Sustainable water governance is essential for maintaining water security in river basins subject to growing pressures from agriculture, livestock and climate variability. This study investigates how governance awareness, community participation and water-use attitudes influence water management along the Gambia River. A structured household survey of 290 respondents from 15 riverine villages in three communes was combined with key informant interviews and focus group discussions to examine regulatory awareness, participation in management structures and sources of water-related conflict. The results show generally low awareness of water regulations and limited involvement in local water management organisations, which constrains effective governance and compliance. Conflicts over water use, particularly between crop farmers and livestock herders, are widespread and are reinforced by resource scarcity, weak institutional coordination and limited administrative presence. Qualitative evidence highlights the important role of community-based organisations, notably the Gambia River Valley Producers Cooperative (COPROVAG), in mediating conflicts, facilitating coordination and promoting more equitable water sharing. The findings indicate that strengthening regulatory communication, improving institutional–community linkages and supporting locally rooted governance structures are key to improving water management in data-scarce river basins.
This study investigates the impact of cylindrical obstacle concentration (C) on flow dynamics in low-slope channels using ANSYS Fluent. Cylinders (D = 12 cm, L = 15 cm) were arranged with varying axial and lateral spacings, producing concentrations from 9 % to 64 %. Simulations under critical flow conditions with a 1 m s−1 inlet velocity employed the VOF method and Kw turbulence model to assess velocity, turbulence, pressure, and shear stress. Results show that increased obstacle concentration enhances energy dissipation, with turbulence intensity decreasing from 0.08 to 0.03–0.05 m2 s−2. Wall shear stress rises to 6.5 Pa at 64 % C due to flow constriction, while velocity deficits downstream reduce from 40 %–50 % to 20 %–30 %. These findings underline how obstacle arrangement influences flow resistance and energy loss. It also provide quantitative design insights for improving hydraulic performance in low-slope floodplain environments. These results directly inform flood resilience strategies and infrastructure design by illustrating how controlled obstacle density can enhance energy dissipation and manage flow resistance.
The study assesses the vulnerability of family farms to rainfall-induced flooding in the municipality of Kandi, northern Benin, using the IPCC vulnerability framework based on exposure, sensitivity, and adaptive capacity. Data were collected from 80 agricultural producers across ten villages through structured interviews and analyzed across five types of capital: human, physical, financial, social, and natural. Results reveal significant disparities between farm categories. Small farms (≤ 5 ha) exhibit very high vulnerability (4.5/5), marked by low education levels (38.9 % uneducated), limited mechanization (83.3 % without access), and poor credit availability (77.8 % excluded). Medium farms (5–20 ha) show moderate vulnerability (≈ 3.0/5), with 61% having access to mechanization and 46.3% to credit, but still constrained by low income diversification. Large farms (>20 ha) demonstrate low vulnerability (≈ 1.5/5), benefiting from strong assets: 76.2 % mechanized, 71.4 % with credit access, 90.5 % participating in cooperatives, and 57.1 % cultivating fertile soils. The analysis highlights an inverse correlation between farm size and flood vulnerability, reflecting structural inequalities in access to productive and adaptive resources. Strengthening human and financial capital among smallholders – through literacy, agricultural training, microfinance, and cooperative mechanization – is crucial to enhance resilience. This research contributes to climate vulnerability literature by integrating socio-economic and biophysical indicators into a composite framework, emphasizing the multidimensional nature of vulnerability and the need for inclusive adaptation policies in northern Benin.
In Benin, the Lower Ouémé Valley is a region of intense agricultural activity whose soil, hydrological, and climatic conditions are favourable to rice cultivation. Despite this potential, water management remains one of the challenges facing rice production in the area. The development of new land management approaches and agricultural practices is an ideal alternative for improving water management for agricultural production in a context of climate variability. Among these, the Smart-Valleys (SV) land management approach and the System of Rice Intensification (SRI) have been introduced to make rice production profitable in several regions of West Africa. This study aims to compare two land management approaches (Smart-valleys vs. Conventional) and three levels of irrigation, namely Low Variable Irrigation (IR1), Low Constant Irrigation (IR2), and Intermittent Irrigation (IR3) for efficient water management in rice production in the lower Ouémé valley. The experimental design consists of split plots with two replicates per treatment, where the management approach and irrigation levels represent the primary and secondary factors, respectively. The results of the experiment show that Smart-valleys (SV) management has a positive effect on yield (p-value = 0.01) and water productivity (p-value < 0.001). As for irrigation, the IR3 method yields the best performance in terms of water productivity (p-value < 0.001). In addition, the SV-IR2 combination maximizes paddy rice yields (8.5 t ha−1, an increase of 4.7 t ha−1), while the SV-IR3 combination optimizes water productivity (1.4 kg m−3, an increase of 1.06 kg m−3). This highlights the importance of an integrated approach that combines appropriate land management and optimal irrigation strategies to maximize water efficiency in rice production systems. An economic analysis of the different treatments will help identify the best approach to combine yields, water use, and profitability.
The Lake Nokoué and Porto-Novo Lagoon complex represents the most important Lagoon system in Benin and is influenced by saltwater intrusion during Low water period via Cotonou channel. The main objective was to determine the composition and structure of benthic macroinvertebrates based on their preferred habitat. Samples were collected from 15 stations between November 2022 and October 2023, following the fluctuations of the hydrological regime notably High water (October and November), Low water (January and March) and Slight rise water (June and August). The results reveal a total of 79 species across the entire studied Lagoon complex. For Lake Nokoué, the following abundances were obtained for: strictly freshwater taxa (4.27 %), strictly brackish taxa (44.58 %), and strictly saltwater taxa (11.86 %). In the Porto-Novo Lagoon, the following abundances were recorded for: strictly freshwater taxa (7.78 %), strictly brackish taxa (6.96 %), and strictly saltwater taxa (16.83 %). Regarding the hydrological regime, a predominance of strictly freshwater taxa was noted during the High water period in Lake Nokoué. Furthermore, this predominance was recorded during both High and Low water periods within the Porto-Novo Lagoon. Thus, the variation of these taxa was found to be more pronounced in Lake Nokoué (p<0.01) than in the Porto-Novo Lagoon (p>0.05).
Lake Toho is one of the important freshwater ecosystem in southern Benin, under intense human activities. This study aims to assess the spatial and temporal variations of water physicochemical parameters in Lake Toho. A total of 54 water samples were taken during three campagns at 6 stations from February to June 2024. Water depth and Secchi Disk Depth (SDD) were recorded in situ using a Secchi disk. Turbidity was determined using a turbidimeter. Parameters such as temperature, pH, dissolved oxygen, oxygen saturation, salinity, Electrical Conductivity (EC), and Total Dissolved Solids (TDS) were measured using a probe multiparameter. Nutrient concentrations were quantified using specific reagents and a spectrophotometer. Analyses of variance revealed spatial and temporal significant variations (p < 0.05) for water depth (1.71–2.24 m), SDD (21.33–26.44 cm), pH (7.06–7.68), temperature (30.4–32.25 °C) and suspended solids (22.56–27.22 mg L−1). EC (470.56–508.72 µS cm−1), salinity (0.22–0.24 PSU), nitrate (7.29–10.66 mg L−1), ammonium (0.18–0.28 mg L−1) and orthophosphate (0.08-0.13 mg L−1) were showed only very significant variation between months (p < 0.001). Significant correlations (p < 0.001) were observed between SDD and turbidity, between nitrate and pH, water depth, salinity, EC and TDS. The nutrient enrichment observed in this lake could be responsible for organic pollution, likely driven by anthropogenic inputs. This study constitutes a preliminary assessment of the ecosystem, and further investigations are needed to better understand its biogeochemical functioning and the nature of the disturbances affecting it.
In centenary celebration of IAHS, Converging knowledge, shared in global embrace, Hydrological sciences in captivating displays, A graphic chaptering, and poetic interlace.
The oases of the pre-Saharan basin of Wadi Ferkla in southeastern Morocco receives low and erratic rainfall (annual average of 141 mm and inter-annual standard deviation of 70 mm). From the 1980s, surface water and groundwater are increasingly used due to the expansion of irrigation, mainly along two wadis, namely Wadis Ferkla and Satt originating in the High-Atlas and the Anti-Atlas Mountains, respectively. Their flows reach the Ferkla's irrigated perimeters only when the volume of the flood events exceed upstream evaporation, withdrawals and riverbed's infiltration. Nowadays, these irrigated perimeters exert significant pressure on groundwater resources, through numerous drillings equipped with pumping systems, most of them being powered by solar energy. This increasing water demand situation incentivizes individual farmers to design and implement innovative techniques to increase water access for their farms. For instance, the spreading of floodwaters – an ancestral and collective irrigation practice in traditional oases – is currently being modernized by individual farmers. The new technique consists in partially diverting flood flows into earthen basins. The stored water either infiltrates to recharge local aquifers, or is pumped for flood irrigation of date palms. An experimental protocol was set up to characterize groundwater recharge below one of these on-farm basins equipped with a recharge well. Barometric probes were installed in the basin, in the recharge well and in neighboring boreholes to automatically monitor water levels. A topographic survey of the monitoring points and of the basin aimed at deriving piezometric levels from water levels measurements and estimating the height-surface-volume curves of the basin. After 7 months of continuous monitoring, 3 flood events were recorded. The establishment of the basin water balance at a fine time-resolution allowed estimating its different components including the infiltration rate influencing groundwater recharge. An analytical modeling of this process was developed to assess its effect on groundwater level variations. This approach aims to contribute to a broader reflection on securing water management in this fragile oasis ecosystem.
Due to pronounced hydroclimatic fluctuations and rapid urban growth, coastal lagoonal systems in the Southern Mediterranean semi-arid areas undergo pronounced shoreline retreats and increased coastal floodings. The socioeconomic impacts of these alarming coastal changes remain poorly uncharacterized. To address this deficiency, we calculate the Socioeconomic Vulnerability Index (SVI) based on the decadal changes in shoreline retreat and land use occupation considering the study case of the coastal lagoon of Ghar El Melh in Tunisia which is representative of several lagoonal systems in the southern Mediterranean basin. We first monitor the diachronic shoreline changes from 1882 to 2016 using aerial and orbital photogrammetric scenes combined with topographic and bathymetric maps. Using the Digital Shoreline Analysis System (DSAS) and historic bathymetric records, we then measure the changes in shoreline position from 1882 to 2016. Secondly, the above is correlated with the Land Use/Land Cover (LULC) assessment using a supervised classification algorithm from multiple Landsat 5-8 orbital photogrammetric scenes. We assess the SVI using five socioeconomic parameters: (1) population density, (2) land use change, (3) road network, and (4) settlements. Our results reveal the occurrence of severe coastal erosion with a maximum Net Shoreline Movement of −1580 m (±6 m) between 1882 and 2016. Moreover, the changes in land use from 1985 to 2021 reveal the extension in urban growth around the lagoon, rising from 5.4 % to 13.5 %. Whereas the vegetation coverage is decreasing by 9 % over the same period. The resulting SVI map reveals that 85 % of the lagoon area is characterized by high to very high vulnerability. This high coastal vulnerability is found to be primarily due to the extensive change in land occupation over the last few decades and is aggravated by the increase in hydroclimatic extremes.
This study aims to analyze future snowmelt runoff and snow extent for the Upper Euphrates Basin (41 109 km2) which is the most upstream basin of the water tower Mesopotamia and located in the Eastern mountainous part of Türkiye. The future characterization of snowmelt runoff and snow water equivalent is investigated taking the regional climate model projections into account through hydrological model applications. The basin is divided into two major sub-basins Karasu Basin and Murat Basin. The conceptual hydrological models, HBV and HEC-HMS have been utilized to establish a rainfall-runoff relationship. The models are calibrated and validated with observed daily total precipitation and average temperature data for the 1980–2011 period. Future projections are selected for the 2025–2100 periods using EU-CORDEX data with various global circulation models. MPI-ESM-LR and CNRM-CM5 data sets and RCP4.5 and RCP8.5 emission scenarios are used for future projections. The results indicate a decrease in snow cover extent and an increase in snowmelt runoff. The overall assessment will help us to understand how these changes will affect the operations of water resources systems (downstream reservoirs) in terms of flood control, energy production, irrigation, water supply, etc.
Fair and safe allocation of natural resources for the Euro-Mediterranean area, especially for semi-arid regions, strongly relies on the adoption of WEFE (Water Energy Food Ecosystem) Nexus strategies. Transitioning to WEFE Nexus requires novel quantifiable assessment for interlinked analysis of the four WEFE sectors. Several indicator-based tools exist for agricultural sustainability at the farm scale. This contribution investigates on the application of such tools in relation for WEFE Nexus approaches. The IDEA method was selected for extending its applicability as a novel WEFE Nexus indicator toolkit and the following challenges are identified: (1) some WEFE aspects need to be reinforced in order to expand the scope beyond the actual agro-ecological focus; (2) the application at the farm scale needs to be articulated with larger scales where the WEFE Nexus displays emerging consistencies; (3) Nexus interactions, trade-offs and synergies could be further accounted for. These three challenges help identify how the IDEA indicator-based tool could be adapted to assimilate the WEFE Nexus approach, and so to allow applications in new agro-hydrological contexts.
Global climate changes significantly contribute to increased frequency of hydrologic extremes. This significantly underestimates the hydrologic design parameters, bringing of hydro systems to increased failure risk. In order to address this concern, the current practice of development of hydrologic frequency tools need to be updated accounting for non-stationarity. This study first considered a diverse set of statistical tests to examine the trend, change points, non-stationarity and randomness of streamflow, rainfall and temperature time series of scales ranging from daily to annual. The annual maxima time series indicated non stationarity against the stationary behaviour of daily series of hydro-meteorological datasets of the basin. Subsequently, this study developed the Temperature Duration Frequency (TDF), Rainfall Intensity Duration Frequency (IDF) and Flood Frequency (FF) curves of Greater Pamba river basin in Kerala India, the part of which was most severely affected by the near century return period flood event of 2018. The analysis was performed for a multitude of combinations of variations in distribution parameters with time and climatic drivers as physical covariates in the extreme value formulations. The study proposed a novel wavelet coherence (WC) based driver selection of most dominant combination of climatic precursors in developing FF and IDF relations of three locations of Kalloopara, Malakkara and Thumpamon and TDF curve of Kuttanad region in the basin, considering data of 1985–2015 period. The proposed WC framework considers bi-multi-and partial effects of climatic oscillations (COs) like El Niño Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), Pacific Decadal Oscillation (PDO) and North Atlantic Oscillation (NAO) in identifying potential drivers. The different WC formulations captured in-phase relationships of streamflows and rainfall with COs at intra-annual, annual and inter annual scales up to 4 years. The methods showed that addition of climatic precursors improved the NS estimates of flood and rainfall quantiles by more accurately capturing the magnitudes of extreme streamflows and rainfalls of 2018, 2021 than the time covariate formulations. However, the role of COs on extreme temperature is not found to be influential in developing TDF relationships, which needs further investigation.
The Po River District Authority promoted the MOVIDA project with the aim to define appropriate methodologies for flood risk assessment and being compliant with the European Floods Directive (Directive 2007/60/EC). A dedicated Open Source Geographic Information System (i.e. QGIS geoprocessing modules) has been developed for mapping the expected damages in all areas at significant risk in the Po District (Northern Italy), considering five categories of exposed elements (population, infrastructures, economic activities, environmental and cultural heritage, and na-tech sites). Focusing on road and railway infrastructures, the methodology proposed within the project adopts information coming from different data sources (Regional Geoportals, Open Street Map, etc.) and allows to qualitatively estimate the potential risk associated with a flood event. Different risk classes (High, Medium, Low and Null) are assigned in relation to roads category (i.e., Highways, Main, Secondary, Service, Other) or railways type (High-Speed train or not), thus considering both the relevance of the infrastructure itself (as well as its topographical characteristics: e.g. tunnel, bridge, etc.) and the magnitude of the expected event (i.e., hazard). The definition of the risk matrix led to the estimation of the lengths of the sections exposed to different risk levels, which is useful to support the definition of potential mitigation measures and support the competent bodies in the organization of the rescue.
The alluvial aquifer of the transnational Roya River watershed is an important water resource for drinking water supply. Through successive European projects, a monitoring network has been implemented over the alluvial plain to improve the understanding of the functioning of this aquifer. For instance, studies highlighted the predominant role of surface water in the recharge of the aquifer. Following the storm Alex and the resulting exceptional flood event in the Roya valley in October 2020, a general decrease of the piezometric levels was observed in the alluvial aquifer. Changes in the river morphology and in the granulometry of the hyporheic zone have impacted surface water – groundwater exchanges and reduced the aquifer recharge.
Erosion and sediment-related problems are well documented globally and continue to warrant further scientific investigation, as well as improved policies and management strategies to protect soil and water resources. The International Commission on Continental Erosion (ICCE) has long been a very active commission of the International Association of Hydrological Sciences (IAHS) focussing on progressing scientific understanding of erosion and sediment systems. This paper provides a brief overview of its main scientific foci, examples of previous contributions to scientific conferences and finally, concludes by paying tribute to two key former members of the international scientific community engaged with its remit.
In Mediterranean oak-savannas (known as dehesas in Spain), it is important to better understand the interactions between vegetation structure and local climate regulation at scales relevant to farm management and the dominant hydrological regime. This study evaluated the water use patterns of dehesa vegetation patches (open grasslands, lowland grasslands with high soil moisture, tree + grass, and riparian vegetation), estimating actual evapotranspiration (ET). We used different models, previously validated in the area, that integrate remotely sensed data. They apply (a) a soil water balance (Kc-FAO56), (b) a surface energy balance (ALEXI/DisALEXI, and SEBS), and (c) a sharpening algorithm (STARFM), obtaining products at multiple spatial resolutions (30 m, 1 km, 5 km). The conceptual and operational differences between the methodologies reinforce the idea of a combined application of models. We demonstrated the need for high spatial and temporal resolution for on-farm livestock management due to the importance of the grasslands layer. This scale is crucial to determine the grass's emergence/drying cycle, which is key for livestock feeding planning. In humid/denser areas that provide essential ecosystem services (e.g., refuge, pasture rotation), transpiration rates are higher throughout the year and were underestimated when coarser spatial scale data was used. Over the typical system (grass with dispersed trees), the ET maps at low spatial resolution reflected the water use trends, and all models correlated well. Higher differences were found when comparing the models' performance over open grasslands.
