- As a result of floods, pathogens and toxic substances including chemicals, solvents, oils, grease, industrial waste and pesticides are washed off (primarily urban or industrial areas) and are transferred downstream and released into the local environment, contaminating local water courses. Water contamination can also be associated with flooding of sewage systems, which is quite common in case of severe flood events. In addition, floods may result in the destruction of crops, especially those that normally grow in dry land, since crop roots can be repelled from a soil oversaturated with water. In several cases, soil oversaturation can provoke landslides and earth instability, giving rise to safety concerns.
- Forest fires have both direct and indirect ecological impacts. In particular, forest fires affect directly the diversity and viability of wildlife populations and often threaten endangered species making their habitats unsuitable to host wildlife communities. Furthermore, the transfer of dangerous burnt material to water in adjacent riparian and aquatic systems has a significant impact on their quality and consequently the viability of fish populations in these rivers is threatened. The quality of the burnt soils themselves is deteriorated due to changes in physical and chemical soil properties, since the conversion of organic ground cover to soluble ash results in reduced productivity of the affected soils. The quality of air in areas affected by fires as well as the radiation balance within the atmosphere can be severely affected, either directly or indirectly by greenhouse gas (GHG) emissions during wildfires. These gases include inter alia CO, CO2, CH4 and N2O. Furthermore, the destruction of the vegetative cover of a forest affects indirectly the environment in terms of contributing to increased flood risk in the burnt area. The water repellent soils which are formed as a result of forest fires act as a barrier to water infiltration and as a consequence the runoff volume and peak discharges increase. Ultimately, the resulting ecological degradation raises concerns on the sustainability of the forest and the surrounding ecosystems.
Area of ImplementationFLIRE’s area of implementation is the peri-urban environment of the Eastern Attica region, more specifically the Rafina river basin (Greece), a typical Mediterranean area extends over approx. 130 km2 with rapid and uncontrolled urbanization. This area is quite prone both to flash floods and forest fires resulting in its gradual ecological degradation, with significant consequences for the almost 5 million inhabitants of Athens.
Eastern Attica region includes forests (~30%), arable soils and grasslands (~50%) mainly located upstream and urban cells (~20%) located downstream. The dominant vegetation in the forests is represented by evergreen-broadleaved shrublands, conifers (mainly Aleppo pine) and sclerophyllous vegetation. All of these species are very flammable and prone to forest fires. Large scale wildfire events are frequent in the area (appr. 80 fires occur in the wider Attica region annually, burning appr. 4.500ha of forested land), devastating its upstream vulnerable forests and significantly modifying its land cover. Regarding the water bodies of the area, the main watercourse is the stream of Rafina which discharges to the south Evoikos Gulf and its main tributaries are the streams of Lykorema, Ag. Paraskevi and New Voutza, that drain at the south hillsides of Mt. Penteliko. During the summer the water flow in the tributaries of the Rafina stream often remains low and during particularly hot summers the tributaries may even dry up. Despite the low flow rates of the water bodies during the hot periods, the area is particularly prone to flash floods. This can be attributed mainly to:
- extended urbanization during the last 30 years (and the resulting alteration of extended areas into impermeable land)
- occurrence of frequent fire events (which devastate the upstream forests)
- particular geomorphological and geological conditions (steep upstream slopes, dense upstream hydrographic network, erodible soil etc.)
The same causes give rise to significant erosion, increased sediment loads and hydromorphological changes in the water bodies of the pilot area with obvious impacts on their status.