Hydrograph recession analysis using wavelet transforms

A technique for determining hydrograph recession characteristics is presented based on the wavelet transforms analysis. Like a signal, a flood hydrograph can be decomposed into a number of wavelet components. By using the wavelet component values in the form of wavelet maps, the recession characteristics such as a recession constant and a cut-off frequency are easily determined. The technique is demonstrated on three catchments ranging from small to large catchment areas at eastern New South Wales, Australia. The proposed method gives promising results and minimizes a number of problems associated with hydrograph recession analysis.