The Greek Forest Service’s restoration projects, involving reforestation, soil retention, and water flow control, effectively mitigated flooding and erosion, offering valuable strategies for combating climate change and desertification in the Mediterranean.
One of the important effects of climate change has to do with obvious alterations in the water cycle of various regions, including the Mediterranean. The changes involve the total amount of water that an area receives but also include significant modifications in the distribution of precipitation: prolonged periods of drought combined with high temperatures affect agriculture and even forest vegetation; they are often followed by sudden, often unprecedented, downpours that result in extensive flooding, causing serious damage.
In Greece, starting on 4 September 2023, an autumn storm named “Daniel”, which followed a hot and dry summer, created unprecedented flooding. It dropped more than 700 mm of rain within a few hours in many parts of Thessaly in the central part of the country. Pelion mountain suffered serious damage, but the situation was even worse in the plain of Thessaly, where 93,270 ha of land were covered by water, mud and stones for many months (Picture 1), destroying homes and infrastructure and taking large parts of the plain out of agricultural production for years. Then Daniel moved to the south of the Mediterranean Sea, where, on 10 September, it dropped eight months’ worth of rain on Libya’s northeast region. On 11 September 2023, two dams collapsed, sending 30 million cubic metres of water into already inundated areas, most notably in the city of Derna, resulting in an estimated death toll of more than 10,000 people.
Such events are becoming more frequent and intense as the creation mechanism is likely becoming stronger over time. The torrential rain that resulted in devastating flooding in Valencia, Spain, on 29 October 2024, causing more than 230 fatalities, is yet another reminder of this new reality. Protection infrastructure, such as dams, drainage canals, roads, bridges, railways, etc., which were built with past “worst-case” scenarios in mind, are increasingly likely to be inadequate in the near future. There is an urgent need to recognise the problem and to invest in planning and measures that will reduce the likelihood of damage. In Greece, the past experience of the Forest Service in flood damage mitigation, which focused on mountainous areas, showcases time-honoured practices that have proven effective and can complement any large-scale constructions (dams, reservoirs, canals, etc.) that may be employed in the plains.
Restoration projects in degraded water catchments by the Greek Forest Service
In the steep terrain of many mountainous areas in Greece, the combination of heavy overgrazing and repeated fires (especially during the Second World War and the civil war that followed) led to the loss of forest vegetation and soil. As a result, by the 1950s, it became evident that hundreds of torrents across the country were causing flooding on a regular basis, destroying agricultural areas in the plains and damaging settlements. At that time, the Greek Forest Service (GFS) undertook the task of restoring many water catchments where such torrents originated through soil retention measures, including reforestation and the creation of water flow control infrastructure. Many such projects were executed in the following decades with impressive results, substantially mitigating flooding damage.
An example of the restoration projects carried out by the GFS was the one targeting the heavily degraded catchment area of the Metsovitikos torrent, near the town of Metsovo, on the Pindos mountain range, a few kilometres to the west of Thessaly (Pictures 2 & 3). The total area of the catchment is 2,696 hectares, with elevations ranging from 720 to 1,830 m, and the average yearly rainfall is 1,400–1,550 mm.
In 1955, a comprehensive project was initiated, constructing over 1,000 check-dams, 70 gabions, and numerous other phytotechnical works, followed by reforestation with 1.8 million seedlings over more than 500 hectares. The project’s success and its results are evident today, showcasing its environmental value in preventing erosion, fostering vegetation growth, and mitigating flooding and associated damage. In light of the climate crisis, such programmes are crucial to counter desertification, particularly in the Mediterranean region.
A series of photographs of the works, taken at the time they were made and a few decades later, allows immediate comparisons and serves as a reminder that with a strong work ethic and attention to detail, even without the advanced technological tools available today, the Forest Service officers, forest guards, and local workers achieved their objective of soil protection and flood prevention. The small, environmentally friendly works and the vegetation cover they established increased water infiltration into the soil, reduced the rate of water runoff, controlled soil erosion and the production of silt and rocks, and ultimately mitigated the damage caused by the torrent.
Conclusion
In the era of climate change, it is necessary to remember such good practices and employ them again, aiming to control the flow of water coming out of the mountains (quantity, peak discharge, silt and rocks) in parallel with any protection infrastructure that can be developed in the plains.
Currently, documentation of these time-honoured techniques is being publicised in Greece and across the Mediterranean through projects such as ResAlliance, in the hope of contributing towards the development of timely restoration initiatives before flooding disasters become even worse. The expertise will have to be redeveloped, as such works have been abandoned to a large extent over the last three decades due to serious reductions in funding for the Forest Service. Personnel will need to be trained, and methods may have to be modified to incorporate new knowledge, techniques and equipment — and possibly to address new needs. For example, as the forest fire problem worsens and expands to areas previously thought immune, such as high-elevation forests, it might make sense to create taller dams and develop small lakes in strategically located places. These lakes could serve both as water sources for firefighting helicopters in case of fire and as reservoirs to hold peak water flows during heavy rains. Such initiatives could achieve both effectiveness and efficiency.
A series of restoration demonstration projects across the Mediterranean, similar to the Metsovitikos one, with funding from a European source such as LIFE+ or INTERREG, could be the solution for the reintroduction of these techniques. However, any such effort should be accompanied by a long-term monitoring programme to gauge effectiveness and propose refinements if needed.
This article was originally written by:
Gavriil Xanthopoulos – Hellenic Agricultural Organization “DIMITRA”, Institute of Mediterranean Forest Ecosystems
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