Global Water Challenges in Sub-Saharan Africa and how to strengthen science-policy dialogues on transboundary governance and cooperation.

The United Nations Water Conference 2023 highlighted the need for concrete actions to boost integrated water resources management for achieving the Sustainable Development Goals and called for strategies to enhance cooperation among stakeholders. Technical cooperation between countries and institutions in transboundary systems, e.g., on environmental data collection, is an effective way to promote international diplomacy and prevent disputes between riparian states. Still, establishing collaborations to inform bilateral dialogues on the identification of environmental challenges, their causes, and development priorities may be a difficult task in itself. This is particularly true in the African context because of limited resources and lack of data. In this paper, we analyse the case of nine transboundary river basins in Sub-Saharan Africa to identify which water-management challenges are perceived as most important by the different riparian countries from a policy and scientific perspective. Our insights are based on the most up-to-date scientific papers, open access reports and technical literature, river basin authority's strategy papers, projects' summary reports, and national policy documents. We also complement these sources with the pieces of information we gained through collaborations with regional and local experts, and management bodies (such as river basin authorities). We highlight the current water-related conflicts and the gap between the priorities identified by the scientific community and different riparian countries on how to tackle hydro-climatic change and improve food and energy security, human and environmental health. Based on our experience, we discuss some keys to building trust among stakeholders, strengthening cooperation, and identifying shared water-governance measures in transboundary river basins. They are: (i) connect science and policy to provide sound knowledge for the right questions, (ii) value local knowledge and exploit the complementarity of different perspectives, (iii) consider multiple spatial scales and multi-level stakeholders to leave no one behind, (iv) promote a culture which values trade-offs and handles complexity, and (v) co-create data and knowledge to facilitate stakeholder dialogue from problem definition to intervention identification.

Identifying efficient agricultural irrigation strategies in Crete.

Water scarcity and droughts are a major concern in most Mediterranean countries. Agriculture is a major user of water in the region and releases significant amounts of surface and ground waters, endangering the sustainable use of the available resources. Best Management Practices (BMPs) can mitigate the agriculture impacts on quantity of surface waters in agricultural catchments. However, identification of efficient BMPs strategies is a complex task, because BMPs costs and effectiveness can vary significantly within a basin. In this study, sustainable agricultural practices were studied based on optimal allocation of irrigation water use for dominant irrigated crops in the island of Crete, Greece. A decision support tool that integrates the Soil and Water Assessment Tool (SWAT) watershed model, an economic model, and multi-objective optimization routines, was used to identify and locate optimal irrigation strategies by considering crop water requirements, impact of irrigation changes on crop productivity, management strategies costs, and crop market prices. Three spatial scales (crop type, fields, and administrative regions) were considered to point out different approaches of efficient management. According to the analysis, depending on the spatial scale and complexity of spatial optimization, water irrigation volumes could be reduced by 32%-70% while preserving current agricultural benefit. Specific management strategies also looked at ways to relocate water between administrative regions (4 prefectures in the case of Crete) to optimize crop benefit while reducing global water use. It was estimated that an optimal reallocation of water could reduce irrigation water volumes by 52% (148 Mm3/y) at the cost of a 7% (48 M€) loss of agricultural income, but maintaining the current agricultural benefit (626.9 M€). The study showed how the identification of optimal, cost-effective irrigation management strategies can potentially address the water scarcity issue that is becoming crucial for the viability of agriculture in the Mediterranean region.

A decision support tool to enhance agricultural growth in the Mékrou river basin (West Africa).

We describe in this paper the implementation of E-Water, an open software Decision Support System (DSS), designed to help local managers assess the Water Energy Food Environment (WEFE) nexus. E-Water aims at providing optimal management solutions to enhance food crop production at river basin level. The DSS was applied in the transboundary Mékrou river basin, shared among Benin, Burkina Faso and Niger. The primary sector for local economy in the region is agriculture, contributing significantly to income generation and job creation. Fostering the productivity of regional agricultural requires the intensification of farming practices, promoting additional inputs (mainly nutrient fertilizers and water irrigation) but, also, a more efficient allocation of cropland. In order to cope with the heterogeneity of data, and the analyses and issues required by the WEFE nexus approach, our DSS integrates the following modules: (1) the EPIC biophysical agricultural model; (2) a simplified regression metamodel, linking crop production with external inputs; (3) a linear programming and a multiobjective genetic algorithm optimization routines for finding efficient agricultural strategies; and (4) a user-friendly interface for input/output analysis and visualization. To test the main features of the DSS, we apply it to various real and hypothetical scenarios in the Mékrou river basin. The results obtained show how food unavailability due to insufficient local production could be reduced by, approximately, one third by enhancing the application and optimal distribution of fertilizers and irrigation. That would also affect the total income of the farming sector, eventually doubling it in the best case scenario. Furthermore, the combination of optimal agricultural strategies and modified optimal cropland allocation across the basin would bring additional moderate increases in food self-sufficiency, and more substantial gains in the total agricultural income. The proposed software framework proves to be effective, enabling decision makers to identify efficient and site-specific agronomic management strategies for nutrients and water. Such practices would augment crop productivity, which, in turn, would allow to cope with increasing future food demands, and find a balanced use of natural resources, also taking other economic sectors-like livestock, urban or energy-into account.

Modelling water and nutrient fluxes in the Danube River Basin with SWAT.

This study provides an innovative process-based modelling approach using the SWAT model and shows its application to support the implementation of the European environmental policies in large river basins. The approach involves several pioneering modelling aspects: the inclusion of current management practices; an innovative calibration and validation methodology of streamflow and water quality; a sequential calibration starting from crop yields, followed by streamflow and nutrients; and the use of concentrations instead of loads in the calibration. The approach was applied in the Danube River Basin (800,000km2), the second largest river basin in Europe, that is under great nutrients pressure. The model was successfully calibrated and validated at multiple gauged stations for the period 1995-2009. About 70% and 61% of monthly streamflow stations reached satisfactory performances in the calibration and validation datasets respectively. N-NO3 monthly concentrations were in good agreement with the observations, albeit SWAT could not represent accurately the spatial variability of the denitrification process. TN and TP concentrations were also well captured. Yet, local discrepancies were detected across the Basin. Baseflow and surface runoff were the main pathways of water pollution. The main sinks of TN and TP diffuse emissions were plant uptake which captured 58% of TN and 92% of TP sources, then soil retention (35% of TN and 2% of TP), riparian filter strips (2% both for TN and TP) and river retention (2% of TN and 4% of TP). Nitrates in the aquifer were estimated to be around 3% of TN sources. New reliable "state-of-the-art" knowledge of water and nutrients fluxes in the Danube Basin were thus provided to be used for assessing the impact of best management practices and for providing support to the implementation of the European Environmental Directives.

Validation of the Artsana CSI 610 automated blood pressure monitor in adults according to the International Protocol of the European Society of Hypertension.

BACKGROUND: There is evidence that blood pressure measurement outside the doctor's office can provide valuable information for the diagnostic evaluation of hypertensive patients and for monitoring their response to treatment. Home blood pressure monitoring devices have a major role in this setting, provided that their accuracy in measuring blood pressure is demonstrated by validation studies. OBJECTIVE: This study aimed at verifying whether the automatic electronic oscillometric blood pressure measuring device Artsana CSI 610 complied with the standard of accuracy indicated by the ESH International Protocol. METHODS: Sequential measurements of systolic and diastolic blood pressure were obtained in 33 participants using the mercury sphygmomanometer (two observers) and the test device (one supervisor). A standard adult cuff was always employed during the study. According to the ESH validation protocol, 99 couples of test device and reference blood pressure measurements were obtained during the two phases of the study (three pairs for each of the 33 participants). RESULTS: The Artsana CSI 610 device successfully passed phase 1 of study validation with the number of absolute differences between test and reference device never <35 within 5 mmHg and never <40 within 10 and 15 mmHg. The test device also passed phase 2 of the validation study with a mean (+/-SD) device-observer difference of -1.4+/-4.8 mmHg for systolic and -0.9+/-3.5 mmHg for diastolic blood pressure. CONCLUSIONS: According to the results of the validation study on the basis of the ESH International Protocol, the Artsana CSI 610 can be recommended for clinical use in adults.