| Product(s): | Bentley StormCAD, CivilStorm, SewerGEMS |
| Version(s): | V8i, Connect Edition |
| Area: | Results and Outputs |
The purpose of this article is to provide guidelines and best practices for hydraulic model calibration of storm water systems.
Currently StormCAD, CivilStorm and SewerGEMS do not have an automated calibration tool similar to Darwin Calibrator in WaterGEMS.
When you are dealingworking with storm water, it is more related to hydrology than hydraulics, the key factors are comparing hyetograph data from actual storms with model results. You may pair up a rain gage with each catchment and instrument it to collect rainfall data at regular intervals. See this article for information on rain files. Stormwater monitoring at the outlets of catchments is common way of calibration. Also documented flood data can be used for calibration purpose by comparing that with model results.
Studies showed that the most relevant parameters for model calibration are Manning’s roughness coefficient for conduits, percentage of the impervious surface area, storage depth of the impervious area, Manning’s roughness coefficients for overland flows and width of the subcatchment. Other parameters have smaller effects on the calibration results. Rainfall data used during calibration can consist of days or even years of continuous time series data, as well as event-based subsets that consider one or more storm events extracted from continuous time series data as per the studies.
Calibration criteria for storm water models could be like following,
(1) minimizing errors in simulated peak flow, and
(2) minimizing errors in total flow volume.
(3) Comparison of flood model results with field values.
Below are some videos related to calibration.
Tips for Calibrating a Sewer Collection System Model
These are more focused on sanitary as opposed to stormwater but the concepts are still relevant and useful.
FAQ
Why are model results not matching with field results? Check following,