Júcar Region Socio-Ecological System (SES)

Authors:	Artemio Cerda, Félix González Peñaloza
Editors:	Alexandros Kandelapas, Vassilis Koutsoukos, Jane Brandt

Editor's note 11Feb13: Source D131-4.2

The Júcar river basin is located in the Eastern part of the Iberian Peninsula, in an area of 4,287,020 ha. The territory includes all watersheds that drain into the Mediterranean Sea between the rivers Segura and Cenia, and parts of the provinces of Albacete, Alicante, Castellón, Cuenca, Tarragona, Teruel and Valencia and their municipalities. The Júcar river basin has a semi-arid (70%) or dry sub-humid (23%) Mediterranean climate, with warm, dry-hot summers and wet-warm winters. In October and November appears a meteorological phenomenon ("cold drop"), which leaves precipitation that causes floods. The rainfall shows high spatial and temporal variability. The upper river basin has a Continental climate whereas the coastal area has high moisture (60%), and average annual precipitations (400 – 800 mm), with maximum monthly in spring and autumn. Seasonal droughts are also frequent.

Most of the Júcar basin shows rolling and gently undulating landforms and also steep slopes and rugged terrain. Karst type landscapes predominate and parent materials are mainly Limestones, Marls, Keuper clays.

The main geomorphologic categories are:

• mountain ranges: the Iberian System mountain range in the north of the Júcar River Basin and the Betic Range, extending from the South of Spain to Palos Cape along the Mediterranean.
• Continental plain: the Mancha plateau (average height 650m), in the western part of the Júcar river basin.
• coastal plain: an alluvial plain over 400 km long and 40 km broad in its widest section, delimited by the Iberian System, the continental plateau and the Betic System.

With regard to elevation, half of the Júcar River Basin ranges between 500 and 1000m and 20% of the area is over 1000m. The eastern part (coastal plain) with altitude lower than 250m covers about 13 % of the basin, interrupted by the extension of the inner relief.

With regard to aspect, the Júcar river basin aspect is mainly flat (about 30%). Northeast, East, Southeast, and South aspects follow with around 10% each.

Soils are primarily Calcic Cambisols and generally of medium texture. Soil depth data is scarce but where they exist they indicate generally shallow soils.

Hydrology, water resources and management

The river system is characterized by ephemeral rivers flowing in the rainy season and drying up in the summer. The hydrological system is completely dominated by human interventions. Gross water demand in the Júcar River Basin in 2008 was 3652 hm³/year.

The singularity of these streams is due to their hydrological regimes, which are very variable on both spatial and temporal scales. There are only three rivers which the averages flows are above 10 cubic meters per seconds (m³/s): Mijares, Turia and Júcar. Canyoles is the main river of Canyoles watershed that shows an irregular flow regime with large fluctuations between wet periods and a dry and warm condition. Surface water resources are regulated through large dams.

Urban water use is 118.64 hm³/year for 1,030,979 people and irrigated surface is 187,855 ha, consuming 1,394 hm³ / year.

A Committee of Competent Authorities (CCA), comprising of national, regional and local authorities, is in charge of water management in the Júrcar river basin. Its principal activities include but are not limited to: water resource management, administrating the hydraulic public domain, developing, monitoring and updating the hydrological plan, and constructing and operating hydraulic infrastructures.

Croplands are generally rain fed in the upper part of the basin but drip irrigation is growing, especially for vines. In the lower part of the valley, traditional flooding irrigation has almost completely replaced by drip irrigation during the last two decades.

Land use and cover

Forests and semin natural areas cover about 50% of the Júcar river basin surface, while cultivated land - mainly located in the valley of Canyoes river - 46%. Between 1986 and 2006, 17,685 hectare have converted to cultivated land and 14,350 to permanent crops, facilitated by irrigation system. Waters bodies cover about 0.5% of Júcar river basin and inland water covers only 0.25% of area. Human settlements are concentrated in the coast, in the cities of Albacete, Alicante, Castellón de la Plana, Elche and Valencia.

Climatic variability of Júcar River Basin favors highly specialized flora, high biodiversity and a large number of endemic species. The area covered by Natura 2000 sites is approximately 9,500 km², about 30 % of the total surface.

Sclerophyllous vegetation covers 17.44% of the River Basin, transitional woodlands – shrub 14.14% and coniferous forest 12.46%. Non- irrigated arable land covers 14.23%, complex cultivation patterns 13%, fruit trees and berry plantations 8.32%, Vineyards 2.89% and Olive groves 2.27%.

Vegetation is dominated by crops and maquia and garrigue shrubland mixed with Aleppo pine. Few sites are covered by remains of oak forest.

Population and infrastructure

Current population is about 4,360,000 inhabitants, expanding by at least 30% due to tourism in the coastal area of Valencia. Nevertheless, Júcar Population density ranges from over 20,000 inhabitants per square kilometers in the metropolitan area of the city of Valencia at the Mediterranean coast, to less than 2 inhabitants per square kilometers in mountain areas. About 5% of the population of the region is of foreign origin rising to 6% in rural areas. The infrastructure of the area includes the road and railway system. The number of primary and secondary schools in the river basin has increased about 20,5% in last ten years; however, the number of students has decreased in the same period about 16%. Most educational centers are located in Valencia province. The economic importance of tourism (and transport) in the river basin has risen dramatically in the last years driven by the growth of coastal areas, particularly Alicante. The river basin now has a total of 1788 tourism establishments and about 140,000 beds.