Seasonal suspended sediment concentrations and their relationship with discharge in the Anoia River basin, NE Spain

The relations between suspended sediment concentration and discharge in the Anoia River basin are reported. The scatter is mainly a consequence of seasonality of events and the hysteretic loops that take place within them. The seasonal concentration-discharge relationship improves the complete data set relationships reinforcing the seasonality of events. Concentrations are greater during autumn than during spring. For instance, at the upper site mean suspended sediment concentration in autumn is 480 mg 1(-1) while in spring it is 200 mg 1(-1). At the downstream site, maximum concentration during autumn was 15 400 mg 1-1 and during spring was 10 700 mg 1(-1). The rating curve has a regression coefficient of r(2) = 0.2 whereas with seasonal subdivision the coefficients are r(2) = 0.6 for the autumn period and 0.5 for the spring period. Events exhibit hysteretic clockwise and anticlockwise loops increasing the degree of scatter in the concentration-discharge relationships.