International Law Commission Adopts Draft Articles of a Transboundary Aquifers Convention

Kerstin Mechlem
August 27, 2008


On August 5, 2008, the International Law Commission (ILC) adopted draft articles for an international framework convention on transboundary aquifers.[1] These draft articles represent six years of work by the ILC and constitute a landmark event for the protection and management of groundwater resources, which have been neglected as a subject of international law despite the social, economic, environmental, and strategic importance of groundwater. This Insight provides some background on groundwater, describes the ILC's work on transboundary aquifers, analyzes the ILC's draft articles, and provides some concluding thoughts on the future of these articles.

Background on the Importance of Groundwater Resources

Groundwater makes up 97% of the Earth's fresh water resources, excluding the resources locked in polar ice. Globally, it provides about 50% of the current potable water supplies. It also delivers approximately 40% of water used by industry and between 20-30% of the water used in irrigated agriculture. Groundwater ensures the baseflow of rivers and lakes, keeps springs flowing, vegetation growing, and wetlands wet. Although a worldwide inventory of transboundary aquifers has not yet been compiled, the number of transboundary aquifers is estimated to be similar, if not greater, than the more than 260 transboundary river basins.[2] Europe alone has more than 89 transboundary aquifers.[3]

In addition, aquifers provide a range of more exotic services, including storage or withdrawal of heat due to natural geothermal aquifer properties, storage of non-toxic fluids such as liquefied greenhouse gases for carbon sequestration, or disposal of some wastes that can biodegrade because of properties in the aquifer matrix. Unfortunately, over the last 60 years, groundwater resources and the social, economic, and environmental systems dependent on them have come under increasing stress from over-abstraction and pollution.[4]

International Law and Groundwater Resources

Prior to the ILC's efforts on transboundary aquifers, states and international organizations had not used international law directly to address problems with groundwater resources. Surface water has been dealt with in numerous international agreements and other instruments. When not intentionally or unintentionally left out of such instruments, groundwater is only nominally included in their scopes of application. Further, substantive treaty norms and the powers of joint bodies in these instruments are biased towards surface water management (see, e.g., the United Nations Convention on the Non-Navigational Uses of International Watercourses (UN Watercourses Convention)[5]). Few treaties and other legal instruments exclusively address groundwater or contain groundwater-specific provisions.[6]

The ILC's Work on Transboundary Aquifers

In 2002, the ILC included the topic "Shared Natural Resources of States," comprising oil, gas, and "confined" groundwaters, in its long-term program of work[7] and appointed Ambassador Chusei Yamada as Special Rapporteur for Shared Natural Resources.[8] The ILC's work on groundwater follows its work on the law of international watercourses (1971-1994), which culminated in the adoption of draft articles that became the basis of the UN Watercourses Convention.

When preparing the draft articles for international watercourses, the ILC did not cover aquifers that receive no significant contemporary recharge.[9] The ILC called these aquifers (in a scientifically incorrect manner) "confined" transboundary aquifers and recommended that states "be guided by the principles contained in the draft articles on the non-navigational uses of international watercourses, where appropriate, in regulating transboundary groundwater."[10] The resolution also recognized a "need for continuing efforts to elaborate rules pertaining to confined transboundary groundwater."[11]

Between 2003 and 2008, the Special Rapporteur presented five reports. Early in this process, the ILC decided to broaden the topic from "confined" groundwaters to all transboundary aquifers. In 2006, it adopted on first reading 19 draft articles and commentaries thereto. In 2008, it completed the second reading. During the drafting process, the ILC received comments and observations from 47 governments. An overwhelming majority of states supported the priority the ILC was giving groundwater and the ILC's general approach. Views were divided on whether the draft articles should lead to a binding convention or a non-binding set of guidelines.[12]

Therefore, the final fate of the draft articles is yet to be determined. The ILC followed the two-step approach adopted in 2001 for the draft articles on the Responsibility of States for Internationally Wrongful Acts[13]: It recommended to the General Assembly that it take note of the draft articles in a resolution, annex them to the resolution, and recommend that states make appropriate arrangements bilaterally or regionally for the proper management of transboundary aquifers on the basis of the principles enunciated in the draft articles. The ILC further recommended that the General Assembly consider, at a later stage, the elaboration of a convention on the basis of the draft articles.[14]

Overview of the Draft Articles

Application and scope of the draft articles

The UN Watercourses Convention inspired the ILC's approach in the draft articles, but the ILC adapted the Convention's principles to the specific characteristics of groundwater resources. The draft articles apply to single transboundary aquifers and to transboundary aquifer systems consisting of a series of two or more hydraulically connected aquifers (Article 2 (b)).

The draft articles- scope covers (a) the utilization of transboundary aquifers; (b) other activities that have or are likely to have an impact upon those aquifers; and (c) measures for the protection, preservation, and management of transboundary aquifers (Article 1). Article 1(b) is new compared to the UN Watercourses Convention because the ILC recognized the need to protect aquifers against harm resulting, for example, from fertilizer or pesticide use or industry discharges in aquifer recharge zones.

The draft articles enshrine the fundamental principles of customary international law on water resources, namely the principle of equitable and reasonable utilization (Article 4), the obligation not to cause significant harm (Article 6), and the obligation to cooperate (Article 7).

The draft articles interpret equitable and reasonable utilization to mean utilization of an aquifer in a manner that is consistent with:

  • The equitable and reasonable accrual of benefits from the aquifer;
  • The aim of maximizing the long-term benefits to be derived from the use of aquifer waters;
  • The establishment of individual or joint comprehensive utilization plans, taking into account present and future needs and alternative water sources; and
  • Not utilizing a recharging aquifer at a level that would prevent the continuance of its effective functioning.

Obligation not to cause significant harm (Article 6)

The obligation not to cause significant harm is a duty "to take all appropriate measures" to prevent harm to aquifers, which is equivalent to an obligation of due diligence. The draft articles cover significant harm caused through an aquifer's direct utilization (e.g., excessive water abstraction) and caused by other activities that affect and cause harm to or through the aquifer (e.g., pesticide or industrial pollution seeping into the aquifer's water).

During the drafting process, the ILC engaged in considerable debate about whether, given the unique vulnerability of aquifers, the threshold of "significant harm" would be adequate or whether a lower threshold would be more appropriate. The ILC finally agreed that the concept of "significant harm" is flexible enough to protect aquifers. For instance, a smaller amount of a pollutant could cause greater harm to an aquifer than it may create in surface water.

Duties on cooperation and other obligations (Article 7)

Other obligations refer to cooperation (Article 7), to the exchange of data and information, where specific attention is paid to the fact that knowledge about the nature and extent of a transboundary aquifer is often inadequate (Article 8), and to bilateral and regional agreements (Article 9).

Protection and preservation provisions, and the absence of the precautionary and "polluter pays" principles

Part III of the draft articles is dedicated to protection, preservation, and management. It deals with the protection and preservation of ecosystems (Article 10); recharge and discharge zones (Article 11); the prevention, reduction, and control of pollution, including by taking a precautionary approach (Article 12); monitoring (Article 13); management (Article 14); and planned activities, including a notification requirement (Article 15).

No consensus among states and ILC members could be reached on directly including the precautionary principle in the draft articles because of the principle's still contested status in customary international law. Thus, the draft articles refer in Article 12 to a "precautionary approach" rather than to the "precautionary principle."[15] Other principles, such as the polluter-pays principle, which many water law treaties contain, are not mentioned at all. [16]

The obligations in the draft articles concerning planned activities which may affect a transboundary aquifer and thereby may have a significant adverse effect on another state are relatively vague and do not comprise an obligation to carry out an environmental impact assessment. Given that the draft articles do not make pre-activity fact-finding compulsory and that they contain no provisions on dispute resolution, the extent to which the draft articles provide actual guidance to states in the case of planned activities is not clear.[17]

Evaluation and Outlook

The ILC's decision to prioritize development of the international law on transboundary groundwater resources and to treat it separately from work on oil and gas should be welcomed. Its speedy preparation of the draft articles reflects recognition that groundwater resources have come under increasing stress globally and that international action is required.

Despite their shortcomings the draft articles are a significant step ahead in the protection of transboundary aquifers. They strike a good compromise between building on the accepted rights and obligations of international water law and devising new rules that take adequate account of the specific characteristics of groundwater resources. The draft articles are compatible with the UN Watercourses Convention, but independent of it. Thus, the protection of groundwater does not depend on the fate of the UN Watercourses Convention, which, given the slow progress of its ratification, might never enter into force.[18]

The ILC's decision to recommend that the General Assembly adopt a resolution supporting the draft articles and consider convening a negotiating conference at a later stage is prudent at the moment. This approach reduces the risk of rushing towards a convention prematurely, which at this stage might not attract the necessary amount of ratifications. Instead, it allows for a period during which the impact of the draft articles on relations among states can be evaluated and during which they could become a catalyst and frame of reference for the development of general or aquifer-specific bilateral, multilateral, or regional treaties. Such treaties will be indispensable to adequately manage specific shared aquifers.

In the longer term, the draft articles would ideally become a binding framework convention. As aquifer specific treaties are largely absent and customary international law is not yet very developed, such a convention would represent the only source of binding international law specific to transboundary aquifers and would, thereby, contribute to legal certainty concerning the rights and obligations of states sharing groundwater resources. Even if more aquifer-specific treaties are concluded in the future, a binding framework convention, which sets out general principles, can usefully guide and complement such treaties. This synergistic relationship has been seen in the area of transboundary watercourses through the mutually supportive dynamic between the United Nations Economic Commission for Europe's Convention on the Protection and Use of Transboundary Watercourses and International Lakes (Helsinki Convention)[19] and the numerous treaties on rivers within the geographical scope of the Helsinki Convention.

About the Author

Kerstin Mechlem is a lecturer in Human Rights and International Law at the Transitional Justice Institute of the University of Ulster, U.K. From 2002 to 2006, she worked as a Legal Officer for the Food and Agriculture Organization of the United Nations and was a member of an interdisciplinary group convened by UNESCO advising the ILC's Special Rapporteur for Shared Natural Resources, Ambassador Chusei Yamada.


[1] Report of the International Law Commission to the General Assembly on Its Sixtieth Session, Chapter IV, Shared Natural Resources. At the time of writing, the report had not yet been publicly released. It should soon be available at The adoption is reported in the ILC's summary of the session ( For the text of the draft articles as adopted by the drafting committee, see ILC, Shared Natural Resourcs - The Law of Transboundary Aquifers - Title and Texts of the Preamble and Draft Articles 1 to 19 on the Law of Transboundary Aquifers Adopted on Second Reading by the Drafting Committee, UN Doc. A/CN.4/L.724 (29 May 2008).

[2] Shaminder Puri and Alice Aureli, Transboundary Aquifers: A Global Program to Assess, Evaluate, and Develop Policy, 43 GROUND WATER 661, 664 (2005).

[3] UNECE Task Force on Monitoring and Assessment/E. Almássy and Zs Busas, INVENTORY OF TRANSBOUNDARY GROUNDWATERS (Lelystadt, 1999), 10 and 64 (available at:

[4] Jacob J. Burke and Marcus Moench, Groundwater and Society: Resources, Tensions and Opportunities, U.N. Sales No. E.99.II.A 1, 7 (2000).

[5] United Nations Convention on the Non-Navigational Uses of International Watercourses, annexed to G.A. Res. 229, U.N. GAOR, 51st session, UN Doc. A/Res/51/229 (1997); also reprinted in (1997) 36 ILM 700 (not yet entered into force).

[6] For legal instruments that address groundwater, see GROUNDWATER IN INTERNATIONAL LAW: COMPILATION OF TREATIES AND OTHER LEGAL INSTRUMENTS (Stefano Burchi and Kerstin Mechlem eds., 2004).

[7] Report of the International Law Commission to the General Assembly on Its Fifty-Fourth Session, U.N. GAOR, 57th Session, Supp. No. 10, UN Doc. A/57/10 (2002), chap. X.A.1, para. 518.

[8] Ibid. at para. 519.

[9] "No significant contemporary recharge" refers to average annual recharge rates that are very low compared to the overall storage capacity of an aquifer. Such aquifers are non-renewable resources and often contain water that infiltrated millennia ago under climatic conditions different to the present and that has been stored underground since that time. Such resources are mainly found in large transboundary aquifer systems located in the arid and semi-aird regions of North Africa and the Arabian Peninsula where they provide a most important source of water. NON-RENEWABLE GROUNDWATER RESOURCES (Stephen Foster and Daniel P. Loucks, eds., 2006), 13-14, 18-19.

[10] ILC, ?Resolution on Confined Transboundary Groundwater,? Art. 1, in Report of the Commission to the General Assembly on the work of its forty-sixth session, II (2) YBILC 135 (1994).

[11] Id. at preambular para. 4.

[12] ILC, Fifth Report on Shared Natural Resources: Transboundary Aquifers by Chusei Yamada, Special Rapporteur, U.N. Doc. A/CN.4/591 (2008), paras. 5?8.

[13] Report of the International Law Commission to the General Assembly on Its Fifty-Third Session, U.N. GAOR, 56th Sess., Supp. No. 10, U.N. Doc. A/56/10 and Corr. 1 (2001), paras. 72 and 73.

[14] Report of the International Law Commission to the General Assembly on Its Sixtieth Session, Chapter IV, Shared Natural Resources, supra note 1.

[15] Among the water law treaties that contain the precautionary principle are the United Nations Economic Commission for Europe (UN ECE) Convention on the Protection and Use of Transboundary Watercourses and International Lakes, (1992) 31 ILM 1312; the Protocol on Water and Health to the 1992 Convention on the Protection and Use of Transboundary Watercourses and International Lakes (London Protocol, 1999), U.N. Doc. MP.WAT/2000/1; the Convention on Cooperation for the Protection and Sustainable Use of the River Danube (1994), O.J. L.342, 12.12.1997, p. 19; the Convention on the Protection of the Rhine (1999), O.J. L.289, 16.11.2000, p. 31; the Convention on the Sustainable Development of Lake Tanganyika (2003), available at: FAOLEX (FAO legal database online,; and the Convention on the Sustainable Development of Lake Victoria Basin (2003), FAOLEX (FAO legal database online,

[16] See, e.g., the United Nations Economic Commission for Europe (UN ECE) Convention on the Protection and Use of Transboundary Watercourses and International Lakes, (1992) 31 ILM 1312.

[17] The ILC considered it premature to address dispute settlement given that it is not yet clear whether the draft articles will form the basis of a binding legal instrument.

[18] Whereas 35 ratifications are necessary for the entry into force of the 1997 Convention (Art. 36), to date, there are only 16 signatories and 16 parties.

[19] United Nations Economic Commission for Europe (UN ECE) Convention on the Protection and Use of Transboundary Watercourses and International Lakes, (1992) 31 ILM 1312.