ABSTRACT Nature-based Solutions (NbS) are increasingly recognized as sustainable approaches for addressing water insecurity, land degradation, biodiversity loss, and climate resilience. However, robust long-term field evidence quantifying their hydrological and ecological effectiveness remains limited. This study presents a multi-decadal (1985–2025) evidence synthesis evaluating bamboo-based NbS for restoring degraded ravine landscapes in India by integrating long-term field observations, experimental watershed investigations, hydrological monitoring, project datasets, and peer-reviewed literature. Results demonstrate that bamboo functions as living hydrological infrastructure by enhancing rainfall retention, increasing infiltration, reducing runoff and sediment transport, improving soil quality, and accelerating ecological recovery. Bamboo-based interventions reduced runoff by 80–90%, soil loss by 85–95%, and sediment yield by over 90%, while stabilizing gullies within 2–3 years. Infiltration increased substantially (up to ∼140 cm h−1) together with improvements in soil organic carbon and micro-ecological conditions. Economically, bamboo systems generated annual returns of ₹33,500–48,000 ha−1 with internal rates of return of 18–22%. The study proposes an integrated Nature-Based Hydrological Engineering framework, establishing bamboo as a scalable, climate-resilient solution for watershed restoration, erosion control, and sustainable water management in degraded landscapes worldwide.
ABSTRACT Water scarcity remains a critical global challenge, with over two billion people lacking access to safely managed drinking water, threatening progress toward the United Nations’ sixth Sustainable Development Goal for universal access to water and sanitation. While contemporary water governance predominantly relies on centralized technological solutions, increasing attention is being directed toward indigenous knowledge systems as sustainable, decentralized, and context-specific alternatives. This study examines stepwell architecture (vav/baoli) in medieval western India (800–1700 CE) as an integrated socio-technical system combining hydraulic engineering, community-based governance, and cultural practices. Adopting a mixed-methods approach, the study draws upon architectural analysis, historical records, and comparative case studies of Rani ki Vav, Adalaj Vav, and Chand Baori. It applies Elinor Ostrom's Common Pool Resource framework alongside indigenous knowledge theory to analyze institutional and ecological dimensions. The findings indicate that stepwells functioned as decentralized water governance systems characterized by participatory management and ecological sustainability, with governance structures at all three sites persisting across dynastic transitions and political change. The study's contributions include advanced hydro-engineering techniques, governance structures that satisfy Ostrom's design principles across centuries, and strong alignment with global water and sanitation targets, particularly water efficiency and community participation.
ABSTRACT Proper assessment of sodium adsorption ratio (SAR) in groundwater is an important component for controlling the quality of irrigation water in semiarid areas. Traditional approaches based on direct physicochemical measurements are less sophisticated in capturing nonlinear threshold behaviour as well as the multiscale temporal dynamics. This paper presents a hybrid wavelet-fuzzy-random forest framework employing a sequential integration strategy, where discrete wavelet transform first extracts multiscale temporal features from groundwater variables, fuzzy inference generates uncertainty-aware membership features, and the combined original, wavelet-derived, and fuzzy-derived feature set is subsequently used for ensemble machine learning prediction. The preprocessing of groundwater samples from hydrogeochemical domains in Gujarat retained three key features: sodium, sulphate, and fluoride. Complementary feature engineering was then applied: base measurements (Level 1:3 features), fuzzy membership functions (Level 2:12 features), and wavelet decomposition (Level 3:21 features). Although SAR was calculated using the conventional hydrochemical formulation involving Na+, Ca2+, and Mg2+ ions, the feature engineering framework emphasized sodium, sulphate, and fluoride due to their stronger statistical variability and predictive significance within the investigated groundwater dataset. Random forest, extra gradient boosting, and light gradient boosting machine ensemble models were all optimized using grid search and five-fold cross-validation on a dataset comprising 601 groundwater samples, which was divided into 481 training samples (80%) and 120 independent testing samples (20%) for model development and evaluation. The best Level 3 hybrid model was the one that performed well with a coefficient of determination = 0.8442, root mean squared error = 0.9014, and mean absolute error = 0.5252. The feature importance analysis showed that fuzzy functions (59.54%) ranked higher than raw measurements (30.57%). This indicates that multiperspective feature engineering is more effective than single-method approaches for accurate groundwater quality prediction and sustainable irrigation in water-scarce regions.
ABSTRACT Traditional methods for calculating embankment flood control benefits (FCBs) fail to fully consider multiple benefit categories and require repeated flood simulations and loss estimations. This study defines embankment FCB as encompassing economic, life, health, and environmental benefits, which arise from the embankment's mitigation of flood-induced economic losses, loss of life, health impacts, and environmental damage. By introducing the value of a statistical life (VSL), a monetary quantification method of loss of life is proposed. By analyzing the ratio of injuries to deaths and the ratio of value of statistical injury to VSL, a monetary quantification method for health impacts is proposed. Combined with the environmental loss rate and the monetary value of the environment, the monetary value of environmental impacts is calculated. Based on the monetized value of comprehensive flood losses, this study proposes a simplified frequency method that only requires flood simulations and loss calculations under no-project conditions. A case study is conducted to verify the method, and the results indicate that economic benefits hold an absolute advantage in the total FCB, but the life, health, and environmental benefits should never be overlooked. The method has broad application prospects in comprehensive benefit evaluation and benefit–cost analysis of embankments.
ABSTRACT The Upper Inaouène watershed, located in northern Morocco, is characterised by marked hydrological variability and recurrent extreme events, particularly floods and droughts. This review synthesizes hydrological research conducted on the watershed between 1971 and 2025, focusing on extreme hydrological dynamics, hydrological and hydraulic modelling, water quality, and climate-related pressures. A structured literature review was conducted using scientific databases and institutional sources, with predefined inclusion and exclusion criteria. The reviewed studies show that the watershed is highly sensitive to both flood and drought conditions, while recent research increasingly relies on hydrological modelling, hydraulic simulation, remote sensing, and water-quality assessment. However, the synthesis also reveals important limitations, including fragmented and discontinuous hydrometeorological records, heterogeneous methodological approaches, limited model calibration and validation, insufficient integration between hydrology, climate, land use, and water quality, and limited consideration of hydrological non-stationarity. These limitations constrain the robust assessment of long-term changes and future hydrological extremes. Future research should therefore combine historical and recent observations, spatial data, hydrological and hydraulic modelling, and climate projections within an integrated framework adapted to non-stationary conditions. Such an approach is essential for improving flood and drought assessment and supporting sustainable water-resource management in the Upper Inaouène and the broader Sebou basin.
