Water Resources Management of the “Kefalari Agios Ioannis” Spring, Dimitsana, Greece

The “Kefalari Agios Ioannis” spring, situated at approximately 871 m elevation and about 1,650 m south-southeast of the picturesque village of Dimitsana (Peloponnesus, Greece), is used for both drinking water supply and irrigation.

The spring is a contact spring, discharging the karst aquifer developed in the Upper Cretaceous platy limestones of the Pindos Unit, at their contact with the underlying impermeable red cherts, siltstones, and “First Flysch” (Upper Jurassic – Lower Cretaceous) of the same unit.

The recession coefficient of the “Kefalari Agios Ioannis” spring, calculated from flow measurements conducted between 14 July 2024 (711.1 m³/h) and 27 October 2024 (69.4 m³/h), is 8.69 × 10^-³ days^-¹. This value indicates that groundwater flow occurs mainly through fractures and intra-stratigraphic voids within the Upper Cretaceous platy limestones of the Pindos Unit. The calculated recession coefficient is consistent with values reported in the literature for karst aquifers developed in the Pindos Unit and equivalent formations, which are on the order of 10^-³ days^-¹ (Soulios, 1985; Giannatos, 1999; Karalemas, 2010).

The hydrological year 2023-2024 was particularly dry (1,109.2 mm), and the calculated recession coefficient should therefore be interpreted with caution, as it reflects flow conditions under prolonged drought and water scarcity. Such conditions may alter groundwater circulation, which is not uniform across the hydrogeological basin and becomes more evident under extreme hydrological conditions—either surplus (wet years) or deficit (dry years)—when different sections and levels of the recharge area are activated or operate differently. Notably, the recession period lasted at least 105 days. The following hydrological year, 2024-2025, was also dry (1,135.6 mm), in contrast to the wetter years 2021-2022 and 2022-2023, which recorded precipitation totals of 1,436.4 mm and 1,426.6 mm, respectively. For the ongoing 2025-2026 hydrological year, a total of 602.4 mm of precipitation has been recorded as of 14 January, indicating that dry conditions persist.

Effective water resources management should prioritize the protection and zoning of the karst aquifer, include systematic monitoring of spring discharge and groundwater quality, regulated and sustainable planning of groundwater abstraction through controlled boreholes, and the enhancement of natural and artificial recharge where feasible. Such adaptation measures are essential to mitigate the impacts of extreme hydrological events and prolonged droughts, ensuring the long-term availability of water for both human consumption and downstream cultural heritage sites.

Under the currently observed low-discharge conditions (98.2 m³/h as of 7 August 2024), the operation of the Open-Air Water Power Museum of the Piraeus Cultural Foundation, which is located immediately downstream, is significantly affected, as the available spring flow becomes insufficient during the summer months. Consequently, the museum is periodically forced to suspend its operation, highlighting the direct dependence of cultural and touristic activities on the hydrological regime of the “Kefalari Agios Ioannis” spring.

In conclusion, the sustainable management of water resources in the Dimitsana area, and particularly of the karst aquifer discharged by the “Kefalari Agios Ioannis” spring, is imperative given the combined pressures of ongoing tourism development and climate variability.