34
4 Laws of Transboundary Water Governance
ing to the non-navigational uses of international watercourses (McCaffrey 2015)
and received immediate judicial endorsement by the ICJ in the above-mentioned
Gabˇ cíkovo-Nagymaros case in the same year. However, despite the lengthy preparatory phase, it took another 17 years to gather a sufficient amount of ratifications to
trigger its entry into force.
The Convention contains, for the most part, highly general provisions whose fil
conducteur is the “combination of the principles of equitable and reasonable utilization, on the one hand, and prevention of significant harm, on the other” (McCaffrey
2015).
The principle of equitable and reasonable utilisation, as codified by the Convention, implies a broad range of obligations (Art. 5.). First of all, the use and development of the transboundary rivers must take place “with a view to attaining optimal
and sustainable utilization thereof and benefits therefrom” taking into account the
interests of other riparian countries. Second, the principle encompasses the right of
states to utilise the shared river as well as the duty to cooperate in the protection
thereof. The Convention also enumerates the most important factors that have to
be taken into account in determining whether a particular use can be considered
equitable and reasonable (Art. 6.1.). Importantly, there is no set hierarchy among
competing water uses, but in the case of a conflict among competing uses, special
attention must be paid to the “requirements of vital human needs” (Art. 10.).
The other overarching principle of international water law enshrined in the Convention is the so-called “no-harm” rule that has grown out of the Roman law maxim
of sic utero tuo ut alineium non laedes.
11 It implies that states utilising their share
of the international watercourse must take all necessary measures to prevent causing significant harm to other riparian states. If such harm is nevertheless caused, all
appropriate measures must be taken to eliminate or mitigate it (Art. 7.). The “noharm” rule is not a passive obligation. It implies the continuous, long-term, pro-active
and anticipatory engagement of basin states to avert not only large scale and apparent
incidents, but also the “accumulation of small and isolated modifications of water
quality and quantity” that may generate unforeseeable adverse effects (Tanzi and
Kolliopoulos 2015). (Evidently, such progressive interpretation raises the threshold
of due diligence well-above the original formulation of the rule by the Trail Smelter
Arbitration that only called for the avoidance of “injuries […] to the territory of
another […] when the case is of serious consequence and the injury is established
by clear and convincing evidence”, Rieu-Clarke et al. 2012).
The Convention also describes the duties of states to cooperate over planned
measures that may have a significant negative impact on other riparian states as
well as the related procedures that include prior notification and consultation (Art.
11-19.). In fact, the Convention treats this obligation equal to the previous ones,
actually devoting more provisions to this subject that any other issue in the entire
text (McCaffrey 2015).
In addition to the above bedrock principles, the Convention sets out basic requirements concerning pollution prevention and control and the protection of riverine
11 “Do not use your property so as to injure the property of another”.
4 Laws of Transboundary Water Governance
ing to the non-navigational uses of international watercourses (McCaffrey 2015)
and received immediate judicial endorsement by the ICJ in the above-mentioned
Gabˇ cíkovo-Nagymaros case in the same year. However, despite the lengthy preparatory phase, it took another 17 years to gather a sufficient amount of ratifications to
trigger its entry into force.
The Convention contains, for the most part, highly general provisions whose fil
conducteur is the “combination of the principles of equitable and reasonable utilization, on the one hand, and prevention of significant harm, on the other” (McCaffrey
2015).
The principle of equitable and reasonable utilisation, as codified by the Convention, implies a broad range of obligations (Art. 5.). First of all, the use and development of the transboundary rivers must take place “with a view to attaining optimal
and sustainable utilization thereof and benefits therefrom” taking into account the
interests of other riparian countries. Second, the principle encompasses the right of
states to utilise the shared river as well as the duty to cooperate in the protection
thereof. The Convention also enumerates the most important factors that have to
be taken into account in determining whether a particular use can be considered
equitable and reasonable (Art. 6.1.). Importantly, there is no set hierarchy among
competing water uses, but in the case of a conflict among competing uses, special
attention must be paid to the “requirements of vital human needs” (Art. 10.).
The other overarching principle of international water law enshrined in the Convention is the so-called “no-harm” rule that has grown out of the Roman law maxim
of sic utero tuo ut alineium non laedes.
11 It implies that states utilising their share
of the international watercourse must take all necessary measures to prevent causing significant harm to other riparian states. If such harm is nevertheless caused, all
appropriate measures must be taken to eliminate or mitigate it (Art. 7.). The “noharm” rule is not a passive obligation. It implies the continuous, long-term, pro-active
and anticipatory engagement of basin states to avert not only large scale and apparent
incidents, but also the “accumulation of small and isolated modifications of water
quality and quantity” that may generate unforeseeable adverse effects (Tanzi and
Kolliopoulos 2015). (Evidently, such progressive interpretation raises the threshold
of due diligence well-above the original formulation of the rule by the Trail Smelter
Arbitration that only called for the avoidance of “injuries […] to the territory of
another […] when the case is of serious consequence and the injury is established
by clear and convincing evidence”, Rieu-Clarke et al. 2012).
The Convention also describes the duties of states to cooperate over planned
measures that may have a significant negative impact on other riparian states as
well as the related procedures that include prior notification and consultation (Art.
11-19.). In fact, the Convention treats this obligation equal to the previous ones,
actually devoting more provisions to this subject that any other issue in the entire
text (McCaffrey 2015).
In addition to the above bedrock principles, the Convention sets out basic requirements concerning pollution prevention and control and the protection of riverine
11 “Do not use your property so as to injure the property of another”.