Ebro River Basin (Spain)

The Ebro River system flows on the North-East of the Iberian Peninsula through 9,309 km and the basin includes a surface of around 85,000 Km² and 347 main rivers. It passes through seven different Autonomous Communities in Spain, starting with Cantabria in the very north east and finishing in Valencia in the west, going though Castilla y León, Basque Country, Navarra, Aragón and Catalunya. It gathers most of it waters from the North Spain (mainly from the Pyrenees and pre-Pyrenees) and is probably the most important river basin in Spain in terms of water resources that provides. According to the Ministry for the Environment, Rural Affairs and Fisheries of the Spanish Government, the Ebro directly and indirectly provides drinking water for many important cities such as Bilbao, Vitoria-Gasteiz, Logroño or Zaragoza. It provides drinking water to up to 1.5 million inhabitants not located in the basin and it is also the source for most of the water for agricultural use on the region. The latter comprises 783,948 ha of irrigated land with an estimated water demand of 6,310 hectometre (hm³) per year. Other uses include 340 hydroelectric stations, three nuclear stations and other industrial uses with a demand of 470 hm³ per year.

Drinking water is estimated at 524 hm³ per year of which in fact only 319 hm³ for drinking, out of which 66 hm³ are for stockbreeding. An additional 150 hm³ are transferred for Bilbao metropolitan area and extra 55 hm³ for Tarragona's lands.

The river flows through territories characterized by the three different types of climate, Atlantic, Mediterranean and a transition area with a great range of evapotranspiration and precipitation rates. From the point of view of biodiversity, this basin includes the greatest variety of flora among the rivers in Spain, mainly thanks to the different climates that can be found in its way.

In terms of capacity the Ebro River is well supplied of water but in a quite irregular manner. During the summer it can carry up to 10 times less water than average mean water flow. The range of the annual water flow can vary from 3.811 hm³ to 26.134 hm³ and the level of the water can go up to 7- 9 meters above average in some areas during the heavy rain season. It also severely affected by the winter snows in the Pyrenees and the Cantabrian mountains. Looking back at the average flow, this has been decreasing with around 18,286.7 hm³ /year in the 1960s to 8,253.8 hm³ /year at the 1990´s, and an average of 8,832 hm3/year for the period 2000- 2008. In 2008, the scientific community suggested that a variable ecological flow beset at a level of 12,783 hm³ for years of heavy of large rain periods, 9.691 hm³ for medium regime and 7,305 hm³ for dry regimes. The proposal was accepted by the Spanish Government.

It is well known what the IPCC as well as the Spanish Climate Change Office (Government of Spain) state regarding the changes in precipitation intensity and its effect in droughts and water shortages expected as a result of climate change. These impacts can thus affect rivers such as the Ebro in quite a severe manner. In fact, during the late 1980´s and early 1990`s, together with 1940 and 1950´s, were characterized by a very low precipitation rates that generated some water shortages problems heavily affecting drinking and domestic water use as well as agricultural use. The weakness of the drinking water capitation system in the selected area, mainly dependent on this river basin, as well as the increasing attempts to use some of the resource for other areas of Spain and so deeply criticised by many experts (Arrojo 2001) -the so called "Trasvase" (water transfer) projected in the National Hydrologic Plan to carry water from Ebro basin to areas such as a Castellón , Valencia , Alicante , región de Murcia , Almería or Barcelona -, suggests that climate change adaptation strategies should undoubtedly look very carefully at this issues.

The river basin is managed by the Conferederación Hidrográfrica del Ebro (CHE) dependent of the Ministry for the Environment with joint management of the Northern area with the Basque Water Agency (URA) . This case study will look to the northern part of the basin where a great deal of information is available, attending to the water shortage problems and weakness of the sub-basins and water provision systems that are operating in the area.

Although drought in this area are not as severe as in other parts of the basin the 1989-1990 period was characterised as a dramatic episode with up to 12 hours water restrictions in the cities of Bilbao and Vitoria-Gasteiz. Since then, there is a package of policy measures coordinated and included in Ebro River Basin Drought Especial Plan (PES) prepared for it. There exist ongoing works to adapt this plans to incorporate climate change in line with the ongoing work by the Basque Climate Change Office (water authorities are members) and the preparation of the Climate Change Bill.

The area covers urban and rural sites. Among the urban area we will focus in Vitoria-Gasteiz (capital of the province of Alava) and Bilbao (capital of the province of Bizkaia) that get most of its drinking water from this basin. The rural site includes all the Agricultural land of the Province of Alava. The case study will deal jointly with both areas and separately as most of the industrial activity in Alava is scattered throughout the rural land.