Possible climate impacts on the water resources of the Danube river basin - Some first results of the Danube river water balance study in the frame of the IHP Danube Regional Cooperation

The existing information concerning precipitation, air temperature and runoff in the Danube river basin during the observational period is reviewed. The existing major fluctuations are analysed and discussed. The results show a severe drought period in the central and lower Danube basin, starting with the year of 1983, approximately. But a similar drought period is to be found in the last century. Thereafter, the main water uses in the Danube basin are summarised and their influence on runoff is analysed. Finally, the possibilities for applying climate change scenarios to the Danube river basin are considered. Some major difficulties appear. It is even difficult to judge about the sensitivity of the basin as a whole to climate change. Because of the large extent of the basin, theoretical constant scenarios cannot be applied. On the other hand, the GCM scenarios are still unreliable concerning their regional forecasts, so that only some general tendencies can be derived. But it is shown that some of the major recent fluctuations of the hydrometeorological elements appear to be consistent with GCM-predictions.