CLIMATIC EFFECTS ON THE RUNOFF CONDITIONS IN HUNGARY

Using runoff and climatic observations from 37 small watersheds in Hungary a regional climate-runoff relationship has been established. This non-linear relationship is a modification of Budiko's similar equation and can be used to estimate the effect of climate changes on long-term average runoff. The degree of change in runoff depends not only on changes in precipitation and temperature, but also on the present climate characteristics. The regional relationship is verified only within a relatively narrow range of precipitation and temperature and this fact limits its use in climate impact assessment. Model calculations show that a relatively slight shift in climate, an increase in annual temperature by 0.5-degrees-C, and a decrease of annual rainfall by 0.08 mm d-1 may lead to a decrease of runoff by 25-30 per cent in small watersheds of Hungary.