Quantity Method of River Bed Surface Form Based on Fractal Theory

The river bed surface fractal dimension(BSD)is put forward to measure river bed.Based on improvements in some aspects of Surface area-Scale Method,such as,estimation of surface area,boundary treatment and judgment of non-scale range,the calculation method of surface fractal dimension with irregular boundary was obtained,and the new method had good applicability on the bed surface fractal dimension calculation.The fractal characteristics of river bed surface morphology were discussed by combination with river-pattern,river regime,river process and changes of BSD.The results showed that BSD could change with river process,the more severe bed form undulates,the greater BSD was.The BSD could reflect complexity of bed form quantitatively,which could be used to study some related problems,such as analysis of river regime,distinction of river pattern,calculation of river resistance and so on.