In parallel with the implementation of this project, Mercosur, Mercosur, has put the Guarani Aquifer on the agenda. In 2004, a high-level ad hoc group was established to develop an agreement on the common management of aquifers between the parties.15 The MERCOSUR Parliament also proposed: (i) the creation of a commission to study, analyse and compare legislation on each country`s water resources; (ii) an agreement on the joint management of the GAZ and a transitional project ensuring the continuity of the gas project structure; and (iii) the creation of a regional research and development institute for Guarani Aquif and other state-divided aquifers17. The agreement on guarani Aquifer (Portuguese, Spanish, unofficially) ratified by Argentina, Brazil, Paraguay and Uruguay will enter into force on 26 November 2020. After a long waiting process, countries have finally and officially decided that they can resume their efforts to continue cooperation. Guarani`s Aquifer was at the centre of a long cooperative process that began in the 1990s within the Epistemian community. This priority was transferred between 2000 and 2009 to the four Guarani countries and international organizations that reached their peak in August 2010 with the signing of the agreement in San Juan, Argentina. The entry into force of the agreement will allow the Guarani Countries to deepen the cooperation process which involves: (a) the creation of a commission for the guarani aquifer (Article 15); (b) determining the arbitration procedure for dispute resolution by issuing an additional protocol (Article 19); (c) the implementation of groundwater cooperation programmes (Article 12) and (article 12) the identification of critical areas, particularly in border areas where the river is cross-border. The most urgent of these measures is undoubtedly the establishment of a Commission to coordinate cooperation in accordance with the principles and objectives of the agreement. In the absence of a commission with a status to define its structure and powers, the agreement will have limited effectiveness in the regional context. Unfortunately, none of MERCOSUR`s proposals have been implemented. Many factors contributed to this: the institutional fragility of the Mercosur Parliament; Ongoing tensions within the bloc over trade relations; Differences of opinion on the admission of new members; and the failure of regional commercial architecture to address conflicts over the construction of pulp mills on the Uruguay River.