Projected changes in temperature and precipitation are expected to have severe impacts on river discharges and water resources availability. Temperatures are the most important drivers for the water cycle and changes in the parameters are expected to have considerable impacts.
During the last century temperatures have shown an increasing trend over Europe. Higher temperatures in winter mean that less precipitation will be falling as snow and snowmelt will be occurring earlier, thus changing the seasonal time of river discharge.
Summer precipitation is projected to decrease in southern, western and central Europe with drought periods becoming more common. Climate change will hence strongly change variability of summer climates both for precipitation and temperature.
Climate change will not just affect water quantity; low water levels can have a negative impact on water quality by bringing physico-chemical and biological changes. Higher runoff will increase pollution from diffuse sources, (e.g. capacity overloads of urban sewer systems), further deteriorating water quality.
On the other hand reduced water levels mean that pollutants will be less diluted. However, concerning the Hungary-Slovakia transboundary areas overall water availability is projected to decrease although not as drastically as in south and south-eastern Europe, in general.
Nevertheless, water management strategies need to adapt to climate changes that are distinguished at regional scales considering potential impacts in general.
In an effort to proactively find solutions to the current and future challenges of water, a project Environmental state and sustainable management of Hungarian-Slovakian transboundary groundwater bodies (ENWAT), supported by EU Initiative INTERREG IIIA was launched in 2006.
Water management plans were developed for three transboundary groundwater bodies in Hungary and Slovakia Ipoly River Valley, Bodrog River Region and Aggtelek-Slovak Karst. It also provided data on groundwater quality and quantity for decision makers as well as local inhabitants.
The characteristics of the river basin district and review of the environmental impact of human activity have been carried out by authorities. At the same time, physico-chemical parameters and the ecological indicators relevant for the surface water ecological and chemical status were also analyzed in Hungary-Slovakia.
The physico-chemical parameters measured included also mineral nitrogen concentrations, which do not suggest good status for any of the sub-catchments.
The main participants of the ENWAT project were the Geological Institute of Hungary and Geological Survey of Slovak Republic. Geological Survey of Finland (GTK), Smaragd-GSH, Hungary and HYDEKO, Slovakia were subcontractors of the project. GTK was responsible for the water management plans. Comprehensive work has been done on delineation of the ground water groups, preparation of existing data sets for harmonization.
A research Group for Water Resource Management also did a risk classification of Hungarian rivers according to hydromorphological risk led by Hungarian Academy of Sciences. The assessment has been carried out based on comprehensive analysis of the information available for the whole water body.
In general, the final classification of the surface water bodies in the study areas directly associated with groundwater bodies have important implications on the classification of the chemical status of groundwater bodies in central Europe.
Using independent third party in preparing groundwater management plan gives a good overview of actual strength or weaknesses related to groundwater management.
The problems with groundwater quality occur locally rather than at water-body scale. More so, localized pollution within a groundwater body does not mean that the groundwater body does not have a good chemical status.
The results of water quality studies in Slovakia are consistent with the Hungarian studies of groundwater quality. The quality standards for nitrates and pesticides are exceeded in a few sampling points.
Due to inflow from streams and rivers during dry season essentially groundwater, elevated concentrations of pesticides or nitrates in surface waters provide an indication on groundwater pollution in the river basin.
The observation in the nature protection areas in Aggleteki-Slovakian karst areas suggests that groundwater levels are getting lower.
Cross border co-operation works better on the lowest possible level, i.e. local municipalities and expert organizations rather than on the higher level.
Photo credit: GWP CEE/Muller