Availability of water resources under climate change in SE Europe Climate Change and Impacts on Water Supply supported by ERDF and IPA Availability of water resources under climate change in SE Europe Zoltán Simonffy Department of Sanitary and Environmental Engineering Budapest University of Technology and Economics

Climate Change and Impacts on Water Supply 2009-2012 Countries: Austria Bulgaria Croatia Greece Hungary Italy Romania Serbia Slovenia 15 partners

Climate Change and Impacts on Water Supply General objective of the EU water policy: Safe, healthy drinking water supply for long-term!

Climate Change and Impacts on Water Supply Objectives of the project: to assess the impact of CC (and CC induced land use changes) on water resources used for drinking water supply and on water demand; to evaluate availability and safety of public drinking water supply for several future decades (risk assessment); to delineate critical areas where measures are needed; to propose management options (decision support for suppliers and authorities); to propose methodolgy for such assessment

Climate Change and Impacts on Water Supply Structure and methodology: Climate change (WP3) WP4 Meteorological and hydrological chracteristics Quantity and quality of water resources Ecological and environmental criteria Water demand Economic assessment WP6 Water Supply Management (WP7) Proposals and tools Land use & water quality (WP5)

Climate Change and Impacts on Water Supply WP4 Availability of water resources

Assessment is based on 19 test areas Climate Change and Impacts on Water Supply Assessment is based on 19 test areas

Climate Change and Impacts on Water Supply Modular structure Precipitation Water balance model Surface runoff, flow in the river Recharge Sprigs Baseflow transpiration Evapo- Groundwater flow model Lateral flow to neighboring grwbody abstractions Surface runoff MODELLING MODULES available discharge spring flow available for capture available grw. for abstractions Evaluation of available groundwater resources EVALUATION MODULE + IMPACT OF CLIMATE CHANGE AND LANDUSE ecological criteria ECOLOGICAL MODULE

Stucture of models (example) Climate Change and Impacts on Water Supply Stucture of models (example) Precipitation Groundwater level Topography (slope) Landuse, Soil type Discharge in river (separation of surface runoff) Hydrogeological data Water courses Water abstraction Shallow and deep ground water level Baseflow input calibration input calibration Flux at gw level and baseflow harmony Water balance model of the unsaturated zone Hydrodynamic model (3D) (MODFLOW) Surface runoff, flux at gw. level (evapotranspiration, recharge) Gw. level, glux at gw. level, baseflow, exchange with neighbouring aquifers

Ecological criteria Climate Change and Impacts on Water Supply Groundwater dependent ecosystems: Swamp Swamp-meadow High water demanding marsh Marsh-meadow Wet salt-marsh Dry salt-marsh Riverside forest Gw demanding forest ETA needed from grw. Critical depth acc. to required fluctuation Surplus of evapotranspiration from groundwater at the wetland and in the surrounding area (too)

Changes in meteorological conditions Climate Change and Impacts on Water Supply Changes in meteorological conditions Blue: Westren part: Austria, Slovenia Green: Middle part: Hungary, Romania Southern part: Croatia and Serbia Summer Winter 2021- 2050 2051- 2100

Changes in meteorological conditions Climate Change and Impacts on Water Supply Changes in meteorological conditions Blue: Westren part: Austria, Slovenia Green: Middle part: Hungary, Romania Southern part: Croatia and Serbia Annual

Changes in water resources Climate Change and Impacts on Water Supply Changes in water resources Blue: Westren part: Austria, Slovenia Green: Middle part: Hungary, Romania Southern part: Croatia and Serbia Precipitation – pot. ET [mm] 2021- 2050 2051- 2100

Climate Change and Impacts on Water Supply Conclusions by regions HU, karstic springs: No channge, but ecological water demand is already problematic HU, porous aquifers: Considerable decrease, Shortage is likely, ecology already AT, karstic springs: Large system: no problem of quantity Small springs: possible shortage (low flow)  new resources (available) SI, porous aquifers: Slight decrease, No problem of quantity RO, porous aquifers: Slight decrease No problem of quantity RS, alluvial aquifer: Considerable decrease, Possible shortage. RS: small karstic springs: Slight decrease, Possible shortage at low flow CR, karstic lake, fields: Considerable decrease, Seawater intrusion already, shortage is likely,

Climate Change and Impacts on Water Supply General conclusions Different sensitivity indexes related to CC and drought (i.e. How does CC modify them?): recharge and available water resources GWDE (ecological water demand / recharge) extremities (droughts and „flash floods”) global exploitation, frequence of shortage Clear presentation and possible decrease of uncertainties. Revision (understanding) of ecological water demand (source of conflict)! Research based on case studies. Evapotranspiration is a key factor in the estimation of the recharge and the water demand of ecosystems. Research is necessary!!

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