Statistics

Mean Annual Load statistics are calculated by summing the load (flow x concentration) for all time-steps, and dividing this result by the number of years in the dataset. This value provides a simple summary of the overall performance of a particular stormwater treatment measure or treatment train. Note that peak flows represents the peak flow rate over the period modelled.

Treatment Train Effectiveness statistics are a form of Mean Annual Load statistics in which the program traces back up the catchment and compares the output from the current node or link with the combined output from the contributing source nodes. Note that if there is a potential loop present in the treatment node, this options does not appear in the Statistics contextual menu item.

Node Water Balance provides detailed statistics on all inflows and outflows from a node. In the case of a Source Node, this includes rainfall inputs, evapotranspiration, baseflow and stormflows, along with change in soil moisture storage. Fluxes of pollutants are also reported. In the case of a treatment node, inflows are reported, along with evaporation and infiltration losses, bypass flows, and discharges through weirs and outlets. Amounts of stormwater harvesting (‘reuse’) demanded and supplied are also reported. The Node Water Balance function can thus be used to provide detailed information on water and pollutant fluxes, without having to create a flux file.