On 6 June 2016, Chile instituted proceedings against Bolivia before the International Court of Justice (ICJ) with regard to a dispute concerning the status and use of the waters of the Silala River System. This step has been taken after a series of failed bilateral meetings on the matter between the years 2004 and 2010 as well as the announcement by Bolivian President Morales on 26 March 2016 that Bolivia would bring a claim against Chile before the ICJ to protect the Silala waters.
According to Chile's Application, the dispute between the Parties "concerns Bolivia's contention that the Silala River system is not a transboundary watercourse and therefore Bolivia is entitled to the use of 100% of its waters" (Application, para 3). Chile maintains that the Silala River is an international watercourse under customary international law and requests the Court to adjudge and declare that (Application, para 50):
(a) The Silala River system, together with the subterranean portions of its system, is an international watercourse, the use of which is governed by customary international law;
(b) Chile is entitled to the equitable and reasonable use of the waters of the Silala River system in accordance with customary international law;
(c) Under the standard of equitable and reasonable utilization, Chile is entitled to its current use of the waters of the Silala River;
(d) Bolivia has an obligation to take all appropriate measures to prevent and control pollution and other forms of harm to Chile resulting from its activities in the vicinity of the Silala River;
(e) Bolivia has an obligation to cooperate and to provide Chile with timely notification of planned measures which may have an adverse effect on shared water resources, to exchange data and information and to conduct where appropriate an environmental impact assessment, in order to enable Chile to evaluate the possible effects of such planned measures, obligations that Bolivia has breached.
As to the obligation to cooperate mentioned under (e), Chile states that "[u]nder customary international law, Bolivia is under an obligation to cooperate and prevent transboundary harm to the utilization of the waters of the Silala River system in Chile" (Application, para 48).
Although neither Chile nor Bolivia are parties to the Convention on the Law of the Non-Navigational Uses of International Watercourses (which entered into force on 17 August 2014), Chile relies on the principles of customary international law on the non-navigational uses of international watercourses as "evidenced" by this Convention (Application, para 42).
In considering the claim under (e), the Court would therefore have to pronounce - if it holds that the Silala River is an international watercourse - on the legal status, content, and scope of Article 8 of the Convention, which stipulates:
General obligation to cooperate
1. Watercourse States shall cooperate on the basis of sovereign equality, territorial integrity, mutual benefit and good faith in order to attain optimal utilization and adequate protection of an international watercourse.
2. In determining the manner of such cooperation, watercourse States may consider the establishment of joint mechanisms or commissions, as deemed necessary by them, to facilitate cooperation on relevant measures and procedures in the light of experience gained through cooperation in existing joint mechanisms and commissions in various regions.
In addition, in relation to the obligation to notify planned measures with possible adverse effects (Article 12), the Court would have to consider Article 14 of the Convention, which provides that during the period of reply (Article 13) to such notification, the notifying State:
(a) Shall cooperate with the notified States by providing them, on request, with additional data and information that is available and necessary for an accurate evaluation; and
(b) Shall not implement or permit the implementation of the planned measures without the consent of the notified States.
Pursuant to item (e) of the Chilean request (Application, para 50), the Court would not only have to determine whether and how these obligations to cooperate apply, but also whether they have been breached.
Finally, it should be noted that Chile also reserves its right to request the Court to indicate provisional measures, "should Bolivia engage in any conduct that may have an adverse effect on Chile's current utilization of the waters of the Silala River" (Application, para 52). Given claim (e), in such a scenario the Court might have to consider whether it would indicate provisional measures of protection involving an obligation to cooperate. While this would be a first for the ICJ, it has in recent years become a recurring feature of cases brought before the ITLOS and UNCLOS Annex VII Tribunals (see previous posts here and here).