The Brahmaputra River (BR) is one of the world's most dynamic rivers, and its channel migration significantly impacts the land use and land cover (LULC), and socio-economic stability of Assam, India. This study evaluates LULC changes within the river corridor and their impact on socio-economy of the region. Multi-temporal satellite imagery from 1976 to 2020 was analysed using hybrid classification techniques and manual recoding to map seven LULC classes. River dynamics was quantified through bankline shift and overlay analysis. Results indicate a pronounced south-westward shift of the river, with average bankline shifts of 1.71 km on the left bank and 1.74 km on the right bank. Over 44-years, 1552.2 km2 of land was lost to erosion, while 286.5 km2 was formed through deposition. Erosion severely affected agriculture (705.9 km2), threatening food security and livelihoods, and vegetation (446.3 km2), reducing ecological resources. Critically, Built-up losses (78.7 km2) exposed settlements to displacement and infrastructure damage, representing the most immediate socio-economic impact. Conversely, deposition resulted in constructive change supporting agriculture expansion (131.1 km2), vegetation growth (63.6 km2), and settlement development (17.1 km2). These findings underscore that agriculture, vegetation and settlements, the core socio-economic pillars of Assam's floodplain communities are directly shaped by river dynamics.
To successfully execute stakeholders' engagement (SE) in Integrated River Basin Management (IRBM), it is important to pay attention to all the key factors that are required but have typically been neglected, disregarded, or omitted. Based on the findings from research, this study identifies five essential independent variables for successful engagement: stakeholder inclusiveness, stakeholder characteristics, engagement strategies, organizational factors, and cultural and religious aspects. These variables help organizations to structure their engagement efforts in line with broader goals and regulatory frameworks. Additionally, the study highlights the inclusion and application of three enhancers for SE: multi-stakeholder platforms, environmental social governance principles, and a whole-of-government and whole-of-society approach, all promoting inclusivity, sustainability, and comprehensive collaboration. These three enhancers will improve the three dependent variables: knowledge transfer, decision impact, and stakeholders' satisfaction. The interactions and linkages of the independent variables, the enhancers, and the dependent variables provide the basis for a novel conceptual framework for measuring stakeholder engagement effectiveness, offering best practices among others, a structured method for documenting, monitoring and evaluating the engagement process. This framework enhances stakeholder communication by establishing clear objectives, facilitating informed decision-making, and early identification of potential issues. Its adoption will help ensure more sustainable outcomes in water resource management at the river basin level.
Reliable streamflow simulation is essential for effective water resources planning and management in semi-arid river basins. This study evaluated the hydrological response of the Kunderu River watershed using both a process-based model and data-driven machine learning (ML) approaches for monthly discharge simulation.Land Use/Land Cover (LULC) classification for 2022, achieved an overall accuracy of 85.42% and a Kappa coefficient of 0.80, confirming its suitability for hydrological applications. Monthly calibration of SWAT model yielded good simulation performance, with NSE values of 0.72 during calibration and 0.81 during validation, R & sup2; values up to 0.92, and PBIAS within +/- 10%. For data-driven modeling, eXtreme Gradient Boosting (XGBoost), Categorical Boosting (CatBoost), Random Forest (RF), and Long Short-Term Memory (LSTM) models were evaluated. Under the fixed 2022 validation framework adopted for direct comparison with SWAT, CatBoost achieved the best performance (R & sup2; = 0.90, NSE = 0.90, PBIAS = +4.38%), followed by LSTM (R & sup2; = 0.88, NSE = 0.88, PBIAS = -5.44%). An additional Leave-One-Year-Out (LOYO) analysis was used to assess temporal robustness across multiple independent validation years. The LOYO results identified CatBoost as the most accurate and stable model, with the highest average R & sup2; (0.98) and NSE (0.96), followed by RF (average R & sup2; and NSE of 0.91). Overall, the ML models outperformed the SWAT in predictive accuracy and bias control, proving to be effective complements or alternatives to conventional hydrological models for semi-arid basin discharge forecasting.
Floods are among the most significant natural hazards and are expected to affect both urban and rural areas increasingly under climate change. Engineering-based solutions alone have proven insufficient for addressing flood risks associated with extreme weather events. This study investigates how indigenous knowledge can be integrated with scientific approaches to improve understanding of flood-generating factors and support more inclusive flood management. Focusing on the D & uuml;zce Melen Basin in northwestern T & uuml;rkiye, the research incorporates the experiential knowledge of village heads from flood-prone rural communities. Data were collected through descriptive semi-structured interviews with 30 village heads and analyzed using thematic analysis. The findings identify eight main themes related to flood causes: climate and meteorology, hydrology and topography, socio-economic and behavioural factors, institutional practices and administrative structures, natural cycles and indigenous knowledge, forest and land use, settlement and construction, and infrastructure and river improvement. The study also examines local and academic experts' perceptions of the role of indigenous knowledge in flood management. Results indicate that local knowledge can complement scientific data, particularly in data-scarce rural areas, improving flood susceptibility assessment and supporting more context-specific risk reduction strategies. The study proposes a framework for integrating community-based knowledge into flood susceptibility analysis.
An experimental investigation was carried out to examine local scour downstream of grade-control structures (GCSs) under the influence of a two-dimensional jet flow. The impinging jet downstream of a GCS generates substantial erosive forces, leading to pronounced local scour that can compromise the structural stability and safety of the system. Therefore, a key aspect of GCS design is developing a comprehensive understanding of the scouring process and enhancing the ability to predict the temporal and spatial evolution of the scour hole.This study focuses on the development of a scour hole downstream of a sloped grade-control structure (GCS) in alluvial channels with a noncohesive sediment bed. Based on a series of laboratory experiments and data collected from previous studies, the effect of the downstream face slope of a GCS on scour morphology was analyzed. The results led to the proposal of a new scaling approach, yielding general equations for predicting equilibrium scour profiles at a wide range of hydraulic structures and flow conditions in fluvial and coastal areas. A set of predictors for the scour characteristic parameters under equilibrium conditions is also proposed. To facilitate practical application, these equations were expressed as functions of variables that practitioners can easily define.
Water scarcity is a major challenge in semi-arid regions where limited water availability and increasing demand threaten populations and ecosystems. This study assessed seasonal water scarcity at the sub-watershed level in the Gongola River catchment, northeast Nigeria, using a Water Scarcity Index (WSI) based on naturalised water availability and sectoral water use for domestic, agricultural, and industrial activities. Seasonal WSI values were combined with population data to estimate exposure, while sensitivity tests evaluated uncertainty in hydrological and demand parameters. Three machine-learning models (Random Forest, XGBoost, and GBM) were applied to identify key scarcity drivers. Results show strong seasonal variability, with agricultural withdrawals causing acute deficits in SW 5, 6, 8, and 9 where water use exceeds availability. More than one million residents are exposed to moderate-to-severe scarcity, particularly during the Transition season. Machine-learning results identify irrigated area, precipitation, evapotranspiration, and soil texture as dominant controls. Overall, water scarcity in the Gongola catchment is demand-driven, spatially heterogeneous, and seasonally amplified.
This work examines international perspectives on hydrological drought research across its diverse manifestations, focusing on the period 2000-2024, with special emphasis on Africa. Using a structured conceptual framework, the review addresses both the thematic evolution of hydrological drought research and the methodological approaches employed. A total of 25 relevant publications were identified through Web of Science (WoS) and Scopus and manually coded according to predefined criteria, including methodology type, geographic focus, and institutional context. The findings reveal significant differences in the volume and methodological diversity of scientific production between Africa and other regions. Advanced techniques such as machine learning, statistical modeling, and integrated frameworks remain underutilized in African studies, despite the widespread use of hydrological indicators including the Standardized Precipitation Index (SPI), the Standardized Precipitation Evapotranspiration Index (SPEI), and satellite-derived data. Quantitative weighting analysis indicates that Africa lags behind global trends in drought assessment approaches. The study also highlights persistent physical and institutional challenges, including limited scientific capacity and insufficient data availability. These results emphasize the urgent need to strengthen training programs, research infrastructure, and the scientific visibility of African contributions to hydrological drought management.
Morphometric analysis, driven by basic linear, areal, and relief parameters, is acknowledged as an effective method for evaluating watershed characteristics and estimating their vulnerability to flash floods. This research utilizes satellite-derived data to define and measure 26 morphometric parameters of the Palongkhali River Basin in Cox's Bazar, Bangladesh. A 30-meter Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) was utilized to delineate the basin and its sub-watersheds, which were then prioritized based on morphometric indices to assess their hydrological response and overall susceptibility to flash floods. The basin was classified as a sixth-order system according to Strahler's stream ordering. Morphometric variables, such as form factor, elongation ratio, circularity ratio, and compactness coefficient, all suggest that the basin exhibits a primarily circular shape. The sub-watersheds SWS-1, SWS-8, SWS-9, SWS-10, SWS-12, SWS-13, and SWS-14 were classified as very vulnerable, exhibiting compound factor values < 9.00 based on the standardized ranking of morphometric parameters. Pearson correlation analysis revealed that Total Basin Relief has a positive correlation with Ruggedness Number and Stream Length, suggesting that sub-watersheds with steeper gradients exhibit increased terrain ruggedness and elevated erosion potential, consequently heightening flash-flood vulnerability. These findings support watershed planning, hazard zoning, warnings, and erosion mitigation.
Droughts have been reported to cause socio-economic disruption in the Vietnamese Mekong Delta (VMD), threatening the region's sustainable development. However, it is difficult to monitor droughts in the VMD due to the lack of ground-based rainfall stations. Alternatively, remote-sensing technologies that provide regular temporal and spatial data are analysed. We verify the correlation between the Tropical Rainfall Measurement Mission (TRMM) 3B42 product and rainfall data collected from meteorological (gauged) stations in the VMD. Next, we assess the reliability of TRMM for monitoring meteorological drought and quantifying the drought characteristics based on the standardised precipitation index (SPI) at a wide range of time scales (1-12 months) during the period 1998-2018. TRMM shows a good match to station data at the monthly scale, as evidenced through biases < 5% and RMSE < 80 mm at selected sites. The driest episode was from 2014 to 2016, with a widespread drought area, most severely (with SPI < -1.5) in the northern part (Dong Thap, Tien Giang and parts of adjacent provinces). We also show that drought severity follows an increasing trend during 1998-2018, as indicated through Mann-Kendall tests on SPI time series, potentially due to changes in regional climate variability.
Riparian vegetation is a functionally important ecosystem that stabilizes riverbanks, regulates hydrological processes, and supports local community livelihoods. Despite their ecological and socio-economic importance, there is a dearth of information on the long-term shifts in riparian vegetation and their underlying drivers. This study assessed two decades (2000-2020) of shifts in the boundaries of riparian vegetation in the Black Volta Basin and identified the drivers associated with these changes. Landsat surface reflectance imagery was classified using an ensemble of Maximum Likelihood and Support Vector Machine algorithms. NDVI and MNDWI were derived to quantify vegetation greenness and surface water extent, while Mann-Kendall trend tests, ANOVA, and multiple regression were used to analyze biophysical trends and drivers. Encroached land expanded between 2000 and 2010, while sparse vegetation declined from 2010 to 2020. NDVI increased significantly from 0.138 to 0.166, despite declines in precipitation. NDVI was positively associated with precipitation and temperature but negatively associated with MNDWI, indicating that hydrological expansion reduces greenness while climatic warming enhances vegetation productivity in drought-tolerant or human-modified landscapes. These findings reveal greening that coexists with degradation of natural riparian vegetation, highlighting the need for integrated landscape management, enforcement of riparian buffers, and restoration of gallery forests.
Community participation through Water User Associations (WUAs) is intended to support sustainable water resource management in Tanzania, yet its effectiveness remains uncertain, particularly in the Wami-Ruvu Basin. This study investigates the extent and quality of participation across five stages of water management: identification, planning, implementation, monitoring, and evaluation. Using Arnstein's Ladder of Citizen Participation and Participatory Development Theory, a cross-sectional design was applied to 385 WUA members, supported by household surveys, focus group discussions, and key informant interviews. Data were analysed using a Linear Mixed Model. Findings indicate that participation is generally low and largely symbolic rather than empowering. Engagement is highest during identification activities but declines significantly in planning, implementation, monitoring, and evaluation stages (p < 0.001). Major barriers include limited time, weak communication systems, restricted opportunities for input, and elite capture by dominant individuals. The results reveal a gap between policy expectations of participatory governance and actual practice within WUAs. The study concludes that WUAs, while structurally designed for inclusivity, do not yet facilitate meaningful or equitable participation. Strengthening institutional capacity, improving communication, and adapting interventions to local socio-cultural and economic contexts are recommended to enhance effectiveness and transform WUAs into genuine platforms for community-driven water governance systems.
Overlooking the socio-political dynamics in the management of complex river basins is a significant factor contributing to the failure of water governance initiatives. This study employs the TWINS Matrix to analyse the evolution of inter-provincial cooperation and conflict in the Zayandehrud River Basin (ZRB). Additionally, it utilises the Institutional Analysis and Development (IAD) framework to assess the design and performance of the multiple River Basin Organisations (RBOs) established in the basin. Adopting a case study strategy, the findings reveal that the limited effectiveness of the RBOs is deeply rooted in context-specific socio-political dynamics, including weak state and its limited implementation capacity, identity-based conflicts, and pervasive mistrust among stakeholders. The study concludes by emphasising the necessity of context-sensitive, problem-driven approaches as a starting point for rethinking the problem of the Zayandehrud River Basin (ZRB).
Urbanization and economic activities in floodplains have altered river dynamics, increasing flood risks, environmental degradation, and ecosystem services loss. This study explores river-floodplain restoration as a sustainable solution to mitigate urban flooding, using the rectified lower part of the Maca & eacute; River Basin, Brazil, as a case study. Conventional flood control strategies, like levees and channelization, have often exacerbated flooding downstream by disconnecting rivers from their floodplains and reducing water retention. In contrast, Nature-based Solutions (NbS) allow rivers to restore natural functions, while providing social, economic, and ecological co-benefits. This research proposes a systematic approach for mapping a functional fluvial space, by integrating GIS analysis, historical cartographic records, satellite imagery, and a multi-criteria decision-making (MCDM) method. Flood susceptibility, terrain features, and fixed points that constrain river flow are evaluated, to identify possibilities of river-floodplain restoration. The findings emphasize the role of peri-urban areas, highlighting a solution that prioritizes re-meandering and floodplain reconnection over engineered interventions. Integrating river restoration into urban resilience frameworks indicates the need for adaptive water management policies that balance flood mitigation, ecological restoration, and urban safety. In this context, strategic river restoration enhances resilience and biodiversity, providing long-term flood protection while fostering coexistence between natural and built environments.
Quantitative morphometric parameters help assess the landscape evolutionary history at the basin scale and recognise and link prevalent field- regional-scale tectono-climatic processes. In this paper, the spatial distributions of morphometric parameters are assessed on a second-order watershed scale to evaluate relative influences of tectonic, climatic, and lithological controls within the Vaigai River Basin, Southern India. The results show that the elongated eighth-order Vaigai River Basin is prone to high surface run-off, low infiltration rates and headward erosion. Prevalent and ongoing tectonic activities in the upstream regions are recognised by the index of relative active tectonics and evidenced by the frequent occurrences of knickpoints. The geomorphic indices, namely, sinuosity, transverse symmetry, basin shape index, and asymmetry factor, indicated the dominance of structural controls, and are also evidenced by the occurrences of only small meanders, and migration of river channels away from the midline of the watersheds. Compilation of these results and interpretations characterises the Vaigai River Basin as an antecedent basin that is in transience, though restricted/delimited by inherited structural-geomorphic features. Resurgence of tectonic activism, relicts of paleoclimatic signatures and localised lithological controls are all documented by the present study.
India's Dam Safety Act (2021) stipulates the objectives and functions of the organisational entities concerned with dam safety. A time-bound action by dam owners has been mandated only with respect to (i) comprehensive dam safety evaluation, (ii) emergency action plan, and (iii) risk assessment. Exigency for these actions stem from urgency to prioritise India ' s ageing dams for a satisfactory level of dam safety assurance through structural rehabilitation and/or non-structural measures. Despite earnest efforts to meet the 5-year timeline for mandated actions, the dam owners are encountering serious challenges, especially regarding the risk assessment part. Since prevailing guidelines specify a complex methodology for assessing dam risks, a rapid risk assessment approach - involving an abstract exercise of risk indexing - is being attempted as a shortcut. However, compliance in this manner fails to prioritise India's ageing dams for expeditious safety assurance. Demystifying the risk assessment, the paper points out an alternative pathway, which the Act itself advocates as an integration of dam safety evaluation, risk assessment, and risk management. The Paper develops an integrated framework that leverages the overlapping nature of mandated actions, in which the outcome of one action serves as input to the other, substantially simplifying overall implementation of the Act.
Despite growing recognition of the ecological significance of Intermittent Rivers and Ephemeral Streams (IRES), critical knowledge gaps persist regarding the hydrospatial mechanisms governing their variability and vulnerability. These non-perennial systems, characterized by pronounced temporal and spatial heterogeneity, are insufficiently represented in global hydrological policies and conservation frameworks. This review synthesizes three decades of global research to elucidate the dominant hydrological drivers of seasonal and spatial variability in IRES while evaluating the compounded impacts of climate variability and anthropogenic disturbances on ecosystem degradation, resilience, and restoration. Employing systematic literature review and bibliometric analysis of peer-reviewed articles retrieved from Scopus and the Web of Science (1995-2024), this study identifies key research clusters, emergent themes, and geographic disparities in scholarly attention. The findings reveal that altered flow regimes driven by climate change, groundwater exploitation, and land-use modification significantly disrupt ecosystem connectivity and function, whereas research and policy responses remain fragmented and unevenly distributed. These insights underscore the urgent need for spatially adaptive water governance, inclusive monitoring frameworks and conservation strategies. Strengthening policy integration is essential to ensure that IRES are adequately recognized within national water management and sustainability planning, enabling their contributions to SDG targets linked to water security, climate adaptation and livelihood resilience.
