International Commision for the Protection of the Danube River – an Overview

Review article

Ivan Zavadsky1, Jelena Krstajić2


1    ICPDR Permanent Secretariat, Vienna, Austria; E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

2    University of Belgrade, Belgrade, Serbia; E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it



At the very beginning it is worth mentioning a few facts about the world's most international river basin, the Danube River Basin (DRB). It includes the territories of 19 countries, and is home to 81 million people with a variety of languages and historical backgrounds. The River Danube itself, stretches over 2,780 km between its source in Germany’s Black Forest and the Danube Delta. Floodplain forests, marshlands, deltas, floodplain corridors, lakeshores and other wetlands are essential components in the basin’s biodiversity and hydrology. Many are transboundary in nature and represent valuable drinking water reserves for millions of people. The International Commission for the Protection of the Danube River (ICPDR) comprises 15 Contracting Parties who have committed themselves to implementing the Danube River Protection Convention (DRPC). All Danube countries with territories of 2,000 km2 or more in the Danube River Basin are Contracting Parties to the DRPC. Since its establishment in 1998, the ICPDR has grown into one of the largest and most active international bodies engaged in river basin management in Europe. Its activities relate not only to the Danube River, but also the tributaries and groundwater resources which will be the focus of this chapter.

Goals and Legal Basis

The ultimate goal of the ICPDR is to implement the Danube River Protection Convention (DRPC) and thus to co-operate on fundamental water management issues and to take all appropriate legal, administrative and technical measures to maintain and improve the quality of the Danube River and its environment. The DRPC mission is to promote and coordinate sustainable and equitable water management, including conservation, and improvement and rational use of waters for the benefit of the Danube River Basin countries and their people. The ICPDR pursues its mission by making recommendations for the improvement of water quality, developing mechanisms for flood and accident control, agreeing on standards for emissions and by assuring that these measures are reflected in the Contracting Parties’ national legislations and are applied in their policies.

It is important to mention that the daily work of the ICPDR is built around the most relevant legislation for river ecosystem management at the European level - the Water Framework Directive (WFD). Adopted in 2000, it establishes a governance framework for all waters in the European Union, which prevents further deterioration and protects and enhances the status of aquatic ecosystems, promotes sustainable water use, aims at enhanced protection and improvement of the aquatic environment, ensures the progressive reduction of pollution of groundwater and prevents its further pollution and contributes to mitigating the effects of floods and droughts by applying a river basin approach. The Directive is legally binding for all EU Member States and serves as an umbrella for measures related to drinking and bathing water, urban wastewater treatment, groundwater protection, floods and protection of waters against the impacts of agricultural pressures such as from nitrates in organic and chemical fertilizers and/or industrial emissions. The contracting parties of the ICPDR which are not the EU member states also committed themselves to implement the WFD within the frame of the DRPC. In addition, the ICPDR serves as a coordination platform for the basin-wide implementation of the EU Floods Directive (EFD, formally Directive 2007/60/EC).

Modern water legislation strives to build the institutional foundation for sustainable water resource management and protection of important habitats and species. At an international level, the most prominent legal acts for improving freshwater governance and fostering the equitable and sustainable sharing of transboundary watercourses are the UNECE (United Nations Economic Commission for Europe) Convention on the Protection and Use of Transboundary Watercourses and International Lakes as well as the UN (United Nations) Convention on the Law of the Non-Navigational Uses of International Watercourses. The Sustainable Development Goals (SDG), launched in 2015, include a target to ensure everyone has access to safe water by 2030, making water a key issue in the fight to eradicate extreme poverty, where goal 6 covers the entire water cycle. The ICPDR as one of few freshwater River Basin Organisations (RBOs) in the world sees its role as direct contributor to achieving the Sustainable Development Goals which are part of a global agenda for the survival of the planet.


Modus Operandi

The ICPDR meets twice a year, once at the Ordinary Meeting which is held in Vienna in December, while another meeting with the Heads of Delegations is held in June in the country that currently holds the Presidency. The meetings comprise of delegations of contracting parties and observer organisations. Every contracting party has one Head of Delegation representing the country. For every decision, the primary goal is to reach some form of consensus between the members while the current ICPDR President chairs each meeting. The ICPDR Presidency is passed on from one country to another in an alphabetical order every year.

In addition, much of the work of the ICPDR is done by Expert Groups (EG), which are formed by national experts from the Contracting Parties and representatives of ICPDR observer organisations. Eight Expert Groups deal with a variety of issues and make recommendations to the ICPDR (See Figure 1 below). The technical work within the ICPDR relies very heavily on the work of these EGs. These panels of specialists are not only essential to the operation of the ICPDR they also link the work of the commission to the national administration of its contracting parties and are comprised of national experts as well as delegates from observer organisations that have no formal vote.


Figure 1: ICPDR Organisational chart.


Currently, the ICPDR has 7 regular Expert Groups (River Basin Management, Flood Protection, Pressures and Measures, Accident Prevention and Control, Monitoring and Assessment, Information Management and Geographic Information Systems, Public Participation) and 1 ad-hoc Expert Group for legal and administrative questions (Figure 1). The 7 Expert Groups report to the ICPDR and propose decisions to the commission at its plenary meetings. The EGs typically meet twice a year at changing locations and are chaired by Chairpersons elected by the ICPDR upon nomination of the EG. The Expert Groups have proven vital for allowing the ICPDR to work in a decentralised manner as the ICPDR deals with a broad range of issues, despite its small number of staff. This is only possible because most of the technical decisions are prepared through the Expert Group bodies, which draw from over 200 people which are specialists in their respective countries or organisations. In the case of the Groundwater Task Group the responsible EG is the Monitoring and Assessment Expert Group.

For efficiency and proportionality purposes that are in line with one of the governing principles of the ICPDR, the principle of subsidiarity, the management of the DRBD is based on 3 levels of coordination:

Part A: International, basin-wide level – the Roof Level;
Part B: National level (managed through the competent authorities) and/or the international coordinated sub-basin level for selected sub-basins (Tisza, Sava, Prut, and Danube Delta);
Part C: Sub-unit level, defined as management units within the national territory (see Figure 2)


Figure 2: Instruments of the ICPDR.


One of the main benefits provided by the ICPDR is the ability to help national decision-makers balance the competing needs and uses of the Danube River, such as hydropower, agriculture and the management of climate risks. The ICPDR serves its member countries as a fully-functioning platform for consultation, coordination and the integrated management (IRBM) of the Danube River Basin.

Given the complexity of the Danube River Basin (the many countries, differences in economic performance, biological assets, past damages and continued threats from human impacts) it was clear from the start that one overall framework or mechanism was required to sustainably manage the basin environment. “Integrated river basin management”, otherwise known as IRBM, became the primary mechanism to address the issues and their impacts. For a set of selected hazardous substances called priority substances, limit values were set on the European level which are defining so-called good chemical status. Clean water, not polluted by organic substances, nutrients and dangerous substances is essential. However, it is not sufficient in cases where the natural ecosystem, including its flora and fauna, is significantly damaged or dysfunctional. To meet these objectives, the ICPDR developed its first Danube River Basin Management Plan (DRBM Plan) in 2009, including assessments and measures towards the achievement of good status by 2015. Aware of the fact that not all waters would reach the target values in six years, the WFD foresaw updates to the DRBM Plan in 2015 and 2021.

The measures foreseen in the ICPDR's management plan for the Danube River Basin improve the purity of rivers, lakes and groundwater, and make rivers and lakes thriving ecosystems for animals and plants. The 2015 update of the Danube River Basin Management Plan is building on a previous plan for the period from 2009 to 2015, which resulted in significant improvements of the Danube River and its tributaries. As one of the examples, a 30 percent reduction of phosphorus emissions was registered when compared to the 2009 figures, which represented a highly positive effect on ecosystems throughout the basin and in the Black Sea.


Groundwater and its Regional Importance

Despite the fact that there are many publications dealing with groundwater processes and groundwater treatment, their role in overall management of the large river basin remains a challenge. As the groundwater is recognized as a dominant source of drinking water supply, the groundwater related issues are an integral part of the River Basin Management Plan. The river’s self-purification capacity results in the improvement of water quality or at least stabilisation of its quality making groundwater sources suitable for water supply. The self-purification ability is especially characteristic for intergranular aquifers. It is important to mention that groundwater is often an essential factor during dry periods when they are the major contributor to river flows.

Despite the fact that the groundwater resources are managed within the scope of the overall natural water cycle and overall human activity in an integrated manner, due to their specific behavior and conditions, related issues have to be addressed in a different manner to those addressing surface water issues. In many regions during the previous decades groundwater used to be an inexhaustible and accessible source of high quality water supply. However, the expansion of different human activities (agriculture, production) and general human population growth has led to increased rates of abstractions and thus, constraints on water management including the use and protection of groundwater.

The Danube region is an example of a noticeable gap in the economic power between countries which makes the implementation of all the required elements of the sustainable water management challenging. Besides this, an additional factor which should be considered as one of the modern agents influencing the nature of water management, is the factor of Climate Change. The fact that there is a re-distribution of atmospheric precipitation with regard to area, intensity and time is undeniable and therefore, water management in general has to be adaptive. Here, it is important to bear in mind that the velocities of groundwater flows are much lower in comparison with the velocities of surface waters and therefore the physical and biochemical processes present in groundwater systems tend to be of a more local nature. The regional management such as ICPDR deals with the transboundary aquifers of basin wide importance, enhancing constant efforts on the common approach in the region. One of the main goals at the regional level is to enhance the cooperation between the countries in this respect via an established legal and institutional framework for such water management.


Role of the Groundwater Task Group

Within the ICPDR the groundwater issues are dealt for nominated transboundary groundwater bodies of Danube River Basin-wide importance and with all aspects of groundwater management in line with the implementation of the EU Water Framework Directive and the EU Groundwater Directive. These nominations and further observations and discussions are conducted in the ICPDR’s Groundwater Task Group (GW TG) by the experts nominated by the ICPDR’s member countries and reported further to the ICPDR Monitoring and Assessment Expert Group.

Over the years, the ICPDR and Danube countries have identified 12 transboundary groundwater bodies of basin-wide importance. The transboundary GWBs of basin-wide importance were defined as follows:

  1. important due to the size of the groundwater body, i.e. an area > 4,000 km² or
  2. important due to various criteria, e.g. socio-economic importance, uses, impacts or pressures, interaction with aquatic eco-system.

The GW TG is enabling and supporting the international coordination as required by the WFD and contributing to transboundary harmonisation of the implementation of the Directive. The aim of GW TG is to provide the ICPDR with information on the state of groundwater bodies of basin-wide importance in the Danube River Basin. The role of GW TG is also to coordinate the monitoring programmes (or compilation of monitoring information) necessary to ensure that the appropriate information is available, in line with the Danube River Protection Convention (DRPC) and the relevant EU legislation. The GW TG is providing the ICPDR with all further groundwater related information necessary for preparation of future Danube-level reports to come.

According to the Danube River Basin Analysis (DBA) the main reasons for the pollution of groundwater were identified as:

  • Insufficient wastewater collection and treatment on the municipal level;
  • Insufficient wastewater treatment at industrial premises;
  • Water pollution caused by intensive agriculture and livestock breeding;
  • Inappropriate waste disposal sites.

These pressures, in combination with the high vulnerability of some of the aquifers, necessitate the development of appropriate GWB protection strategies based on conceptual models. The overall assessment of pressures on the quality of the selected GWBs of basin-wide importance showed that pollution by nitrates from diffuse sources is the key factor affecting the chemical status of these groundwaters. The major sources of this diffuse pollution are agricultural activities, non-sewered population and urban land use. Groundwater used for the supply of drinking water plays a major role in Danube countries, estimating that about 60% of the population in the DRB depends on groundwater sources (according to Article 5.). In general, groundwater quantity in the DRB is affected by groundwater abstraction for drinking water supply or industrial and agricultural purposes. The expected development of water demand has to be taken into account when identifying water exploitation and protection strategies. The assessment of pressures on the quantity of the selected transboundary GWBs of basin-wide importance showed that over-abstraction prevents the achievement of good quantitative status for several of the GWBs.

Taking into account that contamination by nitrates is a key factor against achieving good chemical status of a significant portion of the GWBs of basin-wide importance, and in line with the management objectives, it is essential to eliminate or reduce the amount of nitrates entering groundwater bodies. Prevention of groundwater quality deterioration and any significant and sustained upward trend in concentrations of nitrates in groundwater has to be achieved primarily through the implementation of the EU Nitrates Directive and also the EU UWWTD.

To avoid the presence of hazardous substances in groundwater aquifers, additional measures need to be taken as required under the following Directives:

  • Drinking Water Directive (80/778/EEC) as amended by Directive (98/83/EC);
  • Plant Protection Products Directive (91/414/EEC);
  • Habitats Directive (92/43/EEC);
  • Integrated Pollution Prevention Control Directive (96/61/EC).

To prevent pollution of GWBs by hazardous substances from point source discharges liable to cause pollution, the following measures are needed: an effective regulatory framework ensuring prohibition of direct discharge of pollutants into groundwater, the setting of all necessary measures required to prevent significant losses of pollutants from technical installations, the prevention and/or reduction of the impact of accidental pollution incidents.

The ICPDR vision for groundwater quantity stipulates that water use in the DRB has to be appropriately balanced taking into account the conceptual models for particular GWBs and should not exceed the available groundwater resource in the DRB. In line with this vision, the over-abstraction of GWBs within the DRB should be avoided by effective groundwater and surface water management. Therefore, appropriate controls regarding abstraction of fresh surface water and groundwater and impoundment of fresh surface waters (including a register or registers of water abstractions) must be put in place as well as the requirements for prior authorisation of such abstraction and impoundment. In line with the WFD, it must be ensured that the available groundwater resource is not exceeded by the long-term annual average rate of abstraction.

To prevent deterioration of groundwater quantity as well as the deterioration of dependent terrestrial ecosystems, solutions for rehabilitation have to be explored. These should include restoration of wetland areas which are in direct contact with aquifers.

The ICPDR elaborated a Groundwater Guidance document that summarizes the groundwater management approaches agreed within the ICPDR. It provides brief technical information on the characterisation and grouping of GW bodies and necessary explanation on monitoring parameters, aggregation procedures, data reporting including reporting frequencies and the presentation of status in order to contribute to a harmonisation of approaches within the Danube River Basin.


Groundwater Monitoring Network Under TNMN

The ICPDR Transnational Monitoring Network (TNMN) has been in operation since 1996 and its major objective is to provide an overview of the overall status and long-term changes of surface water and, where necessary, groundwater status in a basin-wide context (with particular attention paid to the transboundary pollution load). The transnational groundwater management activities in the DRB were initiated in 2002 and were triggered by the implementation of the WFD. Monitoring of the selected transboundary GWBs of basin-wide importance has been integrated into the TNMN of the ICPDR. For groundwater monitoring under the TNMN (GW TNMN) a 6-year reporting cycle has been set, which is in line with reporting requirements under the WFD.

GW TNMN includes both quantitative and chemical (quality) monitoring. It shall provide the necessary information to assess groundwater status, identify trends in pollutant concentrations, support GWB characterisation and the validation of the risk assessment, assess whether drinking water protected area objectives are achieved and support the establishment and assessment of the programmes of measures and the effective targeting of economic resources. To select the monitoring sites, a set of criteria has been applied by the countries, such as aquifer type and characteristics (porous, karst and fissured, confined and unconfined groundwater) and depth of the GWB (for deep GWBs, the flexibility in the design of the monitoring network is very limited). The flow direction was also taken into consideration by some countries, as well as the existence of associated drinking water protected areas or ecosystems (aquatic and/or terrestrial).

The qualitative monitoring determinants of GW TNMN, which are set as mandatory by the WFD, include dissolved oxygen, pH-value, electrical conductivity, nitrates and ammonium. The measurement of temperature and a set of major (trace) ions is recommended as they can be helpful to validate the Article 5 risk assessment and conceptual models. Selective determinants (e.g., heavy metals and relevant basic radionuclides) would be needed for assessing natural background concentrations. It is also recommended to monitor the water level at all chemical monitoring points in order to describe (and interpret) the physical status of the site and to help in interpreting (seasonal) variations or trends in chemical composition of groundwater. In addition to the core parameters, selective determinants will need to be monitored at specific locations, or across GWBs, where the risk assessments indicate a risk of failing to achieve WFD objectives. Transboundary water bodies shall also be monitored for those parameters that are relevant for the protection of all uses supported by groundwater.

As regards quantitative monitoring, WFD requires only the measurement of groundwater levels but the ICPDR has also recommended monitoring of spring flows, flow characteristics and/or stage levels of surface water courses during drought periods, stage levels in significant groundwater dependent wetlands and lakes and water abstraction as optional parameters.

The results of the status assessment of the selected transboundary GWBs of basin-wide importance are provided for the whole national part of a particular ICPDR GWB (so called: aggregated GWB). If a national part of an ICPDR GWB consists of several individual national-level GWBs, then poor status in one national-level GWB is decisive in characterising the whole national part of an ICPDR GWB as having poor status. To indicate the diversity of different status results of individual GWBs within aggregated groundwater bodies a concept of the aggregation confidence levels was developed by the ICPDR. The reason of introducing these specific confidence levels for the DRBM Plan was the need to distinguish between the cases when all individual GWBs in an aggregated GWB have the same status (high confidence) or not (medium confidence) or the assessment is based on the risk assessment data (low confidence).

More detailed description of the technicalities of the GW TNMN and groundwater status assessment are given in the ICPDR Groundwater Guidance.


Groundwater in the 2009 vs the 2015 Danube River Basin Management Plan

The analysis and review of groundwater bodies (GWBs) in the DRBD, as required under Article 5 and Annex II of the WFD, was updated in 2013.

The pressures on groundwater bodies of basin-wide importance have not changed since 2009. Pollution by nitrates from diffuse sources is the key factor posing significant pressure on the chemical status while the over-abstraction is the key pressure affecting quantitative status of groundwater bodies. Since the DRBM Plan in 2009 for the GWBs of basin-wide importance failed to achieve good chemical status, new sewer systems were constructed and new legislation (e.g. extension of nitrate vulnerable zones or application of whole territory approach) was developed. GWBs failing good quantitative status were addressed by new projects and new legislation as well.

Nutrient pollution is caused by significant releases of nitrogen (N) and phosphorus (P) into the aquatic environment. Nutrient emissions can originate from both point and diffuse sources. Point sources of nutrient discharges are highly interlinked to those of organic pollution. Municipal wastewater treatment plants with inappropriate technology, untreated wastewater, industrial enterprises and animal husbandry can discharge considerable amounts of nutrients into surface waters besides organic matter. Diffuse pathways, however, have higher importance considering nutrients. Direct atmospheric deposition, overland flow, sediment transport, tile drainage flow and groundwater flow can remarkably contribute to emissions into rivers, conveying nutrients from agriculture, urban areas, atmosphere as well as from naturally covered areas.

The importance of the pathways for diffuse pollution is different for N and P. For N, groundwater flow and urban run-off are the most relevant diffuse pathways. In the case of P, groundwater is usually replaced by sediment transport generated by soil erosion.

A remarkable decrease is visible regarding nutrient point source emissions in the Danube basin. For the reference year of the 1st DRBM Plan (2006) 130,000 tons per year TN and 22,000 tons per year TP pollution was reported via direct urban waste water discharges. The reported emissions from UWWTPs used in the 2nd DRBM Plan were significantly lower in comparison to those of the 1st DRBM Plan, the TN and TP discharges declined by 32% and 45%, respectively. The measures under implementation have been substantially contributing to the reduction of nutrient inputs into surface waters and groundwater but further efforts are still needed. Continued implementation measures in urban waste water, industrial, market production and agricultural sectors is necessary.

Diffuse pathways have a dominant share in the total nutrient emissions, therefore implementation of measures addressing land management is of high importance. A key set of best agricultural practices to reduce nutrient inputs and losses related to farming and land management has been identified as an appropriate management tool to be applied in agricultural areas. In the EU MS a collection of these measures needs to be implemented under the action programs required by the Nitrates Directive. Moreover, application of good agricultural practices is either ensured by regulatory actions (cross-compliance) or encouraged by economic incentives (rural development programmes) of the financial mechanism of the Common Agricultural Policy. Non EU MS are also highly encouraged to implement similar best agricultural practices.

Regions with high agricultural surplus and shorter groundwater residence time and/or bedrock layers with lower denitrification capacity produce the highest area-specific emissions. Urban areas with significant point sources and urban runoff generate remarkable local fluxes as well.

Groundwater flow (base flow and interflow) dominates the distribution of the pathways in most of the countries, particularly in the upper and middle basin. Point sources and urban runoff show significant relative contributions in the downstream countries. Regarding the sources, agricultural activities have a principal role in nitrogen emission generation, whereas atmospheric deposition is an equally important nitrogen input as fertilizers in many countries.

When it comes to hazardous substances, diffuse emission pathways are substance-specific. In general surface run-off, sediment transport and groundwater flow are the main contributing routes.

The importance of groundwater can also be seen in a case of decreasing water table of the Danube and the associated adverse impacts on groundwater which endanger the ecology of the floodplains in the “Donau-Auen National Park”. In addition, inadequate and seasonally widely fluctuating fairway depths in this section of the river substantially affect navigation. The Integrated River Engineering Project on the Danube to the East of Vienna was launched to improve the hydromorphology of the river and ecology of the floodplains (in line with equivalent levels of flood protection) as well as to improve the fairway conditions in this section of the Danube. One of the main measures is the granulometric improvement of the river bed to provide long-term stabilisation of the river bed and of groundwater conditions.

Sound quantitative management of water resources is a pre-requisite for addressing water scarcity and drought events but also for achieving WFD objectives, including the need to ensure the quantitative status of groundwater bodies and to achieve good ecological surface water status (in addtition to supporting river flows) as specified by the WFD.

The basic principles and assessment of pollution sources for surface waters also provide relevant background information for groundwater due to the very close interrelation between the two water categories. Specifically, synergies between groundwater and the three SWMIs of organic, nutrient and hazardous substance pollution are of importance.


Groundwater and Joint Danube Surveys

The findings of Joint Danube Surveys (JDS) are supportive to the implementation of WFD as they provide an extensive homogeneous production of datasets predominantly based on WFD compliant methods commonly used by the Danube experts. Even though these data have no ambition of replacing the national data used for the assessment of the ecological and chemical status they are an excellent reference database serving for future efforts of method harmonisation in the DRB, especially concerning the development of a concerted type-specific approach to the status assessment of large rivers.

During the JDS2 the main hydrological objectives were to use the isotope methods to better understand the impacts of tributary inputs and mixing in the Danube, including the distribution of groundwater discharge, and to provide a more complete baseline of isotope data for assessing future impacts within the Danube Basin. Isotopes can be good indicators of change because they are often sensitive to land-use or major hydro-climatic factors. In addition to being a hydrological tracer, 3H can also be viewed as a water quality parameter related to, for example, nuclear power plant discharges. The radon isotope investigations showed higher radon concentrations in the Upper Danube, which suggests that this is the area where groundwater contributions to the river are the largest (although tributaries may still be major inputs as well). The isotope data reported in JDS2 also provided an important environmental baseline needed for the implementation of the EU Groundwater Directive, more specifically in monitoring and conceptual assessment of river/groundwater interactions in the major transboundary aquifers in the Danube Basin.

During JDS3 a total of 68 sites were sampled along a 2,581 km stretch of the Danube, 15 of which were located in the mouths of tributaries or side arms. Sampling at the JDS3 stations included five different sample types – surface water, biological quality elements, sediment, suspended particulate matter (SPM) and biota for chemical analysis (fish and mussels) – each with a different determinant list.

For the first time the link between contamination of surface water and groundwater was explored. A number of emerging substances were detected during JDS3 in the abstraction wells at bank filtration sites. This phenomenon can be expected for substances like amidotrizoic acid, iopamidol, acesulfame, benzotriazole or carbamazepine which are known to be quite persistent in the aquatic environment and which are mostly not completely retained by bank filtration. However, due to the relatively low concentration levels in the Danube, concentrations in the abstraction wells were mostly below 0.1 μg/l for most substances. An exception was the artificial sweetener acesulfame which occurred in concentrations up to 1.1 μg/l in the Danube and was detected in most of the abstraction wells with a maximum concentration of 0.45 μg/l. Acesulfame is used as a food additive and the observed concentrations are not considered to be harmful for humans. However, acesulfame can act as an example for a more or less persistent and very mobile substance which is consumed in large quantities.


ICPDR Climate Change Adaptation Strategy and Groundwater

Climate Change (CC) is recognized by the ICPDR as one of the burning issues of global importance and therefore the first ICPDR Climate Change Adaptation Strategy was produced in 2012 and later updated in 2018. As an integral part of both publications are the issues related to the impact of CC on groundwater resources. Concerns related to the effects of CC on the groundwater regime in the Danube River Basin (DRB) remains the same in both documents. An assumption given in the first Adaptation Strategy (2012), which is a general decline in groundwater storage and recharge for Central and Eastern Europe, especially in summer, is still actual. Besides shortages in water availability, a decline in groundwater recharge could also lead to negative effects for groundwater quality. The exact numbers and changes in water temperature differ regionally and locally, but 1-2 °C are often mentioned, particularly of surface waters and groundwater in summer. After long droughts, preferential flow paths are of particular relevance in groundwater protection zones given the fact that pollutants can pass rapidly along them and almost unimpeded into groundwater. That is why the water quality issues are considered as one of the most relevant climate change impacts.

Additionally, a possible increase in irrigation using groundwater resources could intensify the decline. An increase may deteriorate the ecological and chemical balance of freshwater bodies and could lead to an increase of contaminated surface and groundwater bodies after enhanced agricultural use.

An increased risk of conflicts over water use can occur in the event that no adequate adaptation measures are taken. Due to less precipitation in summer, the extreme events will occur more frequently in summer than in winter. In some parts of the DRB, the drought risk is expected to increase drastically in the future, leading to possible economic loss, potential for water conflicts and water use restrictions. Possible consequences are difficulties in water supply with an increased risk of water shortages and an over-exploitation of aquifers in the future. Besides climate change impacts, future water demand is also triggered by anthropogenic impacts, political regulations and restrictions, and new technologies.

Regarding regional differences, a pronounced decline is particularly indicated for the Pannonian Plain Area, which has already been monitored in the past. For some alpine regions, however, a local increase in groundwater storage is likely to occur.

Some additional, quantitative assessments for smaller regions were carried out within INTERREG-projects and other European research projects. Other national projects are covering only local areas or catchments or certain water-related issues like groundwater. The necessity of a basin wide vulnerability assessment is also addressed in the recently published outline of the Climate Adaptation Strategy of the Sava River Basin.

As a recommendation and further steps, the Adaptation Strategy points out the importance of monitoring and status assessment. To maintain both surface and groundwater surveillance monitoring sites for long time series is suggested as an important and continuous procedure.

Furthermore, it is necessary to set up an investigative monitoring programme for climate change and for monitoring climate change “hot spots”, and to try to combine them as much as possible with the results from the operational monitoring programme.

Integral approaches are needed which are aimed at enhancing synergy effects between different sectors. An example of a synergy effect is an increase in water retention areas which can lead to higher groundwater recharge, a reduction of flood peaks and positive effects for biodiversity.

The River Basin Management Plans are tools to make full use of the Water Framework Directive environmental objectives, e.g. the requirement to achieve good groundwater quantitative status helps to ensure a robust water system, which is more resilient to climate change impacts.

Further positive synergies which can be achieved by such adaptation measures can include the improved linkage between surface- and groundwater, leading to increased robustness with regard to potential periods of water scarcity and droughts.
These steps should enhance sustainable groundwater management.


Groundwater – The River’s Invisible Twin

As an illustrative overview for the wider public, the ICPDR has produced the Groundwater brochure under the name Groundwater – the river’s invisible twin. Nearly 72% of all drinking water consumed in the DRB is produced from groundwater sources, serving an overall population of some 59 million people. Therefore, the brochure describes the groundwater importance, vulnerability and differences between the media where the groundwater has been stored. This brochure briefly informs the public about the ICPDR’s work related to the groundwater issues and describes the role of the relevant EU legislation. The brochure is available online on the ICPDR’s website and in a hard copy.


ICPDR on Groundwater Related Events

Over the past twenty years the ICPDR became a globally recognised role model for transboundary management of shared river basins and water resources therein, including groundwater in transboundary aquifers.

The institutional set-up, working methods and established practices in transboundary cooperation on shared groundwater systems became the subject of interest of many governments and their institutions, inter-governmental organisations, scientists and international NGOs. The ICPDR, therefore, have been given numerous opportunities at international conferences and high-level events to share its experiences and lessons learned on cooperation and management of shared groundwater systems. Several examples follow:

In March 2015 the ICPDR Executive Secretary (ES), Mr Ivan Zavadsky, served on the panel at the EWA Spring Days in Budapest discussing the importance of sound management and protection of groundwater resources, as drinking water in Danube countries is predominantly secured from gorundwater. He has delivered similar messages at the 4th EU Water Conference in Brussels in 2015. In November 2015, he facilitated the side event titled, Focus on Groundwater in the 2030 Agenda at the 7th Meeting of Parties (MOP) of the UN ECE Water Conference in Budapest, co-organised by UNESCO IHP.

The Ministers of CPs to DRPC adopted a Danube Declaration at their meeting in Vienna in February 2016. The Declaration emphasised the importance of implementation of measures addressing the pollution of groundwater by nitrates from diffuse sources – in addition to those addressing various sources of pollution of surface water – and agreed upon the need for appropriate controls regarding over abstraction of groundwater in the DRB. In June 2016, the ES has been given an opportunity to address the IWA Specialists Groundwater Conference in Belgrade at the opening high-level session.

The 2017 ICPDR President, Peter Gammeltoft, addressed, inter alia, the importance of sound groundwater management and protection for drinking water supply at the Danube Water Conference, organised by the IAWD and the World Bank in Vienna; he also delivered a speech at the Water and Climate Summit in Rome in October 2017, underlying the role of groundwater maagement for adaptation to climate change.

Another opportunity for the 2018 ICPDR President Helge Wendenburg and the ES to address the global freshwater community, including political leaders, scientists and representatives of civil society and youth was the 8th World Water Forum in Brasilia in March 2018. The GEF Biannual International Waters Conference in Marrakech in November 2018 invited the ICPDR to share its experience and working frameworks from the RBM perspective; the ES, at this conference, moderated a session on RBM planning “from formulation through implementation”, including aspects of groundwater management.

Numerous governmental departments, institutions, universities and international water focused organisations are organising study tours to ICPDR premises to learn and extract experiences and practices suitable for them to implement, e.g. a delegation from China led by the Deputy Minister of Water Resources, several high-level delegations from India, the Korean Water Agency, senior water managers for Central Asian countries, facilitated by the UICN, etc.


Dimkić, M., Brauch H. J., and M. Kavanaugh (2008). Groundwater Management in large River Basins, Internatonal Water Assocciation (IWA)

International Commission for the Protection of the Danube River (ICPDR) (2007). Joint Danube Survey 2 (JDS2), Final Scientific Report, source

International Commission for the Protection of the Danube River (ICPDR) (2009). Danube River Basin Management plan 2009, source htts://

International Commission for the Protection of the Danube River (ICPDR) (2012). Strategy on Adaptation to Climate Change 2012, source

International Commission for the Protection of the Danube River (ICPDR) (2013). Joint Danube Survey 3 (JDS3), Final Scientific Report, source

International Commission for the Protection of the Danube River (ICPDR) (2015). Danube River Basin Management plan 2015, source

International Commission for the Protection of the Danube River (ICPDR) (2015). Groundwater – the river’s invisible twin, source

International Commission for the Protection of the Danube River (ICPDR) (2016). Groundwater Guidance, source

International Commission for the Protection of the Danube River (ICPDR) (2018). International Commission for the Protection of the Danube River, Strategy on Adaptation to Climate Change 2018, source

Liska, I. (2015). The Danube River Basin, Springer