The Experience of the Drought

The most severe droughts in Spain in the last century occurred in 1941-45, 1979-83, and 1990-95. These three droughts were extensive and affected most of the country. The map in Figure 2 shows the percentage decrease in average rainfall from October 1990 to September 1995 compared to the average rainfall for the 1940-1996 period. Several river basins suffered decreased rainfall percentages, around 30%. The resulting reduction in runoff in most of the country was more than 40% and amounted to more than 70% in two basins (Guadiana and Guadalquivir).

The drought of 1990-1995 affected more than one-third of the total population of Spain. For example, during these years, there were severe restrictions on water use in cities like Granada, Malaga, and Seville, and irrigation was banned during 1993-95 in the Guadalquivir River basin. The situation forced cities and regions to adopt different measures. For example, the search for new groundwater resources was car-

Figure 2 Percentage decrease in rainfall during 1990-1995 in Spain in comparison with the average values for the period 1940-1996.

ried out on a large scale. The city of Granada, with a population of 300,000 and a yearly demand of around 35 million m3, had to be supplied mainly with groundwater, changing its water supply system, which had previously used mainly surface water. Groundwater was also used to solve problems in irrigated areas such as the Jucar and Segura River basins. Unconventional methods were applied, such as increasing water reuse and even transporting water by boat to cities like Cadiz and Majorca. New desalinization plans were proposed, but most were never carried out. Regulations were adopted to allow emergency measures to be taken. For example, the so-called Commissions on Droughts in each RBD had the power to reduce or suspend water use and require users to install specific devices for saving water. A decree issued by the Council of Ministers empowered the government, after consulting the Commissions on Droughts, to adopt "such measures as shall be necessary as regards the utilization of the public water domain, even if a concession has been granted for its exploitation," if an extraordinary drought occurs.

Continue reading here: Water Balance in Spain

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