VARIABILITY AND TRENDS IN THE VIȘEU RIVER RUNOFF REGIME

Abstract

Variability and Trends in the Vișeu River Runoff Regime. The classic hydrological water management dealt with the changing resources by assuming the existence of stationarity. Once stationarity is neglected in the design of hydraulic engineering, numerous errors and risk may exist in the operations and management strategies and will lead to unforeseen losses. Thus, one of the most important questions in today’s hydrology are: Did stationarity die? and if it is true How did stationarity die? As we know the climatic change is widely accepted so it is sad that by 2050 the effects of climate change may have a generally larger effect on flow regimes than it is estimated that dams and water withdrawals. If this is so, we must consideration that in this moment one of the most important aspect/moment is the change point identification in a period, from where significant change has occurred in a time series, for this we choose to use the Ms Excel Addinsoft XLStat to assess the homogeneity of the data by the Pettitt’s test, the von Neumann ratio test, the Buishand range test and also the standard normal homogeneity tests (SNHT). For the trend analysis we used the Mann-Kendall test and the classic linear regression test. Based on the results, we conclude that in case of the Vișeu watershed stationarity is questionable if not totally missing. As we see even if the precipitation values do not show significant changes regarding their homogeneity, the runoff series are changing, and in most cases this change is identified in the 20^thcentury last decade. These results urge us to rethink and to reevaluate our sustainable water resource management for the future.