An Overveiw of Version 2 of the Contaminant Load Model

The Contaminant Load Model (CLM) was first developed in 2006, and is now used within the Auckland regional and nationally. It is a spreadsheet tool to estimate the annual loads of total suspended solids (TSS), total zinc (TZn), total copper (TCu) and total petroleum hydrocarbons (TPH) discharged from stormwater networks serving areas of mixed urban land use and rural land. Version 2 is set for release, accompanied by two reports: a Model Development Report and a User Manual. The new version includes updated model parameters and the option for users to enter the load reduction factors, which were fixed at optimum values in the previous version of the model. The improved parameters include the source yields, which have been updated to take account of local and international studies published since May 2006. This paper discusses the model background, key features of the model, parameters, calibration, validation and model limitations.