Article 27

27.1 Commentary

In recent years there has been a growing recognition that climate change will continue to cause an increase in the magnitude and frequency of extreme events. Such events will have a range of impacts on social, economic and environmental uses of international watercourses (See Figure 5.1). Article 27 of the UN Watercourses Convention deals with the prevention and mitigation of such events or ‘harmful conditions’. Pursuant to the article, these ‘harmful conditions’ include ‘flood or ice conditions, water-borne diseases, siltation, erosion, salt-water intrusion, drought or desertification.’ While limited in content, this Article provides an important link between the law of international watercourses, and international law and policy relating to climate change adaptation.

In terms of international law relating to climate change, the 1992 Climate Change Framework Convention obliges states to, ‘cooperate in preparing for adaptation to the impacts of climate change; develop and elaborate appropriate and integrated plans for coastal zone management, water resources and agriculture, and for the protection and rehabilitation of areas, particular in Africa, affected by drought and desertification, as well as floods.’400

Along similar lines but in more general terms Article 27 of the UN Watercourses Convention requires states to adopt, ‘all appropriate measures’ to prevent or mitigate conditions related to an international watercourse that may be harmful to other watercourse states; thus couching this Article as a due diligence obligation.

While what may constitute ‘appropriate measures’ has been discussed generally within the context of Article 7 of the UN Watercourses Convention,401 it is important to recognise that there has been a growing trend to develop adaptation measures to cope with the impacts of climate change. The importance of such adaptation measures cannot be underestimated. As noted by the UNECE, ‘adaptation to climate change is … indispensable and urgent since the climate is already changing in some respects, and mitigation will take too long to show effects. Further climate change throughout this century and beyond is almost certain even if global mitigation efforts prove successful. In addition it is more cost effective to start preparing adaptation now.’402

Tarlock maintains that, ‘adaptation to the projected adverse hydrological impacts of global climate change requires the presence of a reasonably well-developed property rights regime in the effected basin, and that the regime must be supported by public and private adaptive management institutions’.403 Within the context of international watercourses, joint institutions are therefore considered an effective mechanism by which to cope with the hydrological impacts of climate change. Tanzi and Arcari even maintain that ‘the fact that a state has adopted all the appropriate measures that can be taken individually may not be sufficient to face certain harmful conditions or emergency situations adequately. Cooperation through joint action could be required according to the circumstances pertaining either to the nature of the actual harmful conditions, or to the affected area’.404

Within the context of Article 27 of the UN Watercourses Convention, the ILC identifies a number of measures that may assist in the prevention and mitigation of harmful conditions and might be facilitated through joint institutions, namely the regular and timely exchange of data and information, holding consultations concerning planning and implementation of joint measures, and the preparation of studies of the efficacy of measures that have been taken’.405 Cooley and others also suggest that an important role that can be played by joint institutions is ‘to convene a technical committee to develop a common hydrological model of the basin and common climate change scenarios’.406

Within the context of flooding, the ILA identifies a number of areas where states may cooperate, including:

(i) the collection and exchange of relevant data;

(ii) the preparation of surveys, investigations and studies and their mutual exchange;

(iii) planning and designing of relevant measures;

(iv) execution of flood control measures;

(v) operation and maintenance of works;

(vi) flood forecasting and communication of flood warnings; and

(vi) setting up of a regular information service charged to transmit the height of water levels and the discharge quantities.407

Along similar lines is the UNECE’s Model Provisions on Flood Management, that states should cooperate in order to:

(i) monitor/ data collection, exchange of hydrological and meteorological data, and development of a forecasting model covering the whole river basin or of a linkage between the Parties’ respective forecasting models;

(ii) prepare surveys, studies (including cost-benefit or cost-effectiveness analysis), flood plain maps, flood risk assessments and flood risk maps, taking due account of local knowledge, and exchange of relevant national data and documentation;

(iii) develop a comprehensive flood action plan or a set of co-ordinated flood action plans addressing prevention, protection, preparedness and response and providing common objectives, joint action, contingency plans, information policy, flood plain management and, where appropriate, flood control works and financing mechanisms;

(iv) raise awareness and provide access to information, publication participation and access to justice408 (see also the 2007 EU Floods Directive).

400 UN Framework Convention on Climate Change (adopted 9 May 1992, entered into force 24 March 1994 (1992) 31 International Legal Materials 849, art 4(1) (e).

401 See Section 7.1.

402 UNECE, Guidance on Water and Adaptation to Climate Change (UN 2009), 11.

403 D Tarlock, ‘How Well Can International Water Allocation Regimes Adapt to Global Climate Change?’ (2000) 15 Journal of Land Use and Environmental Law 423, 424.

404 A Tanzi and M Arcari, The United Nations Convention on the Law of International Watercourses (Kluwer Law International 2001), 222. See also S C McCaffrey, ‘The Need for Flexibility in Freshwater Treaty Regimes’ (2003) Natural Resources Forum 156, 160-161.

405 1994 Draft Articles at 129.

406 H Cooley and others, Understanding and Reducing the Risk of Climate Change for Transboundary Waters (Pacific Institute 2009), 16.

407 ILA, ‘Flood Control’, in S Bogdanovic, International Law of Water Resources – Contribution of the ILA (1954 – 2000) (Kluwer Law International 2001), 151. See also A Rieu-Clarke, ‘A Survey of International Law Relating to Flood Management: Existing Practices and Future Prospects’, (2008) 48 Natural Resources Journal 649.

408 UNECE, ‘Declaration of Bonn, Rules of procedures for Meetings of the Parties and Model Provisions on Transboundary Flood Management’ (23 December 2008), ECE/MP.WAT/19/Add1. See also, UNECE, ‘Sustainable Flood Prevention’ (14 January 2000), MP.WAT/2000/7.

Figure 5.1 - Effects of climate change and its impacts on water services Figure 5.1Effects of climate change and its impacts on water services.Amended from BC Bates, ZW Kundzewicz, S Wu and JP Palutikof (eds.), Climate Change and Water (IPPC 2008), 70.

Adaptation Planning and Practices – Work Area 6 of the Nairobi Work Programme

Work Area 6 of the Nairobi Work Programme, under the UN Climate Change Framework Convention, seeks to collect, analyse and disseminate information on past and current practical adaptation actions and measures so that governments, relevant organisations, business, communities, decision makers, and other regional and national stakeholders can learn from each other to reduce vulnerability and adapt to the impacts of climate change in the most effective manner. The range of potential adaptation actions include shortand long-term strategies and projects involving changes in lifestyle and behaviour, resource management such as farming, food and water storage, and changes in regulatory frameworks and laws such as for housing and infrastructure. The effectiveness of a practice tends to be contextspecific, although there is still much value in sharing knowledge and information on practices so that they can be considered, replicated, improved and/or adapted to suit different needs, scales and geographic locations.

For more information see

The 2007 European Union Floods Directive

The EU Floods Directive focuses on three areas:

(1) preliminary flood risk assessment;

(2) flood maps; and

(3) flood risk management plans.

In the context of flood risk assessment, member states are obligated to conduct a preliminary assessment, which should include maps of the river basin district, a description of past floods which have had a significant adverse impact, and the likely adverse consequences of future floods. Following the preliminary flood risk assessment, member states must identify those river basin districts where potential significant flood risks exist or might be considered likely to occur. The Floods Directive also provides that preliminary flood assessments must be made available to the public.

For areas where a potential significant flood risk exists or might be considered likely to occur, member states must prepare flood hazard maps and flood risk maps. Flood hazard maps should contain information on the potential extent of floods, water depths or water level, and flow velocity or relevant water flow, where appropriate.’ Flood risk maps should show the potential adverse consequences associated with likely floods, in terms of, inter alia, inhabitants, economic activities, and installations affected. Under the Floods Directive, member states are obliged to ensure that the maps are made available to the public.

Finally, member states are required to establish flood risk management plans. Active involvement of ‘interested parties’ in the production, review, and updating of the flood risk management plans must be encouraged by the member states, and the plans must be made available to the public. Management plans should include conclusions made after the first preliminary flood risk assessment, flood hazard and flood risk maps, a description of the appropriate objectives of flood risk management, and a summary of measures and their aims to achieve the appropriate objectives of flood risk management. The flood risk management plan should also include:

‘(1) a description of the prioritisation and the way in which progress in implementing the plan will be monitored;

(2) a summary of public information and consultation measures/action taken;

(3) a list of competent authorities and, as appropriate, a description of the coordination process within any international river basin district.’

For more informations see


Floods and the Mekong River Commission

Within the context of the Mekong, the Mekong River Commission has implemented a programme for Flood Management and Mitigation.

The programme was established in 2005 and consists of five components, namely:

(i) the establishment of a regional flood centre in Phnom Penh, Cambodia that provides floodrelated tools, data and knowledge at national and regional levels, produces regional flood forecasts, and provides tools for flood risk assessment and transboundary impact analysis;

(ii) structural measures and flood proofing, including reservoirs, embankments and waterways;

(iii) mediation of transboundary flood issues, that facilitates dialogue and resolution of issues concerning land management and land use planning, infrastructure development and crossborder emergency management of floods;

(iv) flood emergency management, which seeks to deal with the negative impacts of floods more effectively through capacity building, knowledge sharing and public awareness campaigns; and

(v) land management, which covers issues such as land use planning and damage reducing land management policies.


UNECE – Key steps for the development of an adaptation strategy:

1. Establish the policy, legal and institutional framework

a. Assess existing international commitments, policies, laws and regulations for water and related sectors (e.g. agriculture, health case, hydropower development, inland water transport, forestry, disaster management, nature conservation) in relation to their effectiveness in reducing climate-induced vulnerabilities and to their capacity to support the development of adaptation strategies and then revise and complement them as needed;

b. Define the institutional processes through which adaptation measures are or will be planned and implemented, including where decision-making authority lies at the transboundary, national and local levels and what the links are between these levels;

2. Understand the vulnerability of society

a. Ascertain the information needed to assess vulnerability

b. Gauge the future effects of climate change on the hydrological conditions of the specific transboundary basin in terms of water demand and water availability, including its quality, based on different socio-economic and environmental scenarios;

c. Identify the main current and climate-induced vulnerabilities that affect communities, with particular attention paid to water resources and the health-related aspects;

d. Determine, through participatory processes, the needs, priorities and adaptive capacities of different states;

3. Develop, finance and implement an adaptation strategy

a. Identify potential adaptation measures to reduce vulnerability to climate change and climate variability by preventing negative effects, by enhancing the resilience of natural, social and economic systems to climate change, or by reducing the effects of extreme events through preventive, preparatory, reactive and recovery measures. Measures should include both structural and non-structural measures as well as the financial means and the institutional changes necessary to implement successful adaptation processes;

b. Based on participatory processes, prioritise the potential measures and investments needed taking into account the financial and institutional resources and other means and knowledge available to implement them;

c. Ensure the step-by-step implementation of the adaptation strategy, in accordance with determined priorities, including coping measures from the local to the states and transboundary level.

4. Evaluate

a. Determine whether the measures are implemented and if those measures that are implemented lead to reduction of vulnerability; if not, adjust the measures accordingly;

b. Assess whether the scenarios as applied materialise in practice and adjust them accordingly.

For more information see: UNECE, Guidance on Water and Adaptation to Climate Change (UNECE 2009).


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