I. Setting the context

Five post-Soviet Central Asian states—Kazakhstan, the Kyrgyz Republic, Tajikistan, Turkmenistan, and Uzbekistan—reappeared in the international arena in the early 1990s. Ensuring the effective and peaceful management of the freshwater resources that cross their borders—mainly the Amudarya and Syrdarya rivers of the Aral Sea BasinFootnote 3—became one of the most pressing issues for these states soon after independence. When the states were part of the Soviet Union, water and related resources were managed regionally via a system of reservoirs and hydropower stations established along the two rivers. Due to landscape and climatic conditions, reservoirs for water storage were built in the upstream states (the Kyrgyz Republic and Tajikistan) and used for irrigation in downstream states (Kazakhstan, Uzbekistan, and Turkmenistan). The system was operated primarily for irrigation purposes with power generation having a secondary role and fossil fuels being used to compensate for electric power deficits in the upstream states.Footnote 4 Early into the regional regime change, it became apparent that new geopolitical considerations and market reforms in the states had undermined the economic basis upon which the Soviet management scheme was designed. As a result, competition over water use between upstream (hydropower) states and downstream (irrigation/food production) states intensified.Footnote 5 Food and energy security issues were further complicated by the environmental neglect inherited from the Soviet period when the extensive exploitation of natural resources had incontestable priority over environmental protection.Footnote 6 Thus, a shortlist of the region's water-related problems includes controversies over water allocation, competition between irrigation and hydropower, and worries over water quality deterioration, environmental degradation, loss of biodiversity, and climate change.Footnote 7

In the switch towards independent political, social, and economic development, the Central Asian republics confirmed their commitment to international law as the basis of their relations. Over the past two decades, the countries have entered into a variety of bilateral, subregional, regional, and global water-related agreements and reaffirmed their adherence to the principles of international water law, including that of equitable and reasonable use, no significant harm, and the duty to co-operate, notify, and consult.Footnote 8 At a subregional level, the countries concluded the 1992 Almaty Agreement that recognizes regional water resources as “common and integral” and validates the Soviet management status quo over shared waters across Central Asia,Footnote 9 the 1993 Kzyl-Orda Agreement that defines the “common objectives” to be pursued to mitigate the Aral Sea crisis,Footnote 10 and the 1998 Syrdarya Agreement regarding the use of the water and energy resources in the Syrdarya river basin, and many others.Footnote 11 Some of these states have also joined agreements at a regional level under the auspices of the Commonwealth of Independent States (the Commonwealth)Footnote 12 and under the auspices of United Nations Economic Commission for Europe (UNECE).Footnote 13 At a global level, Uzbekistan became a party to the United Nations Convention on the Law of the Non-Navigational Uses of International Watercourses [1997 UN Convention],Footnote 14 a framework instrument that—although not yet in force—has already had a positive impact on the international legal environment through the process of codification and crystallization of the customary rules of international water law.Footnote 15 All five states are also parties to a range of multilateral environmental agreements which cover water-related issues to different extents.Footnote 16

Despite the intensity of legal development, the role of international law as it relates to transboundary waters has met a mixed response in the region. The states themselves acknowledge the positive implications of the legal framework for transboundary co-operation and stress the need for strengthening compliance with existing agreements and developing more effective legal and institutional mechanisms.Footnote 17 Some external observers consider these legal developments an important step in promoting co-operation over transboundary waters in the Aral Sea Basin while pointing out their low efficacy in dealing with environmental, economic, and social challenges.Footnote 18 Others appear even less optimistic and note that existing regional agreements and institutions are weak and that the level of co-operation over shared waters is unsatisfactory.Footnote 19 Some regional commentators further claim that one of the difficulties in establishing an effective regulatory regime for transboundary waters in Central Asia is that international water law lacks clarity in guiding the states’ course of action.Footnote 20 Finally, the 2003 United Nations Development Programme's Mission Report considers the irresponsible intervention of donors to be “a dramatic example of legal malpractice” and largely responsible for the “current confusion about international water law in Central Asia”.Footnote 21

Clearly, evaluating the validity of these sentiments requires more careful scholarly attention. But any discussion of how well international law relating to transboundary watercourses works in the Aral Sea Basin would be premature without some prior understanding of what international water law is and how it works. This article will thus set the stage for a deeper understanding of international law and its operation in the context of the transboundary waters in the Aral Sea Basin.Footnote 22 The purpose of the article is to explore the substantive norms operating in the field, namely the rule of equitable and reasonable use, the no-harm rule, and various obligations related to environmental protection, with a view to ascertaining what conduct is required of the states in Central Asia with respect to their shared watercourses and understanding how these substantive norms work.

II. Analytical framework

Norms vary in the way they establish a required standard of conduct. They may set forth either a permission, a prohibition, or a requirement; they may impose either an obligation of conduct or an obligation of result; they may convey either a precise or an indeterminate normative message; and they may be couched in either stringent or “soft” language. The last two characteristics, namely the determinacy and stringency of norms, are perceived by many international legal scholars as especially relevant to understanding the potential operation of norms and therefore deserve a more detailed discussion.Footnote 23

Norm determinacy refers to the degree of specificity required in prescribing normative conduct that “removes the opportunity to claim inadvertence or misinterpretation for those predisposed to violate”.Footnote 24 It distinguishes between norms signalling clear-cut obligations (often referred to as “rule-like” prescriptions) and norms that set forth more open-ended requirements (often referred to as “principle-like” prescriptions).Footnote 25 Franck observed that norm determinacy, which is “a necessary first step toward compliance”, is most often achieved through textual clarity.Footnote 26 He also warned that rules are not always capable of simplistic formulation, and that complex problems may require complex solutions.Footnote 27 Franck and others further maintained that a norm's indeterminacy does not necessarily negate its substantive content but rather indicates that its application is contingent on its context and decision-making framework.Footnote 28 Precise norms essentially define ex ante what conduct is permissible, while open-textured norms leave this determination to ex post decision-making in a specific context which is essential to ensuring adaptability and flexibility in law. To limit the discretion of states in an ex post determination, open-textured norms must be susceptible of being measured by factual and objective standards. As it follows from the work of the International Law Commission (ILC) and the use of the term by authoritative legal scholars, an “objective standard” does not necessarily imply the impartiality of assessment, it rather refers to certain criteria, such as due diligence or reasonableness, against which any individual state's conduct can be measured.Footnote 29

Norm stringency is the degree of normative force with which the norm is phrased.Footnote 30 It relates to the norm's mandatory quality.Footnote 31 Norms expressed through directive verbs such as “shall, must, require, and may not” are stringent. Less stringent norms can be indicated through the use of verbs such as “should, may, and recommend” that convey a normative message in a more hortatory or programmatic way. Importantly, norm stringency should be understood as a spectrum, with different levels of “control intention” shading into one another in the norm-text.Footnote 32 This recognizes that an obligation may be couched in terms conveying a different degree of normative force and consequently different intentions and expectations about the required standard of conduct. Recent practice in the Permanent Court of Arbitration is illustrative in this regard. In the case regarding the Convention for the Protection of the Marine Environment of the North-East AtlanticFootnote 33 (the OSPAR Convention case), the arbitral tribunal cast some light on norm stringency by defining it as “a cascading standard of expression providing for the particular obligations”.Footnote 34 To analyze the obligations imposed on Contracting Parties under the OSPAR Convention with respect to access to information, the Tribunal classified a hierarchy of obligations or different levels of engagement of treaty obligation. The Tribunal stated:

Norm determinacy and norm stringency are alike in the sense that they both help to capture the degree of consensus achieved by the concerned parties as to the form of expression and the content of any norm.Footnote 36 But there is also a clear analytical distinction between them. The latter shows the different degree of the “control intention” expressed by the states as to the normative force of obligations; while the former mostly illustrates the degree of states’ discretion with respect to the implementation of obligations in a particular context.

Thus, analysis of substantive norms on the basis of their determinacy and stringency provides a deeper understanding of their nature and potential operation. It serves as a reminder that different types of norms may require different forms of implementation and operationalization. It also sheds light on the complex interrelations between one norm and another, and the place and role of individual norms within a wider system of international law, which are the key to understanding its operation.

III. The rule of equitable and reasonable use

The rule of equitable and reasonable use is broadly recognized as “a general rule of law for the determination of the rights and obligations of States” with respect to international watercourses.Footnote 37 Article 5 of the 1997 UN Convention codifies this fundamental customary rule of international water law, providing that watercourse states “shall in their respective territories utilize an international watercourse in an equitable and reasonable manner”Footnote 38 and “shall participate in the use, development and protection of an international watercourse in an equitable and reasonable manner”.Footnote 39 Article 6 provides a non-exhaustive list of factors and circumstances that should be taken into account in an objective manner in order to determine “equitable and reasonable utilization”. These include:

1. (a) Geographic, hydrographic, hydrological, climatic, ecological and other factors of a natural character;

2. (b) The social and economic needs of the watercourse States concerned;

3. (c) The population dependent on the watercourse in each watercourse State;

4. (d) The effects of the use or uses of the watercourses in one watercourse State on other watercourse States;

5. (e) Existing and potential uses of the watercourse;

6. (f) Conservation, protection, development and economy of use of the water resources of the watercourse and the costs of measures taken to that effect;

7. (g) The availability of alternatives, of comparable value, to a particular planned or existing use.Footnote 40

No factor or use is accorded inherent priority when balancing the interests of states, but “special regard” should be given to “the requirements of vital human needs”.Footnote 41 The ILC Commentary to the 1994 Draft Articles explains that only “reasonable and beneficial” uses will be relevant to a determination of what is equitable.Footnote 42 Hence, prior to establishing what constitutes an “equitable use” by weighing and balancing the competing interests of states, states should ascertain what constitutes a “reasonable use” by consulting contemporary conceptions of rationality.Footnote 43 For its part, the principle of equity requires, inter alia, that “not only the absolute injury caused to the neighboring State” be considered, but also “the relation of the advantage gained by one to the injury caused to the other”.Footnote 44

Although historically the formula of equitable and reasonable use has been developed as a basis for water allocation, the rule also embraces the issues of water quality and ecosystem considerations. Article 5(1) of the 1997 UN Convention clearly requires that “an international watercourse shall be used and developed … with a view to attaining optimal and sustainable utilization thereof”.Footnote 45 The 1992 UNECE Convention adds to this development. Article 2(2)(c) provides that

The Guide to Implementing the Convention points out that:

Thus, although the rule of equitable and reasonable use is couched in strong terms (“shall utilize”, “shall participate”, “shall take all appropriate measures”) and thus imposes an absolute obligation of an action, the actual determination of conduct is complicated by the norm's complex and open-textured nature. The determination of equitable and reasonable use is in all cases dictated by the objective application of its two-fold standard of “equity” and “reasonableness”, so necessarily including consideration of vital human needs and the protection of watercourses. The rule of equitable and reasonable use pays due regard to changing needs by requiring that the balancing of the relevant factors must be responsive to the circumstances of individual cases. But this inherent flexibility of the rule, considered by many analysts to be its strength,Footnote 48 also entails a considerable level of uncertainty in its application.

To meet this challenge, the concept of equitable participation forms an essential part of the equitable and reasonable use rule. As the ILC's Commentary explains, “[t]he core of this principle is cooperation between watercourse States through participation, on an equitable and reasonable basis, in measures, works, activities aimed at attaining optimal utilization of international watercourse, consistent with adequate protection thereof”.Footnote 49 The character of the principle of co-operation attempts to direct conduct towards a particular goal. It gives some guidance, although abstract, for assessing the performance of interstate co-operation both in substantive and procedural terms. As for the substance of co-operation, it determines that “attaining optimal utilization” and “adequate protection of the watercourse” is the objective of interstate co-operation.Footnote 50 By making reference to the principle of “good faith”, it sets a general but essential procedural prerequisite for co-operation. The Guide to Implementing the 1992 UNECE Convention rightly points out that “[a]ddressing such problems through collective action requires a number of initially unilateral decisions towards cooperation”.Footnote 51 The equitable and reasonable use rule therefore imposes constraints on the exercise of national sovereignty and requires states, inter alia, to develop national laws and policies to implement its objectives. Accordingly, the effective application of this regulatory norm requires “affirmative conduct” from riparian states both at the basin and the national levels.Footnote 52

The rule of equitable and reasonable use does not set forth a legal entitlement to the use of shared waters by states other than the riparians. Nevertheless, the structure of the 1992 UNECE Convention envisages two major categories of obligations, one relating to Parties (Part I) and the other to Riparian Parties (Part II);Footnote 53 it thus allows some room for speculation on the scope of other states’ obligations to ensure an equitable and reasonable use. Article 2(2)(c) of the 1992 UNECE Convention requires the Parties—not only the Riparian Parties—to “take all appropriate measures … to ensure that transboundary waters are used in a reasonable and equitable way”.Footnote 54 Read in tandem with the preambular provision that “the effective accomplishment of [the Convention's tasks] can only be ensured by enhanced cooperation”,Footnote 55 this Article 2(2)(c) seems to emphasize a need for co-operation to ensure that the use of transboundary waters is equitable and reasonable not only for the riparians but also other Parties to the Convention. As the Guide to Implementing the Convention puts it, “each Riparian State is not left alone in its dealing with other riparians, while expectations become the concern of all other Parties sitting in the Meeting of the Parties” through the collective institutional regime.Footnote 56

Since what constitutes “equitable and reasonable” is not capable of precise definition within the global and regional framework instruments, the rule necessitates the adoption of more specific arrangements (e.g. agreements, joint bodies) that can develop an increasingly complex pattern of detailed rules and standards for a particular watercourse. In respect of the Aral Sea Basin, no explicit reference to the equitable and reasonable use rule can be found in the main text of the subregional and basin agreements, yet their preambular recitals refer to “adherence to the principle of international water law”,Footnote 57 “established international practice”,Footnote 58 “common desire to find the most perfect [absolute] and equitable solution in utilization of water and energy resources in the Syrdarya river basin in accordance with norms of international law”,Footnote 59 and “solving the issues of joint management of water resources on the basis of common regional principles and equitable regulation of their consumption”.Footnote 60 The case can be made that the main provisions should be interpreted and applied in line with any preamble as indicated in Article 31(2) of the Vienna Convention, which sets forth that the treaty text includes its preamble and annexes.Footnote 61 The significance of preambular provisions in the legal regulation of the transboundary water management in the Aral Sea Basin can be demonstrated by the fact that the principal substantive provision of the 1992 Almaty Agreement—that the Parties will “respect … the vested pattern and principles of water allocation and [will rely upon] current regulations for water allocation from interstate sources”—is stipulated in its preamble.Footnote 62

The 1992 Almaty Agreement validates the Soviet Schemes for Complex [Integrated] Water Resources Use and Protections,Footnote 63 which provide for detailed regulations on water allocation and use between the Central Asian republics. However, the “equity” of these norms has been questioned. For instance, concerns were raised by some states’ representatives that the agreement favours a status quo that does not take into account current political, economic, and social circumstances and the new national interests of the states.Footnote 64 Existing legal arrangements in the region were not designed to accommodate changing circumstances, nor can they be easily amended. As a result, many treaties became stagnant and lost their effectiveness. The negotiation of new agreements has not succeeded so far. Whereas the equitable and reasonable use rule, being responsive to the necessities of time and place, adopts a flexible all-encompassing approach to reconciling a broad range of existing and new economic, social, and environmental issues and ultimately provides for a legal framework for such discussions and, if necessary, adjustments,Footnote 65 it also allows for the engagement of other riparian states such as Afghanistan in transboundary water management in the region.Footnote 66

It has further been argued that the rule of equitable and reasonable use is better able to reconcile competing interests in the region than the concept of “benefit sharing”Footnote 67 embedded in the subregional agreements on water and energy trade-off between the riparian states to the Syrdarya.Footnote 68 Thus, Tarlock and Wouters argue that the application of the concept of benefit sharing among riparian states can prejudice the application of the equitable and reasonable use rule through introducing “unequal bargaining among states; the premature ‘sale’ of future use opportunities; and the increased risk of aquatic ecosystem degradation”.Footnote 69 To avoid these failures, Article 4 of the draft agreement on the Syrdarya river basin seeks to codify “the equitable and reasonable use of water resources of the basin by each Party” by which the parties agreed to “be guided”.Footnote 70

In summary, the stringency of the equitable and reasonable use rule varies from the mandatory scale of engagement in the 1997 UN Convention and 1992 UNECE Convention to the lesser level of framing the subregional treaties in preambular provisions. As far as determinacy is concerned, the qualifying adjectives “equitable and reasonable” are not without ambiguity and are contingent to the extent that their determination applies to a specific factual context of norm application. Nonetheless, the discretion of states is constrained by the requirement of considering objective factors embedded in the rule itself.Footnote 71 The standard can be further objectified through procedural obligations such as the duty to co-operate, to exchange information, to notify on planned measures, to conduct assessments and the like, and through the more detailed requirements of watercourse-specific agreements.Footnote 72

IV. The no-harm rule

The no-harm rule derives its normative foundation from sic utere tuo ut alienum non laedas, or the good neighbourliness principle. It is now part of the corpus of international customary and treaty law relating to transboundary watercourses.Footnote 73 Article 7(1) of the 1997 UN Convention envisages the no-harm rule, providing that “[w]atercourse States shall, in utilizing an international watercourse in their territories, take all appropriate measures to prevent the causing of significant harm to other watercourse States”.Footnote 74 The ILC's commentary to Article 7 explains that “[t]he obligation of due diligence contained in article 7 … is an obligation of conduct, not an obligation of result”.Footnote 75 In similar fashion, Article 2(1) of the 1992 UNECE Convention provides that “[t]he Parties shall take all appropriate measures to prevent, control and reduce any transboundary impact”.Footnote 76 The Guide to implementing the 1992 UNECE Convention, in recognizing “a reasonable amount of flexibility” of this due diligence obligation, defines a non-exhaustive list of minimum requirements to comply with Article 2(1) based on the provisions of other articles and annexes of the Convention.Footnote 77

The terms of the two instruments clearly suggest that states are not under an absolute obligation to guarantee that no significant harm will occur to other watercourse states. McCaffrey points out that “it is not factual harm per se but injury to a legally protected interest that the law prohibits”.Footnote 78 Consequently, the no-harm rule does not supersede the equitable and reasonable use rule by which “a legally protected interest” is to be established, adjusted, and protected but rather complements it.Footnote 79 This means, inter alia, that the rule constrains the conduct and protects the legitimate interest of all states, irrespective of their geographical location on a watercourse, on an equal footing. Also it should be noted that, as the ILC's commentary to 1994 Draft Articles explains, “[a] use which causes significant harm to human health and safety is understood to be inherently inequitable and unreasonable”.Footnote 80 In turn, the ILC's commentary to the 2001 Draft Articles on the prevention of transboundary harm from hazardous activities provides a useful clarification on the meaning of the word “significant”:

The no-harm rule, requiring from the parties a significant level of engagement, can be found in the treaty law relating to the environment under the auspices of the Commonwealth. Article 2 of the 1998 Commonwealth Agreement on Transboundary Waters provides that “the Parties are under an obligation to refrain from water management activities that may cause negative impact on environment, including water bodies”, “to take measures in order to prevent and eliminate surface and ground water pollution and depletion”, and “estimate damages caused to water bodies by use in a neighboring State according to a unified methodology”.Footnote 82 The preambular recitals of the 1992 Commonwealth Agreement on Environmental Interaction, using mandatory terms, note that “economic and other activities within the territory of a State shall not cause harm to the environment, the quality of life and economic activities in other States”.Footnote 83

Similarly at the subregional level, a substantive obligation embedded in Article 3 of the 1992 Almaty Agreement requires the parties “to refrain from actions on their respective territories that might affect interests of other contracting parties and cause harm to them, lead to deviations from the agreed volumes of water flow and pollution of water sources”.Footnote 84 Unlike the provision of the 1997 UN Convention and the 1992 UNECE Convention, the nature of the obligation imposed by this article appears to be result-oriented. According to its clear-cut formulation, its addressees must take all measures needed to ensure that no transboundary harm originates from their respective territories. It illustrates the application of a strong level of expression. The article does not discuss nor provide guidance to establishing the threshold of harm incumbent upon states,Footnote 85 such as whether significantFootnote 86, appreciable,Footnote 87 substantial,Footnote 88 or seriousFootnote 89 transboundary damage is prohibited. The prohibition of harm is not restricted to damage to the environment but extends to “the interests of other States”, including an obligation to secure the agreed volumes of water flow and avoid water pollution. Arguably, it may imply that even when there are no physical spillovers, unilateral actions are illegal if they, for example, affect other states’ economic interests.Footnote 90 The question may arise whether this provision indeed prohibits any transboundary harm, whether it in fact asks for the impossible.Footnote 91 The more plausible and internally consistent reading of this article in terms of the objective and purpose of the agreement suggests that this provision imposes significant limits on the unilateral actions of states within their jurisdictions and requires that any possibly harmful activity must be co-ordinated and concerted among the parties. This conclusion is supported by the way in which the title and preambular provisions of the agreement are formulated to reflect its spirit of “joint management” and “consolidation and coordination of actions”.Footnote 92 The 1998 Environmental Cooperation Agreement between Kazakhstan, the Kyrgyz Republic, and Uzbekistan is another agreement by which the parties are clearly committed to co-operate and “coordinate their actions in building new facilities in frontier areas or in any areas that might have adverse transboundary impact”Footnote 93 “with a view to attaining practical results”.Footnote 94

In summary, all relevant instruments seem to cast the no-harm rule in forceful language (“shall”, “under an obligation”, and “requires”) whereas the level of the norm's determinacy, specifying these actions, varies. It requires the countries of Central Asia to meet a due diligence standard of conduct in the use of international watercourses under customary law as reflected in the 1997 UN and the 1992 UNECE Conventions. The content of “due diligence” cannot be distilled in abstraction and “cannot be reduced to a clear and accurate definition which might serve as an objective standard for deciding, regardless of the circumstances, whether a State was ‘diligent’ ” [emphasis added].Footnote 95 This is “an eminently flexible concept that is designed to take into account the facts and circumstances of each particular case”.Footnote 96 It thus refers to a number of elements such as the relevant state's capacity, the risk that harm is caused or the degree of care, and the nature of the interest to which the harm is caused, considered in the context of all the circumstances of the case.Footnote 97 The ILC's commentary provides, for instance, that “[t]he State may be responsible … for not enacting necessary legislation, for not enforcing its laws … or for not preventing or terminating all illegal activity, or for not punishing the person responsible for it”.Footnote 98 Further, the no-harm rule as applied in the Aral Sea Basin under the 1992 Almaty Agreement appears to prohibit unilateral actions that detract from the “joint management” of interstate water resources use and protection.Footnote 99

V. Obligations related to environmental protection

The obligations related to the protection of international watercourses and their ecosystems are to be found in a range of customary and treaty obligations of the Central Asian states.

With respect to the 1997 UN Convention, Tanzi and Arcari observe that “the environmental protection factor runs through virtually all the provisions of the convention”.Footnote 100 The Convention's provisions that embody the objective of protection of the watercourse and the principle of sustainabilityFootnote 101 within the framework of equitable and reasonable use clearly reflect a general duty of states and therefore are binding for the Central Asian states.Footnote 102 Further, Tanzi considers that the concept of sustainability has played an essential role in reconciling “the long-standing conflict between the ‘equitable and reasonable utilization’ and the ‘no-harm’ doctrines with respect to which [it] appears to be the lowest common denominator”.Footnote 103 Article 21(2) as “a special application of the general principles contained in Article 5 [equitable utilization] and 7 [no harm]”Footnote 104 requires the parties to exercise due diligence and to co-operate to

To clarify the relationship between these rules, McCaffrey explains that “a use becomes inequitable and unreasonable to the extent that it causes pollution harm to other watercourse states”.Footnote 105 Codifying existing customary international law, Articles 22 and 23 forcefully impose requirements concerning the introduction of alien species and the protection and preservation of the marine environment, respectively.Footnote 106 Finally, inspired by strong support in state practice, the 1997 UN Convention introduced in mandatory terms a general obligation to protect and preserve the ecosystems of an international watercourse that seeks to “enhance a comprehensive and ‘holistic’ approach to the issues of the protection of international watercourses”.Footnote 107 The ILC's commentary treats “protection” as a specific application of the optimal and sustainable use of an international watercourse “consistent with the adequate protection thereof” in Article 5 on equitable and reasonable use, and it refers to “preservation” as to be applied to “freshwater ecosystems that are in pristine or unspoiled condition” which are to “be protected in such a way as to maintain them as much as possible in their natural state”.Footnote 108 The ILC construes the term “ecosystem”, defined as “an ecological unit consisting of living and non-living components that are interdependent and function as a community”, as to bear “a more precise scientific and legal meaning” than the term “environment”.Footnote 109 Despite increasing support for the ecosystem approach in modern treaty practice and the work of international organizations, legal scholars are careful in attributing customary status to the obligation to protect and preserve the ecosystems of international watercourses, while treating it as a “new”, “emerging”, or “developing” obligation.Footnote 110 Still, it is apparent that the 1997 UN Convention provides an essential basis for the protection of international watercourses and their ecosystems in stringent terms, while assuming that more specific standards and rules will be developed for individual international watercourses at a basin level. To bring clarity to the relationship between the environmental provisions of the Convention and equitable and reasonable use and no-harm, Birnie, Boyle, and Redgwell summarize that “[t]he only plausible reading of Articles 7(1), 20 and 21 is that these obligations of due diligence are not themselves subject to equitable balancing, but must be complied with independently of any claim of equitable utilization”.Footnote 111 The 1992 UNECE Convention takes one step further in the protection of international watercourses and their ecosystems, establishing sound rules for the Parties to “take all appropriate measures” in order “to ensure that transboundary waters are used with the aim of ecologically sound and rational water management, conservation of water resources and environmental protection”, and “to ensure conservation and, where necessary, restoration of ecosystems”,Footnote 112 and providing a definition of “transboundary impact” that encompasses environmental considerations.Footnote 113 The Convention stipulates that principles such as the precautionary principle, the polluter-pays principle, and intergenerational equityFootnote 114 shall guide the Parties in their implementation of the above measures, and it calls for measures to promote sustainable water-resources management, including the application of the ecosystem approach.Footnote 115 Article 3 requires the development of limits on pollution discharges based on “best available technology” or “best environmental practices”. The Riparian Parties shall co-operate “in order to develop harmonized policies, programmes and strategies … aimed at the protection of the environment of transboundary waters”.Footnote 116 The Convention's annexes further help to specify the content of due diligence requirement to protect the environment by defining the term “best available technology” (Annex I), and providing guidelines for developing best environmental practices (Annex II), and water-quality objectives and criteria (Annex III).

At the regional level, the 1992 Commonwealth Agreement on Environmental Interaction, “based on understanding of the integrity and indivisibility of the environment”,Footnote 117 stipulates that:

The terms of the 1998 Commonwealth Agreement on Transboundary Waters require more engagement from the parties to achieve the objectives of environmental protection. Using mandatory language, the instrument stipulates a set of general substantive and procedural measures for co-operation over “the protection of water bodies” referred to as “an activity or a set of measures aimed at conservation and restoration of water bodies, including remedial measures for water pollution, clogging and depletion, negative economic intervention into water regime of rivers, water body and groundwater source”.Footnote 119 Among those, “the Parties are obliged to refrain from water management activities that may cause negative impact on the environment, including water bodies” and “to take measures in order to prevent and eliminate surface and ground water pollution and depletion”.Footnote 120

In the Aral Sea Basin, few provisions of the subregional agreements explicitly recognize the Aral Sea itself and its deltas as “a legitimate water user”. Article 1 of the 1993 Kzyl-Orda Agreement states that a “common objective” of the Central Asian states is to ensure that water flows to the Aral Sea in order to “sustain … its lowered but stable, ecologically acceptable, levels and by this means preserve … the Sea as an object of nature”.Footnote 121 A 1988 Decree of the Council of Ministers of the Union of Soviet Socialist Republics established the requirements of minimum flows to the deltas of the Amudarya and Syrdarya and to the Aral Sea.Footnote 122

In addition to the minimum flow requirements to the deltas of the Amudarya and Syrdarya and to the Aral Sea, the subregional treaties stipulate a set of additional ecosystem-related obligations. Article 3 of the 1993 Kzyl-Orda Agreement “recognizes” “common objectives” relating to the protection of the environment to include the maintenance of appropriate water quality, the restoration of degraded ecosystems in the region, and the development and implementation of a co-ordinated strategy for social and economic development that meets environmental security objectives for the peoples of the region. Despite its positive intentions, the 1993 Kzyl-Orda Agreement's provisions seem to be expressed in rather declaratory terms or as overall goals rather than as precisely defined obligations. Nonetheless, these can be viewed as programmatic obligations when read together with the title of the agreement (“On Joint Actions to Resolve the Problems”).Footnote 123 According to the 1998 Environmental Cooperation Agreement, the parties shall co-operate in a wide range of environmental protection areas, including transboundary water resources conservation, rational use, and pollution prevention.Footnote 124 The objective of the 2006 Framework Convention on Sustainable Development, if the agreement enters into force, will require the parties “to ensure effective environmental protection for sustainable development in Central Asia, including … reduction and prevention of transboundary harm to the environment”.Footnote 125 The emphasis on effectiveness seems to suggest a stronger level of expression.

In addition to watercourse-specific treaties, a wide range of multilateral environmental agreements stipulate more general—but still binding—provisions for environmental protection and preservation that contribute substantially to the protection of the ecosystems of international watercourses in Central Asia. For example, the Ramsar Convention,Footnote 126 which arguably includes rivers in its broad definition of wetlands,Footnote 127 provides a co-operative framework for the wise use of wetlandsFootnote 128 and recognizes in its preambular provisions the “fundamental ecological functions of wetlands as regulators of water regimes and as habitats supporting a characteristic flora and fauna, especially waterfowl”.Footnote 129 With respect to transboundary aspects, it stipulates that “[t]he Contracting Parties shall consult with each other about implementing obligations … where a water system is shared by Contracting Parties”.Footnote 130 The Guidelines adopted by the 2002 Resolution of the Eighth Conference of the Contracting Parties encourage those parties with wetlands lying in shared river basins to apply the guidelines for the allocation and management of water to maintaining the ecological function of wetlands within the context of the management of water allocation in transboundary basins.Footnote 131 It should be noted that during the negotiation of the Syrdarya draft agreement the delegation of Uzbekistan raised concerns about the status and water requirements of the Aydar Arnasay Lakes System that was formed in its territory due to anthropogenic activities on the region's transboundary rivers.Footnote 132 Since the Aydar Arnasay Lakes System was registered as a Ramsar site in 2008,Footnote 133 the provisions of the Convention are directly applicable to the situation.

Another multilateral environmental agreement that envisages binding obligations related to international watercourses is the Convention on Biodiversity.Footnote 134 It states that the parties shall “as far as possible and as appropriate” “integrate … the conservation and sustainable use of biological diversity into relevant sectoral or cross-sectoral plans, programmes and policies;”Footnote 135 “promote the protection of ecosystems, natural habitats and the maintenance of viable populations of species in natural surroundings;”Footnote 136 “rehabilitate and restore degraded ecosystems and promote the recovery of threatened species, inter alia, through the development and implementation of plans or other management strategies;”Footnote 137 “prevent the introduction of, control or eradicate those alien species which threaten ecosystems, habitats or species;”Footnote 138 and “cooperate with other Contracting Parties, directly or, where appropriate, through competent international organizations, in respect of areas beyond national jurisdiction and on other matters of mutual interest, for the conservation and sustainable use of biological diversity”.Footnote 139 Similarly to the Ramsar Convention, the Conference of the Parties to the Convention on Biodiversity undertakes significant efforts to specify the deliberately qualifying language of the treaty provisions.Footnote 140

In summary, the obligations to protect international watercourses and their ecosystems are reflected in a range of multilateral, regional, and basin agreements establishing due diligence requirements for the states of Central Asia. The 1997 UN Convention casts the relevant requirements in stringent terms, while assuming that more specific standards and rules will be developed for individual international watercourses at a basin level. The 1992 UNECE Convention introduces the widest spectrum of obligations on the matter in terms of their stringency and determinacy. Relevant provisions of multilateral environmental agreements that are established in mandatory language, albeit “softened” by such phrases as “where appropriate”, “should be guided”, “promote”, and “as far as possible and as appropriate”, are made more specific through decisions of the conference of the parties and the work of the respective scientific and technical bodies. In this respect, close linkages across treaties seem to be essential for effective implementation of the obligations related to environmental protection. The language of the regional and subregional agreements is relatively precise in laying down guiding principles but needs further specification of the practical measures to be taken, including developing national laws and policies to implement the stated environmental objectives. In addition to individual endeavours, procedural co-operation between states and through international river commissions is an important means of giving concrete content to the stated obligations and ensuring that these are consistently implemented and complied with.

VI. Substantive norms within a system of international water law

This article began the task of evaluating the norms of international law as applied to the transboundary waters in the Aral Sea Basin. It explored the main substantive norms operating in the field—the rule of equitable and reasonable use, the no-harm rule, and obligations related to environmental protection of international watercourses—through focusing on their determinacy and stringency.

By exploring the determinacy of the substantive norms, the article demonstrated that open-textured and elastic rules prevail in the law governing international watercourses. For the most part, these substantive norms operate within a due diligence framework. The due diligence nature of obligations—along with the corresponding concept of the “appropriateness” of the measures—implies that a significant degree of flexibility and relativity must be applied to both the contents and time-frame of the conduct of the parties.Footnote 141 Accordingly, the textually indeterminate standards such as equity, reasonableness, and appropriateness that dominate the law of international watercourses generally make it more difficult to define certain obligations and to verify their fulfilment. However, the fact that substantive norms are generally couched in abstract terms does not affect the core of the rights and duties that arise therefrom. Instead, the determination of a required standard of conduct that flows from the rule of equitable and reasonable use, the no-harm rule, and the obligations to protect international watercourses is tied up with the specific context of the norm application and is contingent upon the existence of an adequate procedural and institutional system. Consistency and objectivity in the interpretation and application of contextual norms can be achieved through the further specification (contextualization) of norms, the institutionalized decision-making process, or adjudication.Footnote 142

Addressing the stringency of norms is useful to an understanding of the existence of the different levels of “control intention”Footnote 143 embedded in the norm-text. As evidenced in this article, the equitable and reasonable use rule and the no-harm rule, which represent well-established and highly contextual customary rules of international water law, are expressed in terms situated at the mandatory end of scale. At the same time, the obligations to protect ecosystems are mostly construed as requirements which “more actively work towards” environmental objectives in the UNECE and the Commonwealth Agreements and as programmatic obligations in the subregional agreements.Footnote 144

By focusing on the nature of norms, and what flows from it, the article draws attention to the danger of assessing norms with no reference to their legal and factual context. As McLachlan rightly commented, “[l]egal texts only make sense within the context of the system that gives them authority and meaning”.Footnote 145 This sentiment has been partly demonstrated in the foregoing analysis through focus on the interrelationship between norms. First, although the rule of equitable and reasonable use, the no-harm rule, and an emerging obligation to protect ecosystems qualify as independent norms in the field of international watercourses, these complement each other and work in tandem. Hence, understanding how these substantive norms relate to each other is a prerequisite for comprehending the nature of the law of international watercourses and subsequently for evaluating its performance and effectiveness. Second, the mutual support and complementarities of norms at the global, regional, and subregional levels are additional features of an international legal system that should be taken into account. For instance, whereas the subregional agreements typically stand as a lex specialis between the parties, the 1997 UN and 1992 UNECE Conventions, which in part reflect customary international law, can also provide a framework for their interpretation, if the former do not comprehensively define the rights and obligations of the parties and serve as the sole ground for action in cases not covered by precise rules.Footnote 146 Finally, due to their complex and indeterminate nature, the substantive rules of international water law necessitate that a sound procedural and institutional system is in place to interpret, implement, and develop these rules. Clearly, the highly procedural and contextual character of substantive norms makes the operation of these rules in isolation impossible, and accordingly the assessment of their “individual” effectiveness hardly justifiable. Still, the role of substantive norms in laying down normative benchmarks to follow is unquestionable.

These findings establish the need for further research on understanding the law of international watercourses as a normative and operating system, rather than a set of scattered rules. In his book Universalizing International Law, Judge Weeramantry urges that “[w]e will need to ensure that this international legal system is not a system that exists merely in the books but that it actually operates out there in the field”.Footnote 147 Unless there is a sound understanding on how the international legal system operates, its potential to contribute to addressing transboundary water challenges in the Aral Sea Basin, across Asia, and globally, remains untapped.