Using soil loss models to estimate suspended solids concentrations in stormwater runoff from pre-urban areas

Abstract

[Abstract]: Estimation of pollutant concentrations and mass loads in runoff is often required to develop stormwater management plans for future urban areas. Total Suspended Solids (TSS) is an indicator of stormwater pollution. There is often the need to predict and compare “post-urban” and “pre-urban” conditions to quantify the likely future change in TSS loads due to urban development. This paper will focus on planning-level estimation of TSS concentrations and loads from pre-urban sites, specifically rural grazing land. The proposed method is an adaptation of widely-used variants of the Universal Soil Loss Equation and accounts for site specific characteristics, such as climate, topography, vegetation cover and soil type. A case study is provided to demonstrate the application of the proposed method. The method is considered to be an improvement to current methods based on Event Mean Concentration (EMC), or at least provides guidance on the selection of an appropriate TSS EMC value to apply to pre-urban areas.