Hydrological Impacts of Climate Changes in Romania

Abstract

This chapter provides a comprehensive synthesis of researches on hydro-climatic changes in Romania and presents some original results on hydrological responses to climate changes in Valea Cerbului River basin (area of 26 km2) located in the Carpathian Mountains, based on the analysis of historical data and hydrological simulations. Although there are spatial differences, on the whole of Romania, after 1960, a general decreasing trend of the mean annual streamflow was detected. More or less significant changes in the annual flow regime were also noticed: upward trends in winter (related to the increase of the air temperature and liquid precipitations to the detriment of snowfall), downward trends in summer (induced by the general warming and increase of evaporation), and upward trends in the autumn flow. By 2050, the simulations under climate scenarios indicate a general decline of the mean multiannual discharges, significant increases of the discharges during winter and pronounced decreases in late summer and autumn. In Valea Cerbului River basin we investigated the changes in the magnitude and frequency of floods and low flows based on observational data, as well as the expected streamflow changes, as projected by simulations with WaSiM-Eth model (under B1, A2 and A1B climatic scenario, for the period 2001–2065 relative to 1961–2000 period). The simulations indicate a slight decrease in mean annual discharge (of 2% up to 6%) by 2065, an increase of mean monthly discharges from January to April, and a decline during May–December.