TITLE:
On Redefining the Onset of Baseflow Recession on Storm Hydrographs
AUTHORS:
R. Pizarro-Tapia, F. Balocchi-Contreras, P. Garcia-Chevesich, K. Macaya-Perez, Per Bro, L. León-Gutiérrez, B. Helwig, R. Valdés-Pineda
KEYWORDS:
Baseflow Recession; Hydrograph Separation; Hydrologic Modeling; Recession Analysis; Baseflow Onset
JOURNAL NAME:
Open Journal of Modern Hydrology,
Vol.3 No.4,
November
4,
2013
ABSTRACT: Two methods that define the point of baseflow recession onset were compared using storm hydrograph data for 27 storm events that occurred between 1982-1995 in the Upeo watershed located in the Andes mountain range in central Chile (Figure 1). Three well-known baseflow recession equations were used to determine whether the method we are proposing here, that defines baseflow recession onset as the third inflection point on the logarithmic graph of the falling limb of the storm hydrograph, more accurately models observed data than the most widely used method that defines baseflow onset as the second inflection point on the same graph. Five time intervals were used to modify the recession coefficient in search of a more accurate fit. Results from the coefficient of determination, standard error, Mann-Whitney U test, and Bland-Altman test suggest that redefining baseflow recession onset via the proposed approach more accurately models baseflow recession behavior.