Court's Opinion: ...................................................
THE COURT composed as above, after deliberation, delivers the
...(1) The Court is requested to
(a) whether the Republic of Hungary was entitled to suspend
and subsequently abandon, in 1989, the works on the Nagymaros
Project and on the part of the Gabcíkovo Project for which
the Treaty attributed responsibility to the Republic of Hungary;
(b) whether the Czech and Slovak Federal Republic was entitled
to proceed, in November 1991, to the "provisional solution"
and to put into operation from October 1992 this system ... (damming
up of the Danube at river kilometre 1851.7 on Czechoslovak territory,
with resulting consequences on water and navigation course);
The present case arose out of the signature, on 16 September
1977, by the Hungarian People's Republic and the Czechoslovak
People's Republic, of a treaty "concerning the construction
and operation of the Gabcíkovo-Nagymaros System of Locks"
(hereinafter called the "1977 Treaty"). . . .
.....It provides for the construction
and operation of a System of Locks by the parties as a "joint
investment". According to its Preamble, the barrage system
[an artificial dam, placed on the Danube River, to increase its
depth and divert a portion for irrigation/navigation] was designed
to attain "the broad utilization of the natural resources
of the Bratislava-Budapest section of the Danube river for the
development of water resources, energy, transport, agriculture
and other sectors of the national economy of the Contracting
Parties". The joint investment was thus essentially aimed
at the production of hydroelectricity, the improvement of navigation
on the relevant section of the Danube and the protection of the
areas along the banks against flooding. At the same time, by
the terms of the Treaty, the contracting parties undertook to
ensure that the quality of water in the Danube was not impaired
as a result of the Project, and that compliance with the obligations
for the protection of nature arising in connection with the construction
and operation of the System of Locks would be observed.
The Danube is the second longest river in Europe, flowing along
or across the borders of nine countries in its 2,860- kilometre
course from the Black Forest eastwards to the Black Sea. For
142 kilometres, it forms the boundary between Slovakia and Hungary.
The sector with which this case is concerned is a stretch of
approximately 200 kilometres, between Bratislava in Slovakia
and Budapest in Hungary. Below Bratislava, the river gradient
decreases markedly, creating an alluvial plain of gravel and
sand sediment. This plain is delimited to the north-east, in
Slovak territory, by the Malý Danube and to the south-west,
in Hungarian territory, by the Mosoni Danube. The boundary between
the two States is constituted, in the major part of that region,
by the main channel of the river. . . .
The Danube has always played a vital part in the commercial and
economic development of its riparian States, and has underlined
and reinforced their interdependence, making international co-operation
essential. Improvements to the navigation channel have enabled
the Danube, now linked by canal to the Main and thence to the
Rhine, to become an important navigational artery connecting
the North Sea to the Black Sea. In the stretch of river to which
the case relates, flood protection measures have been constructed
over the centuries, farming and forestry practised, and, more
recently, there has been an increase in population and industrial
activity in the area. The cumulative effects on the river and
on the environment of various human activities over the years
have not all been favourable, particularly for the water regime.
.....Only by international co-operation
could action be taken to alleviate these problems. Water management
projects along the Danube have frequently sought to combine navigational
improvements and flood protection with the production of electricity
through hydroelectric power plants. The potential of the Danube
for the production of hydroelectric power has been extensively
exploited by some riparian States. The history of attempts to
harness the potential of the particular stretch of the river
at issue in these proceedings extends over a 25-year period culminating
in the signature of the 1977 Treaty.
Article 1, paragraph 1, of the 1977 Treaty describes
the principal works to be constructed in pursuance of the Project.
It provided for the building of two series of locks, one at Gabcíkovo
(in Czechoslovak territory) and the other at Nagymaros (in Hungarian
territory), to constitute "a single and indivisible operational
system of works". . . . The Court will subsequently have
occasion to revert in more detail to those works, which were
to comprise, inter alia, a reservoir upstream of Dunakiliti,
in Hungarian and Czechoslovak territory; a dam at Dunakiliti,
in Hungarian territory; a bypass canal, in Czechoslovak territory,
on which was to be constructed the Gabcíkovo System of
Locks (together with a hydroelectric power plant with an installed
capacity of 720 megawatts (MW)); the deepening of the bed of
the Danube downstream of the place at which the bypass canal
was to rejoin the old bed of the river; a reinforcement of flood-control
works along the Danube upstream of Nagymaros; the Nagymaros System
of Locks, in Hungarian territory (with a hydroelectric power
plant of a capacity of 158 MW); and the deepening of the bed
of the Danube downstream.
Thus, the Project was to have taken the form of an integrated
joint project with the two contracting parties on an equal footing
in respect of the financing, construction and operation of the
works. Its single and indivisible nature was to have been realized
through the Joint Contractual Plan which complemented the Treaty.
In particular, Hungary would have had control of the sluices
[artificial water passages, fitted with flow controls] at Dunakiliti
and the works at Nagymaros, whereas Czechoslovakia would have
had control of the works at Gabcíkovo.
[After an agreed upon delay, and as] a result of intense criticism
which the Project had generated in Hungary, the Hungarian Government
decided on 13 May 1989 to suspend the works at Nagymaros pending
the completion of various studies which the competent authorities
were to finish before 31 July 1989. On 21 July 1989, the Hungarian
Government extended the suspension of the works at Nagymaros
until 31 October 1989, and, in addition, suspended the works
at Dunakiliti until the same date. Lastly, on 27 October 1989,
Hungary decided to abandon the works at Nagymaros and to maintain
the status quo at Dunakiliti.
During this period, negotiations were being held between the
parties. Czechoslovakia also started investigating alternative
solutions. One of them, subsequently known as "Variant C",
entailed a unilateral diversion of the Danube by Czechoslovakia
on its territory some 10 kilometres upstream of Dunakiliti. .
. . In its final stage, Variant C included the construction at
Cunovo of an overflow dam and a levee linking that dam to the
south bank of the bypass canal. The corresponding reservoir was
to have a smaller surface area and provide approximately 30 per
cent less storage than the reservoir initially contemplated.
Provision was made for ancillary works, namely: an intake structure
to supply the Mosoni Danube; a weir to enable, inter alia, floodwater
to be directed along the old bed of the Danube; an auxiliary
shiplock; and two hydroelectric power plants (one capable of
an annual production of 4 GWh on the Mosoni Danube, and the other
with a production of 174 GWh on the old bed of the Danube). The
supply of water to the side-arms of the Danube on the Czechoslovak
bank was to be secured by means of two intake structures in the
bypass canal at Dobrohot' and Gabcíkovo. A solution
was to be found for the Hungarian bank. Moreover, the question
of the deepening of the bed of the Danube at the confluence of
the bypass canal and the old bed of the river remained outstanding.
.....On 23 July 1991, the Slovak
Government decided "to begin, in September 1991, construction
to put the Gabcíkovo Project into operation by the provisional
solution". That decision was endorsed by the Federal Czechoslovak
Government on 25 July. Work on Variant C began in November 1991.
Discussions continued between the two parties but to no avail,
and, on 19 May 1992, the Hungarian Government transmitted to
the Czechoslovak Government a Note Verbale terminating the 1977
Treaty with effect from 25 May 1992. On 15 October 1992, Czechoslovakia
began work to enable the Danube to be closed and, starting on
23 October, proceeded to the damming of the river.
... In the meanwhile, the Commission of the European Communities
had offered to mediate and, during a meeting of the two parties
with the Commission held in London on 28 October 1992, the parties
entered into a series of interim undertakings. They principally
agreed that the dispute would be submitted to the International
Court of Justice, that a tripartite fact-finding mission should
report on Variant C not later than 31 October, and that a tripartite
group of independent experts would submit suggestions as to emergency
measures to be taken.
. . .
.....According to Article 4 of the
Special Agreement, "The Parties [agreed] that, pending the
final Judgment of the Court, they [would] establish and implement
a temporary water management régime for the Danube."
However, this régime could not easily be settled. The
filling of the Cunovo dam [in the Slovak Republic] had rapidly
led to a major reduction in the flow and in the level of the
downstream waters in the old bed of the Danube as well as in
the side-arms of the river. On 26 August 1993, Hungary and Slovakia
reached agreement on the setting up of a tripartite group of
experts (one expert designated by each party and three independent
experts designated by the Commission of the European Communities)
"In order to provide reliable and undisputed data on
the most important effects of the current water discharge and
the remedial measures already undertaken as well as to make recommendations
for appropriate measures."
The Court will now turn to a consideration of the questions submitted
by the Parties. In terms of Article 2, paragraph 1 (a), of the
Special Agreement, the Court is requested to decide first
"whether the Republic of Hungary was entitled to suspend
and subsequently abandon, in 1989, the works on the Nagymaros
Project and on the part of the Gabcíkovo Project for which
the Treaty attributed responsibility to the Republic of Hungary".
In the wake of the profound political and economic changes which
occurred at this time in central Europe, the Gabcíkovo-Nagymaros
Project was the object, in Czechoslovakia and more particularly
in Hungary, of increasing apprehension, both within a section
of public opinion and in some scientific circles. The uncertainties
not only about the economic viability of the Project, but also,
and more so, as to the guarantees it offered for preservation
of the environment, engendered a climate of growing concern and
opposition with regard to the Project.
During winter 1989-1990, the political situation in Czechoslovakia
and Hungary alike was transformed, and the new Governments were
confronted with many new problems.
Throughout the proceedings, Hungary contended that, although
it did suspend or abandon certain works, on the contrary, it
never suspended the application of the 1977 Treaty itself. To
justify its conduct, it relied essentially on a "state of
.....Hungary contended that the
various installations in the Gabcíkovo-Nagymaros System
of Locks had been designed to enable the Gabcíkovo power
plant to operate in peak mode. Water would only have come through
the plant twice each day, at times of peak power demand. Operation
in peak mode required the vast expanse (60 km2) of the planned
reservoir at Dunakiliti, as well as the Nagymaros dam, which
was to alleviate the tidal effects and reduce the variation in
the water level downstream of Gabcíkovo. Such a system,
considered to be more economically profitable than using run-of-the-river
plants, carried ecological risks which it found unacceptable.
.....According to Hungary, the principal
ecological dangers which would have been caused by this system
were as follows. At Gabcíkovo/Dunakiliti, under the original
Project, as specified in the Joint Contractual Plan, the residual
discharge into the old bed of the Danube was limited to 50 m3/s,
in addition to the water provided to the system of side-arms.
That volume could be increased to 200 m3/s during the growing
season. Additional discharges, and in particular a number of
artificial floods, could also be effected, at an unspecified
rate. In these circumstances, the groundwater level would have
fallen in most of the Szigetköz. Furthermore, the groundwater
would then no longer have been supplied by the Danube--which,
on the contrary, would have acted as a drain--but by the reservoir
of stagnant water at Dunakiliti and the side-arms which would
have become silted up. In the long term, the quality of water
would have been seriously impaired. As for the surface water,
risks of eutrophication would have arisen, particularly in the
reservoir; instead of the old Danube there would have been a
river choked with sand, where only a relative trickle of water
would have flowed. The network of arms would have been for the
most part cut off from the principal bed. The fluvial fauna and
flora, like those in the alluvial plains, would have been condemned
.....As for Nagymaros, Hungary argued
that, if that dam had been built, the bed of the Danube upstream
would have silted up and, consequently, the quality of the water
collected in the bank-filtered wells would have deteriorated
in this sector. What is more, the operation of the Gabcíkovo
power plant in peak mode would have occasioned significant daily
variations in the water level in the reservoir upstream, which
would have constituted a threat to aquatic habitats in particular.
Furthermore, the construction and operation of the Nagymaros
dam would have caused the erosion of the riverbed downstream,
along Szentendre Island. The water level of the river would therefore
have fallen in this section and the yield of the bank-filtered
wells providing two-thirds of the water supply of the city of
Budapest would have appreciably diminished. The filter layer
would also have shrunk or perhaps even disappeared, and fine
sediments would have been deposited in certain pockets in the
river. For this twofold reason, the quality of the infiltrating
water would have been severely jeopardized.
.....From all these predictions,
in support of which it quoted a variety of scientific studies,
Hungary concluded that a "state of ecological necessity"
did indeed exist in 1989.
In the course of the proceedings, Slovakia argued at length that
the state of necessity upon which Hungary relied did not constitute
a reason for the suspension of a treaty obligation recognized
by the law of treaties. At the same time, it cast doubt upon
whether "ecological necessity" or "ecological
risk" could, in relation to the law of State responsibility,
constitute a circumstance precluding the wrongfulness of an act.
.....In any event, Slovakia denied
that there had been any kind of "ecological state of necessity"
in this case either in 1989 or subsequently. It invoked the authority
of various scientific studies when it claimed that Hungary had
given an exaggeratedly pessimistic description of the situation.
Slovakia did not, of course, deny that ecological problems could
have arisen. However, it asserted that they could to a large
extent have been remedied. It accordingly stressed that no agreement
had been reached with respect to the modalities of operation
of the Gabcíkovo power plant in peak mode, and claimed
that the apprehensions of Hungary related only to operating conditions
of an extreme kind. In the same way, it contended that the original
Project had undergone various modifications since 1977 and that
it would have been possible to modify it even further, for example
with respect to the discharge of water reserved for the old bed
of the Danube, or the supply of water to the side-arms by means
of underwater weirs.
The Court will now consider the question of whether there was,
in 1989, a state of necessity which would have permitted Hungary,
without incurring international responsibility, to suspend and
abandon works that it was committed to perform in accordance
with the 1977 Treaty and related instruments.
The Court has no difficulty in acknowledging that the concerns
expressed by Hungary for its natural environment in the region
affected by the Gabcíkovo-Nagymaros Project related to
an "essential interest" of that State, within the meaning
given to that expression in Article 33 of the Draft of the International
.....The Commission, in its Commentary,
indicated that one should not, in that context, reduce an "essential
interest" to a matter only of the "existence"
of the State, and that the whole question was, ultimately, to
be judged in the light of the particular case; at the same time,
it included among the situations that could occasion a state
of necessity, "a grave danger to ... the ecological preservation
of all or some of [the] territory [of a State]"; and specified,
with reference to State practice, that "It is primarily
in the last two decades that safeguarding the ecological balance
has come to be considered an 'essential interest' of all States.".
.....The Court recalls that it has recently had occasion
to stress, in the following terms, the great significance that
it attaches to respect for the environment, not only for States
but also for the whole of mankind:
"the environment is not an abstraction but represents
the living space, the quality of life and the very health of
human beings, including generations unborn. The existence of
the general obligation of States to ensure that activities within
their jurisdiction and control respect the environment of other
States or of areas beyond national control is now part of the
corpus of international law relating to the environment."
(Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion,
I.C.J. Reports 1996, pp. 241-242, para. 29.)
The verification of the existence, in 1989, of the "peril"
invoked by Hungary, of its "grave and imminent" nature,
as well as of the absence of any "means" to respond
to it, other than the measures taken by Hungary to suspend and
abandon the works, are all complex processes.
.....As the Court has already indicated,
Hungary on several occasions expressed, in 1989, its "uncertainties"
as to the ecological impact of putting in place the Gabcíkovo-Nagymaros
barrage system, which is why it asked insistently for new scientific
studies to be carried out.
.....The Court considers, however,
that, serious though these uncertainties might have been they
could not, alone, establish the objective existence of a "peril"
in the sense of a component element of a state of necessity.
The word "peril" certainly evokes the idea of "risk";
that is precisely what distinguishes "peril" from material
damage. But a state of necessity could not exist without a "peril"
duly established at the relevant point in time; the mere apprehension
of a possible "peril" could not suffice in that respect.
It could moreover hardly be otherwise, when the "peril"
constituting the state of necessity has at the same time to be
"grave" and "imminent".
....."Imminence" is synonymous
with "immediacy" or "proximity" and goes
far beyond the concept of "possibility". As the International
Law Commission emphasized in its commentary, the "extremely
grave and imminent" peril must "have been a threat
to the interest at the actual time". That does not exclude,
in the view of the Court, that a "peril" appearing
in the long term might be held to be "imminent" as
soon as it is established, at the relevant point in time, that
the realization of that peril, however far off it might be, is
not thereby any less certain and inevitable.
.....The Hungarian argument on the
state of necessity could not convince the Court unless it was
at least proven that a real, "grave" and "imminent"
"peril" existed in 1989 and that the measures taken
by Hungary were the only possible response to it.
.....Both Parties have placed on
record an impressive amount of scientific material aimed at reinforcing
their respective arguments. The Court has given most careful
attention to this material, in which the Parties have developed
their opposing views as to the ecological consequences of the
Project. It concludes, however, that, as will be shown below,
it is not necessary . . . to determine which of those points
of view is scientifically better founded.
The Court will begin by considering the situation at Nagymaros.
As has already been mentioned (see paragraph 40 above), Hungary
maintained that, if the works at Nagymaros had been carried out
as planned, the environment--and in particular the drinking
water resources--in the area would have been exposed to serious
dangers on account of problems linked to the upstream reservoir
on the one hand and, on the other, the risks of erosion of
the riverbed downstream.
.....The Court notes that the dangers
ascribed to the upstream reservoir were mostly of a long-term
nature and, above all, that they remained uncertain. Even though
the Joint Contractual Plan envisaged that the Gabcíkovo
power plant would "mainly operate in peak-load time and
continuously during high water", the final rules of operation
had not yet been determined...; however, any dangers associated
with the putting into service of the Nagymaros portion of the
Project would have been closely linked to the extent to which
it was operated in peak mode and to the modalities of such operation.
It follows that, even if it could have been establishedwhich,
in the Court's appreciation of the evidence before it, was not
the casethat the reservoir would ultimately have constituted
a "grave peril" for the environment in the area, one
would be bound to conclude that the peril was not "imminent"
at the time at which Hungary suspended and then abandoned the
works relating to the dam.
.....With regard to the lowering
of the riverbed downstream of the Nagymaros dam, the danger could
have appeared at once more serious and more pressing, in so far
as it was the supply of drinking water to the city of Budapest
which would have been affected. The Court would however point
out that the bed of the Danube in the vicinity of Szentendre
had already been deepened prior to 1980 in order to extract building
materials, and that the river had from that time attained, in
that sector, the depth required by the 1977 Treaty. The peril
invoked by Hungary had thus already materialized to a large extent
for a number of years, so that it could not, in 1989, represent
a peril arising entirely out of the project. The Court would
stress, however, that, even supposing, as Hungary maintained,
that the construction and operation of the dam would have created
serious risks, Hungary had means available to it, other than
the suspension and abandonment of the works, of responding to
that situation. It could for example have proceeded regularly
to discharge gravel into the river downstream of the dam. It
could likewise, if necessary, have supplied Budapest with drinking
water by processing the river water in an appropriate manner.
The two Parties expressly recognized that that possibility remained
open even thoughand this is not determinative of the state
of necessitythe purification of the river water, like the
other measures envisaged, clearly would have been a more costly
The Court now comes to the Gabcíkovo sector. It will recall
that Hungary's concerns in this sector related on the one hand
to the quality of the surface water in the Dunakiliti reservoir,
with its effects on the quality of the groundwater in the region,
and on the other hand, more generally, to the level, movement
and quality of both the surface water and the groundwater in
the whole of the Szigetköz, with their effects on the fauna
and flora in the alluvial plain of the Danube (see paragraph
.....Whether in relation to the
Dunakiliti site or to the whole of the Szigetköz, the Court
finds here again, that the peril claimed by Hungary was to be
considered in the long term, and, more importantly, remained
uncertain. As Hungary itself acknowledges, the damage that it
apprehended had primarily to be the result of some relatively
slow natural processes, the effects of which could not easily
.....Even if the works were more
advanced in this sector than at Nagymaros, they had not been
completed in July 1989 and ... Hungary expressly undertook to
carry on with them, early in June 1989. The report dated 23 June
1989 by the ad hoc Committee of the Hungarian Academy of Sciences
... does not express any awareness of an authenticated perileven
in the form of a definite peril, whose realization would have
been inevitable in the long term.
.....The Court also notes that,
in these proceedings, Hungary acknowledged that, as a general
rule, the quality of the Danube waters had improved over the
past 20 years, even if those waters remained subject to hypertrophic
.....However "grave" it
might have been, it would accordingly have been difficult, in
the light of what is said above, to see the alleged peril as
sufficiently certain and therefore "imminent" in 1989.
The Court concludes from the foregoing that, with respect to
both Nagymaros and Gabcíkovo, the perils invoked by Hungary,
without prejudging their possible gravity, were not sufficiently
established in 1989, nor were they "imminent"; and
that Hungary had available to it at that time means of responding
to these perceived perils other than the suspension and abandonment
of works with which it had been entrusted.What is more, negotiations
were under way which might have led to a review of the Project
and the extension of some of its time-limits, without there being
need to abandon it. . . .
.....Moreover, the Court notes that
Hungary decided to conclude the 1977 Treaty, a Treaty which--whatever
the political circumstances prevailing at the time of its conclusion--was
treated by Hungary as valid and in force until the date declared
for its termination in May 1992. As can be seen from the material
before the Court, a great many studies of a scientific and technical
nature had been conducted at an earlier time, both by Hungary
and by Czechoslovakia. Hungary was, then, presumably aware of
the situation as then known, when it assumed its obligations
under the Treaty. Hungary contended before the Court that those
studies had been inadequate and that the state of knowledge at
that time was not such as to make possible a complete evaluation
of the ecological implications of the Gabcíkovo-Nagymaros
Project. It is nonetheless the case that although the principal
object of the 1977 Treaty was the construction of a System of
Locks for the production of electricity, improvement of navigation
on the Danube and protection against flooding, the need to ensure
the protection of the environment had not escaped the parties,
as can be seen from Articles 15, 19 and 20 of the Treaty.
.....What is more, the Court cannot
fail to note the positions taken by Hungary after the entry into
force of the 1977 Treaty. In 1983, Hungary asked that the works
under the Treaty should go forward more slowly, for reasons that
were essentially economic but also, subsidiarily, related to
ecological concerns. In 1989, when, according to Hungary itself,
the state of scientific knowledge had undergone a significant
development, it asked for the works to be speeded up, and then
decided, three months later, to suspend them and subsequently
to abandon them. The Court is not however unaware that profound
changes were taking place in Hungary in 1989, and that, during
that transitory phase, it might have been more than usually difficult
to co-ordinate the different points of view prevailing from time
.....The Court infers from all these
elements that, in the present case, even if it had been established
that there was, in 1989, a state of necessity linked to the performance
of the 1977 Treaty, Hungary would not have been permitted
to rely upon that state of necessity in order to justify its
failure to comply with its treaty obligations, as it had helped,
by act or omission to bring it about.
In the light of the conclusions reached above, the
Court . . . finds that Hungary was not entitled to suspend and
subsequently abandon, in 1989, the works on the Nagymaros Project
and on the part of the Gabcíkovo Project for which the
1977 Treaty and related instruments attributed responsibility
Hungary further argued that it was entitled to invoke a number
of events which, cumulatively, would have constituted a fundamental
change of circumstances [see § 8.2 of the course
textbook]. In this respect it specified profound changes of a
political nature, the Project's diminishing economic viability,
the progress of environmental knowledge and the development of
new norms and prescriptions of international environmental law.
. . .
.....The Court does not consider
that new developments in the state of environmental knowledge
and of environmental law can be said to have been completely
unforeseen. What is more, the formulation of Articles 15, 19
and 20, designed to accommodate change, made it possible for
the parties to take account of such developments and to apply
them when implementing those treaty provisions.
.....The changed circumstances advanced
by Hungary are, in the Court's view, not of such a nature, either
individually or collectively, that their effect would radically
transform the extent of the obligations still to be performed
in order to accomplish the Project. A fundamental change of circumstances
must have been unforeseen; the existence of the circumstances
at the time of the Treaty's conclusion must have constituted
an essential basis of the consent of the parties to be bound
by the Treaty. The negative and conditional wording of Article
62 of the Vienna Convention on the Law of Treaties is a clear
indication moreover that the stability of treaty relations requires
that the plea of fundamental change of circumstances be applied
only in exceptional cases.
Finally, the Court will address Hungary's claim that it was entitled
to terminate the 1977 Treaty because new requirements of international
law for the protection of the environment precluded performance
of the Treaty.
Neither of the Parties contended that new peremptory norms of
environmental law had emerged since the conclusion of the 1977
Treaty, and the Court will consequently not be required to examine
the scope of Article 64 of the Vienna Convention on the Law of
Treaties. On the other hand, the Court wishes to point out that
newly developed norms of environmental law are relevant for the
implementation of the Treaty and that the parties could, by agreement,
incorporate them through the application of Articles 15, 19 and
20 of the Treaty. These articles do not contain specific obligations
of performance but require the parties, in carrying out their
obligations to ensure that the quality of water in the Danube
is not impaired and that nature is protected, to take new environmental
norms into consideration when agreeing upon the means
to be specified in the Joint Contractual Plan.
.....By inserting these evolving
provisions in the Treaty, the parties recognized the potential
necessity to adapt the Project. Consequently, the Treaty is not
static, and is open to adapt to emerging norms of international
law. By means of Articles 15 and 19, new environmental norms
can be incorporated in the Joint Contractual Plan.
.....The responsibility to do this
was a joint responsibility. The obligations contained in Articles
15, 19 and 20 are, by definition, general and have to be transformed
into specific obligations of performance through a process of
consultation and negotiation. Their implementation thus requires
a mutual willingness to discuss in good faith actual and potential
.....It is all the more important
to do this because as the Court recalled in its Advisory Opinion
on the Legality of the Threat or Use of Nuclear Weapons, "the
environment is not an abstraction but represents the living space,
the quality of life and the very health of human beings, including
generations unborn" (I.C.J. Reports 1996, para. 29; see
also paragraph 53 above).
.....The awareness of the vulnerability
of the environment and the recognition that environmental risks
have to be assessed on a continuous basis have become much stronger
in the years since the Treaty's conclusion. These new concerns
have enhanced the relevance of Articles 15, 19 and 20.
The Court recognizes that both Parties agree on the
need to take environmental concerns seriously and to take the
required precautionary measures, but they fundamentally disagree
on the consequences this has for the joint Project. In such a
case, third-party involvement may be helpful and instrumental
in finding a solution, provided each of the Parties is flexible
in its position.
In the light of the conclusions it has reached above, the Court
. . . finds that the notification of termination by Hungary of
19 May 1992 did not have the legal effect of terminating the
1977 Treaty and related instruments.
The Court now turns to the other legal consequences arising from
.....As to this, Hungary argued
that future relations between the Parties, as far as Variant
C is concerned, are not governed by the 1977 Treaty. It claims
that it is entitled, pursuant to the Convention of 1976 on the
Regulation of Water Management Issues of Boundary Waters, to
"50% of the natural flow of the Danube at the point at which
it crosses the boundary below Cunovo" and considers that
"are obliged to enter into negotiations in order to produce
the result that the water conditions along the area from below
Cunovo to below the confluence at Sap become jointly defined
water conditions as required by Article 3 (a) of the 1976 Convention".
.....Hungary moreover indicated
that any mutually accepted long-term discharge régime
must be "capable of avoiding damage, including especially
damage to biodiversity prohibited by the [1992 Rio Convention
on Biological Diversity]". It added that "a joint environmental
impact assessment of the region and of the future of Variant
C structures in the context of the sustainable development of
the region" should be carried out.
As the Court has already had occasion to point out,
the 1977 Treaty was not only a joint investment project for the
production of energy, but it was designed to serve other objectives
as well: the improvement of the navigability of the Danube, flood
control and regulation of ice-discharge, and the protection of
the natural environment. None of these objectives has been given
absolute priority over the other, in spite of the emphasis which
is given in the Treaty to the construction of a System of Locks
for the production of energy. None of them has lost its importance.
In order to achieve these objectives the parties accepted obligations
of conduct, obligations of performance, and obligations of result.
It could be said that that part of the obligations of performance
which related to the construction of the System of Locks--in
so far as they were not yet implemented before 1992--have been
overtaken by events. It would be an administration of the law
altogether out of touch with reality if the Court were to order
those obligations to be fully reinstated and the works at Cunovo
to be demolished when the objectives of the Treaty can be adequately
served by the existing structures.
Whether this is indeed the case is, first and foremost, for the
Parties to decide. Under the 1977 Treaty its several objectives
must be attained in an integrated and consolidated programme,
to be developed in the Joint Contractual Plan. The Joint Contractual
Plan was, until 1989, adapted and amended frequently to better
fit the wishes of the parties. This Plan was also expressly described
as the means to achieve the objectives of maintenance of water
quality and protection of the environment.
The 1977 Treaty never laid down a rigid system, albeit
that the construction of a system of locks at Gabcíkovo
and Nagymaros was prescribed by the Treaty itself. In this respect,
however, the subsequent positions adopted by the parties should
be taken into consideration. Not only did Hungary insist on terminating
construction at Nagymaros, but Czechoslovakia stated, on various
occasions in the course of negotiations, that it was willing
to consider a limitation or even exclusion of operation in peak
hour mode. In the latter case the construction of the Nagymaros
dam would have become pointless. The explicit terms of the Treaty
itself were therefore in practice acknowledged by the parties
to be negotiable.
The Court is of the opinion that the Parties are under a legal
obligation, during the negotiations to be held by virtue of Article
5 of the Special Agreement, to consider, within the context of
the 1977 Treaty, in what way the multiple objectives of the Treaty
can best be served, keeping in mind that all of them should be
It is clear that the Project's impact upon, and its implications
for, the environment are of necessity a key issue. The numerous
scientific reports which have been presented to the Court by
the Parties--even if their conclusions are often contradictory--provide
abundant evidence that this impact and these implications are
.....In order to evaluate the environmental
risks, current standards must be taken into consideration. This
is not only allowed by the wording of Articles 15 and 19, but
even prescribed, to the extent that these articles impose a continuing--and
thus necessarily evolving--obligation on the parties to maintain
the quality of the water of the Danube and to protect nature.
.....The Court is mindful that,
in the field of environmental protection, vigilance and prevention
are required on account of the often irreversible character of
damage to the environment and of the limitations inherent in
the very mechanism of reparation of this type of damage.
.....Throughout the ages, mankind
has, for economic and other reasons, constantly interfered with
nature. In the past, this was often done without consideration
of the effects upon the environment. Owing to new scientific
insights and to a growing awareness of the risks for mankindfor
present and future generationsof pursuit of such interventions
at an unconsidered and unabated pace, new norms and standards
have been developed, set forth in a great number of instruments
during the last two decades. Such new norms have to be taken
into consideration, and such new standards given proper weight,
not only when States contemplate new activities but also when
continuing with activities begun in the past. This need to reconcile
economic development with protection of the environment is aptly
expressed in the concept of sustainable development.
.....For the purposes of the present
case, this means that the Parties together should look afresh
at the effects on the environment of the operation of the Gabcíkovo
power plant. In particular they must find a satisfactory solution
for the volume of water to be released into the old bed of the
Danube and into the side-arms on both sides of the river.
It is not for the Court to determine what shall be the final
result of these negotiations to be conducted by the Parties.
It is for the Parties themselves to find an agreed solution that
takes account of the objectives of the Treaty, which must be
pursued in a joint and integrated way, as well as the norms of
international environmental law and the principles of the law
of international watercourses. The Court will recall in this
context that, as it said in the North Sea Continental Shelf cases:
"[the Parties] are under an obligation so to conduct
themselves that the negotiations are meaningful, which will not
be the case when either of them insists upon its own position
without contemplating any modification of it" (I.C.J. Reports
1969, p. 47, para. 85).
For these reasons,
.....(1) Having regard to Article
2, paragraph 1, of the Special Agreement,
.....A. Finds, by fourteen votes
to one, that Hungary was not entitled to suspend and subsequently
abandon, in 1989, the works on the
Nagymaros Project and on the part of the Gabcíkovo Project
for which the Treaty of 16 September 1977 and related instruments
attributed responsibility to it;
.....B. Finds, by nine votes to
six, that Czechoslovakia was entitled to proceed, in November
1991, to the "provisional solution" [Variant C] as
described in the terms of the Special Agreement;
.....C. Finds, by ten votes to five,
that Czechoslovakia was not entitled to put into operation, from
October 1992, this "provisional solution";
....D. Finds, by eleven votes to
four, that the notification, on 19 May 1992, of the termination
of the treaty of 16 September 1977 and related instruments by
Hungary did not have the legal effect.of
.....(2) Having regard to Article
2, paragraph 2, and Article 5 of the Special Agreement,
.....A. Finds, by twelve votes
to three, that Slovakia, as successor to Czechoslovakia, became
a party.to the Treaty of 16 September
1977 as from 1 January 1993;
.....B. Finds, by thirteen votes
to two, that Hungary and Slovakia must negotiate in good faith
in the light of the prevailing situation, and must take all necessary
measures to ensure the achievement
of the objectives of the Treaty of 16 September 1977, in accordance
with such modalities as they may
.....C. Finds, by thirteen votes
to two, that, unless the Parties otherwise agree, a joint operational
.........régime must be established
in accordance with the Treaty of 16 September 1977;
.....D. Finds, by twelve votes to
three, that, unless the Parties otherwise agree, Hungary shall
compensate.Slovakia for the damage
sustained by Czechoslovakia and by Slovakia on account.of
the suspension and abandonment by
Hungary of works for which it was responsible; and Slovakia shall
compensate Hungary for the damage
it has sustained on account of the putting.into
operation of the "provisional solution" by Czechoslovakia
and its maintenance in service by Slovakia;
.....E. Finds, by thirteen votes
to two, that the settlement of accounts for the construction
and.operation of the works must
be effected in accordance with the relevant provisions of the Treaty of 16 September 1977
and related instruments, taking due account of such measures
as.will have been taken by the Parties
in application of points 2 B and
C of the present operative.paragraph.