Roman era (3rd century BC-5th century AD)

The Romans built a series of aqueducts and water distribution systems throughout their territories, including the Iberian Peninsula. Notable examples are the Segovia and Tarragona aqueducts.

Al-Andalus (8th century-15th century)

During the period of Muslim rule in the Iberian Peninsula, advanced irrigation and water management systems, such as ditches and waterwheels, were introduced, allowing the development of prosperous agriculture in the region.

Reconquest and growth of the Christian kingdoms (11th century-15th century)

During the time of the Reconquista in Spain, Christian kingdoms adopted and adapted water management techniques developed by Muslims. These techniques included the use of ditches, water wheels and cisterns, with ditches being essential in regions such as Valencia, Murcia and Andalusia for irrigation systems.

The Christian kingdoms developed their own institutions and regulations for the management of water resources, creating courts such as the Water Court of Valencia, one of the oldest in the world, charged with resolving conflicts and guaranteeing fair distribution among water users.

Water infrastructure such as dams, canals and aqueducts were also built and maintained during this period, allowing for the expansion and development of agriculture, as well as the supply of water to growing cities and towns.

Water management and the development of irrigation systems were crucial to agriculture and economic growth in Christian kingdoms. Investment in water infrastructure and irrigation systems allowed the expansion of agricultural production in regions such as Castilla y León, as well as the introduction of new crops and agricultural techniques.

As Christian kingdoms grew and expanded, tensions and conflicts related to water use and management also increased. Cooperation and knowledge exchange between Christian and Muslim communities in border areas, as well as the need to establish agreements and regulations to share and manage water resources equitably, were important aspects of water policy during this period.

16th-19th centuries

During this period, water policies in Spain were largely focused on local and regional water management, and numerous canals, dams and aqueducts were built to improve water supply and distribution. The Teruel aqueduct "Acueducto Los Arcos (Teruel)"), built in the 19th century, is a notable example of these works.[10]​.

The Water Law of 1866 represents the first attempt to specifically regulate Spanish territorial waters, although it did not come into force due to the revolutionary period that gave rise to the First Republic. Its basic principles, however, were largely passed on to the Law of 1879, including that of the public domain of all natural currents, channels and banks of rivers. Groundwater, which belongs to the owner of the land where the lighting will be illuminated, was not included. This provision continued in force until its non-retroactive modification by the 1985 Law, and is one of the causes of the current situation of lack of administrative control of underground sources.

The Law of 1879 includes the right to private use of water linked to an administrative concession. The Law very precisely regulates both the procedure and the general rules on the concession of public water as well as specific provisions for the different uses (supply to populations, irrigation, industrial establishments, etc.). In the case of irrigation, furthermore, the right to use water is linked to the right to own the land. Likewise, the Law establishes the community of irrigators, an institution that is self-governed and has sanctioning power. The subsequent evolution of water uses towards multiple-purpose uses and the concurrence of various users on the same body of water have made it advisable to expand the figure of the community of irrigators to the current communities of users.

The Regulations of the Law of 1879 never came to fruition and said regulatory element was replaced by various lower-ranking provisions that tried to resolve the numerous problems that arose in the application of the Law due to both the wide field covered by it, as well as its prolonged validity that confronted it with situations for which its provisions were not effective.

20th century-Franco regime (1939-1975)

The management of water resources in Spain for much of the century has been characterized by strong state interventionism. This intervention focused on the construction of hydraulic works in an effort to increase the water available for irrigation (supply policy) and hydroelectric power generation, considered the driving force of Spanish economic development policy. The Hydraulic Works Plans of 1902 and 1933, financed for the most part by the state, are an example of this type of policy.[11]​.

The most important of the regulatory developments is the one that refers to the creation, or rather the institutionalization of an existing reality, of basin organizations, with the creation of the first hydrographic confederation in 1926 as the highest body for water management at the basin level. The functions of basin organizations have alternated between specific development and more general water management functions throughout the last century.[12]​.

Until 1955, a growth rate of about 4 dams per year was maintained, going from the nearly 60 dams existing at the beginning of the century to about 270 in 1950. From that year on, the pace accelerated considerably, reaching an average of 20 dams per year, until reaching the current park.[13]​.

Transition to democracy and creation of autonomous communities (1975-1985)

After Franco's death, Spain began a transition to democracy and established autonomous communities. During this period, decentralization in water resources management began and more attention began to be paid to sustainability and public participation in decision-making.

Water Law of 1985

The promulgation of the Water Law established a new legal framework for the management of water resources in Spain, creating a hydrological planning system based on hydrographic basins and establishing criteria for water quality and environmental protection.

Integration into the European Union (1986 onwards)

Spain joined the EU in 1986 and adopted the Water Framework Directive (WFD) in 2000, which involved a more integrated and sustainable approach to the management of water resources in the country.

21st century

Water policy in Spain has evolved to address the challenges of climate change, water scarcity and environmental sustainability. Recent policies have focused on improving water use efficiency.

William Blomquist, in a study on hydrographic confederations carried out in 2005, reflects that their formal structure traditionally gives more weight to user groups for irrigation, leaving public or private organizations that represent urban centers or environmental issues in the background. Likewise, some confederations continue to emphasize their development tasks while they adapt to comprehensively manage, in a broad sense, their water resources.[14]​.

Likewise, the NGO WWF/Adena carried out a study report in 2004 comparing the water management of different European countries and placing Spain among the three worst managers. Among the reasons for poor management WWF/Adena finds that there are too many actors in water management due to a fragmented jurisdiction; and that there is a lack of integration of sectoral policies (agriculture, infrastructure... etc.) that are not in tune with the water management policies of the European Union.[15]​.

The Government of José Luis Rodríguez Zapatero in its second term (2008) chose to merge the Ministry of the Environment with the Ministry of Agriculture "Ministry of Agriculture (Spain)"), leaving the functions of water management at the national level in the hands of the previous Minister of Agriculture Elena Espinosa.[16]​.

Surface and groundwater

Spain has a total area of ​​504,750 km² and an average annual runoff of 220 mm, which is equivalent to a contribution of about 111,000hm³ per year. This contribution includes the river network 109,000 hm³/year and the underground network 2000hm³/year. Located between the Atlantic Ocean and the Mediterranean Sea and between Europe and Africa, its climate is varied. Average rainfall decreases from north to south and from west to east, with the southeastern extreme having the lowest rainfall (of the order of 250 mm). The central core of the peninsula is made up of the two plateaus, flat lands with an average altitude of 600 meters, separated by the Central mountain range and drained by the Duero, Tajo and Guadiana rivers. Next to the plateaus there are two depressions, practically triangular in shape, which correspond to the Ebro basin, with a northern closure made up of the Pyrenees, and the Guadalquivir, closed to the south by the Baetic mountain ranges.

The rivers on the Cantabrian slope and those on the southern Mediterranean slope have permanent flow and are short in length. In the rest of the Mediterranean coast, the rivers give rise to very small basins with the exception of those, such as the Llobregat, the Júcar or the Segura "Segura (river)") with very active rising action. In the longitudinal profiles, the existing step in the rivers when they leave the Plateau is notable, notable in the Duero and the Júcar, a characteristic that has made these sections where important hydroelectric projects are located.[12]​.

Spain has a significant amount of groundwater, 27,000 hm³, which is being extracted for agricultural (75%), urban (20%) and industrial (5%) use. Groundwater extraction has increased in recent years from 500 hm³ in 1900 to 5600 hm³ in 1996.[17]​.

Storage capacity

Spain has the largest number of large dams "Dam (hydraulic)") per inhabitant in the world, the number of dams currently in service exceeds a thousand, with a total storage capacity close to 54,000 hm³.[13] The National Hydrological Plan foresees the construction of 120 new reservoirs, which will probably require environmental compatibility agreements as it affects 46 areas included in the Natura 2000 Network, a European ecological network of biodiversity conservation areas.

Water quality

In the Synthesis Document of the White Paper on Water in Spain of the Spanish government of 2002, its section dedicated to water quality states that "the negative influence of certain anthropogenic actions has caused the natural state of the waters to seriously deteriorate." The degree of pollution of river waters increases as they flow through urban and industrial centers, in some cases reaching a very degraded state in their middle and final reaches. To tackle the problem of urban discharges, the White Paper refers to the National Sanitation and Purification Plan, which thanks to a "significant investment effort" is "achieving that a greater number of inhabitants are connecting to purification systems." The Organization of Consumers and Users carried out a study in 2001 on the effectiveness of purifiers in 15 Spanish cities, concluding that they "work well and are sufficiently controlled." Regarding industrial discharges, a “not insignificant” percentage is carried out without proper authorization. Likewise, fertilizers and pesticides used in agriculture have the "possibility of causing serious problems of eutrophication in reservoirs and contamination of groundwater." Nitrate pollution, mainly attributed to agriculture, significantly affects the Mediterranean coast. The White Paper refers to a study that shows that "reservoirs spread throughout the national territory show that in recent years more than half have increased their degree of eutrophication."

In this same sense, an investigation on water quality in Spain carried out by Greenpeace in 2005 shows that only 11% of the water in Spanish rivers and 16% of aquifers are of acceptable quality, in accordance with the parameters set by the Water Framework Directive of the European Union. Greenpeace considers that the lack of water purification, discharges and overexploitation of demand are the main causes of the poor quality of water in Spain.[18]​.

To evaluate the quality of water in rivers there are different networks, all of them included in the Integrated Water Quality Network (ICA). According to the White Paper, these networks "are not adequate to obtain the necessary information." It is necessary, therefore, to improve the networks for evaluating the state of the waters in terms of definition of locations, density of stations and parameters and sampling frequencies.[19]​.

Water supply and sanitation

Water supply and sanitation in Spain is characterized by uneven drinking water coverage and poor quality of service. In 2020, toxic levels - non-potability - were detected by the Ministry of Health "Ministry of Health (Spain)" in the distribution networks of 4,243 of the 8,131 Spanish municipalities, making it necessary to supply by transporting tankers or new collections. 50% of the water supply is privatized by agreements between municipalities or associations. The majority companies are FCC through its subsidiary Aqualia"), Acciona Agua and the French company Suez "Suez (company, 2015)") through its Catalan subsidiary Aguas de Barcelona and its numerous regional and local subsidiaries.[22]​ The French company Suez with its Catalan subsidiary Grupo Agbar through its regional subsidiaries has around 50% of the private concessions in the market. Spanish.[22]​ Rates for water supply and sanitation in Spain are unequal depending on the territory. The same occurs when compared to European rates, where Spain is in the eleventh position out of seventeen.[23]​[24]​[25]​ In Spain there is a great controversy over water privatizations"), its quality, the associated political corruption and the pressure of private interests to avoid the municipalization of public services.[26]​.

Irrigation

Currently, 3,344,637 hectares are irrigated in Spain, representing 7% of the national surface area and 13% of the useful agricultural surface area. The existence of 1,810,000 hectares transformed before 1960, of which 1,077,000 hectares are more than 100 years old, means that today there are 735,000 hectares in which the distribution networks, largely made up of earthen channels, have high water losses. In turn, of the 1,295,000 hectares currently irrigated by concrete ditches, 392,000 hectares present serious conservation and maintenance problems. Likewise, these irrigation systems were designed in accordance with the technology then existing, using the traditional gravity irrigation system (1,981,000 ha), and a large part of them (1,635,000 ha) with shift irrigation. The loss of efficiency of the pipelines over time and the modification of cultivation alternatives has meant that 1,129,000 hectares are currently underfunded and 694,000 hectares are slightly underfunded. Irrigation obtains 50% of the final agricultural production in only 13% of the agricultural area, with a gross value of annual production per hectare between 2,500 and 3,000 Euros, which is equivalent to just over 6 times that of dry land.[27]​.

Hydroelectric power

Spain is in line with other OECD countries regarding the production of electrical energy, with 18.5% of this energy of hydraulic origin. The evolution of hydroelectric energy in Spain in recent decades has always been growing, although its share in the total electricity produced has been decreasing (92% in 1940 vs 18% in 2001). This is due to the increase in thermal and nuclear energy production in the last 50 and 30 years respectively.

The hydraulic production plant with the highest installed power is Cortes-La Muela, in Júcar (Valencia), with 1600 MW, followed by Aldeadávila, in Duero (Salamanca), with 1140 MW, and Alcántara, in Tajo (Cáceres), with 915 MW. Other reservoirs with power above 500 MW are those of Villarino, in the Tormes (Salamanca), or Saucelle, in the Duero (Salamanca).[28]​.

Aquatic ecosystems

The wetlands in Spain, of great natural wealth and 49 of them on the list of the Ramsar convention, act as wintering areas for migratory birds from northern Europe. The unique characteristics of these ecosystems, which in Spain are very abundant and of great diversity, have favored the development of a wide range of human activities, from hunting and fishing, to tourism, through the cultivation of rice or livestock, creating an associated economy.[29]​.

(See Ramsar Sites in Spain for more information).

International legal framework

Europe The framework directive 2000/60/EC of the European Parliament and of the Council, of October 23, 2000, establishes a community framework for action in the field of water policy. Through this Directive, the European Union organizes the management of surface, continental, transitional, coastal and groundwater waters, in order to prevent and reduce their pollution, promote their sustainable use, protect the aquatic environment, improve the situation of aquatic ecosystems and alleviate the effects of floods and droughts.

International Agreements In 1998 Spain and Portugal formed the “Cooperation Agreement for the protection and sustainable use of the waters of the Spanish-Portuguese hydrographic basins”, better known as the Albufeira Convention. It is applicable to the basins of the Miño, Limia, Duero, Tajo and Guadiana rivers, which represent 41% of the total surface area of ​​Spain and 62% of that of Portugal. As a novelty of this agreement, Spain acquired the commitment to provide Portugal with minimum annual contributions depending on the hydrological situation.[30]​.

National legal framework

The Water Law of 1985 Archived May 16, 2008 at the Wayback Machine. It was published in the Official State Gazette on August 2, 1985 and came into force on January 1, 1986. Today the current regulation is given by Royal Legislative Decree 1/2001, of July 20, which approves the consolidated text of the Water Law. This text substantially maintains contents of the previous legislation. Its basic principles include:

The public nature of waters One of the most innovative contributions of the Law is to establish that all continental, surface and underground waters are an integral part of the public hydraulic domain. In this way, individuals only acquire the right to use it, not the ownership of the water, except for the rights acquired under previous legislation that considered groundwater as the property of the owner of the property where it was located. Its allocation and use therefore requires prior administrative concession and its allocation corresponds to the Administration, without the market intervening. The extraordinary power conferred on the Administration has not been matched by an adequate provision of personal and material resources, which explains the lack of control of thousands of clandestine wells and the overexploitation of aquifers.[11]​.

Hydrological planning The Law establishes Hydrological Planning as an instrument for organizing water management in the basin. Hydrological plans are not simple works programs but instruments of a normative nature that adapt the generic provisions of the law to the unique conditions of each basin. Despite the Hydrological Plans being key pieces for the application of the Law, their preparation has been slow and their approval has suffered significant delays.

Basin organizations Basin organizations are the entities in charge of preparing the hydrological plans of the inter-community and intra-community basins as a specialized, decentralized and participatory authority for water planning and management.

Law 29/1985 has been modified by Law 46/1999, delving into environmental aspects such as the authorization of discharges, the discharge control fee, reuse of wastewater and desalination of seawater. Of particular interest is the introduction of contracts for the transfer of water use rights, the first step towards the creation of an incipient water market at the national level.

The Regulation of the Hydraulic Public Domain"), was approved by Royal Decree 849/1986, of April 11.[31]​.

Institutional framework

An institutional framework is made up of public or private entities that interact in order to provide goods and services linked to water that meet the basic requirements of the population, allow the maintenance of ecosystems and make possible the development of economic activities. This complex institutional framework in which elements with concurrent and even shared powers coexist, making coordination – not always easy – between different institutions necessary.

The Ministry for the Ecological Transition is the national authority for water resources management. The Ministry exercises this function through the General Directorate of Water, which is responsible for:

The National Water Council, already provided for in the 1985 Law, is the highest advisory body with hydrological planning functions in Spain. These basically consist of mandatory reporting on the National Hydrological Plan project and the Basin Hydrological Plans, among others.

The basin organizations are the highest authority in the management of water resources at the basin level and are in charge of the administration of the public hydraulic domain, including the allocation of resources, which can be done well under the figure of the administrative concession; the auction of quotas or market mechanisms or any other formula, as well as the allocation of discharge permits (quotas).

The public administration, through entities included between the State or Autonomous Administration itself and the Local Entities, is responsible for promoting economic activities linked to water and their public promotion. City councils play a very important role in providing final services to users, such as those corresponding to the supply of drinking water, sanitation and purification. There is a growing trend towards the participation of the private sector in these services through administrative concessions, with the municipality retaining the regulatory function.

The private sector also performs a relevant function in the management of water resources with regard to the end user. The User Communities (called Irrigators when the priority use of water is irrigation) and the concessionaires with rights to private use of the resource are the two main institutions that shape the participation of the private sector in this field.

Water quality management is carried out by different administrations, regional, local or central, depending on whether it is an intra-community or inter-community section. This competency framework presents a challenge in terms of the coordination of the different activities.

National hydrological plan

The National Hydrological Plan is an instrument for water management and rebalancing aimed at the sustainable use of water and the environmental recovery of the public domain and affected environment. It is not intended to promote the use of water or increase water supply and demand, but rather it should be aimed at correcting existing supply problems both for supply to the population and for various economic activities, particularly irrigation, and to eliminate the problem of degradation of the public hydraulic domain and overexploitation of aquifers.[11] The National Hydrological Plan, approved in 2001 under the government of José María Aznar (Popular Party), provided for the transfer of 1050 hm³ of water from the Ebro River to the Mediterranean coast. This Plan found great popular opposition, especially from the Catalan and Aragonese regions.[32]​.

The government of José Luis Rodríguez Zapatero (PSOE) approved the A.G.U.A. Program. (Actions for the Management and Use of Water), which proposes supplying the Spanish east through the construction of desalination plants and eliminating the transfer of the Ebro. This measure has also had popular rejection, this time from the provinces of the Levant.[33] Other important aspects of the A.G.U.A. Program. is the emphasis on popular and autonomous community participation in water management carried out by hydrographic basins. The A.G.U.A. Program It has begun to be applied to the Mediterranean coast (Southern, Segura, Júcar, Ebro and Internal Basins of Catalonia Hydrographic Basins) and plans to extend it to the rest of Spain in the coming years.

Basin organizations

Starting in 1926, water management in Spain was decentralized, adapting territorially to the basin level. This administration model that has been used in other countries, especially in Latin America, represents a good management practice.

The powers over the public hydraulic domain are exercised directly by the State through the Hydrographic Confederations if the corresponding basin extends across several autonomous communities (intercommunity basins). Currently there are nine Hydrographic Confederations: Norte, Duero, Tajo, Guadiana, Guadalquivir, Sur, Segura, Júcar and Ebro. The hydrographic confederations occupy approximately 85% of the Spanish territory.

In the case of intra-community basins, all the powers have been transferred to the corresponding autonomous community, which exercises them through specific organizations. Royal Decree 125 of 2007 added new demarcations to the existing ones, with a total of seven: Galicia-Coast, Basque Country, Catalonia, Atlantic Andalusia, Mediterranean Andalusia, Balearic Islands and Canary Islands.

[34]​.

Hydrographic confederations are public law entities with their own legal personality, different from that of the State, with full functional autonomy, attached, for administrative purposes, to the Ministry of the Environment and Rural and Marine Environment or to the corresponding departments in the autonomous communities. In accordance with the 1985 Law, the functions of the hydrographic confederations are: the preparation, monitoring and review of the basin Hydrological Plan, the administration and control of the public hydraulic domain, granting authorizations and concessions and monitoring compliance with them; the design, construction and operation of works carried out with its own funds and those entrusted to it by the State or other territorial entities; and any other function that emanates from the agreement of the confederation with other public or private entities.

Each Confederation executes its functions through a set of bodies: government, planning and management. The governing bodies are the president and the Governing Board. The President is responsible for the highest executive and representation functions of the organization. He is appointed and dismissed by the Council of Ministers at the proposal of the Minister of the Environment and Rural and Marine Environment, and there is no deadline for the exercise of his mandate. The Governing Board is the collective governing body and is made up of representatives of the users, representatives of the different Ministries and local representatives. Its composition varies depending on the specific characteristics of each Confederation but, in any case, the users – who are elected in the User Assembly – are at least a third of the total.

The Planning body is constituted by the Basin Water Council. Its composition is similar to that of the Governing Board, always with a presence of no less than a third of users, although with a greater number of people incorporating conservation organizations as well as independent technicians of recognized prestige.

Example of water resources management at the basin level – The Guadalquivir Hydrographic Confederation

The largest authority at the basin level is the Guadalquivir Hydrographic Confederation, created by the central government in 1927 and is the second of its kind following that of the Ebro created in 1926. The confederation is attached to the Ministry of the Environment since the Guadalquivir passes through two autonomous communities. Within the framework of its jurisdiction, the decisions made with the confederation are final and can only be discussed in court and due to excess of jurisdiction. The confederation also has sanctioning power. The president of the confederation, currently Mr. Francisco Tapia Granados, has executive and representative functions of the confederation and is appointed and dismissed by the council of ministers at the proposal of the Ministry of the Environment. There is no deadline for the exercise of his mandate.

The legal and institutional development produced in the last two decades has been accompanied by a friction in the competencies of the different institutions in charge of water management in the Guadalquivir basin. According to a study by William Blomquist, the confederation appears to remain focused on tasks related to development and initiatives such as licensing and demand management. These tasks have been carried out with little rigor and few positive results. The water deficit continues to be a problem that increases the area's vulnerability to droughts. Likewise, flooding continues to be a problem despite the amount of hydraulic works produced because urban development and the agricultural frontier have extended to areas prone to flooding. Irrigation water rates are based on acreage cultivated rather than the amount of water used, providing no financial incentive to save. The president of the confederation continues to have great weight in decision-making while the incorporation of interest groups in decision-making is being carried out slowly, causing the confederation to continue to be seen as a group focused on irrigation, rather than the decision-making forum for all water users. Finally, the confederation remains financially dependent on the central government, despite the fact that it has the power to administer all water rates collected in the basin. In 2001, the confederation made public an annual budget of 115,800,000 euros, 35% coming from the central government, 30% from water users, and 35% from other sources of income.[35]​.

Irrigation. The irrigation rate applied in Spanish irrigation can be determined by irrigable surface, by volume of water consumed or by means of a binomial or mixed formula established on the basis of the irrigable surface and the water actually consumed. The surface irrigation rate is applied to 82% of the irrigable surface, while the volumetric rate is applied to 13% of the surface, and the binomial formula to 5%.

[36]​

The Federation of Consumers in Action (FACUA) has observed differences of up to 346% when analyzing the rates for home water supply in twenty-eight Spanish cities during the years 2004 and 2005.[37]​.

Home use. However, Spain has the third cheapest water bill in the European Union, with 1.22 euros per cubic meter, behind Lithuania, with an average of 0.64 euros/m³, and Italy, with 1.14 euros/m³, according to data from the Spanish Association of Water Supplies and Sanitation (AEAS).[38]​.

Droughts

Precipitation in Spain has high temporal and spatial variability. If rainfall has an average annual value of about 700 mm/year, 1600 mm falls in the North and less than 300 mm in the areas of the Southeast of the peninsula and the Canary Islands, making the latter more vulnerable to drought. Regarding temporal variability, the series of average rainfall in Spain shows high variability. The spells of dry years are longer than the wet ones. Since 1940, 3 different periods have been observed: Dry 1940 -1957, Humid 1958 -1978, Dry from 1979-1995...[40]​ In 2004 a new dry period began that ended in 2008, while in 2014 a new dry period began that continues in 2017 and has already caused the so-called great drought. Iberian. The effects of the current drought are still unknown, but according to data collected by the Júcar Hydrographic Confederation, the drought from 1991 to 1995 had the following effects in Spain:

Floods

Although the rainfall in Spain is not abundant, sometimes there is rainfall that in a few hours reaches values ​​higher than the annual average. These extraordinary rains cause extreme flows, usually called floods, floods or floods, which, when they overflow their usual channel, cause the flooding of land, affecting people and property.

The great disproportion between the ordinary and extraordinary flows of some rivers makes the problem of flooding in Spain particularly serious. The most torrential rainfall occurs along the Mediterranean and Cantabrian coasts, the Pyrenees, and the Guadiana and Tagus watersheds, producing generally more uniform rainfall on the two plateaus. However, isolated episodes can be found throughout the entire territory. For example, in 1996 two floods stood out in severity: the river floods in western Andalusia that caused losses of 70,000 million pesetas and four fatalities in traffic accidents; and the Bisecas, a torrential type, caused more than 80 fatalities, with very little material damage.[41]​ (Watch video).

Possible impact of climate change on water resources

The climate scenarios predicted for Spain by the National Climate Council assume a decrease in average annual precipitation and an increase in temperatures, which would lead to a decrease in total runoff.

A greater impact is expected in the territories of the Southeast of the peninsula, the Guadiana basin, the Ebro valley and the archipelagos, areas that are currently characterized by their water problems. An increase of one degree Celsius and a 5% decrease in precipitation would mean a decrease in the contributions from these areas of the order of 20%.[13]​.

Climate change adaptation strategies

The National Plan for Adaptation to Climate Change presented in 2006 lists a series of concrete actions for the evaluation of the impacts of climate change on water resources. The National Plan for Adaptation to Climate Change includes "Work Programs" and has planned annual monitoring reports for each of the ongoing activities and projects, which will be compiled in a general report every four years by the Spanish Climate Change Office. The first Work Program, presented in 2006, which has as one of its objectives the carrying out of an evaluation of the impacts of climate change on water resources and irrigation demands, will be developed over the next four years.

The former Minister of the Environment, Cristina Narbona (2004-2008), in the presentation of the National Plan for Adaptation to Climate Change, expressed her interest in making the "progress and results of the plan" available to the administration, organizations and society in general through the ministry's website.[42] The first results of the Work Program, scheduled for the end of 2007, are not yet available on the Ministry's website.

Roman era (3rd century BC-5th century AD)

The Romans built a series of aqueducts and water distribution systems throughout their territories, including the Iberian Peninsula. Notable examples are the Segovia and Tarragona aqueducts.

Al-Andalus (8th century-15th century)

During the period of Muslim rule in the Iberian Peninsula, advanced irrigation and water management systems, such as ditches and waterwheels, were introduced, allowing the development of prosperous agriculture in the region.

Reconquest and growth of the Christian kingdoms (11th century-15th century)

During the time of the Reconquista in Spain, Christian kingdoms adopted and adapted water management techniques developed by Muslims. These techniques included the use of ditches, water wheels and cisterns, with ditches being essential in regions such as Valencia, Murcia and Andalusia for irrigation systems.

The Christian kingdoms developed their own institutions and regulations for the management of water resources, creating courts such as the Water Court of Valencia, one of the oldest in the world, charged with resolving conflicts and guaranteeing fair distribution among water users.

Water infrastructure such as dams, canals and aqueducts were also built and maintained during this period, allowing for the expansion and development of agriculture, as well as the supply of water to growing cities and towns.

Water management and the development of irrigation systems were crucial to agriculture and economic growth in Christian kingdoms. Investment in water infrastructure and irrigation systems allowed the expansion of agricultural production in regions such as Castilla y León, as well as the introduction of new crops and agricultural techniques.

As Christian kingdoms grew and expanded, tensions and conflicts related to water use and management also increased. Cooperation and knowledge exchange between Christian and Muslim communities in border areas, as well as the need to establish agreements and regulations to share and manage water resources equitably, were important aspects of water policy during this period.

16th-19th centuries

During this period, water policies in Spain were largely focused on local and regional water management, and numerous canals, dams and aqueducts were built to improve water supply and distribution. The Teruel aqueduct "Acueducto Los Arcos (Teruel)"), built in the 19th century, is a notable example of these works.[10]​.

The Water Law of 1866 represents the first attempt to specifically regulate Spanish territorial waters, although it did not come into force due to the revolutionary period that gave rise to the First Republic. Its basic principles, however, were largely passed on to the Law of 1879, including that of the public domain of all natural currents, channels and banks of rivers. Groundwater, which belongs to the owner of the land where the lighting will be illuminated, was not included. This provision continued in force until its non-retroactive modification by the 1985 Law, and is one of the causes of the current situation of lack of administrative control of underground sources.

The Law of 1879 includes the right to private use of water linked to an administrative concession. The Law very precisely regulates both the procedure and the general rules on the concession of public water as well as specific provisions for the different uses (supply to populations, irrigation, industrial establishments, etc.). In the case of irrigation, furthermore, the right to use water is linked to the right to own the land. Likewise, the Law establishes the community of irrigators, an institution that is self-governed and has sanctioning power. The subsequent evolution of water uses towards multiple-purpose uses and the concurrence of various users on the same body of water have made it advisable to expand the figure of the community of irrigators to the current communities of users.

The Regulations of the Law of 1879 never came to fruition and said regulatory element was replaced by various lower-ranking provisions that tried to resolve the numerous problems that arose in the application of the Law due to both the wide field covered by it, as well as its prolonged validity that confronted it with situations for which its provisions were not effective.

20th century-Franco regime (1939-1975)

The management of water resources in Spain for much of the century has been characterized by strong state interventionism. This intervention focused on the construction of hydraulic works in an effort to increase the water available for irrigation (supply policy) and hydroelectric power generation, considered the driving force of Spanish economic development policy. The Hydraulic Works Plans of 1902 and 1933, financed for the most part by the state, are an example of this type of policy.[11]​.

The most important of the regulatory developments is the one that refers to the creation, or rather the institutionalization of an existing reality, of basin organizations, with the creation of the first hydrographic confederation in 1926 as the highest body for water management at the basin level. The functions of basin organizations have alternated between specific development and more general water management functions throughout the last century.[12]​.

Until 1955, a growth rate of about 4 dams per year was maintained, going from the nearly 60 dams existing at the beginning of the century to about 270 in 1950. From that year on, the pace accelerated considerably, reaching an average of 20 dams per year, until reaching the current park.[13]​.

Transition to democracy and creation of autonomous communities (1975-1985)

After Franco's death, Spain began a transition to democracy and established autonomous communities. During this period, decentralization in water resources management began and more attention began to be paid to sustainability and public participation in decision-making.

Water Law of 1985

The promulgation of the Water Law established a new legal framework for the management of water resources in Spain, creating a hydrological planning system based on hydrographic basins and establishing criteria for water quality and environmental protection.

Integration into the European Union (1986 onwards)

Spain joined the EU in 1986 and adopted the Water Framework Directive (WFD) in 2000, which involved a more integrated and sustainable approach to the management of water resources in the country.

21st century

Water policy in Spain has evolved to address the challenges of climate change, water scarcity and environmental sustainability. Recent policies have focused on improving water use efficiency.

William Blomquist, in a study on hydrographic confederations carried out in 2005, reflects that their formal structure traditionally gives more weight to user groups for irrigation, leaving public or private organizations that represent urban centers or environmental issues in the background. Likewise, some confederations continue to emphasize their development tasks while they adapt to comprehensively manage, in a broad sense, their water resources.[14]​.

Likewise, the NGO WWF/Adena carried out a study report in 2004 comparing the water management of different European countries and placing Spain among the three worst managers. Among the reasons for poor management WWF/Adena finds that there are too many actors in water management due to a fragmented jurisdiction; and that there is a lack of integration of sectoral policies (agriculture, infrastructure... etc.) that are not in tune with the water management policies of the European Union.[15]​.

The Government of José Luis Rodríguez Zapatero in its second term (2008) chose to merge the Ministry of the Environment with the Ministry of Agriculture "Ministry of Agriculture (Spain)"), leaving the functions of water management at the national level in the hands of the previous Minister of Agriculture Elena Espinosa.[16]​.

Surface and groundwater

Spain has a total area of ​​504,750 km² and an average annual runoff of 220 mm, which is equivalent to a contribution of about 111,000hm³ per year. This contribution includes the river network 109,000 hm³/year and the underground network 2000hm³/year. Located between the Atlantic Ocean and the Mediterranean Sea and between Europe and Africa, its climate is varied. Average rainfall decreases from north to south and from west to east, with the southeastern extreme having the lowest rainfall (of the order of 250 mm). The central core of the peninsula is made up of the two plateaus, flat lands with an average altitude of 600 meters, separated by the Central mountain range and drained by the Duero, Tajo and Guadiana rivers. Next to the plateaus there are two depressions, practically triangular in shape, which correspond to the Ebro basin, with a northern closure made up of the Pyrenees, and the Guadalquivir, closed to the south by the Baetic mountain ranges.

The rivers on the Cantabrian slope and those on the southern Mediterranean slope have permanent flow and are short in length. In the rest of the Mediterranean coast, the rivers give rise to very small basins with the exception of those, such as the Llobregat, the Júcar or the Segura "Segura (river)") with very active rising action. In the longitudinal profiles, the existing step in the rivers when they leave the Plateau is notable, notable in the Duero and the Júcar, a characteristic that has made these sections where important hydroelectric projects are located.[12]​.

Spain has a significant amount of groundwater, 27,000 hm³, which is being extracted for agricultural (75%), urban (20%) and industrial (5%) use. Groundwater extraction has increased in recent years from 500 hm³ in 1900 to 5600 hm³ in 1996.[17]​.

Storage capacity

Spain has the largest number of large dams "Dam (hydraulic)") per inhabitant in the world, the number of dams currently in service exceeds a thousand, with a total storage capacity close to 54,000 hm³.[13] The National Hydrological Plan foresees the construction of 120 new reservoirs, which will probably require environmental compatibility agreements as it affects 46 areas included in the Natura 2000 Network, a European ecological network of biodiversity conservation areas.

Water quality

In the Synthesis Document of the White Paper on Water in Spain of the Spanish government of 2002, its section dedicated to water quality states that "the negative influence of certain anthropogenic actions has caused the natural state of the waters to seriously deteriorate." The degree of pollution of river waters increases as they flow through urban and industrial centers, in some cases reaching a very degraded state in their middle and final reaches. To tackle the problem of urban discharges, the White Paper refers to the National Sanitation and Purification Plan, which thanks to a "significant investment effort" is "achieving that a greater number of inhabitants are connecting to purification systems." The Organization of Consumers and Users carried out a study in 2001 on the effectiveness of purifiers in 15 Spanish cities, concluding that they "work well and are sufficiently controlled." Regarding industrial discharges, a “not insignificant” percentage is carried out without proper authorization. Likewise, fertilizers and pesticides used in agriculture have the "possibility of causing serious problems of eutrophication in reservoirs and contamination of groundwater." Nitrate pollution, mainly attributed to agriculture, significantly affects the Mediterranean coast. The White Paper refers to a study that shows that "reservoirs spread throughout the national territory show that in recent years more than half have increased their degree of eutrophication."

In this same sense, an investigation on water quality in Spain carried out by Greenpeace in 2005 shows that only 11% of the water in Spanish rivers and 16% of aquifers are of acceptable quality, in accordance with the parameters set by the Water Framework Directive of the European Union. Greenpeace considers that the lack of water purification, discharges and overexploitation of demand are the main causes of the poor quality of water in Spain.[18]​.

To evaluate the quality of water in rivers there are different networks, all of them included in the Integrated Water Quality Network (ICA). According to the White Paper, these networks "are not adequate to obtain the necessary information." It is necessary, therefore, to improve the networks for evaluating the state of the waters in terms of definition of locations, density of stations and parameters and sampling frequencies.[19]​.

Water supply and sanitation

Water supply and sanitation in Spain is characterized by uneven drinking water coverage and poor quality of service. In 2020, toxic levels - non-potability - were detected by the Ministry of Health "Ministry of Health (Spain)" in the distribution networks of 4,243 of the 8,131 Spanish municipalities, making it necessary to supply by transporting tankers or new collections. 50% of the water supply is privatized by agreements between municipalities or associations. The majority companies are FCC through its subsidiary Aqualia"), Acciona Agua and the French company Suez "Suez (company, 2015)") through its Catalan subsidiary Aguas de Barcelona and its numerous regional and local subsidiaries.[22]​ The French company Suez with its Catalan subsidiary Grupo Agbar through its regional subsidiaries has around 50% of the private concessions in the market. Spanish.[22]​ Rates for water supply and sanitation in Spain are unequal depending on the territory. The same occurs when compared to European rates, where Spain is in the eleventh position out of seventeen.[23]​[24]​[25]​ In Spain there is a great controversy over water privatizations"), its quality, the associated political corruption and the pressure of private interests to avoid the municipalization of public services.[26]​.

Irrigation

Currently, 3,344,637 hectares are irrigated in Spain, representing 7% of the national surface area and 13% of the useful agricultural surface area. The existence of 1,810,000 hectares transformed before 1960, of which 1,077,000 hectares are more than 100 years old, means that today there are 735,000 hectares in which the distribution networks, largely made up of earthen channels, have high water losses. In turn, of the 1,295,000 hectares currently irrigated by concrete ditches, 392,000 hectares present serious conservation and maintenance problems. Likewise, these irrigation systems were designed in accordance with the technology then existing, using the traditional gravity irrigation system (1,981,000 ha), and a large part of them (1,635,000 ha) with shift irrigation. The loss of efficiency of the pipelines over time and the modification of cultivation alternatives has meant that 1,129,000 hectares are currently underfunded and 694,000 hectares are slightly underfunded. Irrigation obtains 50% of the final agricultural production in only 13% of the agricultural area, with a gross value of annual production per hectare between 2,500 and 3,000 Euros, which is equivalent to just over 6 times that of dry land.[27]​.

Hydroelectric power

Spain is in line with other OECD countries regarding the production of electrical energy, with 18.5% of this energy of hydraulic origin. The evolution of hydroelectric energy in Spain in recent decades has always been growing, although its share in the total electricity produced has been decreasing (92% in 1940 vs 18% in 2001). This is due to the increase in thermal and nuclear energy production in the last 50 and 30 years respectively.

The hydraulic production plant with the highest installed power is Cortes-La Muela, in Júcar (Valencia), with 1600 MW, followed by Aldeadávila, in Duero (Salamanca), with 1140 MW, and Alcántara, in Tajo (Cáceres), with 915 MW. Other reservoirs with power above 500 MW are those of Villarino, in the Tormes (Salamanca), or Saucelle, in the Duero (Salamanca).[28]​.

Aquatic ecosystems

The wetlands in Spain, of great natural wealth and 49 of them on the list of the Ramsar convention, act as wintering areas for migratory birds from northern Europe. The unique characteristics of these ecosystems, which in Spain are very abundant and of great diversity, have favored the development of a wide range of human activities, from hunting and fishing, to tourism, through the cultivation of rice or livestock, creating an associated economy.[29]​.

(See Ramsar Sites in Spain for more information).

International legal framework

Europe The framework directive 2000/60/EC of the European Parliament and of the Council, of October 23, 2000, establishes a community framework for action in the field of water policy. Through this Directive, the European Union organizes the management of surface, continental, transitional, coastal and groundwater waters, in order to prevent and reduce their pollution, promote their sustainable use, protect the aquatic environment, improve the situation of aquatic ecosystems and alleviate the effects of floods and droughts.

International Agreements In 1998 Spain and Portugal formed the “Cooperation Agreement for the protection and sustainable use of the waters of the Spanish-Portuguese hydrographic basins”, better known as the Albufeira Convention. It is applicable to the basins of the Miño, Limia, Duero, Tajo and Guadiana rivers, which represent 41% of the total surface area of ​​Spain and 62% of that of Portugal. As a novelty of this agreement, Spain acquired the commitment to provide Portugal with minimum annual contributions depending on the hydrological situation.[30]​.

National legal framework

The Water Law of 1985 Archived May 16, 2008 at the Wayback Machine. It was published in the Official State Gazette on August 2, 1985 and came into force on January 1, 1986. Today the current regulation is given by Royal Legislative Decree 1/2001, of July 20, which approves the consolidated text of the Water Law. This text substantially maintains contents of the previous legislation. Its basic principles include:

The public nature of waters One of the most innovative contributions of the Law is to establish that all continental, surface and underground waters are an integral part of the public hydraulic domain. In this way, individuals only acquire the right to use it, not the ownership of the water, except for the rights acquired under previous legislation that considered groundwater as the property of the owner of the property where it was located. Its allocation and use therefore requires prior administrative concession and its allocation corresponds to the Administration, without the market intervening. The extraordinary power conferred on the Administration has not been matched by an adequate provision of personal and material resources, which explains the lack of control of thousands of clandestine wells and the overexploitation of aquifers.[11]​.

Hydrological planning The Law establishes Hydrological Planning as an instrument for organizing water management in the basin. Hydrological plans are not simple works programs but instruments of a normative nature that adapt the generic provisions of the law to the unique conditions of each basin. Despite the Hydrological Plans being key pieces for the application of the Law, their preparation has been slow and their approval has suffered significant delays.

Basin organizations Basin organizations are the entities in charge of preparing the hydrological plans of the inter-community and intra-community basins as a specialized, decentralized and participatory authority for water planning and management.

Law 29/1985 has been modified by Law 46/1999, delving into environmental aspects such as the authorization of discharges, the discharge control fee, reuse of wastewater and desalination of seawater. Of particular interest is the introduction of contracts for the transfer of water use rights, the first step towards the creation of an incipient water market at the national level.

The Regulation of the Hydraulic Public Domain"), was approved by Royal Decree 849/1986, of April 11.[31]​.

Institutional framework

An institutional framework is made up of public or private entities that interact in order to provide goods and services linked to water that meet the basic requirements of the population, allow the maintenance of ecosystems and make possible the development of economic activities. This complex institutional framework in which elements with concurrent and even shared powers coexist, making coordination – not always easy – between different institutions necessary.

The Ministry for the Ecological Transition is the national authority for water resources management. The Ministry exercises this function through the General Directorate of Water, which is responsible for:

The National Water Council, already provided for in the 1985 Law, is the highest advisory body with hydrological planning functions in Spain. These basically consist of mandatory reporting on the National Hydrological Plan project and the Basin Hydrological Plans, among others.

The basin organizations are the highest authority in the management of water resources at the basin level and are in charge of the administration of the public hydraulic domain, including the allocation of resources, which can be done well under the figure of the administrative concession; the auction of quotas or market mechanisms or any other formula, as well as the allocation of discharge permits (quotas).

The public administration, through entities included between the State or Autonomous Administration itself and the Local Entities, is responsible for promoting economic activities linked to water and their public promotion. City councils play a very important role in providing final services to users, such as those corresponding to the supply of drinking water, sanitation and purification. There is a growing trend towards the participation of the private sector in these services through administrative concessions, with the municipality retaining the regulatory function.

The private sector also performs a relevant function in the management of water resources with regard to the end user. The User Communities (called Irrigators when the priority use of water is irrigation) and the concessionaires with rights to private use of the resource are the two main institutions that shape the participation of the private sector in this field.

Water quality management is carried out by different administrations, regional, local or central, depending on whether it is an intra-community or inter-community section. This competency framework presents a challenge in terms of the coordination of the different activities.

National hydrological plan

The National Hydrological Plan is an instrument for water management and rebalancing aimed at the sustainable use of water and the environmental recovery of the public domain and affected environment. It is not intended to promote the use of water or increase water supply and demand, but rather it should be aimed at correcting existing supply problems both for supply to the population and for various economic activities, particularly irrigation, and to eliminate the problem of degradation of the public hydraulic domain and overexploitation of aquifers.[11] The National Hydrological Plan, approved in 2001 under the government of José María Aznar (Popular Party), provided for the transfer of 1050 hm³ of water from the Ebro River to the Mediterranean coast. This Plan found great popular opposition, especially from the Catalan and Aragonese regions.[32]​.

The government of José Luis Rodríguez Zapatero (PSOE) approved the A.G.U.A. Program. (Actions for the Management and Use of Water), which proposes supplying the Spanish east through the construction of desalination plants and eliminating the transfer of the Ebro. This measure has also had popular rejection, this time from the provinces of the Levant.[33] Other important aspects of the A.G.U.A. Program. is the emphasis on popular and autonomous community participation in water management carried out by hydrographic basins. The A.G.U.A. Program It has begun to be applied to the Mediterranean coast (Southern, Segura, Júcar, Ebro and Internal Basins of Catalonia Hydrographic Basins) and plans to extend it to the rest of Spain in the coming years.

Basin organizations

Starting in 1926, water management in Spain was decentralized, adapting territorially to the basin level. This administration model that has been used in other countries, especially in Latin America, represents a good management practice.

The powers over the public hydraulic domain are exercised directly by the State through the Hydrographic Confederations if the corresponding basin extends across several autonomous communities (intercommunity basins). Currently there are nine Hydrographic Confederations: Norte, Duero, Tajo, Guadiana, Guadalquivir, Sur, Segura, Júcar and Ebro. The hydrographic confederations occupy approximately 85% of the Spanish territory.

In the case of intra-community basins, all the powers have been transferred to the corresponding autonomous community, which exercises them through specific organizations. Royal Decree 125 of 2007 added new demarcations to the existing ones, with a total of seven: Galicia-Coast, Basque Country, Catalonia, Atlantic Andalusia, Mediterranean Andalusia, Balearic Islands and Canary Islands.

[34]​.

Hydrographic confederations are public law entities with their own legal personality, different from that of the State, with full functional autonomy, attached, for administrative purposes, to the Ministry of the Environment and Rural and Marine Environment or to the corresponding departments in the autonomous communities. In accordance with the 1985 Law, the functions of the hydrographic confederations are: the preparation, monitoring and review of the basin Hydrological Plan, the administration and control of the public hydraulic domain, granting authorizations and concessions and monitoring compliance with them; the design, construction and operation of works carried out with its own funds and those entrusted to it by the State or other territorial entities; and any other function that emanates from the agreement of the confederation with other public or private entities.

Each Confederation executes its functions through a set of bodies: government, planning and management. The governing bodies are the president and the Governing Board. The President is responsible for the highest executive and representation functions of the organization. He is appointed and dismissed by the Council of Ministers at the proposal of the Minister of the Environment and Rural and Marine Environment, and there is no deadline for the exercise of his mandate. The Governing Board is the collective governing body and is made up of representatives of the users, representatives of the different Ministries and local representatives. Its composition varies depending on the specific characteristics of each Confederation but, in any case, the users – who are elected in the User Assembly – are at least a third of the total.

The Planning body is constituted by the Basin Water Council. Its composition is similar to that of the Governing Board, always with a presence of no less than a third of users, although with a greater number of people incorporating conservation organizations as well as independent technicians of recognized prestige.

Example of water resources management at the basin level – The Guadalquivir Hydrographic Confederation

The largest authority at the basin level is the Guadalquivir Hydrographic Confederation, created by the central government in 1927 and is the second of its kind following that of the Ebro created in 1926. The confederation is attached to the Ministry of the Environment since the Guadalquivir passes through two autonomous communities. Within the framework of its jurisdiction, the decisions made with the confederation are final and can only be discussed in court and due to excess of jurisdiction. The confederation also has sanctioning power. The president of the confederation, currently Mr. Francisco Tapia Granados, has executive and representative functions of the confederation and is appointed and dismissed by the council of ministers at the proposal of the Ministry of the Environment. There is no deadline for the exercise of his mandate.

The legal and institutional development produced in the last two decades has been accompanied by a friction in the competencies of the different institutions in charge of water management in the Guadalquivir basin. According to a study by William Blomquist, the confederation appears to remain focused on tasks related to development and initiatives such as licensing and demand management. These tasks have been carried out with little rigor and few positive results. The water deficit continues to be a problem that increases the area's vulnerability to droughts. Likewise, flooding continues to be a problem despite the amount of hydraulic works produced because urban development and the agricultural frontier have extended to areas prone to flooding. Irrigation water rates are based on acreage cultivated rather than the amount of water used, providing no financial incentive to save. The president of the confederation continues to have great weight in decision-making while the incorporation of interest groups in decision-making is being carried out slowly, causing the confederation to continue to be seen as a group focused on irrigation, rather than the decision-making forum for all water users. Finally, the confederation remains financially dependent on the central government, despite the fact that it has the power to administer all water rates collected in the basin. In 2001, the confederation made public an annual budget of 115,800,000 euros, 35% coming from the central government, 30% from water users, and 35% from other sources of income.[35]​.

Irrigation. The irrigation rate applied in Spanish irrigation can be determined by irrigable surface, by volume of water consumed or by means of a binomial or mixed formula established on the basis of the irrigable surface and the water actually consumed. The surface irrigation rate is applied to 82% of the irrigable surface, while the volumetric rate is applied to 13% of the surface, and the binomial formula to 5%.

[36]​

The Federation of Consumers in Action (FACUA) has observed differences of up to 346% when analyzing the rates for home water supply in twenty-eight Spanish cities during the years 2004 and 2005.[37]​.

Home use. However, Spain has the third cheapest water bill in the European Union, with 1.22 euros per cubic meter, behind Lithuania, with an average of 0.64 euros/m³, and Italy, with 1.14 euros/m³, according to data from the Spanish Association of Water Supplies and Sanitation (AEAS).[38]​.

Droughts

Precipitation in Spain has high temporal and spatial variability. If rainfall has an average annual value of about 700 mm/year, 1600 mm falls in the North and less than 300 mm in the areas of the Southeast of the peninsula and the Canary Islands, making the latter more vulnerable to drought. Regarding temporal variability, the series of average rainfall in Spain shows high variability. The spells of dry years are longer than the wet ones. Since 1940, 3 different periods have been observed: Dry 1940 -1957, Humid 1958 -1978, Dry from 1979-1995...[40]​ In 2004 a new dry period began that ended in 2008, while in 2014 a new dry period began that continues in 2017 and has already caused the so-called great drought. Iberian. The effects of the current drought are still unknown, but according to data collected by the Júcar Hydrographic Confederation, the drought from 1991 to 1995 had the following effects in Spain:

Floods

Although the rainfall in Spain is not abundant, sometimes there is rainfall that in a few hours reaches values ​​higher than the annual average. These extraordinary rains cause extreme flows, usually called floods, floods or floods, which, when they overflow their usual channel, cause the flooding of land, affecting people and property.

The great disproportion between the ordinary and extraordinary flows of some rivers makes the problem of flooding in Spain particularly serious. The most torrential rainfall occurs along the Mediterranean and Cantabrian coasts, the Pyrenees, and the Guadiana and Tagus watersheds, producing generally more uniform rainfall on the two plateaus. However, isolated episodes can be found throughout the entire territory. For example, in 1996 two floods stood out in severity: the river floods in western Andalusia that caused losses of 70,000 million pesetas and four fatalities in traffic accidents; and the Bisecas, a torrential type, caused more than 80 fatalities, with very little material damage.[41]​ (Watch video).

Possible impact of climate change on water resources

The climate scenarios predicted for Spain by the National Climate Council assume a decrease in average annual precipitation and an increase in temperatures, which would lead to a decrease in total runoff.

A greater impact is expected in the territories of the Southeast of the peninsula, the Guadiana basin, the Ebro valley and the archipelagos, areas that are currently characterized by their water problems. An increase of one degree Celsius and a 5% decrease in precipitation would mean a decrease in the contributions from these areas of the order of 20%.[13]​.

Climate change adaptation strategies

The National Plan for Adaptation to Climate Change presented in 2006 lists a series of concrete actions for the evaluation of the impacts of climate change on water resources. The National Plan for Adaptation to Climate Change includes "Work Programs" and has planned annual monitoring reports for each of the ongoing activities and projects, which will be compiled in a general report every four years by the Spanish Climate Change Office. The first Work Program, presented in 2006, which has as one of its objectives the carrying out of an evaluation of the impacts of climate change on water resources and irrigation demands, will be developed over the next four years.

The former Minister of the Environment, Cristina Narbona (2004-2008), in the presentation of the National Plan for Adaptation to Climate Change, expressed her interest in making the "progress and results of the plan" available to the administration, organizations and society in general through the ministry's website.[42] The first results of the Work Program, scheduled for the end of 2007, are not yet available on the Ministry's website.