The Zarqa River in Jordan has become heavily dependent on treated wastewater from the As-Samra WWTP, resulting in degraded water quality, high pathogen loads, and risks to crop safety and groundwater resources (transport emerging contaminants). The FEMAR project addressed this challenge by implementing a pilot riverbank filtration (RBF) system to naturally attenuate contaminants, improve irrigation water quality, and reduce pressure on high-quality groundwater used for agriculture. Through field installation of monitoring wells, hydrogeological characterization, pumping tests, and water-quality analyses including pathogens and pharmaceuticals, the project demonstrated substantial reductions in coliforms, DOC, and several micropollutants. The results confirm RBF as a low-energy, cost-effective WEFE solution that protects ecosystems, supports farmers, and enhances water and food security in a water-stressed Mediterranean environment.
The Zarqa River Basin faces a combination of agro-environmental, hydrological, climatic, and socio-economic challenges that directly threaten water security and agricultural productivity. The river receives a major portion of treated wastewater from As-Samra WWTP, which constitutes more than 75% of its flow, resulting in elevated nutrient loads, microbial contamination, and persistent micropollutants, particularly pharmaceuticals. Groundwater abstraction in the region is unsustainably high, causing declining groundwater levels, deteriorating quality, and increasing salinity, which reduces its suitability for irrigation and ecosystem health. Farmers along the Zarqa River increasingly rely on direct pumping from the river for irrigation causing a high risk from pathogens and emerging contaminants transport to their crops. Climate change further exacerbates these pressures through reduced recharge, rising temperatures, and increased frequency of droughts, intensifying competition for limited water resources. Socio-economic constraints, including limited awareness, weak enforcement mechanisms, and reliance on agriculture as a key livelihood, create additional barriers to adopting safer and more sustainable water-food solutions.
This combination of pressures highlighted the urgent need for a WEFE-integrated intervention capable of improving water quality, protecting ecosystems, enhancing agricultural resilience, and reducing pressure on groundwater resources. This was demonstrated by riverbank filtration next to Zarqa River.
The demonstrator aimed to introduce riverbank filtration (RBF) as a low-energy, nature-based solution to improve irrigation water quality, safeguard groundwater resources, and enhance ecosystem functioning along the Zarqa River. The intervention primarily targeted three pillars of the WEFE Nexus (Water, Food, and Ecosystems) while also contributing indirectly to the Energy pillar by reducing reliance on high-energy treatment processes such as water pumping and mechanical systems. Through stakeholder consultations with farmers, local landowners, and national water authorities (RSS, MWI), project partners agreed on shared objectives: improving water quality for irrigation, reducing abstraction of high-quality groundwater, and promoting safe, sustainable agricultural practices.
The envisioned solution integrated hydrological modelling, monitoring well installation, field sampling, and water-quality analysis to demonstrate how natural subsurface filtration can reduce pathogen loads, organic contaminants, and selected pharmaceuticals. The short-term goal was to generate scientific evidence on the feasibility and performance of RBF in shallow alluvial sediments along the Zarqa River. The long-term goal is to establish RBF as a scalable, community-supported approach that enhances water and food security, strengthens ecosystem resilience, and aligns with Jordan’s national strategies for sustainable groundwater management.
To address the water-quality, agricultural, and ecosystem challenges along the Zarqa River, the demonstrator implemented a set of coordinated technical and soft WEFE interventions. Technically, the project installed a riverbank filtration (RBF) monitoring cross-section consisting of three RBF water monitoring wells (positioned approximately 18 km downstream of the As-Samra WWTP. These installations enabled the assessment of hydraulic connection, travel times, natural attenuation capacity, and safe abstraction rates. A pumping test revealed feasible abstraction capacities between 500 and 3,000 m³/day, depending on lateral length and site-specific hydraulic properties. Extensive field sampling was conducted for pathogens, organic carbon, nutrients, metals, and pharmaceutical compounds to evaluate RBF performance in improving irrigation water quality.
In parallel, a significant set of “soft” interventions supported the WEFE objectives. These included stakeholder engagement activities with local farmers, landowners, and the Jordanian Ministry of Water and Irrigation, along with capacity-building actions involving researchers, technicians, and students from RSS & HTWD, and local institutions. Many experts and practitioners were involved across field investigations, modelling workshops, and decision-support meetings. The project followed a structured sequence: (1) initial stakeholder consultations and site reconnaissance; (2) geological and topographic surveying; (3) drilling and installation of monitoring wells; (4) two-month continuous monitoring of water levels and temperature; (5) laboratory analyses of contaminants; and (6) numerical modelling to evaluate RBF well design options.
Together, these actions demonstrated how a low-energy, nature-based solution can strengthen the Water–Food–Ecosystems components of the WEFE nexus by improving the quality of irrigation water, reducing pressure on high-value groundwater sources, and supporting safer agricultural productivity.
The RBF demonstrator produced measurable improvements in water quality, agricultural resilience, ecosystem protection, and local capacity, confirming the suitability of RBF as a practical WEFE solution in the Zarqa River basin. Continuous monitoring showed a 70% reduction in dissolved organic carbon (DOC), 1–3 log₁₀ removal of coliform bacteria, and 15–82% attenuation of selected pharmaceutical compounds (e.g., ofloxacin, diclofenac, triclosan), demonstrating significant natural purification within short subsurface travel distances. Numerical modelling confirmed that horizontal collector wells could sustainably provide 500–3,000 m³/day of treated bank filtrate, reducing reliance on high-quality groundwater sources for irrigation and supporting more stable food production.
Co-benefits were observed across the WEFE pillars.
Water: RBF improved microbial and chemical quality, reducing contamination risks for farmers using river water.
Food: Safer irrigation water supports higher crop quality and reduced soil pollutant accumulation.
Ecosystems: Reduced pollutant loads entering the floodplain help protect riparian habitats.
Energy: Compared to engineered treatment systems, RBF requires almost no external energy, offering a low-carbon solution for rural water-scarcity conditions.
Project objectives were largely achieved, particularly in demonstrating hydraulic feasibility, natural attenuation potential, and stakeholder acceptance of RBF for agricultural irrigation. The primary challenges included persistent contaminants (e.g., carbamazepine) and uncertainty about long-term clogging and riverbed pollution, which require extended monitoring.
Beyond technical results, the demonstrator generated broader impacts. It strengthened national capacity through the training of over many practitioners and students, contributed to updates in the national MAR/RBF knowledge base, and aligns directly with the Jordan National Water Strategy (JS 893/2021), which prioritizes artificial recharge and reuse for irrigation. The work improved collaboration between research institutions (RSS, HTWD), farmers, and water authorities which has provided the foundation for new MAR/RBF initiatives in Jordan and the wider MENA region.
The FEMAR demonstrator showed that riverbank filtration (RBF) is a highly sustainable and low-energy WEFE solution that can be integrated into water-scarce agricultural systems across the Mediterranean. One of the most important lessons learned is that RBF can substantially improve the quality of treated wastewater-impacted rivers, producing safer irrigation water while reducing stress on freshwater aquifers which is might be scaled in regions facing similar hydrological pressures. The project demonstrated that shallow alluvial systems, even with limited lateral extent, can support small-to-medium irrigation demands when supported by hydrogeological mapping, groundwater modelling, and stakeholder cooperation.
Scalability potential is high because RBF requires minimal energy, limited infrastructure costs, and relies on natural subsurface processes. Its replicability is strengthened by the fact that the methodology parts such as hydrogeological assessment, monitoring well transects, flow-path modelling, and farmer engagement can be transferred to other basins with similar river–aquifer interactions. Countries with increasing wastewater reuse, such as those in the MENA and Mediterranean regions, can adopt these methods to enhance irrigation reliability while protecting groundwater resources.
A key lesson is that WEFE interventions must combine technical design with governance and social acceptance. Engagement with farmers along the Zarqa River was essential to demonstrate the benefits of shifting from direct river pumping to RBF-derived water. Finally, the project showed that managing flood risks, riverbed clogging, and informal wastewater discharges are critical for long-term sustainability. These insights provide a strong evidence base for national policies seeking to integrate Nature-based Solutions, strengthen groundwater protection, and align with Nexus-based resource management frameworks.
