Hydro-strategy in the Balkans: the Sava River Basin from conflict to transboundary cooperation

Eleonora Sala - Novembre, 8 2026

Sarajevo, 29 November 2001. In a city that only six years earlier was still under siege, the delegates of Bosnia and Herzegovina, Croatia, Slovenia and the Federal Republic of Yugoslavia sit down at the same table to sign a Letter of Intent on a river, the Sava basin, that only a few years before had also been a dividing line between warring armies. A little over a year later, on 3 December 2002 in Kranjska Gora, the same four States sign a binding agreement to manage the entire basin together.[1] By 2006 that river, torn apart by conflict, will have a permanent commission, an operational secretariat and its first shared technical protocols: the textbook case of transboundary water cooperation in South-Eastern Europe. How, in so short a time, a basin fragmented by war came to be a model of shared governance is the question that guides this contribution.

1. Scenario analysis

To grasp the significance of this transition, we must start from the geographical and hydrological context in which it took place. The Balkans, often referred to by different names depending on the historical and political perspective adopted, form a peninsula of South-Eastern Europe enclosed between the Adriatic Sea, the Ionian Sea, the Aegean Sea and the Black Sea. The territory is predominantly mountainous, crossed by young and rugged ranges: the Dinaric Alps to the west, the Pindus Mountains to the south, the Balkan Mountains and the Serbian Carpathians to the east. The hydrogeological characteristics of the area are strongly shaped by the karstic nature of much of the bedrock. Numerous rivers flow underground for long stretches, carving tunnels and cavities into the limestone rock; the alternation between phases of abundance and scarcity of this groundwater makes the overlying surfaces more or less dry depending on the season, complicating the planning of surface water resources. The Balkan hydrographic network is divided into three main drainage areas: the Black Sea basin, which collects the largest share of the region's waters through the Danube network; the Adriatic and Ionian basin, fed by shorter rivers with a torrential regime such as the Neretva, the Drin and the Vjosa; and the Aegean basin, towards which watercourses such as the Vardar and the Strymon flow. The Sava basin lies within the first of these.

The Sava basin

The Sava is the main right-bank tributary of the Danube by water volume. It rises in Slovenia at the confluence of the Sava Dolinka and the Sava Bohinjka, flows eastwards through Slovenia, Croatia, Bosnia and Herzegovina and Serbia, and officially ends in Belgrade, where it joins the Danube, of which it is the main collector for the entire Balkan region. The Sava basin is considered one of the “jewels” of Europe's natural heritage: it is home to 8.1 million inhabitants, extends over about 97,200 km² and involves the territory of six countries — Slovenia, Croatia, Bosnia and Herzegovina, Serbia, Montenegro and a small portion of northern Albania. From its Alpine sources to the confluence with the Danube, on the southern edge of the Pannonian plain, the basin displays exceptional biological and landscape diversity: vast alluvial wetlands (the Posavina, the central basin of the Sava), lowland forests, national parks — including Triglav, Plitvice, Sutjeska and Durmitor — and numerous Ramsar sites[2]. A large part of the alluvial plains has remained intact, contributing to flood mitigation and biodiversity conservation.[3]

2. The strategic importance of the Sava basin

The Sava is not merely a geographical feature, but a veritable driver of economic development and a security factor for the entire Balkan region. Its importance operates on several levels. The first is water supply, since the basin supplies drinking water to millions of inhabitants in four countries. The widespread presence of karst formations in the hinterland makes surface reserves uneven, turning a perennial river like the Sava into an irreplaceable source for the urban centres it crosses. Moreover, the alluvial plains of the Posavina, at the heart of the basin, are one of the region's main granaries. Intensive irrigation drawing on the river and its tributaries is vital for the food self-sufficiency of Croatia, Bosnia and Herzegovina and Serbia. The contribution the basin makes to the Croatian, Bosnian and Serbian industrial and manufacturing complexes that historically arose along the Sava axis, in order to guarantee access to process water and the disposal of wastewater, should not be underestimated. Today, what has just been described is one of the basin's main environmental challenges. Several urban settlements such as Ljubljana, Zagreb, Sisak, Slavonski Brod, Brčko and Belgrade have developed along the course of the Sava, which regulates their microclimate and shapes their urban layout. As regards transport and trade, the Sava is a pan-European commercial navigation corridor (Corridor VII), which allows heavy goods (raw materials, coal, grain) to be shipped by river to central Europe and the Black Sea at low cost. Looking at ecosystems and biodiversity, we can state with certainty that the basin hosts one of the best-preserved freshwater ecosystems in Europe: the Posavina marshes and the numerous Ramsar sites support endemic species and bird migration corridors of continental importance. The basin's sensitivity to climate change exposes it to a growing oscillation between large-scale flood events, such as those that occurred in May 2014[4], and periods of prolonged drought. Shared management of the river is therefore crucial for risk assessment and the protection of human life. Since the basin is transboundary and crosses four States, which moreover have survived an armed conflict, water acts as an instrument of political interdependence: whoever controls the upstream stretches exerts considerable influence over the downstream countries, making the hydropolitics of the Sava a pillar of regional security and, as will be seen, also a test bed for post-war reconciliation.

3. Historical roots: from unified management to wartime fragmentation

The current hydrographic and institutional configuration of the Sava basin is the direct result of the profound political upheavals of the twentieth century. Under the Socialist Federal Republic of Yugoslavia (1945-1991), the basin's water resources were conceived and managed on a macro-regional scale, transcending the administrative boundaries of the individual internal republics. In terms of infrastructure, large dams, irrigation canals, reclamation systems and hydroelectric plants were designed by a single central authority, with the aim of maximising the economic and energy efficiency of the entire political space, then unitary, as in the case of the Sava hydroelectric system. Following the collapse of the federal State of Yugoslavia in the early 1990s, the centralised water architecture underwent changes and was then effectively shattered. A river that flowed entirely within the borders of a single country became, overnight, an international watercourse, shared by four independent sovereign States. At the management level this change brought considerable friction. During the armed conflicts of the 1990s, particularly in Croatia and Bosnia and Herzegovina (the two countries with the longest stretch of the river), numerous water and industrial infrastructures along the basin were directly damaged. The presence of serious pollution episodes is also acknowledged[5], for which the occurrence of permanent consequences cannot be ruled out with certainty. One of the most significant repercussions of the war was the interruption of the exchange of hydrological and meteorological data between the former republics, increasing the risk of uncoordinated natural disasters. In the immediate post-war period, the management of the basin's waters passed to separate national ministries and agencies, often lacking mutual channels of communication and with divergent legislative standards. This was a regulatory and operational vacuum that for years hindered the maintenance of embankments, canals and dams, aggravating the effects of transboundary floods. It is in this scenario - that of a strategic river broken into four national sections, lacking coordination and emerging from a bloody conflict - that the following question arises: how did we move, in less than a decade, from wartime fragmentation to one of the most solid models of transboundary water cooperation in Europe?

4. From conflict to cooperation: building trust in the Sava basin

The transition did not arise from a spontaneous, bilateral initiative between the former Yugoslav republics, still marked by mutual distrust, but was made possible by an external political framework: the Stability Pact for South Eastern Europe, launched in 1999 as the main international instrument of post-war stabilisation in the region. Under this international political umbrella, which offered political legitimacy, coordination among international donors and a multilateral framework perceived as neutral, there took shape, in 2001, the Sava River Basin Initiative, promoted by the four riparian nations: Bosnia and Herzegovina, the Federal Republic of Yugoslavia (Serbia and Montenegro), Croatia and Slovenia.[6] The negotiation process followed an incremental logic, typical of trust-building strategies (confidence-building) between parties emerging from a conflict: first a non-binding political commitment, then a legally binding framework agreement, finally a permanent institution. On 29 November 2001 the four Parties signed a Letter of Intent in Sarajevo, the symbolic city of the conflict, as the hardest hit. A little over a year later, on 3 December 2002 in Kranjska Gora, Slovenia, they signed the Framework Agreement on the Sava River Basin (FASRB). A provisional Commission began operating as early as March 2003, with a temporary seat in Brussels. This was no accident: it symbolically placed the process within the orbit of the European institutions at a time when the region's political stabilisation was still uncertain. Only after ratification by all the signatory States did the FASRB formally enter into force on 29 December 2004; the International Sava River Basin Commission held its permanent constituent session on 27 June 2005 in Zagreb, and the Secretariat became operational in January 2006.[7]

The functionalist choice: starting from “low politics”

A decisive element of the success was the decision to anchor cooperation in a technical and economically advantageous objective for all parties, rather than in the most politically sensitive issues. The first and most binding objective of the FASRB concerns neither security nor control of the waters, but the establishment of an international navigation regime on the Sava. This was a “low politics” domain, perceived as neutral, which offered immediate and shared economic benefits: the reopening of a commercial corridor (the future Corridor VII) interrupted by the war. On this technical and depoliticised basis, the States gradually built mutual trust, which later made it possible to extend cooperation to more delicate matters, including sustainable water management and the prevention of risks from floods, ice, drought and pollutants. How? Through sectoral protocols adopted in the years following the establishment of the Commission.[8][9] The text of the FASRB itself was conceived as an instrument of political reassurance, not merely as a technical agreement. The founding principles explicitly recalled in the agreement - sovereign equality, territorial integrity, common benefit and good-faith cooperation, with mutual respect for national legislation and institutions - answered a precise need: to reassure newly independent States, in some cases still hostile to one another, that none of the Parties would use water management to exert dominance over the others. It is the same mechanism that the literature on environmental security identifies in other international river regimes: shared technical governance of a natural resource as a platform for rebuilding, step by step, a relationship of interstate trust that would otherwise be impossible on the purely political level.[10] It should be stressed that the role of third-party actors as neutral facilitators was fundamental in exercising the function of external mediation and guarantee. The international community, through the Stability Pact, the European Union, the World Bank and the United Nations Economic Commission for Europe (UNECE), embodied this role, not limiting itself merely to financing the process. This allowed the governments involved to present cooperation with their former adversaries not as a bilateral concession, politically costly domestically, but as a technical step necessary for European integration. The explicit link, from the FASRB onwards, to the principles of the EU Water Framework Directive tied the Sava's water cooperation to the prospect of EU accession, shared — then as now, albeit at different speeds — by all four States of the basin, turning a potentially divisive issue into an overarching common objective.

5. The institutional framework and results: the Sava Commission

The Sava Commission is made up of two representatives from each of the four Parties, has a permanent Secretariat based in Zagreb, and takes its decisions on navigation with binding effect for all member States; on all other matters, it formulates recommendations and coordinates the development of integrated water resources management plans for the basin.[11] Since its establishment, the Commission has promoted the adoption of sectoral protocols on the navigation regime, on flood protection, on the prevention of pollution caused by navigation and on sediment management. In addition, it has supported the development of the first Sava River Basin Management Plan. A significant test for the cooperation system came with the floods of May 2014, which hit Bosnia and Herzegovina, Serbia and Croatia hard, causing more than 40 deaths and forcing tens of thousands of people to leave their homes, in what has been described as the worst hydrogeological event in the region in decades.[12] The coordinated response, which also involved rescue teams from Germany, Slovenia, Hungary, Austria and the Czech Republic under the auspices of the International Commission for the Protection of the Danube River (ICPDR), reinforced the need for shared warning and protection systems along the entire basin, demonstrating, less than ten years after its establishment, that the institution born of the peace process was able to withstand a concrete test and not merely a procedural one.

In financial terms, in 2020 the World Bank launched the Sava and Drina Rivers Corridors Integrated Development Program (SDIP), a ten-year programme of about USD 332 million, whose first phase, with a share (EUR 123.2 million) divided among Serbia, Bosnia and Herzegovina and Montenegro, aims to protect about 400,000 people and 300,000 hectares of land from 100-year floods and to improve the navigability of more than 200 km of the Sava: a sign of the confidence that international investors now place in the long-term resilience of the cooperation mechanism.[13] The Sava Commission operates in close coordination with the ICPDR, with which it shares principles of subsidiarity. The Danube Commission deals with the general framework of the Danube basin, while the Sava Commission manages its sub-regional specificities, in a relationship described by the ICPDR itself as an example of successful cooperation between basin bodies of different scale.[14] Despite the results, some imbalances remain: coordination on water quality and integrated management remains weaker than that achieved on navigation, proof that, although the functionalist logic made it possible to launch cooperation, it has not yet fostered its full completion in all its dimensions. The implementation of the management plans also requires infrastructure investment, still partly to be completed, above all in the countries that are not yet members of the European Union.

6. Future prospects

The future of cooperation in the Sava basin will be shaped by at least three converging factors. The first is climate change. South-Eastern Europe is warming at a rate above the global average, with impacts already measurable in the region: summer 2024 recorded the longest heatwave ever documented in south-east Europe, a 13-day episode with an anomaly of 9.2°C, and exceptionally low river flow levels in about a third of the monitored watercourses. According to projections cited by the Copernicus Climate Change Service, with global warming of 1.5°C about 18% of the European population would be exposed to moderate water scarcity conditions; with warming of 2°C this share would rise to 54%.[15] For a basin already marked by the oscillation between destructive floods, like that of 2014, and prolonged droughts, climate adaptation is the next, and perhaps most severe, test for a cooperation mechanism born to respond to a political, not a climatic, legacy. Through the Danube Water Program and the process of regulatory alignment with the Water Framework Directive and the Urban Waste Water Directive, the latter described as the most onerous ever adopted by the Union in terms of the investment required, the EU is today the main driver of water sector reform for the basin countries not yet members of the Union.[16] The EU Strategy for the Danube Region, launched in 2011 and now in its fifteenth year of implementation, also offers a framework for macro-regional cooperation which, in close coordination with the ICPDR, continues to strengthen the European anchoring that has underpinned cooperation on the Sava from the outset.[17] The third point is the consolidation of “low politics”. The long-term challenge for the Sava Commission is to replicate, in the more politically sensitive domains of water quality and integrated resource management, the same level of effectiveness achieved on navigation. The Sava basin remains, in this sense, an experiment still under way rather than a concluded model, but an experiment that, unlike other post-war contexts in the region, has demonstrated an institutional resilience of more than twenty years since its inception.

7. Conclusions

The case of the Sava basin shows that post-war water resource management is not a purely technical process, but the direct product of specific political choices: an international umbrella that offers legitimacy and political cover to the parties. That is, an incremental sequence of verifiable commitments that builds trust step by step, a technical, low-politics starting point that allows the most sensitive issues to be postponed, and a common horizon which in the Balkan case is represented by European integration, capable of making cooperation advantageous for all the parties involved rather than imposed on any of them.[18] None of these elements, on its own, would have guaranteed success: it was their combination, together with timing, that made possible, in barely a decade, the passage from a river broken by war to one of the most solid basin institutions in South-Eastern Europe. This analysis shows that even in the most difficult post-war contexts, water can serve as a trailblazer of political reconciliation, provided that its management is deliberately separated, in the initial phases, from the disputes that have made it contested. Investing in water diplomacy, even before infrastructure, is probably still the most effective tool for turning a potential factor of instability into a pillar of shared regional security.

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[1]International Sava River Basin Commission, “History of Cooperation”, savacommission.org/en/history-of-cooperation/235.

[2] The term “Ramsar site” refers to a wetland (such as marshes, peatlands, lakes or river deltas) of international importance recognised under the Ramsar Convention, an intergovernmental treaty signed in 1971 and dedicated to the conservation and sustainable use of these ecosystems, which are crucial for biodiversity and water regulation.

[3]Sava Commission, “The Countries Sharing the Sava River Basin”, savacommission.org.

[4]ICPDR – International Commission for the Protection of the Danube River, “Worst Floods in the Balkans for Decades”, icpdr.org.

[5]International Sava River Basin Commission, “2nd Sava River Basin Management Plan”, FAOLEX, 2022, faolex.fao.org/docs/pdf/mul230466.pdf

[6]International Sava River Basin Commission, “History of Cooperation”, savacommission.org/en/history-of-cooperation/235.

[7]International Sava River Basin Commission, “History of Cooperation”, op. cit.

[8]International Sava River Basin Commission, “Framework Agreement on the Sava River Basin”, savacommission.org.

[9] FAO, FAOLEX Database, “Framework Agreement on the Sava River Basin”, faolex.fao.org/docs/pdf/mul45452.pdf

[10]Cf. S. Stec, J. Kovandžić, M. Filipović, A. Čolakhodžić, “A river ran through it: post-conflict peacebuilding on the Sava River in former Yugoslavia”, Water International, 36(2), 2011; A. Čolakhodžić, “Environmental Security and the Role of River Regimes in Fostering (Environmental) Cooperation: Case of the International Sava River Basin Commission”, in Rescue of Sturgeon Species in the Ural River Basin, NATO Science for Peace and Security Series C: Environmental Security, Springer, Dordrecht, 2008, pp. 5-27.

[11]ICPDR, “Sava Commission”, icpdr.org/about-icpdr/partners/sava-commission; International Sava River Basin Commission, “History of Cooperation”, op. cit.

[12]ICPDR, “Worst Floods in the Balkans for Decades”, op. cit.

[13]World Bank, “Sava and Drina Rivers Corridors”, press release, 6 August 2020, worldbank.org.

[14]ICPDR, “Sava Commission”, op. cit.

[15]Copernicus Climate Change Service, “Heat and Drought in Southeastern Europe”, 2024, climate.copernicus.eu.

[16]World Bank Blogs, “Getting the Water Sector in the Western Balkans Ready for EU Membership”, blogs.worldbank.org.

[17]ICPDR, “EU Danube Strategy”, icpdr.org; Danube Strategy Point, “The EU Strategy for the Danube Region Turns 15”, danube-region.eu.

[18]A. Čolakhodžić, “Environmental Security and the Role of River Regimes…”, op. cit.