PULP MILLS (JUDGMENT) 19 Convention on the Law of Treaties — Distinction between taking account of other international rules in the interpretation of the 1975 Statute and the scope of the jurisdiction of the Court under Article 60 of the latter. * Alleged breach of procedural obligations. Question of links between the procedural obligations and the substantive obligations — Object and purpose of the 1975 Statute — Optimum and rational utilization of the River Uruguay — Sustainable development — Co-operation between the parties in jointly managing the risks of damage to the environment — Existence of a functional link, in regard to prevention, between the procedural obligations and the substantive obligations — Responsibility in the event of breaches of either category. Interrelation of the various procedural obligations laid down by Articles 7 to 12 of the 1975 Statute — Original Spanish text of Article 7 — Obligation to inform, notify and negotiate as an appropriate means of achieving the objective of optimum and rational utilization of the river as a shared resource — Legal personality of CARU — Central role of CARU in the joint management of the river and obligation of the parties to co-operate. Obligation to inform CARU (Article 7, first paragraph, of the 1975 Statute) — Works subject to this obligation — Link between the obligation to inform CARU, co-operation between the parties and the obligation of prevention — Determination by CARU on a preliminary basis of whether there is a risk of significant damage to the other party — Content of the information to be transmitted to CARU — Obligation to inform CARU before issuing of the initial environmental authorization — Provision of information to CARU by private operators cannot substitute for the obligation to inform laid down by the 1975 Statute — Breach by Uruguay of the obligation to inform CARU. Obligation to notify the plans to the other party (Article 7, second and third paragraphs, of the 1975 Statute) — Need for a full environmental impact assessment (EIA) — Notification of the EIA to the other party, through CARU, before any decision on the environmental viability of the plan — Breach by Uruguay of the obligation to notify the plans to Argentina. Question of whether the Parties agreed to derogate from the procedural obligations — “Understanding” of 2 March 2004 — Content and scope — Since Uruguay did not comply with it, the “understanding” cannot be regarded as having had the effect of exempting Uruguay from compliance with the procedural obligations — Agreement setting up the High-Level Technical Group (GTAN) — Referral to the Court on the basis of Article 12 or Article 60 of the 1975 Statute : no practical distinction — The agreement to set up the GTAN had the aim of enabling the negotiations provided for in Article 12 of the 1975 Statute to take place, but did not derogate from other procedural obligations — In accepting the creation of the GTAN, Argentina did not give up the procedural rights belonging to it by virtue of the Statute, nor the possibility of invoking Uruguay’s responsibility ; nor did Argentina consent to suspending the operation of the procedural provisions of the Statute (Article 57 of the Vienna Convention on the Law of Treaties) — Obligation to negotiate in good faith — “No construction obligation” during the negotiation period — Preliminary work approved by Uruguay — Breach by Uruguay of the obligation to negotiate laid down by Article 12 of the 1975 Statute. 9