In this example model of nonpoint pollutant runoff, time series of streamflow and runoff are used with an exponential buildup/washoff representation to model the generation of a pollutant. Run the model and look at the time history element of Runoff_Concentrations in this container.
The model also demonstrates how to use GoldSim's optimization ability for automated calibration. Observed pollutant concentrations are supplied as a time series of discrete changes (in the Calibration_Calcs container). There are four variables that control pollutant buildup and washoff and these are all varied in the optimization. Go to the Run menu to Optimization to run and optimization and watch the progress towards the best fit parameters that reduce the sum of squared errors between the model and observed data. You may experiment with changing the optimization precision between high and maximum.