Modeling storm-water runoff quantity and quality from marine drydocks

Storm-water runoff from a floating marine drydock can be a major source of pollution for the waterway in which the drydock is located. Significant amounts of pollutants build up over drydock surfaces because of intensive industrial activity. During periods of rainfall these pollutants can be washed off and quickly transported into the receiving water. In this study, a mathematical model has been developed to simulate the quantity and quality of storm-water runoff from marine drydocks. The mathematical model is based on the two-dimensional kinematic-wave and convective transport equations for total suspended solids. An empirical formula is used to model the wash-off process. An implicit finite-difference scheme is employed to solve the governing equations of the model numerically. In support of the modeling effort, the quantity and quality of storm-water runoff from a private drydock was monitored under actual rainfall-runoff conditions. The samples collected were analyzed in the laboratory to determine the pollutant loading of the runoff, and these data were subsequently used to calibrate and verify the mathematical model.