Natural Disasters in Spain: Droughts and Torrential Rains

Natural Disasters and Environmental Risks

A natural disaster is known as a physical phenomenon of an extreme environmental, fortuitous, and unpredictable character. This character is what makes it a risk to society. Two risks are particularly relevant in our country: drought and torrential rainfall. Some areas of the peninsula are periodically affected by earthquakes, caused by the collision between the Eurasian and African plates.

Drought: A Fact of Life

The deficit of water resources is one of the main factors of environmental degradation in our country. Drought can be defined as an unusual water deficit. However, it is necessary to differentiate between drought and aridity:

• Aridity refers to regular and permanent conditions of water scarcity.
• Drought refers to a cyclical and anomalous water deficit, which can occur in any kind of weather, even the oceanic type.

This climatic anomaly, if prolonged, prevents to a greater or lesser degree the development of life and people's economic activities, which can be affected by restrictions on water use and health problems. The excessive and uncontrolled use of water resources causes a serious environmental impact, manifested, inter alia, by:

• The reduction of the flow of rivers: This causes a modification and alteration of their wealth with serious problems of contamination and desiccation affecting wetlands, bays, and estuaries.
• The loss of biodiversity: The disappearance of fauna and flora consequently contributes to the advance of desertification.
• The overexploitation of groundwater: The irrational exploitation of aquifers leads to salinization, salt concentration of ponds, or desiccation.

Regional Risks and Precipitation Fluctuations

The potential risk of drought in Spain is high due to the high degree of fluctuation in precipitation from one year to another. The irregularity index is more marked on the Mediterranean and southern facades; the maximum values are reached in Almeria. The risk is even higher in those places which have lower rainfall.

Torrential Precipitation and Flash Floods

Torrential rains are considered capable of producing fast, violent, and short-lived streams. Among various situations causing torrential rainfall, the best known is the cold drop (gota fría), but some cold storms and cold fronts from the west are also capable of triggering high-intensity showers.

These heavy rains cause floods and large river surges that sometimes cause catastrophic flooding. For example, the rivers Turia, Júcar, and Segura have experienced disastrous flooding because the floodplains of these rivers on the Mediterranean slope are usually densely populated areas.