteorological and hydrological input by Bureau of Meteorology staff, to estimate the risk of reaching pre-specified river height thresholds at locations across the continent. A flood watch provides information about a developing weather situation including forecasting rainfall totals, catchments at risk of flooding, and indicative severity where required. Although there is uncertainty attached to a flood watch, its early dissemination can help individuals and communities to be better prepared should flooding eventuate. This paper investigates the utility of forecasts of daily gridded national runoff to inform the risk of riverine flooding up to 7 days in advance. The gridded national water balance model (AWRA-L) runoff outputs generated using post-processed 9-day Numerical Weather Prediction hindcasts were evaluated as to whether they could accurately predict exceedance probabilities of runoff at gauged locations. The approach was trialed over 75 forecast locations across North East Australia (Queensland). Forecast 3-, 5- and 7-day accumulations of runoff over the catchment corresponding to each location were produced, identifying whether accumulated runoff reached either 95% or 99% historical levels (analogous to minor, moderate and major threshold levels). The performance of AWRA-L runoff-based flood likelihood was benchmarked against that based on precipitation only (i.e., not rainfall–runoff transformation). Both products were evaluated against the observed runoff data measured at the site. Our analysis confirmed that this runoff-based flood likelihood guidance could be used to support the generation of flood watch products. Full article

Achieving sustainable development in agricultural catchments requires well-designed policy measures. This study examines the intricate interactions between social dynamics and hydrological processes within agricultural systems to propose targeted policy interventions. By employing socio-hydrology models that integrate socio-economic and hydrological data, the research provides valuable insights into the feedback loops and interdependencies that influence catchment sustainability. In this study, we find that policies on population management should aim to balance natural growth rates with the carrying capacity of the basin. Strategies such as education, healthcare access, and family planning can help manage demographic pressures. Migration policies should consider the economic and environmental impacts of population influx and support balanced regional development to distribute the demographic pressures more evenly. Wage growth should be aligned with economic productivity to prevent unemployment and inequality. Policies that promote equitable wage structures and enhance labor mobility between sectors can mitigate disparities. The findings emphasize the necessity of adaptive policies that address both environmental and societal factors, advocating for interdisciplinary approaches in water resource management and agricultural policy development. This study also highlights the pivotal role of technological innovations and the societal values and norms that shape sustainability and resilience in agricultural catchments. Full article

The ecosystem of Dal Lake, an important freshwater lake in Srinagar, India, has been rapidly degraded in recent decades due to intensified eutrophication. The main causes of eutrophication were determined to be different types of human activities in the catchment area and its inappropriate development as well as excessive loads of pollutants introduced into the lake. The heightened algal blooms brought significant water quality deterioration, a reduction in indigenous fish populations, and a general disturbance of the ecological balance of the lake. Such changes adversely influenced the living conditions of the inhabitants depending on the lake for tourism, fishing, and other economic pursuits. The aim of the research was the evaluation of the specificity of the course and spatio-temporal dynamics of Dal Lake eutrophication process on the base of accurate assessment of its actual trophic state. The applied assessment methodology was based on the biotic balance approach. As an indicator of the biotic balance in water, the Index of Trophic State (ITS) was chosen and adopted for the conditions of the lake ecosystem in humid subtropical climate conditions. The assessment was based on data from a five-year lake monitoring period (2019–2023) and analyzed for four lake basins: Hazaratbal, Nishat, Nagin, and Gagribal. The results indicated a steady increase in the lake’s trophic status, with the Hazaratbal basin evolving from mesotrophic to eutrophic, while the other basins progressed from meso-eutrophic to eutrophic during the research period. At the end of the research period, the whole lake was classified as eutrophic, with a modest inclination towards heightened eutrophication severity. The research underscores the pressing need for elaboration of a holistic lake management approach, where ITS, which has proven to be a valuable and reliable express-monitoring tool, can be used for obtaining information necessary for solving different applied tasks for protection and conservation strategies. Full article

The potential of inland valleys to enhance food security and improve agricultural resilience to climate change in Africa is constrained by a limited understanding of their hydrological functioning and inadequate water management. In order to synthesize knowledge on hydrological responses in inland valley areas, this work reviewed 275 studies from tropical Sub-Saharan Africa (SSA). Data from the literature search were collected from Scopus™, ScienceDirect™, Web of Science™, Google Scholar™, and doctoral theses repositories such as ZEF, HAL, and Theses.fr, covering studies published from the inception of these databases through 31 May 2023. Our approach involved, firstly, a bibliometric analysis of all papers to gain insights into research trends and interests. Secondly, we performed a quantitative synthesis of results from 66 studies examining stream flows in a set of 79 inland valleys to better understand factors that govern runoff dynamics in these environments. Correlative analyses and clustering methods were applied to identify potential links between runoff and watershed physical parameters. The findings highlight the varied responses of inland valleys over both time and space, influenced by a combination of catchment drivers. The correlation matrices between hydrological indices and physical parameters indicate a strong relationship among runoff and a range of parameters, of which the most significant are rainfall (R² = 0.77) and soil silt content (R² = 0.68). Challenges in accurately spatializing information related to potential determining components of the water cycle, such as groundwater dynamics and soil moisture, seem to have limited the exploration of interactions between river flow, soil moisture, and groundwater. Future works should prioritize the development of accurate and user-friendly hydrological models that balance complexity and data availability to enhance the understanding of inland valley behavior at fine scales and consolidate food security in Africa. Full article

Modeling non-point source pollution dynamics in inland lake basins is essential for safeguarding water quality, maintaining ecosystem integrity, protecting public health, and advancing long-term environmental sustainability. This study explores non-point pollution dynamics in the Sapanca Lake basin, Turkey, in association with the basin’s land use, land cover, hydrology, pollutant sources, and water quality parameters. The required data were gathered via a three-year monitoring program, which was carried out at 12 sampling stations around the lake, as well as using the collecting field measurements and GIS databases. Stepwise multiple regression analysis was employed to determine the best relation between non-point pollutants and land features. The results showed that urbanization and population density have significant correlations with the total nitrogen (TN) and total phosphorus (TP) in the study areas. Rivers crossing pristine areas, such as forests and uncultivated lands, demonstrated better water quality, thereby positively contributing to the lake ecosystem conservation. The highest nutrient loads were observed in streams that flow through highly urbanized sub-basins, followed by predominantly agricultural areas. This is likely due to runoff from urban environments, leaching from cultivated land, and contributions from livestock and tourism facilities. Conversely, densely forested regions exhibited the lowest levels of nutrient loads, highlighting their capacity for nutrient retention. The peak levels of non-point source pollution (TN = 5.22 mg/L and TP = 0.53 mg/L) were recorded in catchments with the highest degree of urbanization, whereas the lowest values (TN = 0.28 mg/L and TP = 0.04 mg/L) were found in the least urbanized areas. These findings emphasize that nutrients primarily impact water quality because of increasing urban and agricultural activities, while forested land plays a vital role in preserving lake water quality. To ensure sustainable water quality in lake basins, it is essential to strike a careful balance between protective measures and utilization policies, prioritizing conservation efforts. Full article