The Guadiana was one of the main routes of navigation of the south of the Peninsula, and for that reason, since the Neolithic was privileged place for the fixation of populations.
More recently, between 1858 and 1965, it allowed the ore to flow from the mines of São Domingos With the end of the mining operation, and ceasing regular commercial navigation, the navigability of the river has lost importance and the maintenance of the canal has ceased to exist, thus over time sedimentation and alteration of the funds have taken place.
However, since the end of the 1980s, this river, navigable to Mértola, has become a tourist attraction, with a growing increase in traffic of tourist and recreational vessels and, consequently, maritime- tourist in the area. However, since the conditions deemed necessary for safe navigation were not met at the time, the desalination of the navigable channel would have to be demarcated, appropriately marked and the corresponding nautical cartography produced. Thus, the Portuguese and Spanish authorities prepared projects to make a river of great importance for Portugal and Spain again navigable.
In these terms, the reestablishment of navigability conditions in the Guadiana, from its mouth to Mértola, was divided into three phases, corresponding to three sections:
- Phase 1: International section between Vila Real de Santo António and Alcoutim, implemented through the "Guadiana - an inland waterway" project, co-financed by the ERDF, under the Spain-Portugal Cross-Border Cooperation Program 2007-2013 (POCTEP 2007-2013 ), and that allowed to establish a safe channel with the following navigation conditions: navigable channel with a minimum width of 30 m, and service quota of -2.00 m ZH, project boat of 70 m in length, mouth of 10 m and draft of 1.80 m, minimum radius for curves of 210 m and visibility of beacon lights 2 miles away.
- Phase 2: International section between Alcoutim and Pomarão, is currently underway, through the project "Guadiana: Patrimony Natural Navigable", approved under the INTERREG VA Spain-Portugal 2014-2020 Program (POCTEP 2014-2020) . This project aims to rehabilitate the navigability of the river in the international section between Alcoutim and Pomarão, under the above mentioned navigation conditions, as well as to rehabilitate existing port infrastructures in both banks.
- Phase 3: The exclusively national stretch between Pomarão and Mértola, which has not yet secured financing, and has technical and environmental constraints, such as the sinuosity of the canal, the bottom is partially rocky and part of the section is inserted in the protected area of the Guadiana Valley Natural Park. Preliminary top-hydrographic surveys have already been carried out and a detailed hydrographic survey is planned to be carried out during the year 2018 to define the navigation conditions to be implemented in this section, with a project vessel of 25 m length, mouth of 6m and draft of 1.0 m.