Testing and sensitivity of a simple method for predicting urban pollutant loads

摘要

This paper tests a simple two-parameter regression model, based on rainfall intensity, for calculating event loads of total suspended solids, total phosphorus, and total nitrogen from urban catchments. It also examines the sensitivity of the model to its two parameters and to the rainfall time step. This was done by using large data sets collected at six urban catchments in temperate Melbourne. It was found that the two-parameter model typically explains approximately 90% of the variation in event loads at a site. The model also predicts the within-event behavior of pollutants when the flow lag time is taken into account, with R~2 correlations greater than 0.6 in most cases for both loads and concentrations at a six minute time step. Despite its acknowledged correlation with flow, rainfall intensity over short time steps is shown to be the primary driver of pollutant mobilization, and provides a practical means of predicting pollutant loads by using readily available data.