The project of a hydroelectric power plant in the Côa Valley threats to submerge an area of 17 km2 comprising the Archaeological Park of Côa Valley.
In 1991, during the beginning of dam construction, prehistoric engravings dated from 22,000 to 10,000 years BC were found in this valley, which is located in Trás-os-Montes region in northeastern Portugal.
In 1992, the concession contract was assigned to Portugal’s energy company, Energias de Portugal (EDP). The Environmental Impact Assessment-EIA Evaluation Commission approved the project, although requiring the submission of additional studies on the area’s archaeological heritage, whose 11 locations were attributed to be exceptional by the EIA itself.
The EIA provoked a scandal in the Portuguese public opinion; the rejection of the plan to flood the Côa Valley to use as a reservoir for a hydroelectric power plant met with support from the international community, which intervened to ask for the preservation of these sites. When members of the International Committee on Rock Art and the International Federation of Rock Art Organizations came to visit the site in 1994, the case attracted extensive media attention.
The decision-making process consisted of two divergent positions: on the one hand, the EDP company pushed for the continuation of works, while proposing compatibility solutions (such as removing the most important engravings to a new location); on the other hand, the archaeologists and large sections of the public opinion, advocated for the preservation of the findings in situ by combining the integral defense of the engravings as key elements of the local landscape, a solution that was only possible with the abandonment of the dam construction Several civil society organizations together with the students of the High School of Vila Nova de Foz Côa organized in 1995 a "major campsite" of young people from all around the country, with public debates also in others towns.
Eventually, the Socialist Party-PS, which won the elections in October 1995, suspended the works. This victory highlighted the importance of coalitions between local and international actors in building capacity to disseminate information on a large scale, getting support from international organizations.
The Prehistoric Rock-Art Sites in the Côa Valley were designated a World Heritage Site by UNESCO in 1998 and are considered by the Rock Art Committee the world´s largest outdoor Paleolithic site.
The Côa Park Foundation was created in 2011 to jointly manage the Archaeological Park of the Côa Valley and the Museum of Art and Archaeology of the Côa Valley. Both play a critical role in the development and territorial planning, most notably the balance between visitors pressure (in 2007 had reached 170,000 visitors), construction quality, changes in land use, environmental quality and landscape preservation.