Groundwater constitutes the largest reservoir of freshwater in the world, accounting for over 97% of all freshwaters available on earth (excluding glaciers and ice caps). The remaining 3% is composed mainly of surface water (lakes, rivers, wetlands) and soil moisture. By incorporation into the Water Framework Directive (WFD), groundwater became part of an integrated water management system.
The analysis and review of groundwater bodies (GWBs) in the DRB, as required under Article 5. and Annex II of the WFD, was performed in 2004 and identified 11 transboundary GWBs or groups of GWBs of basin-wide importance. In 2019, a twelfth Hungarian/Slovak transboundary GWB of basin-wide importance was adopted by the ICPDR.
The main reasons for the pollution of groundwater are the following:
- 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 transboundary 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.
Over 59 million people in the Danube River Basin get their drinking water from groundwater – that’s 72% of the total population. Yet groundwater is extremely vulnerable to over-abstraction, when more water is used than can be replaced by nature.
The assessment of pressures on the quantity of the transboundary GWBs of basin-wide importance showed that over-abstraction is the key factor preventing the achievement of good quantitative status.
The way forward
Danube countries are undertaking projects throughout the region to tackle this problem on all fronts. Measures include improved farming techniques, water use regulation, pollution clean-up and a wide range of ingenious economic activities. In Bavaria, a number of improved agricultural practices are underway to reduce nitrogen discharge through annual soil analysis, organic-farming, reduction or elimination of organic and mineral fertilizers, water-conserving crop rotation, the avoidance of high-yield crops like oilseed rape, winter greening, and extended grasslands and wildflower planting. The Bavarian Ministry of Food, Agriculture and Forestry has also appointed advisors to help individual farmers put optimal groundwater protection measures in place. Romania completed several water clean-up projects between 2012 and 2018, including constructing new sewer systems and manure storage facilities as well as increasing the number of populated areas connected to wastewater treatment facilities. New legislation has established protected areas and banned activities that contribute to water contamination. Hungary has its own set of initiatives, and the number of inhabitants connected to a sewer system nationwide has increased by 5% in as many years. Slovakia has tackled its nitrate pollution problem in similar ways, and the number of households connected to a sewer system has risen by 7% in as many years.
Over-abstraction of groundwater has been addressed throughout the region by establishing registers of groundwater extraction, which collect data on water usage that can be used to provide information for a variety of water conservation measures. In Hungary, for example, reconstruction of the drinking water supply network decreased abstractions between 2009 and 2015. Hungary has also revised legislation concerning licensing for wells and construction, as well as adopted demand management measures and adapted agricultural production by using innovative techniques such as drought-resistant crops. Similar registers and legislation in Romania and Slovakia have resulted in improved data on water use, and an increase in the number of established protected areas and abstraction permits. Water consumption by the public and other users is also an issue. Water-saving techniques, including using less water in manufacturing by reusing water or using water saving devices in households are already in place and are becoming more popular.
The ICPDR elaborated a Groundwater Guidance document that summarizes the groundwater management approaches agreed within the ICPDR. It provides brief technical information on the characterization 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 harmonization of approaches within the Danube River Basin.