|The Convention applies to groundwater systems but only to the extent that groundwater is connected hydrologically to a system of surface waters, parts of which are situated in different states (Article 2(a) and (b)) and also see Figure 1.6. According to the ILC commentary, ’groundwaters’ refers to the hydrologic system composed of a number of different components through which water flows, both on and under the surface of the land. These components include rivers, lakes, aquifers, glaciers, reservoirs and canals. So long as these components are interrelated with one another, they form part of the watercourse.114 The definition does not mean that a particular aquifer containing groundwater has to be situated across a boundary to be covered by the Convention; it is sufficient for such groundwater to be located in one state but connected to transboundary surface water.115 In the preparatory work of the ILC leading up to the adoption of the Convention, agreement could not be reached on whether aquifers containing ‘confined groundwater’116 should be included within the scope of the Convention. In 1992 Special Rapporteur Robert Rosenstock recommended that confined aquifers should be governed by the same rules as those applicable to international watercourses117 however, the final text of the Convention does not apply directly to confined aquifers.118 Following this issue, in 1994 the ILC adopted a Resolution on Confined Transboundary Groundwater which recognised the need for continuing efforts to create rules regarding confined transboundary groundwater and recommended that states be guided by the principles contained in (what is now) the UN Watercourses Convention, where appropriate, when regulating confined transboundary groundwater.119
The level of inclusion of groundwater systems in the Convention is important given that the total volume of groundwater represents 97 percent of our planet’s freshwater resources (excluding Antarctica) and yearly consumption of groundwater worldwide is estimated at 900 cubic kilometres.120 Figure 1.6 on the right gives the types and sources of groundwaters in the world.121 In response to this remaining issue of confined transboundary groundwater, and as part of a wider initiative on Shared Natural Resources, in 2002 the ILC commenced further study on transboundary groundwater initially with a focus on non-renewable or fossil groundwater unconnected to surface water.122 Shortly thereafter, the ILC broadened the topic from ‘confined’ transboundary groundwater to include all transboundary aquifers and aquifer systems containing both renewable and non-renewable groundwater.123 This decision to move the subject of study from the law of (confined) transboundary groundwater to the law of transboundary aquifers has repercussions in terms of the alignment and overlap between the physical and legal scope covered by the 1994 Draft Articles and the UN Convention.124 The word ‘aquifer’ was defined in the Draft Articles as a ‘permeable water-bearing geological formation underlain by a less permeable layer and the water contained in the saturated zone of the formation’.125 It is argued that this definition prioritises the geological formation above the water contained within, and it is this fact, in combination with the other provisions on sovereignty found elsewhere in the 1994 Draft Articles, that has lead several leading commentators to conclude that this change in scope is a potentially regressive step in the codification of international water law.126 In 2008, the ILC Draft Articles on the Law of Transboundary Aquifers were adopted and apply to single transboundary aquifers and transboundary aquifer systems consisting of a series of two or more hydraulically connected aquifers (Article 2(b)). Unlike the UN Convention, the Draft Articles apply to transboundary confined aquifers (Art 1(a) and Art 2(a)).127
However they also apply to renewable transboundary aquifers, the latter application being an overlap with the scope of the UN Convention.128 The 2008 Draft Articles on the Law of Transboudary Aquifers do not apply, however, to an unconfined aquifer that is situated entirely in one state but contributes water to a river that flows from that state into another state.129 This is a contrast to the UN Convention – which does cover such aquifers. Neither the UN Convention nor the 2008 Draft Articles cover a domestically situated confined aquifer, even in circumstances where it may be remotely connected to a transboundary surface water body, or where the aquifer is domestically located, recharged solely from rain and discharges either into the sea or into a second aquifer, or where the other domestically situated aquifer itself is the end point due to evaporation. The legal coverage of groundwater is shown in Figure 1.4 on the right.
The future shape and role of this draft instrument are uncertain.130 Although, the 2008 ILC Draft Articles build on the 1997 UN Convention and adjust many of its principles to the special case of groundwater, the ILC turned down the suggestion proposed by Special Rapporteur Chusei Yamada to examine the relationship and possible coordination between the Draft Articles and other treaties including the Convention.131
Numerous prominent experts have identified several fundamental criticisms of the scope, and substantive principles of the 2008 Draft Articles, which arguably create irreconcilable difficulties for future coordination and alignment of the provisions of these two instruments. A first major criticism of the Draft Articles rests on the matter of overlap in scope between the Draft Articles and the UN Convention as discussed above. A second major criticism rests on the emphasis by the Draft Articles on sovereignty132 under Article 3, where ‘[e]ach aquifer state has sovereignty over the portion of a transboundary aquifer or aquifer system located within its territory’. McCaffrey asserts that this use of the concept of sovereignty will reinforce the historic tendency of states to claim absolute sovereignty over the portion of even transboundary surface waters within their territories and may also give a state the impression that it has absolute discretion over the water contained in a transboundary aquifer when in fact – and in law – it does not.133 McIntyre argues that ‘the emphasis on State sovereignty over shared water resources appears to represent something of a retreat from the distributive equity inherent in the firmly established principle of equitable and reasonable utilisation and from the intense procedural and institutional cooperation required to achieve the community of interests approach necessary to give meaning to this principle’.134 It remains to be seen how these instruments will be reconciled.135
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