This EIA was not preceded by the preparation of a Scope Definition Proposal (PDA), pursuant to Decree-Law No. 197 /2005, of November 8. However, in its planning, organization and the definition of its work methodologies, the environmental aspects considered most relevant or most sensitive for the analysis of the preliminary draft of Alvito's AH were immediately identified. Thus, a hierarchy of the descriptors analyzed in this EIA was defined, based upon a preliminary assessment of the natural and socio-economic values existing within the study area and the integrated analysis of the various Basic Studies of the Preliminary Project, as well as the elements that constitute it.