A few months ago, Brendan Mulligan and I published a paper entitled “The Silala/Siloli Watershed: Dispute over the Most Vulnerable Basin in South America” in the peer-reviewed International Journal of Water Resources Development. The dispute, pitting Bolivia and Chile, provides a fascinating case study involving both transboundary surface and ground water resources. Of particular interest, it also involves an artificial watercourse traversing the border that may defy application of international water law to the controversy. In 2007, UNEP named the Silala watershed the only “high risk” basin in South America and “one of the most hydropolitically vulnerable basins in the world.”
The dispute focuses on water flowing across the Bolivian-Chilean border in the Atacama Desert via a canal constructed in the early 1900s by Antofagasta & Bolivia Railway Company, a Chilean mining operation, per a concession granted by the Bolivian Prefecture of Potosí. Bolivia claims ownership over the Silala River on grounds that the river originates from springs on its side of the border and that the Silala’s waters are transported artificially to Chile; in essence, Bolivia denies the existence of a Silalar river. In 1997, the Bolivian government revoked the concession on grounds that the waters had long been used for purposes that were different than those agreed to in the original agreement. It also sought to awarded a new 40-year concession to the Bolivian firm DUCTEC SRL for $46.8 million, established a military base on the banks of the Silala River, publicly discussed a plan to bottle the river’s water and sell it with the slogan “Drink Silala water for sovereignty,” and conducted a feasibility study for a hydroelectric plant on the Silala just inside Bolivian territory (see Bloomberg article). At one point, Bolivian officials asserted that any negotiations with Chile should guarantee Bolivia access to the Pacific Ocean (see Spanish-language article), a demand suggesting that the issues surrounding the Silala are not entirely water-focused.
In contrast, Chile bases its ownership claims on grounds that the Silala’s waters were never diverted from its original channel, but rather that the canal works merely augment the natural flow of the Silala River. Hence, Chile argues that the Silala is and always has been a transboundary river subject to international water law. Moreover, it contends that it need not pay for the use of the Silala and that Bolivia’s rescission of the original concession, as well as Bolivia’s awarding of the more recent DUCTEC concession, were illegal. It is noteworthy that while Chile voted in favor of the 1997 Watercourses Convention, Bolivia abstained from the vote and neither has signed or ratified it. Although the two governments have attempted to resolve the dispute, including drafting a bilateral agreement on the use of the waters of the Silala, it remains unresolved.
The applicability of international water law to the Silala scenario depends largely on whether or not the Silala River is described as a natural transboundary watercourse. A manufactured river, in the form of canals or other man-made systems, would not fall within the rubric of international water law since, by definition, such water bodies are proprietary and subject to the agreements that created them. Moreover, international water law does not apply to surface runoff flowing in a marginally defined or in undefined channel (e.g., surface runoff) regardless of whether or not the flow crosses an international boundary.
In the case of the Silala Basin, most of the spring flow is captured by artificial channels, constructed by the mining interests under its 1908 concession from the Bolivian Prefecture of Potosí and that cross into Chile via the principal canal. This would suggest that the water in the canal is subject solely to the terms of the concession agreement rather than to international water law. And when Bolivia rescinded the concession, the waters’ ownership reverted back to Bolivia.
Nevertheless, geological and topographical evidence (including onsite evaluations conducted by my co-author, Brendan Mulligan), as well as certain historical material, indicate that prior to canalization, the Silala springs flowed naturally across the Bolivian-Chilean border in approximately the same path as the principal canal. If this proves true, application of international water law is still unclear since we would have a transboundary river that was captured and canalized for private use.
Chile might argue that the concession trumps international water law since international law allows for the creation of agreements deviating from international standards so long as the deviations do not violate jus cogens (peremptory international norms). On the other hand, Bolivia may contend that the concession was a license revocable at the will of the licensor (Bolivia). If this latter analysis holds, then the rules for the basin reverted back to the default norms of international water law when the Bolivian government revoked the concession in 1997.
Still, to the extent that the flow of the pre-canalized Silala was intermittent rather than perennial, applicability of international norms also may be tenuous. The substantive rules of international water law can be understood, in part, as rules of liability. In other words, violation of the rules mandates the imposition of responsibility and recompense. Violation of the rules, however, can only occur where human actions interfere with the natural flow of the watercourse. Where a river fails to flow for natural reasons, as an intermittent stream is wont to do, no liability may be imposed. Moreover, the absence of state practice or examples in which international water law norms were applied to an intermittent stream suggests that this scenario is, at best, unresolved. Hence, to the extent that prior to canalization water in the Silala flowed across the Bolivian-Chilean border only intermittently, international water law principles may not be applicable to the present dispute.
Further complicating the scenario is the presence of an interrelated transboundary aquifer. As noted above, the Silala River is fed by springs in Bolivia. Those springs, however, emerge from the Silala Aquifer, which is believed to traverse the Bolivian-Chilean border. Unfortunately, as little as is known about the topography and geology of the Silala River Basin, even less information is available about the underlying aquifer. In addition, international law applicable to transboundary ground water resources is still in its infancy and there are only a few examples of state practice from which lessons can be drawn (see my article on Managing Buried Treasure Across Frontiers: The International Law of Transboundary Aquifers).
Whether additional facts and scientific information will be forthcoming from the parties or from independent sources is presently unclear. Moreover, even with such information, international water law, whether for transboundary surface or ground water resources, may not have a ready solution. As is often the case in disputes over shared water resources, negotiations may provide the most optimal solution for this most hydropolitically vulnerable of basins.