¹ See Res 70/1, ‘Transforming our World: The 2030 Agenda for Sustainable Development’ (21 October 2015) UN Doc A/RES/70/1, including a set of Sustainable Development Goals (SDGs). SDG 6 calls for States to ensure ‘the availability and sustainable management of water and sanitation for all’ and identifies several targets relating to access to water, good water management, and the protection of waterbodies and associated ecosystems

² The HLPW was convened in 2016 at the initiative of the UN Secretary-General and the President of the World Bank to champion an agenda to meet SDG 6 and other SDGs relying on water. It consisted of 11 sitting Heads of State and Government and one Special Adviser (a former Head of Government) and it delivered its outcome package, in the form of a galvanizing video, an Open Letter to Global Leaders and an Outcome Document: HLPW, Making Every Drop Count. An Agenda for Water Action (14 March 2018) (‘HLPW Outcome Document’).

³ For up-to-date overviews of water governance see Dupuy, P-M and Viñuales, JE, International Environmental Law (2nd edn, Cambridge University Press 2018) Ch 4CrossRefGoogle Scholar; Sands, P and Peel, J et al. , Principles of International Environmental Law (4th edn, Cambridge University Press 2018) Ch 9CrossRefGoogle Scholar.

⁴ HLPW Outcome Document, at 7.

⁵ Intergovernmental Panel on Climate Change. On this organization see R Encinas de Munagorri (ed), Expertise et gouvernance du changement climatique (LGDJ 2009).

⁶ See HLPW Outcome Document, at 9 (increase global water cooperation). See further at 20 (addressing transboundary water governance) and 30 (addressing global cooperation on water).

⁷ Protocol on Water and Health to the 1992 Convention on the Protection and Use of Transboundary Watercourses and International Lakes (17 June 1999) 2331 UNTS 202 (hereafter referred to as ‘the Protocol’ or the ‘PWH’).

⁸ See eg Australia: Water Act 2007 (Cth), Water Regulations (2008), Water Charge and Water Market Rules, Water Efficiency Labelling and Standards Act (2005); Brazil: National Water Resources Policy Act No 9433 (1998); Canada: Canada Water Act (1985); China: Water Law (1988), Water Pollution Prevention and Control Law (1984), revised in 2016; EU: Directive 2000/60/EC: Water Framework Directive (2000), Directive 2008/105/EC: Environmental Quality Standards (2008), Directive 2013/39/EU: Environmental Quality Standards/Priority substances (2013), Directive 2006/118/EC: Groundwater Directive (2006), Directive 2007/60/EC: Floods Directive (2007), Directive 98/83/EC: Drinking Water Directive (1998), Directive 2006/7/EC: Bathing Water Directive (2006), Directive 91/271/EEC: Urban Waste Water Treatment Directive (1991), Directive 91/676/EEC: Nitrates Directive (1991), Directive 2008/56/EC: Marine Strategy Framework Directive (2008); France: Environmental Code, book II, title I (2000) and regulations; Germany: Federal Water Management Act (1976); India: Water (Prevention and Control of Pollution) Act (1974), Water (Prevention and Control of Pollution) Cess Act (1977); Indonesia: Water Law (1974), reinstated following the revocation by the Supreme Court in 2015 of the Law No. 7/2004 on Water Resources (2004); Japan: Water Pollution Prevention Law, No. 138/1970 (1970), Law Concerning Special Measures for the Conservation of Lake Water Quality, No. 61/1984 (1984); Mexico: National Waters Act (1992); Singapore: Environmental Protection and Management Act (1999), Environmental Protection and Management (Trade Effluent) Regulations (2008), Sewerage and Drainage Act (1999); South Africa: National Water Act 36 (1998); South Korea: Water Quality and Ecosystem Conservation Act (2005), Public Waters Management and Reclamation Act (2010), Groundwater Act (2015), Water Supply and Waterworks Installation Act (2016), Drinking Water Management Act (2016); UK: Water Resources Act (1991), Water Supply (Water Quality) Regulations (2016); US: Clean Water Act (1972).

⁹ See Tarlock, D, ‘Water Governance’ in Lees, E and Viñuales, JE (eds), The Oxford Handbook of Comparative Environmental Law (Oxford University Press, forthcoming 2019)Google Scholar.

¹⁰ This transition is insightfully discussed, by reference to the case of Britain, in Lobban, M, ‘Tort Law, Regulation and River Pollution: The Rivers Pollution Prevention Act and Its Implementation, 1876–1951’ in Arvind, TT and Steele, J (eds), Tort Law and the Legislature: Common Law, Statute and the Dynamics of Legal Change (Hart Publishing 2013) 329–52Google Scholar. Lobban describes, among other things, how the vertical regulatory regime introduced through the 1876 Rivers Pollution Prevention Act was carefully drafted to focus on the negative externalities without interfering with the underlying transaction.

¹¹ See eg Selman, M et al. , Water Quality Trading Programs: An International Overview (World Resources Institute Issue Brief 2009)Google Scholar; Shortle, J, ‘Economics and Environmental Markets: Lessons from Water-Quality Trading’ (2013) 42 Agricultural and Resource Economics Review 57CrossRefGoogle Scholar.

¹² For example, in the US, under the Clean Water Act (1972), Title III, industrial wastewater discharges are subject to a permit (National Pollutant Discharge Elimination System – NPDES Permit) issued by the EPA or by the authorities of federated States, which rely on standards (‘Effluent Guidelines’) that define technology-based requirements for each industry reflecting the highest pollutant reductions that are ‘economically achievable’.

¹³ See eg Brazil: Federal Law No. 9433/1997 (1997) (instituting the national policy on water resources and management), and CONAMA Framework Resolution 357/2005. More generally, many States specifically protect wetlands, a development that was significantly encouraged by the adoption in 1971 of the Convention on Wetlands of International Importance especially as Waterfowl Habitat (2 February 1971) 996 UNTS 245 (Ramsar Convention).

¹⁴ See generally Arthington, AH, Environmental Flows: Saving Rivers in the Third Millennium (University of California Press 2012)Google Scholar.

¹⁵ See eg France: Environmental Code (2000) art R 214-1.

¹⁶ See eg South Africa: National Water Act 36 (1998), section 1(xviii)(b) and 12–13.

¹⁷ For an overview of international experience in river restoration see Smith, B, Clifford, NJ and Mant, J, ‘The Changing Nature of River Restoration’ (2014) 1 Wiley Interdisciplinary Reviews: Water 249CrossRefGoogle Scholar (referring to developments following the adoption of the EU Framework Water Directive).

¹⁸ For an overview of these principles see McCaffrey, S, The Law of International Watercourses (Oxford University Press 2007) Ch 9 and 14Google Scholar.

¹⁹ On the recognition of the customary grounding of these principles by the International Court of Justice (ICJ) see Kohen, M, ‘Les principes généraux du droit international de l'eau à la lumière de la jurisprudence de la Cour internationale de Justice’ in SFDI, L’eau en droit international, Colloque d’Orléans (Pedone 2011) 61–78Google Scholar. There is a vast body of codification initiatives of these principles developed throughout the 20th century, particularly by: the Institut de Droit International (Utilization of Non-Maritime International Waters (except for Navigation), Salzburg, 1961 (‘Salzburg Resolution’)); the International Law Association (ILA) (Helsinki Rules on the Uses of the Waters of International Rivers, adopted at the 52nd conference of the ILA in August 1966 (‘Helsinki Rules’), Seoul Complementary Rules, adopted at the 62nd conference of the ILA in 1986 (‘Seoul Rules’), Berlin Rules on Water Resources, adopted by the ILA on 21 August 2004 (‘Berlin Rules’)); and the UN International Law Commission (ILC) (which resulted in the adoption of the 1997 New York Convention and 2008 Draft Articles on the Law of Transboundary Aquifers, discussed next in this section). This body of work also provides evidence of the customary grounding of the main principles governing watercourses. Of course, customary grounding always requires a case-by-case analysis of specific aspects of a rule, but as a general matter, it is accurate to state that the international law of watercourses rests upon well settled principles. See A Tanzi, The Economic Commission for Europe Water Convention and the United Nations Watercourses Convention: An Analysis of their Harmonized Contribution to International Law (2015) UN Doc ECE/MP.WAT/42.

²⁰ However wide this web of treaties, it does not cover all or even most relevant waterbodies. According to the HLPW Outcome Document (at 20), at the global level, there are over 286 rivers and 600 aquifers which cross borders, and 60 per cent of transboundary river basins still lack any cooperative arrangement.

²¹ For an overview of existing watercourse specific agreements see UNEP, Oregon State University and FAO, Atlas of International Freshwater Agreements (UNEP 2002). The Oregon State University hosts a database of watercourse agreements.

²² The Ramsar Convention has been argued to be an important global water treaty because of its focus on the protection of wetlands as ‘natural infrastructures’ that regulate water quantity and quality. See Dupuy and Viñuales (n 3) 220–1. However, this argument sees the Ramsar Convention approach as a vertical and regulatory one (rather than as horizontal and cooperative).

²³ Convention on the Protection and Use of Transboundary Watercourses and International Lakes (18 March 1992) 1936 UNTS 269 (‘Helsinki Convention’ or ‘Water Convention’).

²⁴ United Nations Convention on the Law of the Non-Navigational Uses of International Watercourses (21 May 1997) 36 ILM 700 (‘New York Convention’).

²⁵ ‘Draft Articles on the Law of Transboundary Aquifers’ (11 December 2008) GA Res 63/124, UN Doc A/RES/63/124 (‘ILC Draft Articles on Aquifers’), as complemented by the UNECE Model Provisions on Transboundary Groundwaters (2014), UN Doc ECE/MP.WAT/40.

²⁶ Committee on Economic, Social and Cultural Rights, General Comment No. 15 (2002) The Right to Water (Arts 11 and 12 of the International Covenant on Economic, Social and Cultural Rights) (26 November 2002) UN ESCOR Doc. E/C.12/2002/11 (‘General Comment 15’). The existence of one right with two aspects (water and sanitation) or of two different rights was unclear for several years. This is apparent from the terminological evolution in the relevant resolutions from the UN General Assembly and the Human Rights Council. See, in ascending chronological order: Res A/64/292, ‘The Human Right to Water and Sanitation’ (28 July 2010) UN Doc A/64/L.63/Rev.1; Res 15/9: ‘Human Rights and Access to Safe Drinking Water and Sanitation’ (24 September 2010) A/HRC/15/L.14; ‘Human Rights Obligations Related to Access to Sanitation’ (1 July 2009) UN Doc A/HRC/12/24; Res 70/169, ‘The Human Rights to Safe Drinking Water and Sanitation’ (17 December 2015) UN Doc A/RES/70/169 (the latter resolution recognized, at para 2, that: ‘the human right to safe drinking water entitles everyone, without discrimination, to have access to sufficient, safe, acceptable, physically accessible and affordable water for personal and domestic use, and that the human right to sanitation entitles everyone, without discrimination, to have physical and affordable access to sanitation, in all spheres of life, that is safe, hygienic, secure, socially and culturally acceptable and that provides privacy and ensures dignity, while reaffirming that both rights are components of the right to an adequate standard of living’).

²⁷ See eg General Comment 15, paras 30–36 (discussing so-called ‘international obligations’, ie what I call here horizontal cooperative obligations. These set of paragraphs is premised on the idea, stated in para 31, that ‘[t]o comply with their international obligations in relation to the right to water, States parties have to respect the enjoyment of the right in other countries’). Yet, as it will be discussed later in this article, the language used in these paragraphs is less assertive than in the other sections of General Comment 15.

²⁸ Report of the United Nations Conference on Environment and Development, A/CONF.151/26/Rev. l (Vol. l), Res 1, Annex 2: Agenda 21, Ch 18. See also Protocol on Water and Health (17 June 1999) 2331 UNTS 202, arts 4(1) and 5(j).

²⁹ See eg Sustainable Development Goal 6.5, in Resolution 70/1, ‘Transforming Our World: The 2030 Agenda for Sustainable Development’ (21 October 2015) UN Doc A/RES/70/1.

³⁰ See Holff, H, Understanding the Nexus. Background Paper for the Bonn 2011 Conference: The Water, Energy and Food Security Nexus (Stockholm Environmental Institute 2011)Google Scholar.

³¹ See Water Convention Secretariat, Reconciling Resource Uses in Transboundary Basins: Assessment of the Water-Food-Energy-Ecosystems Nexus (UNECE 2015).

³² Perhaps as a result of this double-umbrella, the Protocol has enjoyed (and suffered from) a reputation as a strong and credible instrument. This may in part explain why it is still relatively under-studied. One could even say that there is a gap in the literature. Only a handful pieces have been devoted to it. See eg Chuffart, SL and Viñuales, JE, ‘From the Other Shore: Economic, Social and Cultural Rights from an International Environmental Law Perspective’ in Reidel, E, Giacca, G and Golay, C (eds), Economic, Social and Cultural Rights: Current Issues and Challenges (Oxford University Press, 2014) 286–307CrossRefGoogle Scholar; McIntyre, O, ‘The UNECE Water Convention and the Human Right to Access to Water: The Protocol on Water and Health’ in Tanzi, A et al. (eds), The UNECE Convention on the Protection and Use of Transboundary Watercourses and International Lakes: Its Contribution to International Water Cooperation (Nijhoff 2015) 345–66Google Scholar; Tanzi, A, ‘Reducing the Gap between International Water Law and Human Rights Law: The UNECE Protocol on Water and Health’ (2010) 12 International Community Law Review 267Google Scholar. Some books also discuss the Protocol, but not in great detail. See eg Dupuy and Viñuales (n 3) 380–90; Sohnle, J, Le droit international des ressources en eau douce: solidarité contre souveraineté (La documentation française 2002) 198–200Google Scholar.

³³ Aarhus Convention on Access to Information, Public Participation in Decision-making and Access to Justice in Environmental Matters (25 June 1998) 2161 UNTS 447 (‘Aarhus Convention’).

³⁴ See eg Escazú Regional Agreement on Access to Information, Public Participation and Justice in Environmental Matters in Latin America and the Caribbean (4 March 2018) (hereafter ‘Escazú Agreement’, not yet in force); Proposal of a Directive of the European Parliament and of the Council on the quality of water intended for human consumption (recast), Brussels 1.2.2018, COM(2017) 753 Final, 2017/0332 (COD) (Drinking Water Directive Recast Proposal) (combining a vertical regulatory approach with a new art 13 on ‘Access to water intended for human consumption’).

³⁵ PWH, art 4(1)–(2), read in the light of the principles in art 5.

³⁶ ibid, art 6(2)(a)–(n).

³⁷ ibid, art 6 and 7.

³⁸ ibid, art 8.

³⁹ There are five main agreements forming the backbone of the UNECE approach, namely: Convention on Long-range Transboundary Air Pollution (13 November 1979) 1302 UNTS 217 (with its eight subsequent protocols); the Convention on Environmental Impact Assessment in a Transboundary Context (25 February 1991) 1989 UNTS 310 (with a protocol), the Convention on the Transboundary Effects of Industrial Accidents (17 March 1992) 2105 UNTS 457 (with its joint protocol with the Water Convention); the Water Convention (with two joint protocols, including the PWC), and the Aarhus Convention (expanded by a protocol). On this cluster of agreements see Schrage, W, Bull, K and Karadjova, A, ‘Environmental Legal Instruments in the UNECE Region’ (2007) 18 YbIntlEnvL 3Google Scholar.

⁴⁰ PWH, art 9.

⁴¹ ibid, art 10.

⁴² ibid, arts 5(i), 6(2) and 6(5)(b).

⁴³ ibid, art 5(i).

⁴⁴ ibid, arts 11–14.

⁴⁵ See Interpretation of the provisions of the Protocol on Water and Health related to transboundary waters, prepared by the Compliance Committee, with the assistance of the UNECE secretariat, in November 2016, with editorial changes and clarifications introduced by the Compliance Committee in May 2017.

⁴⁶ The Committee was established pursuant to art 15 of the Protocol. See Decision I/2, ‘Review of Compliance’, ECE/MP.WH/2/Add3, EUR/06/5069385/1/Add.3 (3 July 2007).

⁴⁷ Consultation Process: Terms of Reference, available at <https://www.unece.org/fileadmin/DAM/env/documents/2014/WAT/11Nov_25_CC/ToR_Consultation_Process_amended_10th_meeting_Nov14_final.pdf>. This procedure is currently being used to advise Estonia, Latvia and Lithuania on the implementation of the Protocol. Previously, it was used to advise Albania, Azerbaijan and Bosnia and Herzegovina.

⁴⁸ Decision I/2, ‘Review of Compliance’ paras 11(a) and 16–22. Only one communication has been submitted so far against Portugal, for failure to submit its report during the third reporting cycle in 2016. Portugal subsequently submitted its report. The procedure, which had in the meantime changed course as a Committee-initiated procedure, was discontinued.

⁴⁹ See New York Convention, art 5; Water Convention, art 2(2)(b); Berlin Rules, art 12. The ICJ has referred to this principle in the case concerning the Gabčíkovo-Nagymaros Project (Hungary v Slovakia), Judgment, ICJ Reports 1997 at 7, para 78.

⁵⁰ See also Helsinki Rules, art V(2); Berlin Rules, arts 13(2) and 14.

⁵¹ The rights to water and sanitation are not expressly stated in the International Covenant on Economic, Social and Cultural Rights on which General Comment 15 is based. They are based on an interpretation of the rights to an adequate standard of living (art 11) and to health (art 12), which are expressly stated. This caveat has not been forgotten by States. The most recent UNGA resolution on these rights (Res 70/169, ‘The Human Rights to Safe Drinking Water and Sanitation’ (17 December 2015) UN Doc A/RES/70/169) recognizes them ‘while reaffirming that both rights are components of the right to an adequate standard of living’).

⁵² See General Comment 15, paras 32–36.

⁵³ The ‘equitable access’ dimension of the PWH has been actively developed as a follow-up to the UN General Assembly recognition, starting in 2010, of the rights to water and sanitation. Two noteworthy examples are a compilation of good practices (No one left behind. Good practices to ensure equitable access to water and sanitation in the Pan-European region, ECE/MP.WH/6, available at <www.unece.org/index.php?id=29170>) and the development of an ‘Equitable Access Score-card’ for countries to conduct self-assessments (The Equitable Access Score-card, ECE/MP.WH/8, available at: <www.unece.org/index.php?id=34032>).

⁵⁴ PWH, arts 2(10) (defining expansively water management plans), 4(1) (formulating the general due diligence duty of the Protocol as ‘within a framework of integrated water-management systems aimed at sustainable use of water resources, ambient water quality which does not endanger human health, and protection of water ecosystems’), 5(j) (formulating the principle that water resources should be managed ‘in an integrated manner on the basis of catchment areas’) and 6(5)(b) (relating to plans to achieve water targets).

⁵⁵ PWH, arts 5(a) (requiring the establishment of ‘national or local arrangements for coordination between their competent authorities’) and 9(3)(b) (development of integrated information systems).

⁵⁶ See eg PWH, art 4.7 (expressly referring to the Espoo Convention).

⁵⁷ Such possibility was introduced following the first amendment to the Convention, adopted in 2001 and entered into force in 2014.

⁵⁸ Protocol on Pollutant Release and Transfer Registers to the Convention on Access to Information, Public Participation in Decision-Making and Access to Justice in Environmental Matters, Kiev (21 May 2003) 2626 UNTS 119 (known as the PRTR Protocol or the Kiev Protocol).

⁵⁹ ‘Declaration on the Application of Principle 10 of the Rio Declaration on Environment and Development’ (25 July 2012) UN Doc A/CONF.216/13.