ABSTRACT
ABSTRACT: Analytical probabilistic models for urban drainage systems analysis have undergone development at the University of Toronto for over two decades. Towards the prediction of the erosion potential of urban stormwater runoff, a new set of analytical probabilistic models is developed. The marginal probability distributions for the duration of a hydrograph in which the critical channel velocity is exceeded (termed exceedance duration) is computed using derived probability distribution theory. Exceedance duration and peak channel velocity are two random variables upon which erosion potential is functionally dependent. Reasonable agreement exists between the derived marginal probability distributions for exceedance duration and continuous SWMM simulations at low return periods. It is these events of lower magnitude and higher frequency that are the most significant to erosion potential.
