The effectiveness of traditional dry-stone wall terraces in water management and flood prevention: The cases of Syros and Tinos islands, Greece

Traditional dry-stone terraces, locally known as “xerolithies,” have historically characterised the steep terrains of the Cyclades, including the islands of Syros and Tinos. While initially built to secure arable land and prevent soil erosion in semi-arid environments, their current contribution to alleviating climate-related hazards remains underexplored in scientific literature. As climate change leads to more frequent extreme rainfall events in the Mediterranean, the widespread abandonment of these terraced catchments calls for sophisticated hydrological modelling to assess their present effectiveness in regional water management.

By significantly lowering the effective slope of mountainous island catchments, dry-stone terraces act as a nature-based solution (NBS) to slow rainwater to non-erosive velocities, thereby reducing the rapid flow connectivity over the land. The naturally permeable nature of “xerolithies,” which are built entirely without mortar, allows excess water from seasonal storms to gradually infiltrate through structural gaps rather than swiftly flowing over the low impermeability metamorphic lithology of these islands. This temporary storage of storm runoff plays a crucial role in preventing severe soil erosion within the Cycladic landscape while substantially improving deep water infiltration, increasing soil moisture retention, and supporting vital groundwater recharge.

To precisely quantify these environmental benefits under future climate pressures, high-resolution geospatial terrain data from representative catchments on Syros and Tinos are combined with advanced hydrodynamic modelling frameworks (Barnhart et al., 2020). The methodology employs detailed climate simulations to assess how landscapes respond to extreme weather events (Politi et al., 2022), explicitly comparing scenarios with intact terraces to those with heavily degraded or barren slopes. By modelling intense, low-probability extreme precipitation events based on localized climate projections, the approach monitors peak surface discharge, water flow dynamics, and sediment transport across the islands’ complex topography.

Integrating traditional Cycladic engineering systems (Jiménez De Madariaga, 2021), included in UNESCO’s Representative List of the Intangible Cultural Heritage of Humanity since 2024, into modern water management strategies directly supports the broader goals of European Union climate adaptation projects across the Mediterranean. Additionally, restoring “xerolithies” helps preserve critical ecological microhabitats for local flora and fauna, enhances the productivity of agricultural land, and increases resilience against extreme weather events.

 

References

Barnhart, K.R., Hutton, E.W.H., Tucker, G.E., Gasparini, N.M., Istanbulluoglu, E., Hobley, D.E.J., Lyons, N.J., Mouchene, M., Nudurupati, S.S., Adams, J.M., Bandaragoda, C., 2020. Short communication: Landlab v2.0: a software package for Earth surface dynamics. Earth Surf. Dynam. 8, 379–397. https://doi.org/10.5194/esurf-8-379-2020

Jiménez De Madariaga, C., 2021. Dry stone constructions – intangible cultural heritage and sustainable environment. JCHMSD 11, 614–626. https://doi.org/10.1108/JCHMSD-12-2020-0180

Politi, N., Vlachogiannis, · D, Sfetsos, · A, Nastos, · P T, 2022. High resolution projections for extreme temperatures and precipitation over Greece. Climate Dynamics 2022 1, 1–35. https://doi.org/10.1007/S00382-022-06590-W