What are storm hysteresis effects? Generally, in order to investigate the dynamics of stream discharge and solute concentrations (C-Q relationship) in a watershed, researchers and environmental engineers usually set up monitoring stations in the watershed outlet. As the temporal dynamics of discharge and solute concentration is an integration of complex hydrological and biochemical processes, the relationship between solute concentration and discharge, hereafter called C-Q relationship, is mostly non-linear. If we plot the concentration against discharge within one storm event in a plot, we are supposed to see a non-linear loop, instead of a linear regression curve.