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The UN Convention on the Law of the Non-Navigational Uses of International Watercourses - A Commentary edited by Boisson de Chazournes, Laurence; Mbengue, Makane Moïse; Tignino, Mara; Sangbana, Komlan; Rudall, Jason (20th December 2018)

Introduction: The Path to the UN Watercourses Convention and Beyond

Stephen C. McCaffrey

From: The UN Convention on the Law of the Non-Navigational Uses of International Watercourses: A Commentary

Edited By: Laurence Boisson de Chazournes, Makane Moïse Mbengue, Mara Tignino, Komlan Sangbana, Jason Rudall

From: Oxford Public International Law (http://opil.ouplaw.com). (c) Oxford University Press, 2015. All Rights Reserved.date: 26 May 2019

Freshwater — Canals — Lakes — Rivers — Boundaries

(p. 1) Introduction: The Path to the UN Watercourses Convention and Beyond


The UN Watercourses Convention was the culmination of efforts of international organizations, both non-governmental and inter-governmental, over the span of nearly a century to capture in written form the norms governing the relations among States sharing freshwater resources. These efforts, in turn, built on State practice and the writings of scholars in the field.

This chapter will not attempt to retrace all of the various developments that led to the conclusion of the UN Watercourses Convention but will provide a broad-brush treatment of the principal factors that influenced and shaped the agreement. After reviewing the work of two non-governmental organizations that helped lay the groundwork for the Convention (section 1), the chapter will review the work of the International Law Commission (ILC) that provided the basis for the Convention’s negotiation (sections 2–4), discuss the negotiation and conclusion of the Convention (section 5), consider the Convention’s entry into force (section 6), its implementation (section 7) and its reception (section 8), and assess the ILC’s work on transboundary groundwater as an extension of its study of international watercourses (section 9).

1.  Precursors

The work of the ILC that led to the negotiation of the UN Watercourses Convention built upon studies prepared by two international non-governmental organizations, the Institute of International Law (IIL) and the International Law Association (ILA). That work will be reviewed briefly in this section as a foundation for the later work of the ILC on international watercourses.

a.  The Institute of International Law

The IIL, also known by its original name in French, the Institut de Droit International, adopted three resolutions between 1911 and 1979 concerning shared freshwater resources: the 1911 Madrid Resolution on International Regulations regarding the Use of International Watercourses,1 the 1961 Salzburg Resolution on the Use of International (p. 2) Non-Maritime Waters,2 and the 1979 Athens Resolution on the Pollution of Rivers and Lakes and International Law.3

The Madrid Resolution is remarkable for the principles it recognized in the early years of the twentieth century, when the law of the non-navigational uses of international watercourses was still in its formative stages. The ‘Statement of Reasons’ accompanying the resolution notes that international law had dealt mostly with navigation and it therefore seemed ‘expedient to remedy this lack by noting the rules of law resulting from the interdependence which undoubtedly exists between riparian States with a common stream and between States whose territories are crossed by a common stream’.4 The resolution deals separately with contiguous watercourses and boundary lakes, on the one hand, and successive watercourses, on the other. It provides that neither State on a contiguous watercourse may, without the other’s consent, allow changes to be made to the watercourse that are detrimental to the opposite bank. It further states that neither State may utilize the water in such a way as to interfere seriously with the other State’s utilization thereof. Its treatment of successive watercourses is broken down into seven subparagraphs. The most interesting provisions for present purposes are the following: a prohibition of alterations injurious to the water, as by discharges from factories; a prohibition of withdrawing so much water that the ‘utilizable character’ of the stream, when it reaches the downstream State, is seriously modified; a prohibition of violating the right of navigation recognized in international law; a prohibition of flooding an upstream State by erecting works downstream; and a recommendation that permanent joint commissions be appointed to assist in avoiding and settling disputes. This resolution of the IIL was a half-century ahead of its time. It blazed a trail that the Institute as well as other organizations were to follow, but only in the latter half of the twentieth century.

The Salzburg Resolution, adopted by the Institute in 1961, took a more holistic approach than its predecessor, addressing ‘the utilization of waters which form part of a watercourse or hydrographic basin which extends over the territory of two or more States’.5 The resolution declares that a State’s right to make use of shared waters ‘is limited by the right of use by the other States concerned with the same river or watershed’.6 The resolution then provides that any dispute as to the extent of the respective States’ rights ‘shall be settled on the basis of equity, taking into consideration the respective needs of the States, as well as any other circumstances relevant to any particular case’.7 This provision is consistent with the line of US Supreme Court decisions in water disputes between American states, in which the Court articulated and applied the principle of equitable allocation.8 It makes the Salzburg Resolution the first international instrument that clearly (p. 3) identifies equity as the lodestar for accommodating the interests of riparian States. Today, of course, the principle of equitable utilization applies generally to the manner in which States use shared waters, not only to the resolution of disputes. The resolution goes on to provide for advance notice of new uses and negotiations in the event of objections to such uses, obligations that are also reflected in the UN Watercourses Convention.9

Almost two decades later, the Institute took up the subject of pollution of international watercourses. Its 1979 Athens Resolution recognizes the ‘common interest’ of States sharing international rivers and lakes ‘in a rational and equitable utilization of such resources through the achievement of a reasonable balance between the various interests …’.10 The resolution provides that States must ‘ensure’ that activities within their borders ‘cause no pollution in the waters of international rivers and lakes beyond their boundaries’.11 This appears on its face to be a surprisingly strict, and almost unrealistic obligation, even by today’s standards. It is, however, moderated in a subsequent article, which provides that the obligation of prevention may be fulfilled by preventing both new forms of pollution and increases in existing levels of pollution, and by abating existing pollution as soon as practicable.12 The Athens Resolution also contains detailed provisions concerning forms of cooperation between States sharing the same basin, such as exchange of data concerning pollution, prior notification of potential polluting activities, consultation concerning pollution problems, and the establishment of international commissions competent to deal with basin-wide pollution problems.13

This brief overview of the Institute’s work in the field of international watercourses demonstrates the organization’s leadership in developing a regulatory regime on the subject. By 1961 the Institute’s normative standards applied to the entire hydrographic basin, and included recognition that equity was part of the legal regime. It is also in this year that procedural rules begin to appear, in the form of requirements of prior notification of new uses and negotiation of related disputes. The Institute’s final resolution, of 1979, also takes a ‘basin’ approach and refers specifically to the common interest of riparian States—a proxy for the concept of community of interest—in equitable utilization of shared water resources. The resolution also lays down a detailed set of procedures for the implementation of the duty to cooperate, something also found in the UN Convention.

b.  The International Law Association

Like the IIL, the ILA adopts resolutions setting forth rules and recommendations concerning international law. The ILA began its study of international water resources law in 1954 and adopted a number of resolutions on the subject beginning in that year that foreshadowed the comprehensive codification it finalized in 1966.14 In that year at its meeting in Helsinki the ILA adopted its best-known work in the field, the set of articles entitled the Helsinki Rules on the Uses of the Waters of International Rivers.15 The ILA’s (p. 4) Committee on International Water Resources Law, which produced the Helsinki Rules, concluded its activities with its final report to the ILA in 1986.

The Helsinki Rules represent a pioneering effort at codification of the law of international watercourses. They address specific uses (pollution, navigation, and timber floating) but their guiding principle is equitable utilization.

The Helsinki Rules apply to the use of waters of an ‘international drainage basin’, which is defined as ‘a geographical area extending over two or more States determined by the watershed limits of the system of waters, including surface and underground waters, flowing into a common terminus’.16 This definition is noteworthy not only for its broad approach, which is consistent with hydrological reality, but also for its specific mention of ‘underground waters’. This increasingly important source of fresh water had largely escaped international legal regulation up to this point, probably in large part because governments did not fully appreciate its significance or its characteristics, including its relationship to surface water systems.

Along with the international drainage basin approach, the Helsinki Rules are known for having championed equitable utilization as the dominant principle of international watercourse law.17 Article IV of the Helsinki Rules provides simply as follows: ‘Each basin State is entitled, within its territory, to a reasonable and equitable share in the beneficial uses of the waters of an international drainage basin.’ The following article contains a non-exhaustive list of factors to be taken into account in determining what amounts to a ‘reasonable and equitable share’ in a specific case. The causing of harm to another State is not prohibited, but is dealt with as a factor to be taken into account in determining whether a use is equitable.18 The commentary to the Helsinki Rules makes clear that an existing use may have to give way to a new use in order to achieve an equitable apportionment of shared water resources; compensation would, however, have to be paid for the impairment or discontinuance of the existing use.19 As to whether navigation enjoys priority over other uses, Article VI provides that no use or category of uses is entitled to ‘any inherent preference over any other use or category of uses’.

In addition to Equitable Utilization (Chapter 2), the Helsinki Rules also contain chapters on Pollution (Chapter 3), Navigation (Chapter 4), Timber Floating (Chapter 5), and Procedures for the Prevention and Settlement of Disputes (Chapter 6). Chapter 3 on pollution does not ban pollution outright. It instead takes a nuanced approach, requiring the prevention of new pollution or increases in existing pollution, on the one hand, and the taking of ‘all reasonable measures to abate existing water pollution … to such an extent that no substantial damage is caused’ to other States.20 Even if a State fails to take reasonable measures to abate existing water pollution, it is not regarded as being per se in breach of its obligations, but is required to ‘enter into negotiations with the injured state with a view toward reaching a settlement equitable under the circumstances’.21 Chapter 6 on the prevention and settlement of disputes includes procedures for prior notification of proposed projects and resolution of disputes by, inter alia, any joint agency that exists or may be established.22

(p. 5) The Helsinki Rules have had a major impact upon the development of the law of international watercourses and reflect many principles and trends that later found expression in the UN Convention. They take a holistic, basin approach, they deny any inherent priority to navigation, they are based on the doctrine of equitable utilization, and they provide for the use of procedures to prevent disputes as well as to resolve them. It was in fact Judge E.J. Manner, the Finnish Chair of the ILA Committee that prepared the Rules who, in his capacity as a government delegate, proposed in the UN General Assembly that the ILC take up the study of the law of the non-navigational uses of international watercourses, and that it consider using the Helsinki Rules as a model for its work.23 While political considerations prevented the latter part of the proposal from being included in the General Assembly’s referral of the topic to the ILC,24 it is clear that the Helsinki Rules are, in a very real sense, important stepping stones on the pathway to the UN Convention.

2.  Referral of the Watercourses Topic to the International Law Commission

As will be seen presently, in 1970 the UN General Assembly referred the international watercourses topic to the ILC for study. But this was not the first action the Assembly took on the subject. On 21 November 1959, well before the Helsinki Rules were finalized by the ILA, the General Assembly adopted a resolution in which it requested the Secretary-General to prepare and circulate to Member States a report on legal problems relating to the utilization and use of international rivers, ‘with a view to determining whether the subject is appropriate for codification’.25 This indicates that there was a sense among Member States that there might be a need for codification of the law in this field, perhaps because there were several prominent examples of treaty-making26 and disputes27 concerning international watercourses occurring around that time.

The General Assembly’s resolution appears to have been the ultimate result of a proposal made in its Sixth (Legal) Committee by the representative of Bolivia in the same year. That delegate

pointed out that half the world’s arable land remained unworked for lack of water, and that, with the population increasing daily, the problem demanded urgent solution; the utilization of inland waters was not governed by any international statute and the law applied was purely customary, (p. 6) ill-defined and lacking in uniformity; there was accordingly a pressing need to undertake a study of the question of the codification of current laws on the utilization and exploitation of international waterways.28

The Report of the Secretary-General29 was issued in 1963.30 It was updated in a Supplementary Report issued in 1974.31

On 8 December 1970, the General Assembly recommended in Resolution 2669 (XXV), entitled ‘Progressive development and codification of the rules of international law relating to international water courses’, that the ILC take up the study of the law of the non-navigational uses of international watercourses with a view to its progressive development and codification. The story of the provenance of this resolution sheds light on the process of progressive development and codification of international watercourse law.32

In April 1970, the government of Finland requested that an item entitled ‘Progressive development and codification of the rules of international law relating to international watercourses’ be included in the agenda of the twenty-fifth (1970) session of the General Assembly.33 The Assembly included the item in its agenda and referred it to the Sixth (Legal) Committee for consideration and report. As noted earlier, in the Sixth Committee, E.J. Manner—a member of the delegation of Finland who had been the Chair of the ILA committee that prepared the Helsinki Rules—proposed that the ILC be entrusted with the codification of the law of international watercourses, and that the Helsinki Rules be ‘treated as the basis of all codification work’ on the subject.34

The views of delegations in the Sixth Committee differed as to whether a specific draft—be it the 1966 Helsinki Rules or the 1961 Salzburg Resolution of the IIL—should be mentioned in the draft resolution to be sent to the General Assembly. The result was that the Sixth Committee’s report to the General Assembly simply referred generally to the work of ‘intergovernmental and non-governmental studies on the subject, especially those which are of a recent date’, and stated that these ‘should be taken into account by the International Law Commission in its consideration of the topic’.35 The General Assembly’s resolution itself did not give any directive or make any recommendation to the ILC in this regard but, as will be seen below, simply acknowledged in its preamble in general terms that work had been done in the field by various international organizations.36 Yet it seems undeniable that along with the disputes and negotiations occurring at the time, the adoption of the Helsinki Rules in 1966 had a significant influence on the General Assembly’s decision to refer the international watercourses topic to the ILC.

(p. 7) 3.  The General Assembly Resolution

Regardless of the relationship between the Helsinki Rules and the General Assembly’s 1970 decision to refer the watercourses topic to the ILC, it is worth pausing to take note of the preamble to that resolution, which provides a general indication of what animated the Assembly’s decision. The preamble reads in part:

  • Considering that water, owing to the growth of population and the increasing and multiplying needs and demands of mankind, is of growing concern to humanity, that the available fresh water sources of the world are limited and that the preservation and protection of those resources are of great importance to all nations,

  • Conscious of the importance of legal problems relating to the use of international watercourses, inter alia with regard to international water resources development,

  • Recalling that despite the great number of bilateral treaties and other regional regulations, as well as the Convention on the Regime of Navigable Waterways of International Concern, signed at Barcelona on 20 April 1921, and the Convention relating to the Development of Hydraulic Power affecting more than one State, signed at Geneva on 9 December 1923, the use of international rivers and lakes is still based in part on general principles and rules of customary law,

  • Noting that measures have been taken and valuable work carried out by several international organs, both governmental and non-governmental, in order to further the development and codification of the law of international watercourses,

  • Convinced of the necessity to promote … the work on the progressive development and codification of the law of international watercourses and to concentrate this work within the framework of the United Nations …37

The resolution then goes on to ‘[recommend] that the International Law Commission … as a first step, take up the study of the law of the non-navigational uses of international watercourses with a view to its progressive development and codification …’.38

The preamble is remarkable for the understanding it reflects, as early as 1970, of the world’s growing freshwater problems. It also notes the ways in which the law in the field developed, through bilateral, regional and multilateral treaties, customary law, and the work of international organizations. All of this leads up to the Assembly’s statement of its conviction that it is necessary to promote the work on the progressive development and codification of the law of international watercourses and ‘to concentrate this work within the framework of the United Nations’, presumably to ensure its universality and enhance its authoritativeness. It may also be presumed that the considerations that motivated the General Assembly to refer the international watercourses topic to the ILC were some of the same ones that inspired all of the codifiers from the Sumerians and Hammurabi to Napoleon and Jeremy Bentham: the removal of uncertainties, the establishment of uniformity and greater precision, and the filling of gaps. These qualities tend to clarify the legal rights and obligations of States, thus facilitating negotiations and stabilizing international relations generally.

4.  The Work of the International Law Commission

While the watercourses topic was referred to the ILC in 1970, it took several years for the Commission to begin work on it. One reason for the delay was that the ILC concluded (p. 8) at its 1972 session that ‘the problem of pollution of international waterways was of both substantial urgency and complexity’.39 It accordingly requested the Secretariat to continue compiling material relating to the topic with specific reference to pollution.40 As noted above, the secretariat issued a Supplementary Report in 1974.41 In that year, the Commission appointed Richard D. Kearney as Special Rapporteur for international watercourses and established a Sub-Committee to report to it on the topic. The Sub-Committee submitted its report at the same session of the ILC.42 The report contained a series of questions on which the Commission invited comments of governments. The questions were sent to Member States by the Secretary-General in January 1975, with a request that replies be submitted by July of that year. Accordingly, the ILC did not consider the watercourses topic in 1975.

In 1976 the Special Rapporteur submitted his first report.43 A perusal of the document makes clear that the Commission was still attempting to determine what the topic was about and what its scope should be. Instruments from the 1815 Final Act of the Congress of Vienna to the 1966 Helsinki Rules are mentioned by the Special Rapporteur in summarizing the debate in the ILC. The Special Rapporteur noted that ‘[t]he replies of Member States to the Commission’s questionnaire are scanty’.44 Unfortunately, this is consistent with a general pattern with regard to the response of governments to ILC questionnaires. Also consistent, however, is the fact that ‘many delegations commented on the subject in the course of the Sixth Committee debate on the [ILC’s] report [on the work of its 1975 session]’,45 which is another way, although a less structured one, of obtaining States’ views about a topic. In the end, the Special Rapporteur concluded by recommending that ‘the Commission adopt the principle that its task is to formulate legal principles and rules concerning the non-navigational uses of international drainage basins’.46 This was to be Mr. Kearney’s only report as he was succeeded at the Commission’s next session by Stephen M. Schwebel.

Stephen Schwebel’s tenure as Special Rapporteur was marked by significant progress on the topic. In his first report,47 Schwebel focused on attempting to demonstrate the necessity of aligning the applicable rules of law with the physical laws governing water’s behaviour, in particular through the hydrologic cycle. Schwebel’s second report,48 submitted in 1980, adopted a ‘systems’ approach to the elaboration of provisions on the topic and proposed several Draft Articles. The Commission provisionally adopted Draft Articles 1 to 5 and Article X, dealing respectively with the scope of the articles, ‘system states’, ‘system agreements’, parties to the negotiation and conclusion of system agreements, use of waters which constitute a shared natural resource, and the relationship between the articles and other treaties in force. The Commission also decided to indicate provisionally what was meant by the expressions ‘watercourse system’ and ‘international (p. 9) watercourse system’ by adopting a working hypothesis that was subject to refinement and change. The core of that hypothesis, which was set forth in a ‘Note’, reads as follows:

A watercourse system is formed of hydrographic components such as rivers, lakes, canals, glaciers and groundwater constituting by virtue of their physical relationship a unitary whole; thus, any use affecting waters in one part of the system may affect waters in another part.

An ‘international watercourse system’ is a watercourse system, components of which are situated in two or more States.49

This hypothesis is quite similar to the definitions of ‘watercourse’ and ‘international watercourse’ found in the UN Watercourses Convention. Its adoption, though tentative, was thus something of a conceptual breakthrough, even though it was not called a ‘definition’ and was not contained in a draft article. It signalled that the Commission’s work did not concern merely ‘a pipe carrying water’50 but extended to the entire watercourse system.

The Commission did not consider the international watercourses topic at its 1981 session due to the time required to complete work on other topics.51 Stephen Schwebel was elected to the International Court of Justice later that year but had already begun the preparation of a third report, which was circulated during the Commission’s 1982 session.52 At that session Mr. Jens Evensen was appointed the third Special Rapporteur for international watercourses. Because of its influence on the Commission’s subsequent work on the topic, a few words should be said about Schwebel’s third report, notwithstanding that he was no longer a member of the ILC when it was circulated.

The report is massive, in terms of both scope and length (126 pp.). In it, Schwebel proposes six additional Draft Articles: Article 6, Equitable participation; Article 7, Determination of equitable use; Article 8, Responsibility for appreciable harm; Article 9, Collection, processing and dissemination of information and data; Article 10, Environmental pollution and protection; and Article 11, Prevention and mitigation of hazards.53 These proposed Draft Articles form the core of the topic, especially in light of the fact that a procedural system of prior notification of planned activities, one of the most fundamental principles of international watercourse law, is contained within Article 8 on appreciable harm.54 Schwebel went on to give ‘introductory consideration [to] certain other questions’:55 river regulation, hydraulic installations and water security, interaction with navigational uses, administrative arrangements for international watercourse systems, and avoidance and settlement of disputes. Thus, the third report contains a blueprint for the entire topic, providing ideas, formulations, and thorough supporting commentary, on the major components of what became the UN Watercourses Convention.

These ideas provided the basis for an outline of a complete draft convention presented in the first report of Jens Evensen in 1983 as a basis for discussion.56 The draft convention (p. 10) consisted of thirty-nine articles arranged in six chapters, with supporting commentary. It was revised in Evensen’s second report, submitted in 1984.57 These versions of a draft convention refined the provisions contained in Schwebel’s third report but in essence maintained the same approach as that advanced by Schwebel. Jens Evensen was himself elected to the International Court of Justice in November 1984. In 1985 the Commission appointed the present author as his successor.58

Over the course of the ensuing six years, the Commission was able to adopt a complete set of Draft Articles on international watercourses on first reading.59 This was made possible in no small part by more than a decade of work on the topic by 1985. Among the articles provisionally adopted on first reading in 1991 was the crucial Article 2, Use of Terms. The definitions of the terms ‘watercourse’ and ‘international watercourse’ set forth in Article 2 were carried over, in substance, into the Draft Articles finally adopted by the Commission in 1994, and thence into the 1997 UN Convention.60 They make clear that the physical scope of the topic, and thus of the regulatory framework for international watercourses, is broad and recognizes hydrological reality.

In 1992 the Commission appointed Mr. Robert Rosenstock the fifth, and what turned out to be the final, Special Rapporteur for international watercourses.61 Rosenstock shepherded the Draft Articles through the second reading process, the Commission adopting the Draft Articles on second reading in 1994.62 Few changes were made on second reading to the Draft Articles adopted in 1991.63 This may have been due in part to the fact that, as is unfortunately often the case, relatively few comments were received from States on the Draft Articles adopted on first reading.64 However, as always, the Commission did have access to detailed summary records of comments of governments on the 1991 Draft Articles made in the debates on the ILC’s reports in the Sixth Committee of the General Assembly.

In addition to the watercourses articles, the ILC in 1994 adopted a resolution on transboundary confined groundwater. This subject had been addressed in Rosenstock’s first and second reports, which recommended inclusion of ‘unrelated’ confined groundwaters in the watercourses articles.65 Rosenstock’s second report included a study, contained in an annex to the report, of unrelated ‘confined groundwaters’, undertaken at the (p. 11) request of the Commission ‘to determine the feasibility of incorporating them into the topic’.66 The Special Rapporteur concluded that:

in the treatment of [international watercourses] the tendency has been not to distinguish between transboundary confined groundwaters and related groundwaters, i.e., those that contribute water to a system flowing into a common terminus. … [I]t is important for the draft on the law of the non-navigational uses of international watercourses to include provisions on ‘unrelated’ confined groundwaters, in order to encourage their management in a rational manner and prevent their depletion and pollution.67

Unfortunately, the Commission did not accept the Special Rapporteur’s recommendation to include confined groundwater within the scope of the international watercourses topic. Instead, it adopted a ‘Resolution on Confined Transboundary Groundwater’. The resolution ‘[c]ommends States to be guided by the principles contained in the draft articles on the law of the non-navigational uses of international watercourses, where appropriate, in regulating transboundary groundwater …’.68 As will appear below, the ILC eventually decided to take up work on the topic of the Law of Transboundary Aquifers.69

In submitting the final set of Draft Articles to the General Assembly, the ILC also recommended that a draft convention be elaborated by the Assembly or by an international conference of plenipotentiaries on the basis of the Draft Articles.70

5.  Action on the International Law Commission’s Draft Articles in the General Assembly

The General Assembly accepted the ILC’s recommendation, deciding to hold diplomatic negotiations in the Sixth (Legal) Committee of the General Assembly, convening for this purpose as a ‘Working Group of the Whole’.71 The three-week session in October 1996, originally envisaged having proved insufficient for the completion of the negotiations, the Assembly decided to hold a second session, of two weeks, during the spring of 1997. The UN Watercourses Convention was adopted by the General Assembly on 21 May 1997.72

Although every Draft Article was considered carefully in the negotiations, in the end few significant changes were made to the ILC’s draft. The Working Group adopted ‘Statements of Understanding’ regarding certain provisions of the Convention,73 which include the following: ‘Throughout the elaboration of the draft Convention, reference had been made to the commentaries to the draft articles prepared by the International Law Commission to clarify the contents of the articles.’74 The issue that may be said to have given the Working Group the most difficulty was the relationship between the (p. 12) obligations of equitable and reasonable utilization (Articles 5 and 6) and the prevention of significant harm (Article 7). The issue was ultimately resolved through a compromise formula in paragraph 2 of Article 7 which, while rather awkward and somewhat opaque as are many compromise formulae, effectively gave preeminence to equitable and reasonable utilization in the event that a conflict between the obligations could not be resolved. This and other issues dealt with by the Working Group will be the subject of further discussion in the ensuing chapters of the present Commentary.

6.  Entry into Force of the Convention

The Convention provides in Article 36 that thirty-five ratifications are necessary for its entry into force. While the Convention was opened for signature on the date of its adoption, 21 May 1997, it did not enter into force until 17 August 2014. Several reasons have been given for this delay,75 including that many States already have treaties covering their international watercourses, some States have no international watercourses, and States did not perceive any urgency to join the treaty. However, a strong argument can be made, based on the Convention’s provenance as traced above, that it largely constitutes a codification of rules of customary international law.76 Thus, the rights and obligations reflected in the Convention are binding on all States as customary international law even without the Convention’s entry into force. Indeed, this is still an important point, since only thirty-six States have ratified the Convention as of May 2017.77

7.  Implementation of the Convention

In September 2015, Finland, Germany, and the Netherlands, all Parties to the UN Watercourses Convention, organized a two-day event concerning the Convention at UNESCO Headquarters in Paris. On the first day an informal gathering of the Parties was held on the working level. On the second day the Parties were joined by interested countries, potential Parties and international organizations, and NGOs. Being a codification convention, the UN Watercourses Convention does not establish an institutional structure, such as a secretariat and meeting of the Parties, which can assist the Parties in maintaining continuous and active cooperation.78 One of the objects of this event was (p. 13) to discuss whether such a structure was needed and, if so, what form it might take. The Parties held intensive discussions in break-out groups, focusing on three questions put to them by the organizers. The clear result of these discussions was that more time was needed to consider these and other issues. The Parties agreed to remain in contact concerning them.79

In contrast to the UN Watercourses Convention, the ECE Water Convention does establish a secretariat and a meeting of the Parties.80 As many of the States that are Parties to the UN Watercourses Convention are also Parties to the ECE Water Convention, a side-event on the UN Watercourses Convention was held during the seventh session of the Meeting of the Parties (MoP-7) to the Water Convention in Budapest from 17–19 November 2015, giving Parties to the UN Watercourses Convention, as well as non-Parties, a further opportunity to exchange views informally concerning next steps relating to that treaty.

The implementation mechanisms of the ECE Water Convention provide a good indication of the kinds of institutions the Parties to the UN Watercourses Convention may wish to consider establishing. In fact, considerations of efficiency and cost-saving would seem to militate in favour of the possibility of the Water Convention Secretariat serving both that treaty and the Watercourses Convention. This idea of a common secretariat was in fact advanced at the meeting held on the day following the informal gathering of the Parties to the UN Watercourses Convention in September 2015. The UNECE Water Convention website already contains a helpful and informative page on the UN Watercourses Convention, recognizing the common coverage of the two agreements, and the linkages and possible synergies between them. At its sixth session in 2012, the MoP to the UNECE Water Convention ‘decided to promote synergies and coordination with the 1997 Watercourses Convention by sharing the experience collected under the Water Convention to support the implementation of the 1997 Watercourses Convention, promoting exchanges and coordination between the Parties to the two Conventions’.81 Time will tell whether the Parties to the UN Watercourses Convention will decide to establish a link to existing mechanisms to assist them in maintaining active cooperation concerning the Convention, in sharing knowledge gained in implementing the treaty, and in promoting accession to it by other States sharing freshwater resources.

8.  The Convention’s Reception

The UN Watercourses Convention and its preparatory work have generally been well received by States and international tribunals. The 2000 Revised SADC Protocol on Shared Watercourses,82 to which fourteen southern African States are Parties, follows the (p. 14) Convention closely in many respects. The Convention’s provisions and principles, particularly equitable and reasonable utilization, have been relied upon by States on both sides of disputes concerning shared freshwater resources,83 providing further evidence of an opinio juris concerning their status.

The International Court of Justice relied on the Convention and the principle of equitable and reasonable utilization and participation in its judgment in the Gabčíkovo-Nagymaros Project case,84 rendered a mere four months after the Convention was concluded, even quoting from Article 5 of the Convention. And in Pulp Mills the Court referred to the obligation of equitable and reasonable utilization as a free-standing principle, without at the same time mentioning the Convention, indicating the Convention’s influence on the development of the law.85 This may be taken as a confirmation of the status of the Convention as a codification of the principles of international law governing the non-navigational uses of international watercourses.

9.  The International Law Commission’s Further Work on Shared Freshwater Resources: Transboundary Groundwater

It will be recalled that in the resolution it adopted when concluding its work on what became the UN Watercourses Convention the ILC commended the principles in the international watercourses draft to States for guidance on the regulation of transboundary groundwater. Also noted above is the ILC’s later decision to take up work on the topic of the Law of Transboundary Aquifers.86 This work resulted in the adoption, in 2008, of a set of nineteen Draft Articles on the subject.87 The Commission transmitted the draft to the General Assembly, recommending that it (a) take note of the Draft Articles and annex the articles to the resolution; (b) recommend that States make appropriate bilateral or regional arrangements for the proper management of their transboundary aquifers on the basis of the principles reflected in the draft; and (c) consider at a later stage the elaboration of a convention on the basis of the Draft Articles.88 The Assembly followed these recommendations but has not yet been able to decide on the final form to be given to the articles.89

The Commission’s Draft of 2008 is unusual in the respect that it is not well coordinated with the ILC’s Draft Articles on the Law of the Non-Navigational Uses of International Watercourses and hence with the UN Watercourses Convention. The 2008 Draft Articles on the Law of Transboundary Aquifers apply not only to ‘confined’ groundwater, the form of groundwater not covered by the Commission’s Draft Articles adopted in 1994, and thus the UN Watercourses Convention, but also groundwater that is related to surface water. However, the 2008 Draft Articles generally seek to apply the principles of (p. 15) the UN Watercourses Convention, mutatis mutandis, to transboundary groundwater. Most of the substantive provisions of the 2008 Draft Articles are based on the articles of the UN Watercourses Convention, confirming the ILC’s recommendations in its 1994 Resolution that in regulating transboundary groundwater States should be guided by the principles reflected in the Draft Articles on the Law of the Non-Navigational Uses of International Watercourses, as appropriate.

In addition to the curious decision of the Commission to allow the 2008 Draft Articles on the Law of Aquifers to overlap with not only the 1994 Draft Articles but also the UN Watercourses Convention, the ILC adopted a regressive general principle that flies in the face of all of the work that has been done, including the UN Watercourses Convention, to counter any Harmon-Doctrine90 tendencies of States sharing freshwater resources: as the first provision in a section entitled ‘General Principles’, the ILC included an article entitled ‘Sovereignty of Aquifer States’.91 As has been discussed elsewhere,92 such a principle not only ignores the shared nature of transboundary groundwater as a common resource that requires cooperation, but also encourages the worst tendencies of those, virtually never scientists, who would wrap themselves in the banner of sovereignty for political gain. The inclusion of the principle in the 2008 Draft Articles may have been in part the result of the draft’s focus on aquifers—water-bearing geologic formations—rather than the water contained in them—groundwater. While a State unquestionably is sovereign over the portion of the geologic formation, the ‘rock’, that is within its territory, it can be said to have ‘sovereignty’ over the water contained in the formation only in a very limited sense since the water moves and is shared with the other State or States in whose territory parts of the aquifer are situated. The exaltation of sovereignty in this context tends to encourage hegemony and a race to install a more powerful pump than one’s neighbour rather than promoting the cooperation that is essential for the optimal and sustainable utilization of shared natural resources.


The path to the UN Watercourses Convention is a long one, beginning in the early twentieth century and culminating at the end of it with the adoption of the treaty at the United Nations Headquarters in New York. Contributions to the growing stream of principles in the field came largely from non-governmental expert bodies, chiefly the IIL and the ILA. But the United Nations itself showed as early as the 1950s, not long after its establishment, that it was aware of the importance of the issue, an awareness that was crowned by the General Assembly’s decision in 1970 to refer the topic of international watercourses to the ILC. Twenty years and five Special Rapporteurs after it initially began work on international watercourses, the ILC completed work on the topic and sent its Draft Articles to the General Assembly with a recommendation that the Assembly convene a (p. 16) diplomatic conference for the negotiation of a treaty based on the Draft Articles. This the Assembly did, leading to the adoption of the Convention on 21 May 1997.

The path beyond the conclusion of the UN Watercourses Convention is itself at the time of writing nearly twenty years long. The Convention is now in force, with thirty-six Parties. The Parties have held two informal gatherings and may ultimately decide to establish mechanisms to facilitate their cooperation. The UN Watercourses Convention and its preparatory work have generally been well received by States and international tribunals, with the International Court of Justice leading the way in its Gabčíkovo judgment four months after the Convention was concluded. States have also relied on the principles reflected in the UN Watercourses Convention, including in disputes with other States sharing freshwater resources. The ILC has adopted Draft Articles on transboundary aquifers that apply the principles of the Convention to that subject-matter. This tends to confirm the validity of the Commission’s recommendation that the principles contained in the UN Watercourses Convention be applied by States sharing groundwater resources.

It is to be hoped that the number of Parties to the Convention will grow over time, so that a global framework governing the allocation and protection of international watercourses will be strengthened, leading to smooth and peaceful relations between States sharing fresh water.


1  IIL Madrid Resolution, 24 Annuaire de l’Institut de droit international, Madrid Session (April 1911) 365–7. English translation in ILC, ‘Report of the Secretary General on the legal problems relating to the utilization and use of international rivers and documents of the twenty-sixth session of the Commission prepared by the Secretariat’, II:2 YBILC (1974), at 200.

2  IIL Salzburg Resolution on the Use of International Non-Maritime Waters, 49:II Annuaire de l’Institut de droit international, Salzburg Session (September 1961), at 381–4. English translation in II:2 YBILC (1974), ibid., at 202.

3  IIL Athens Resolution, Resolution on the Pollution of Rivers and Lakes and International Law, 58:1 Annuaire de l’Institut de droit international, Athens Session (September 1979) 197, et seq. English translation in Experts Group on Environmental Law of the World Commission on Environment and Development, Environmental Protection and Sustainable Development, Legal Principles and Recommendations (Graham & Trotman/Martinus Nijhoff, 1987), at 171.

4  II:2 YBILC (1974), supra note 1, at 200.

5  Ibid., Art. 1, at 201.

6  Ibid., Art. 2.

7  Ibid., Art. 3.

8  The first case in this line was Kansas v. Colorado 206 U.S. 46 (1907), in which the Court required that there be an ‘equitable apportionment of benefits’ of the river in question between the two States (at 118). See generally the discussion of illustrative cases in S.C. McCaffrey, The Law of International Watercourses (2nd edn., Oxford University Press, 2007), at 244–51.

9  II:2 YBILC (1974), supra note 1, Arts. 5–7, at 201.

10  IIL Athens Resolution, supra note 3, preamble.

11  Ibid., Art. II.

12  Ibid., Art. III.

13  Ibid., Art. VII.

14  The work of the ILA on international watercourses prior to 1966 is traced in II:2 YBILC (1974), supra note 1, at 202–7.

15  ILA, Report of the Fifty-Second Conference, Helsinki (1966), at 484 (Helsinki Rules).

16  Helsinki Rules, Art. II.

17  The commentary to the ILA’s Montreal Rules on Water Pollution in an International Drainage Basin, adopted in 1982, states that ‘the principle of equitable utilization … is the foundation on which the Helsinki Rules are built’. ila, Report of the Sixtieth Conference, montreal (1982), at 536.

18  See, e.g., Art. V(2)(j) and (k).

19  Commentary to Art. V.

20  Art. X(1)(b).

21  Art. XI(2).

22  Art. 31.

23  Progressive Development and Codification of the Rules of International Law Relating to International Watercourses, UN Doc. A/7991, A/C.6/SR.1225, 8 December 1970, at 267.

24  See generally J.L. Wescoat, Jr., ‘Beyond the River Basin: The Changing Geography of International Water Problems and International Watercourse Law’, 3 Colorado Journal of International Environmental Law & Policy (1992) 301.

25  UNGA Res. 1401 (XIV), 21 November 1959, preamble.

26  See, e.g., the negotiations between India and Pakistan which led to the conclusion in 1960 of the Indus Waters Treaty, 19 September 1960, 419 UNTS 290; and the talks between Canada and the United States on the Columbia River Treaty, which was concluded in 1961, Treaty between Canada and the United States of America relating to Cooperative Development of the Water Resources of The Columbia River Basin, available at https://www.crt2014-2024review.gov/Files/International%20Documents%20ColumbiaRiverTreaty.pdf (accessed 1 January 2018).

27  Specifically mentioned in the Report of the Secretary-General are disputes concerning the Jordan (Syria and Israel) and Lauca (Bolivia and Chile) Rivers. UN Doc. A/5409, para. 5 and note 2, reproduced in II:2 YBILC (1974), supra note 1, at 50.

28  II:2 YBILC (1974), supra note 1, at 270, para. 1.

29  UN Doc. A/5409, reproduced in ibid., at 33.

30  Also published in that year was a volume of the United Nations Legislative Series containing the national legislative texts and treaty provisions referred to in the Secretary-General’s report. Legislative texts and treaty provisions concerning the utilization of international rivers for other purposes than navigation, United Nations publication, Sales No. 63.V.4 (1963).

31  UN Doc. A/CN.4/274, 25 March 1974, II:2 YBILC (1974), supra note 1, at 265.

32  In 1959 the General Assembly had requested the Secretary-General to prepare a report on legal problems relating to the utilization and use of international rivers. UNGA Res. 1401 (XIV), 21 November 1959. The report was later published, together with a supplementary report, in the 1974 Yearbook of the ILC. II:2 YBILC (1974), supra note 1, at 33.

33  Note verbale of 24 April 1970, UN GAOR, 25th Session, Annexes, agenda item 91, UN Doc. A/7991.

34  Progressive Development and Codification of the Rules of International Law Relating to International Watercourses, supra note 23, at 268, para. 7.

35  UN GAOR, 25th Session, Annexes, agenda item 91, UN Doc. A/8202, at para. 17.

36  UNGA Res. 2669 (XXV), 8 December 1970, preamble.

37  Ibid.

38  Ibid., at para. 1.

39  II:2 YBILC (1974), supra note 1, at 271, para. 7.

40  Ibid., at 271–2.

41  Ibid., at 265.

42  II:1 YBILC (1974), at 301–4.

43  ILC, ‘Documents of the twenty-eighth session’, II:1 YBILC (1976), at 184.

44  Ibid., at para. 2. Replies were received from twenty-one states. ILC, ‘Report of the Commission to the General Assembly on the work of its twenty-eighth session’, II:2 YBILC (1976), at 157, para. 127. Four more replies were received in time for the ILC’s 1978 session. ILC, ‘Report of the Commission to the General Assembly on the work of its thirtieth session’, II:2 YBILC (1978), at 148, para. 157.

45  II:1 YBILC (1976), supra note 43, at 184, para. 2.

46  Ibid., at 191, para. 49.

47  ILC, ‘Documents of the thirty-first session’, II:1 YBILC (1979), at 143.

48  ILC, ‘Documents of the thirty-second session’, II:1 YBILC (1980), at 159.

49  ILC, ‘Report of the Commission to the General Assembly on the work of its thirty-second session’, II:2 YBILC (1980), at 108, para. 90.

50  II:1 YBILC (1980), supra note 48, at 167, para. 52 (quoting from remarks of the representative of Thailand in the Sixth Committee).

51  ILC, ‘Report of the Commission to the General Assembly on the work of its thirty-third session’, II:2 YBILC (1981), at 8, para. 11.

52  ILC, ‘Report of the Commission to the General Assembly on the work of the thirty-fourth session’, II:2 YBILC (1982), at 121, para. 251. For Schwebel’s third report, see II:2 YBILC (1981), ibid., at 65.

53  Ibid., at 75–161.

54  Ibid., at 103, para. 156, Art. 8(3)–(8).

55  Ibid., at 161–191, paras. 380–528.

56  ILC, ‘Documents of the thirty-fifth session’, II:1 YBILC (1983), at 155.

57  ILC, ‘Summary records of the meetings of the thirty-sixth session’, II:1 YBILC (1984), at 101.

58  ILC, ‘Report of the Commission to the General Assembly on the work of its thirty-seventh session’, II:2 YBILC (1985), at 70, para. 279.

59  ILC, ‘Report of the Commission to the General Assembly on the work of its forty-third session’, II:2 YBILC (1991), at 66, para. 57.

60  See ILC, ‘Report of the Commission to the General Assembly on the work of its forty-sixth session’, II:2 YBILC (1994), at 90, para. 222. The ‘common terminus’ requirement, which the present author views as unnecessary and potentially troublesome, was changed in the version of Art. 2 finally adopted by the insertion of the word ‘normally’ to modify the words ‘flowing into a common terminus’.

61  ILC, ‘Documents of the forty-fourth session’, II:2 YBILC (1992), at 52, para. 350. The present author had not stood for reelection to the ILC.

62  II:2 YBILC (1994), supra note 60, at 89, para. 222.

63  One change was to insert the word ‘normally’ before the ‘common terminus’ requirement in the definition of the term ‘watercourse’. See ibid., at 90, para. 6 of the commentary to Art. 2. Rosenstock had recommended in his second report the deletion of the ‘common terminus’ requirement from the definition of ‘watercourse’. ILC, ‘Documents of the forty-sixth session’, II:1 YBILC (1994), at 114, paras. 6, et seq.

64  The comments that were received in time to be considered by the ILC are contained in ILC, ‘Documents of the forty-fourth session’, II:1 YBILC (1993), at 145 (seventeen sets of comments, one of which was submitted jointly by five Nordic countries).

65  II:1 YBILC (1994), supra note 63, at 114, paras. 2, et seq.

66  Ibid., at para. 2, and Annex, ibid., at 123.

67  Ibid., at paras. 37–8.

68  Ibid., at para. 1.

69  The ILC included the topic ‘Shared natural resources’ in its programme of work in 2002 and appointed Mr. Chusei Yamada as Special Rapporteur. ILC, ‘Report of the Commission to the General Assembly on the work of its fifty-fourth session’, II:2 YBILC (2002), at 100, paras. 518–19. While this topic included not only confined transboundary groundwaters, but also transboundary oil and gas, as of this writing (2017) the ILC has not taken up the latter topic.

70  Ibid., at 88, para. 219.

71  UNGA Res. 49/52, 9 December 1994, at para. 3.

72  UNGA Res. 51/229, 21 May 1997, Annex.

73  Report of the Sixth Committee convening as the Working Group of the Whole, UN Doc. A/51/869, 11 April 1997.

74  Ibid.

75  See, e.g., S.M.A. Salman, ‘Entry into force of the UN Watercourses Convention: Why Should it Matter?’, International Journal of Water Resources Development (8 August 2014), available at http://dx.doi.org/10.1080/07900627.2014.952072 (accessed 1 January 2018).

76  See, e.g., A. Tanzi and M. Arcari, The United Nations Convention on the Law of International Watercourses: A Framework for Sharing (Kluwer, 2001), at 2; and S.M.A. Salman, ‘The World Bank Policy for Projects on International Waterways: An Historical and Legal Analysis’, The World Bank (2009) 57, available at http://documents.worldbank.org/curated/en/276451468325130824/pdf/487410PUB0inte101Official0Use0Only1.pdf (accessed 1 January 2018) (There is ‘general agreement among experts in th[e] field that the provisions of the Convention reflect the basic principles of customary international water law’).

77  There are thirty-six States Parties as of 29 May 2017. See Status of Treaties deposited with the Secretary-General, available at https://treaties.un.org/pages/ViewDetails.aspx?src=TREATY&mtdsg_no=XXVII-12&chapter=27&clang=_en (accessed 1 January 2018).

78  The author, as Special Rapporteur, did propose a provision on the establishment of a Conference of the Parties, which would assist the Parties to any future agreement with its implementation. ILC, ‘Sixth report on the law of the non-navigational uses of international watercourses’, ILC, ‘Documents of the forty-second session’, II:1 YBILC (1990), at 41, UN Doc. A/CN.4/SER.A/1990/Add.1 (Part 1), at 64 (1993). The Commission found that such a possibility would be better considered by any conference negotiating a convention on the basis of the ILC’s Draft Articles. The Working Group of the Whole did not consider such a possibility.

79  A report on the informal gathering may be found at http://www.bmub.bund.de/fileadmin/Daten_BMU/Download_PDF/Binnengewaesser/un_wasserlaufkonvention_report_en_bf.pdf (accessed 1 January 2018).

80  UNECE Convention on the Protection and Use of Transboundary Watercourses and International Lakes, 17 March 1992, 31 ILM 1312, Arts. 17 (meeting of the parties) and 19 (secretariat). On the relationship between the two treaties, see S.C. McCaffrey, ‘UN Watercourses Convention: Implementation and Relationship to the UNECE Water Convention’, 46 Environmental Policy & Law (2016) 35.

81  Brochure on ‘The Global Opening of the 1992 Water Convention’, available at http://www.unece.org/fileadmin/DAM/env/water/publications/brochure/Brochure_on_opening/Brochure_ECE_ENG_WEB_OK.pdf (accessed 1 January 2018), at 15.

82  Revised Protocol on Shared Watercourses in the Southern African Development Community (SADC), 7 August 2000, available at http://www.sadc.int/files/3413/6698/6218/Revised_Protocol_on_Shared_Watercourses_-_2000_-_English.pdf (accessed 1 January 2018).

83  E.g., in the ICJ, Case Concerning Pulp Mills on the River Uruguay (Argentina v. Uruguay), Judgment, 20 April 2010, at paras. 55, 170.

84  ICJ, Case Concerning the Gabčikovo-Nagymaros Project (Hungary v. Slovakia), Judgment, 25 September 1997, at 80, para. 147.

85  Pulp Mills Case, supra note 83, at paras. 177, 266.

86  See supra note 70.

87  ILC, ‘Report of the Commission to the General Assembly on the work of its sixtieth session’, II:2 YBILC (2008), at 19, paras. 53–4. See F. Sindico and L. Movilla Pateiro, ‘The Interplay between the UN Watercourses Convention and the Law on Transboundary Aquifers (Article 2)’, Chapter 19, this volume.

88  II:2 YBILC (2008), supra note 87, at 19, para. 49.

89  At its 71st session in 2016, the Assembly adopted UNGA Res. 71/150, 13 December 2016, repeating what had been said in past resolutions and deciding to take the topic up again at its 74th session.

90  The infamous ‘Harmon Doctrine’ of absolute territorial sovereignty was articulated by US Attorney General Judson Harmon in 1895 in the context of a dispute with Mexico over the Rio Grande. See S.C. McCaffrey, ‘The Harmon Doctrine One Hundred Years Later: Buried, Not Praised’, 36 Natural Resources Journal (1996) 965. The dispute was eventually settled in the 1906 Convention concerning the Equitable Distribution of the Waters of the Rio Grande for Irrigation Purposes, 34 Stat. 2953, U.S. Treaty Series No. 455.

91  II:2 YBILC (2008), supra note 87, at 20.

92  See S.C. McCaffrey, ‘The International Law Commission Adopts Draft Articles on Transboundary Aquifers’, 103 American Journal of International Law (2009) 272, at 285.