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Boquerón Reservoir

Territorial framework.

Physical features of the basin.

The Boquerón riverbed begins after the confluence of ravines and streams draining the Peña Losa, Umbría del Rincón and Peñarrubia mountains. Its basin, up to the dam's closing point, has a surface of 47 km². On the eastern side, it borders with the Romeral and Montesinos mountains separating it from the headwaters of the Pepino watercourse; to the south and the west, the Quebrados mountains mark the boundary with the Mundo river basin; and the Peña Losa and Umbría del Rincón mountains to the north separate it from the endorheic area of the Heruela riverbed.

The basin presents a mountain morphology, where elevation varies from heights of more than 1,000 m in the Peña Losa and Umbría del Rincón mountains (the highest point is at 1,038) up to a height of 558 m at the site of the dam.

The longest watercourse is 12.4 km long with a slope if 1.8%, starting at 780 m and ending, at the dam enclosure, at 558 m.

To the total contributions to the Boquerón basin, we must add the diverted waters of the Mullidar and Rincón del Moro basins through the Mullidar-Boquerón diversion channel, as the flood flows of these riverbeds drain into the Boquerón reservoir through that same diversion channel.

The basin including diverted waters has a surface of 200 km², although there are semi-endorheic areas which are deducted for the hydrologic study, which leaves an effective basin of 121 km².

Perspective of the reservoir basin. The tail end is located at the foot of the mountains which can be seen in the background (Peñarrubia mountain).
Perspective of the reservoir basin. The tail end is located at the foot of the mountains which can be seen in the background (Peñarrubia mountain).

The diversion channel, which has a rockfill cladding, has a length of 9.6 km and can bring in a maximum flow of 190 m³/s.

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Environmental information.

The Boquerón reservoir has a temperate Mediterranean climate. Its climate favors physical erosion processes of certain intensity (torrential rains, frost, etc), thus, creating certain typical morphological features.

The water network of the area does not have important hydrographic arteries but is limited instead to just seasonal watercourses, ravines and streams.

The natural vegetation belongs to the sclerophyllus formations of leathery, evergreen leaves, a defense against the arid environmental conditions of the area.


Potential vegetation would be made up of holm oaks (Quercus rotundifolia), with a shrub border of groves. The current vegetation is grouped in three natural units: fields, thickets and trees.

The fields are grassy areas made up of leguminous and grassy plants, associates with different shrubs: thyme, rosemary, etc. They frequently grow on old esparto fields, currently abandoned, creating the esparto-fields unit.

Thyme, gorse and rosemary thickets occupy a large area of the basin, especially on sharp slopes which are not suitable for agricultural exploitation. Cattle feeds there.

Holm oak and pine forests appear at the highest basin elevations, generally surrounded by thicket and representing the basis for development of the animal community.

On cultivated land, it is possible to find groups of larks, passerines and finches, as well as many corvids.

The plant units support an important bird wildlife, as well as many mammals common in Spain: rabbits, hare, etc.; nevertheless, the predominance of cultivated land over natural vegetation translates into the wildlife characteristics of that unit.

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Geology and seismology.


The area occupied by the reservoir of the Boquerón dam is in the south of the province of Albacete, near the provincial boundary with Murcia. From a geological point of view, it is a transitional area between the two most representative structural units of the Iberian Peninsula: the Iberian System (in the north) and the Pre-Baetic zone of the Baetic System (in the south).

The tectonics of the zone is complex due to the transitional nature that defines it, and it is characterized by sudden changes of direction in the different formations. In the area surrounding the reservoir, predominant structures are in the NW-SE direction, such as the Peña Losa, Umbría del Rincón and Los Quebrados mountains.

Auscultation. Weather station located next to the dam access.
Auscultation. Weather station located next to the dam access.

The lithology of the reservoir area soils is described below:

  • Jurassic
    Jurassic soils are the predominant materials in the reservoir and in most of the catchment basin. The lithological types observed are dolomites, marls and limestone. It is fundamentally a monotonous series of secondary rombohedric dolomites(late dolomitization or much later than deposition) representing the main topography and showing limestone and oolitic limestone disappearing on the sides through dolomitization.
  • Cretaceous
    The Cretaceous is scarcely represented; it is possible to find it far from the dam site. The outcrops from this period are a conglomerate base segment and a segment above of multicolor sands and clays.
  • Tertiary
    Tertiary materials are identified in three formations in the reservoir area: polygenic conglomerates, biocalcarenites and white marls.
  • Quaternary
    Different kinds of Quaternary materials have developed on top of the aforementioned series, among which we should point out alluvial, alluvial fans and colluvial materials. The main feature of all these deposits is to be frequently encrusted in more or less continuous carbonated crusts of different thickness.

The Boquerón reservoir enclosure is made up of Jurassic brecciated karstified dolomites. Nearby, there are two arched overriding edges downstream and two upstream. These are indistinguishable on the surface, except when the Jurassic dolomites cover stratigraphically late geological materials, as established by morphological criteria.


The Boquerón reservoir is located, according to the Seismic Resistance Construction Regulation (NCSE-02), within an area with a basic seismic acceleration of 0.07 g, in the municipality of Hellín, which is the town nearest to the dam.

Among the equipment installed in the dam, there is a seismograph to detect any seismic activity that could occur in the area. No relevant event has been recorded since its installation.

Auscultation. Detail of a three-dimensional joint regulator.
Auscultation. Detail of a three-dimensional joint regulator.

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