Most of it floods lands of the Berdun Canal, in the Aragonese region of Jacetania in the municipalities of Sigüés, Ruesta, Escó, and Tiermas.

It is equipped with a surface spillway located on the left bank and formed by four large mouths (which are striking for their depth as they can be seen from the upper edge), intermediate and bottom drains.

The dam is equipped with a spillway system consisting of four shafts with independent tunnels of an average length of 600.5 m ending in a common damper for all of them.

The minimum level of use is 453.35 m, while that of the riverbed is 427.90 m with the bottom outlet at 428.00 m and the intakes of the Bardenas canal at 453.35 m. The sheet of water can be accessed from the vicinity of the dam, on the left bank, through an entrance that leads to a pebble beach.

In 1702 the engineer Josef Estorguia and a group of hidalgo knights launched the proposal to divert the river so that it would run through Aragonese lands, thus avoiding the payment of tariffs and tolls to the Navarrese.

54 years later, in 1756, a project was drawn up for the construction of a canal that, rising in Tiermas, was to irrigate the Aragonese region of the Cinco Villas.

In 1923 a new project was commissioned, drafted by the engineers Félix de los Ríos, Mariano Vicente, and Antonio Colom, who carried out the study based on an irrigable area of 130 000 ha, to contribute to the Ardisa dam with 400 000 million cubic meters per year and to supply drinking water to Zaragoza.

In 1926 it was estimated that Yesa reservoir would only be used for irrigating of the Bardenas and the Cinco Villas region, and its possible contribution to the Imperial Canal of Aragón was rejected.

The uses to be given to the Yesa water were definitively designated, which were the same as those foreseen in the Félix de los Ríos project, but the irrigable surface area was reduced to 110,000 hectares.

The closure of the gates of the Yesa dam caused the abandonment of several villages, Ruesta, Tiermas, and Escó, with an affected population of more than 1500 people and flooded the valley leaving 2400 ha of arable land under water, of which 1000 were of excellent quality.

A collateral effect was the purchase by the Patrimonio Forestal del Estado of the valley of La Garcipollera, which leads to Castiello de Jaca, by means of a decree of forced repopulation[2][7] to plant laricio pine to prevent erosion and silting of the reservoir.

[1] Ten years later, in 1993, the Modified Project 03/1993 was presented, which maintains similar technical characteristics to the previous one with a heightening level of 521 m and a volume of water of 1525 hm³.

[1] The heightening would entail the disappearance of the urban center of Sigüés and the expropriation of important areas of the municipalities of Artieda and Mianos.

The works began in May 2001, although they had been affected by problems in the consolidation of the left bank, where large cracks appeared in 2004 and in 2006 there was a landslide of 3.5 million cubic meters that threatened to fall into the reservoir.

Since a plan to increase the height of the Yesa dam was made public in 1983, various actions have been carried out to oppose the project by several affected associations led by the Asociación Río Aragón and COAGRET,[8] together with environmental associations such as Ecologistas en Acción, Greenpeace, SEO/BirdLife, WWF/Adena, AEMS-Ríos con Vida, Amigos de la Tierra, and others, which make up the platform "Yesa No".

The legal actions were sentenced between 2006 and 2007 and all of them were adverse to the plaintiffs, declaring innocent and acquitting those responsible for the works and giving free rein to the heightening of the reservoir through the construction of the new dam.

Judgment number 43/2006 related to the abbreviated proceeding number 5/2005 ruled as follows: That we must absolve and acquit Patricia, Lucio, Gonzalo, Rubén, Darío, and Rafael of the crimes of prevarication, catastrophic risk, negotiations and activities prohibited to public officials, against historical and archaeological heritage, against natural resources and the environment, and falsification of public documents, of which they have been accused.

121/01 filed by the Artieda Town Council and the Río Aragón Association against the decisions of the Ministry of the Environment dismissed the appeal and gave permission to the work.

Together with the Ministry, the following organizations were defendants: the General Communities of Bardenas, Riegos del Alto Aragón and the UTE of construction companies awarded the work tender.

The ruling reads as follows: DISMISSAL of the contentious-administrative appeal filed by the Town Council of Artieda de Aragón (Zaragoza) and the Legal Association against the extension of the Yesa reservoir "RÍO ARAGÓN" represented by the Attorney Isacio Calleja García against the resolutions of the Ministry of the Environment dated 12 and 20 December 2000; without imposition of costs.

[12] On 4 January 2011 it is published in the Official State Gazette (BOE) the award of auxiliary works not included in the heightening project for an amount of 24 209 381 euros to the joint venture formed by ACS Proyectos Obras y Construcciones S. A., Ferrovial Agroman S. A., and FCC Construcción.

These works consisted of: stabilization of the right bank of the dam and improvement of the waterproofing and drainage of the right abutment support, thus increasing the safety of the area; conditioning of the land for the access road to the crest on the left bank; construction of 1580 meters of auxiliary construction of the Bardenas canal; replacement of the electrical supply connection to the dam and plant regeneration by spreading topsoil and subsequent hydroseeding.

The location of the reservoir, at the foot of the Leire Range and the fact that its right bank is bordered by the N-240 road makes hiking and cycling activities highly recommended.

The Camino de Santiago passes along its banks and nearby there are many places with relevant buildings such as the monastery of Leyre or the Castle of Xavier or the bridge of the Roncaleses of Roman origin and rebuilt in the 11th century.

Some of the villages on the banks of the Aragón river have been abandoned since the construction of the dam and the subsequent filling of the reservoir flooded the valley's farmland.

Before the filling of the reservoir, there was a famous spa that took advantage of the sulfurous water springs there and that had been used since times before the Roman Empire conquest.