Water Availability Without Reliability: Groundwater-Dependent Irrigation and Governance Challenges in the Arta Plain, Greece

Despite the relative hydrological abundance of northwestern Greece, the Arta Plain exhibits persistent spatial and seasonal mismatches between irrigation demand and the effective capacity of the public network. To clarify the factors mediating between available water resources and actual irrigation coverage, this study applies an integrated framework combining quantitative irrigation modelling (FAO CROPWAT 8.0) with qualitative insights from semi-structured interviews with farmers and institutional stakeholders. Annual irrigation demand was estimated at approximately 49.1 hm3. Although this volume could theoretically be met through available surface water, in practice, it is constrained by conveyance losses and infrastructure degradation. Under these conditions, meeting irrigation needs shifts toward private abstractions. The interviews indicate systematic groundwater use for the four dominant crops; as a share of modelled demand, groundwater use corresponds to approximately 41% of irrigation requirements, with higher reliance in perennial and water-intensive crops such as kiwifruit and citrus, where supply stability is critical. These findings indicate that irrigation dysfunctions in the Arta Plain do not stem from hydrological insufficiency but from structural misalignments between infrastructure, institutional organization, and prevailing practices. Addressing these inefficiencies requires coordinated interventions, including targeted infrastructure rehabilitation, adoption of precision irrigation technologies, transparent volumetric monitoring, and participatory management processes. Overall, the study provides a transparent logic for interpreting irrigation performance when monitoring data are incomplete by linking modelled demand with operational delivery constraints and evidence from primary water users.