Artificial water basins in Sicily: why irrigation alone is not enough for drought resilience

Across the Mediterranean, drought is becoming more frequent and severe, and Sicily is no exception. The island's farmers have always coped with long, hot summers and uneven rainfall, but climate change is making water availability a decisive factor for agriculture. In this context, the network of artificial water basins, reservoirs, and built across Sicily over the decades, managed by irrigation consortia known as Consorzi di Bonifica, is treated as essential infrastructure: it stores water in the wetter months and releases it during the summer peak, when crops need it most.

A new UNU-MERIT policy brief by Claudia Barbetti and Pui-Hang Wong asks whether that infrastructure is actually delivering its promise. Focusing on Sicily, it examines the relationship between artificial water basins, agricultural production, vegetation health, and drought resilience. The method is straightforward: the authors compare the 11 irrigation consortia zones with 5-km buffer rings around them, so each irrigated area is measured against the similar farmland that surrounds it.

The results show a clear but nuanced picture. Artificial basins are associated with higher agricultural production, but their benefits are not evenly distributed across crops or territories. In other words, irrigation infrastructure matters, but it does not automatically produce the same gains everywhere.

At the crop level, the brief finds positive productivity effects for some crops, while for others the relationship is not statistically significant. This variation likely reflects differences in crop water requirements, tolerance to water stress, production cycles, local rainfall patterns, and the timing and reliability of water delivery. The result is not simply that irrigation “works” or “does not work”, but rather that its effects depend on what is being cultivated and how water is made available during the growing season.

The territorial picture is just as uneven. Some provinces appear to benefit much more than others, while in some cases the relationship between artificial basin coverage and production is not statistically significant. This suggests that the presence of irrigation infrastructure alone is not enough. The way the system is managed, maintained, and connected to agricultural needs also matters. Basins, canals, and reservoirs may provide the physical basis for water access, but their actual contribution depends on whether they are operational, reliable, and adapted to local agricultural conditions.

Remote sensing indicators add a further layer. Vegetation is consistently healthier inside irrigation zones than in the surrounding control zones. The Normalized Difference Vegetation Index, which captures vegetation greenness, is higher in irrigated areas. The Vegetation Health Index, which reflects vegetation stress, is also higher. These findings suggest that irrigation infrastructure contributes to healthier and more productive vegetation, even after accounting for seasonal and annual variation.

However, the evidence on drought resilience is much weaker. The authors also examine soil moisture and evapotranspiration indicators, including root-zone soil moisture, surface moisture, infiltration, runoff dynamics, latent heat flux, and leaf area index. Across these indicators, no statistically significant differences are found between irrigation and control zones. This means that, while artificial basins appear to support crop productivity and vegetation health, their broader role in changing the soil-water balance and strengthening drought resilience remains uncertain.

This distinction is important for policy. In Sicily, artificial water basins currently seem to function more as productivity infrastructure than as resilience infrastructure. They help some crops and some territories produce more, but they do not necessarily guarantee a more drought-resilient agricultural system. In the context of increasing water scarcity, this finding shows that infrastructure must be accompanied by better governance, maintenance, data, and planning.

Several recommendations follow. First, Sicily needs more transparent and harmonized data on irrigation systems. Information on water distribution, infrastructure conditions, crop-level performance, delivery volumes, operation calendars, and actual irrigated surfaces remains fragmented and often difficult to access. Better data would allow researchers, local authorities, and irrigation consortia to identify where systems are working, where they are underperforming, and where investment would have the highest return.

Second, policy should focus not only on expanding infrastructure but also on improving the efficiency of existing systems. Ageing pipelines, water losses, delayed maintenance, and partial system operation can all reduce the benefits of irrigation. In high-potential areas, repairing and reactivating existing infrastructure may generate larger gains than simply building new systems.

Third, underperforming territories requires careful performance audits. Where artificial basins are already widespread, but impacts remain weak, further expansion may not be the best solution. A better first step would be to assess whether water is being delivered efficiently, whether networks are functioning, and whether governance arrangements are limiting performance.

Finally, irrigation strategies should be betterligned with crop-specific needs. Crops respond differently to water availability, and timing of irrigation matters. A more adaptive approach should take account of crop calendars, local agronomic conditions, and climate forecasts rather than relying on blanket irrigation designs.

The broader lesson from the brief is that irrigation infrastructure can support agricultural production, but it is not a resilience strategy in itself. As drought risk intensifies across the Mediterranean, Sicily’s experience shows the importance of moving from infrastructure expansion to infrastructure performance.

This blog post summarizes the UNU-MERIT policy brief "Artificial Water Basins in Sicily: Productivity Gains without Drought Resilience" by Claudia Barbetti and Pui-Hang Wong (May 2026). Read the full brief here: http://unu-merit.nl/publications/uploads/1781613568.pdf