Comparison of methods to estimate suspended solids loads in urban stormwater

Abstract

Planning of stormwater management strategies often requires estimating the concentration or mass load of pollutants in storm runoff generated from urban areas. In Australia, it is common practice to use simple methods that adopt a constant event mean concentration (EMC) for all storms under analysis. Alternatively, a stochastic concentration may be used to introduce variability between storm events. A comparison is made between three of these “Mean EMC Methods” and five proposed methods. Each method was evaluated in terms of accuracy in predicting suspended solids EMCs against data measured for a road surface located in Toowoomba, Queensland. The cumulative error in estimating the total load for a sequence of storm events was also assessed. The Mean EMC Methods demonstrated low accuracies compared to the proposed alternatives.

Keywords:

• Stormwater
• road runoff
• particle loads
• suspended solids
• water quality
• event mean concentration

Additional information

Notes on contributors

I Brodie

Since graduating in agricultural engineering from DDIAE (now University of Southern Queensland) in 1983, Ian Brodie has worked for a number of major Australian water engineering consultants. His technical interests are urban stormwater management and design, environmental impact assessment within waterways, and flood hydrology. Ian has completed a Masters in Engineering Science at the University of New South Wales and a PhD on the topic of urban stormwater pollution at USQ.

M Porter

Mark Porter is a water resources and environmental engineer with a strong interest in engineering education. He has been the head of Agricultural, Civil and Environmental Engineering at the University of Southern Queensland since 1987 and is a co-director of the Australian Centre for Sustainable Catchments at the university. He teaches courses in hydrology, water resources engineering and environmental technology, and supervises a number of postgraduate research students. In recent years. Mark has been focusing on research work involving the impact of human activity on water quality and resources in Germany, New Zealand and Queensland, Australia. He developed and delivered the first fully multimedia course on engineering hydrology known in the world for external engineering students. Mark won the USQ Excellence Award for Research in 1993, and was a joint winner of the USQ Excellence Award for the Design and Delivery of Teaching Materials in 2003.