Climate change impacts on water resources (SR1)
The main impacts of climate change on the water resources in the Carpathians are as a result of changes in temperature and precipitation patterns and a higher inter-annual variability. These seasonable changes will effect water availability and water quality. Due to these changes, snow cover and glacier storage will decline and run-off regimes altered, with an increase in flooding events and possibly landslides. In their turn, these events increase the load of pollutants of receiving water bodies downstream and therefore affect the water quality. Run-off is expected to decrease in central and eastern Europe, while groundwater recharge is likely to be reduced, with greater reduction occurring in valley and lowlands. Dry summers will put ecosystem services like for instance drinking water at risk, resulting in water shortages. This will have its impact on economic sectors such as households, agriculture, energy production, forestry, tourism and alternatively, river navigation. These shortages may create tension and conflict among users.
Climate change is expected to increase the frequency of extreme weather events, as well as change the seasonality of river flows across Europe: summer flows are projected to decrease, even in regions where annual flows will increase. Direct impact on fresh water resources are often described in terms of drought, floods, recharge and storage in groundwater and snow/glaciers. These changes impacts rivers, lakes and groundwater and springs in term of flow, water tables and water quality including temperature and health related quality problems.
In general, low flow and drought periods as well as water scarcity events are expected to increase for the impact on rivers. The trend in future occurrence of flood events is uncertain. In particular, southern parts of Hungary and Romania as well as the Republic of Serbia, Bulgaria and region of the Danube Delta are expected to face severe droughts and water shortages. This will in turn affect water quality. In periods of drought and high temperatures less flow will enhance eutrophication and can trigger toxic algal bloom. Pollutants that originate from point and diffuse sources are less diluted, so concentrations of dangerous and emerging substances will increase. Drought will increase the demand of water (agriculture, human consumption, cooling), which in turn can enhance the lowering of flow and water tables and impaired water quality.
Increases in extreme weather events contributes to local flash floods. With respect to water quality, increased flash floods events will lead to (more) uncontrolled discharges from urban areas and increasing storm events, especially a storm after a long period of drought, will flush more nutrients from urban and rural areas [whitebread 2009].
Due to the predicted increase in temperature, snow is expected to melt earlier, resulting in snow-melt floods. It would seem that due to its origin, flooding hardly affects snow cover.
The Special Request 1 addresses main impacts of climate change on the water resources in the Carpathians are as a result of changes in temperature and precipitation patterns and a higher inter-annual variability climate change. Main objective of this study is to deliver the consistent knowledge about expected effect on flood and droughts, changes of snow conditions, water related vulnerability with some regulatory aspects in the Carpathian regions.
Subjects of the study request:
Contact person: Gábor Bálint, e-mail: firstname.lastname@example.org