ASSESSMENT OF THE RELATIONSHIP BETWEEN STREAM FLOW AND BASE FLOW: PATTERNS, ANALYSIS, APPLICATIONS
ABSTRACT. –Assessment of the relationship between stream flow and base flow: patterns, analysis, applications. Base flow indices for low land area from North-Eastern part of Romania are compared, which were calculated with six different separation methods: the local minimum method (LMM), Talaksen filter, Chapman filter, recursive digital filter (RDF) WHAT model and the Ekchardt filter. All filter-based methods indicate a slight increase in BFI values throughout the study period (1981-2013), in agreement with an increase in precipitation levels in the area over the past decades. The correlation matrix between the different values obtained for the BFI indicates that the most appropriate methods for the study area are the Chapman filter and the Eckhardt filter (r=0.98). Both methods suggest the identification of parameters a and BFImax, which, when adjusted for the lowland area of North-Eastern Romania (a=0.925, BFImax=0.7-0.8), indicate that, in the area in question, BFI values exceed 0.5.). This indicates the need for a careful reevaluation of the region from a hydrological point of view, one that takes into account the changes in land use and the numerous hydro-technical works of the past decades.
Keywords: BFI, empirical methods, filter based methods, lowland area