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Groundwater overexploitation and saltwater intrusion

For over the last 40 years groundwater overexploitation in the southern part of Spain has an enormous ecologic impact on the area (Ibáñez and Carola 2010), related to significant lowering of groundwater tables, drying out of springs, degradation of wells and boreholes and saltwater intrusion. In the Ribeiras do Algarve River Basin in Portugal increased water demand for tourism and agriculture during the last decades has caused serious pressure on the area’s environment, including aquifers’ over-abstraction, salinization and water resources’ degradation.

The problem of salt water intrusion due to overexploitation is very common in several coastal aquifers of Italy (Antonellini et al. 2008). In coastal areas in Sardinia, Catanian Plain, Tiber Delta, Versilia and Po Plain freshwater resources are becoming scarcer due to drought, over-exploitation and salinization.

In the Maltese Island because of high water demand resulting in over-abstraction, main groundwater bodies face the risk of failing to achieve the environmental objectives of the WFD (MEPA and MRA 2010).

Loss of biodiversity

According to a research conducted from June 2003 to March 2008 in the Mondego estuary in Portugal, drought conditions have a significant impact on fish communities causing disturbances in their behaviour and functions (Baptista et al. 2010). More specifically, during drought periods due to increased salinity inside the estuary and low freshwater flows the estuarine brackish habitats moved to more upstream areas, while in downstream areas new marine adventitious species were found. Moreover, freshwater species no longer existed inside the Montego estuary during drought, and lower densities were observed for most of the species.

In Romania, severe drought events (i.e. in 2007 and 2009) are reported  to negatively affect forest areas causing changes in the area of several tree species and the boundaries of vegetation zones (moving North and West of the silvo-steppe), encouraging also the appearance of certain Saharian species in the South area of Romania (Lupu, Ionescu, and Borza 2010). Hills and plains covered with forests in areas of South and East Romania, such as Dolj, Olt, Galati, Braila, Ialomita, are proved to be very vulnerable to drought. This vulnerability not only affects the environmental balance but also has a negative socio-economic impact on the population.

In the Czech Republic during the dry years 2003-2004 an increased defoliation of tree species was noticed, especially dieback of unoriginal spruce forests and Pinus nigra. Forests weakened by drought were more vulnerable and consequently attacked by Armillaria ostoyae and bark-beetles (Czech Republic National SD Reports 2008).

In Portugal the 2004-2005 drought resulted in water level fall in many reservoirs (two major reservoirs, Funcho and Arade, completely dried out), reduced rives flows with a parallel degradation in their quality consequently affecting migrating species (e.g. lamprey in Minho river), water table decline in aquifers, salt water intrusion in transboundary waters bodies (e.g. Tagus Estuary), forest fires and removal of 220 tons of fish (Ministério do Ambiente, do Ordenamento do Território e do Desenvolvimento Regional (MAOTDR) 2007).

Related hazards

In Lithuania, during the 2002 summer drought, 123 forest and peat bog fires burst out in July and 374 in August (Sakalauskiene and Ignatavicius 2003).