Optimal water management in irrigation relies, among other things, on soil properties, which can be modified by agronomic interventions such as composting. It is in this context that the present study was carried out in 2024 at the experimental site of the Institut National de l'Eau to determine the optimal compost dose and burial depth with an effect on soil hydrodynamic properties. A completely randomized experimental block design was used, comprising control plots (without compost) and plots treated with three doses of compost (T1 = 3 kg m−2, T2 = 4 kg m−2, T3 = 5 kg m−2), each incorporated at three depths (10, 20 and 30 cm). Statistical analyses were carried out using R.4.4.1 software. Results showed that the application of 5 kg compost at 10 cm (T3 P10) improved water retention (0.466 vs. 0.210 cm3 cm−3 for the control), improved hydraulic conductivity (52.62 cm h−1 vs. 30.35 cm h−1) and reduced bulk density (1.06 g cm−3 vs. 1.88 g cm−3 for the control). In conclusion, burying compost at a depth of 10 cm, particularly at a rate of 5 kg m−2, optimizes soil hydrodynamic properties, contributing to more efficient water management during irrigation under natural conditions for a sandy-loam soil type.
Urban flooding has worsened significantly in Cotonou (major flood events in 2010, 2018, and 2020), yet this deterioration occurs against a backdrop of largely stable extreme precipitation. This study analyses the temporal variability of extreme precipitation indices in Cotonou over 40 years (1984–2024) in order to explain this paradox. Based on daily rainfall data from the Cotonou synoptic station, eleven standardised ETCCDI climate indices were calculated at four temporal scales (annual, monthly, seasonal, and decadal). Monotonic trends were detected using the Mann-Kendall test and Sen's slope estimator, while structural breakpoints were identified through a combined application of the Pettitt and Buishand tests. Contrary to widespread expectations of intensifying extremes, the results reveal that only the Simple Daily Intensity Index (SDII) presents a significant downward trend (Sen's slope = −0.084 mm d−1 yr−1, p=0.034). Three structural breakpoints were detected during the 2008–2012 period based on the Buishand criterion (Q>1.45): SDII in 2011, CWD in 2008, and R50mm in 2012. The frequency and intensity of extreme events (R95p, R99p, R95pTOT, R99pTOT) show no significant trend at any of the temporal scales considered. These findings demonstrate that the worsening of urban flood impacts in Cotonou results primarily from accelerated urbanisation – population growth of +140 % and soil impermeability of 70 %–80 % – rather than from climate change intensification, a pattern consistent with observations in other rapidly urbanising West African coastal cities.
The agroecosystems of the rural continuum of the Sudano-Sahelian region of the Volta River Basin are undergoing severe degradation, resulting in serious declines in ecosystem service capacities and weakening community livelihoods, as agriculture remains the primary source of income in the region. This degradation is mainly driven by poor management of hydroclimatic risks, non-adapted agricultural practices characterized by intensive use of chemical fertilizers and pesticides, and insufficient consideration of spatial heterogeneity in decision-making processes. The objectives of this study are (i) to identify a Network of 30 m resolution Grid Cells (NGC) representative of the spatial heterogeneity of the studied agroecosystem – the Dassari headwater catchment (550 km2), a tributary of the Volta River in northern Benin – and (ii) to regionalize plot-scale socioeconomic data to support improved decision-making. The NGC was derived by combining iterative principal component analysis (IPCA) with a Conditioned Latin Hypercube Sampling (CLHS) approach using 37 satellite-derived variables (e.g. Normalized Difference Vegetation Index, saturation index, coloration index), resulting in the selection of 150 grid cells. Field and laboratory investigations provided soil properties (e.g. texture, carbon, field capacity, nitrogen content) and socioeconomic data (e.g. harvest quantity, input costs, total production cost, and gross income), which were standardized and analyzed for major crops (millet, sorghum, maize, and cotton). Results show that natural spatial disparities among NGC cells translate into additional labor and input costs that may be unsustainable for farmers. Multiple linear regression models were developed to relate socioeconomic indicators to soil and remote sensing variables for each crop type, and the resulting regional models proved robust, with predicted and observed values closely aligned within the 95 % confidence interval, coefficients of determination exceeding 70 %, and p-values below 0.01.
Commercial water tanker services provide an important alternative source of drinking water in rapidly urbanizing cities where piped water supply is inadequate. However, concerns remain regarding water quality deterioration during transportation and storage. This study assessed the physicochemical and microbial quality of water supplied by commercial tanker operators in the Tamale Metropolis, Ghana, and examined operational practices influencing water safety. A total of 54 water samples were collected from nine tanker operators and analysed using standard APHA methods, while structured questionnaires were administered to 50 operators to evaluate water sources, cleaning frequency, and hygiene practices. The results showed mean values of 30.16 ± 0.66 °C for temperature, 7.48 ± 0.31 for pH, 269.1 ± 0.04 NTU for turbidity, 126.49 ± 9.28 µS cm−1 for electrical conductivity, 0.073 ± 0.007 ppt for salinity, and 0.52 ± 0.42 mg L−1 for dissolved oxygen. Total and faecal coliform counts averaged 47.96 ± 104.90 and 40.59 ± 84.96 CFU/100 mL, respectively. While most physicochemical parameters complied with WHO (World Health Organization) drinking-water guidelines, turbidity exceeded the recommended limit in all samples, and oxidation–reduction potential values indicated inadequate disinfection. Total coliforms and faecal coliforms were detected in 38.9 % and 29.6 % of the samples, respectively, confirming post-treatment contamination during transportation and storage. Survey findings revealed that although most operators sourced water from the Ghana Water Company Limited, variations in cleaning frequency and hygiene practices likely contributed to the deterioration in water quality. These findings highlight the need for strengthened regulatory oversight, routine tanker inspection and disinfection, improved operator hygiene practices, and continuous water quality monitoring to safeguard public health.
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.
