Determination of Surrogate Indicators for Phosphorus and Solids in Urban Stormwater: Application of Multivariate Data Analysis Techniques

Abstract

Solids and phosphorus found within urban stormwater have the potential to cause environmental damage to ecological systems in receiving waters. The evaluation of these pollutants in urban stormwater is usually undertaken by physico-chemical monitoring programs which sample streamflow for laboratory assessment. In this study, data from two such monitoring programs have been examined for the catchment characteristics which influence solids and phosphorus discharge behaviour and the potential for the use of surrogate indicators to predict streamflow concentrations. The study involved partitioning of the components on the basis of the dissolved and particulate fractions. Suspended solids and particulate phosphorus were found to depend on the extent of impervious area within the catchment. Surrogate indicators were evaluated in order to provide supplementary key indicators that can be used for site based measurements with fewer requirements for laboratory based analysis. Investigation of the physical and chemical behaviour of solids and phosphorus by univariate and multivariate data analysis techniques allowed the identification of a number of parameters with the potential for interrelationship. Thus, relationships were developed for suspended and dissolved solids using turbidity and conductivity, and for dissolved and particulate phosphorus using suspended and dissolved solids. These relationships will enhance rapid generation of vital information on spatial and temporal variation of indicator concentrations in urban stormwater