Molino de Zúñiga Dam, Spain

Removing a dam located at the headwaters of the River Ega (Navarre, Spain), in a Nature Reserve and Natura 2000 site.


The Molino de Zúñiga dam is located in a natural environment of great ecological relevance, declared a Nature Reserve and Natura 2000 site by the Government of Navarre, on the Ega, in the Ebro basin. This is the most important area for the spawning of endemic fish species such as Parachondrostoma miegii and Achondrostoma arcasii, considered Key Elements for the Natura 2000 management plan and both included in the Habitat Directive. Other species linked to the aquatic environment, such as the European mink and the otter, are also found in the area. 

At a glance

Project typeDam removal: demolition
Project statusLive
Date of removalAutumn 2024
Km to be opened15 – including the demolition of the other dam (Molino de Gastiáin)
Focal speciesParachondrostoma miegii, Achondrostoma arcasii, Mustela vison, Mustela lutreola

Project context and opportunity

The project is a great opportunity to return the Ega River to its free flow in an area as important as its headwaters. In addition, last year, CIREF developed the dam demolition project with the support of the ORP, discovering that, as it is an area in a very good ecological state, the river’s recovery after removing the barrier would be very fast and natural. Furthermore, the local population has been involved in the demolition project. They are aware of the damage the dam causes to the River Ega and agree with its demolition. Finally, there is also the support of the water and local authority and the dam’s owner.

Project aims

The project’s primary objective is to demolish the Molino de Zúñiga dam following the technical project and prior programme-supported studies conducted in 2023. This demolition will enable the free movement of fish species and the release of sediments that have been trapped by the dam for years. The project will employ minimally invasive bioengineering techniques to minimize environmental impact. Waste generated by the demolition, primarily local stones, will be treated on-site to reduce the use of heavy machinery. Plant material removed to facilitate machinery access will be restored to the site by constructing plant lattices and biodiversity refuges.