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Model Calibration An Overview. Victorian Modelling Group Workshop 29-11-2010 Facilitators: Stephen D’Agata – AECOM Matthew White – City West Water. Introduction. Why Bother? Do Models always need to be calibrated? Built model represents network as it should be…
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Model CalibrationAn Overview Victorian Modelling Group Workshop 29-11-2010 Facilitators: Stephen D’Agata – AECOM Matthew White – City West Water
Introduction • Why Bother? • Do Models always need to be calibrated? • Built model represents network as it should be… • Or as it appears to be in the GIS • Need models to represent networks as they are. • Models are virtual representations of…… REAL SYSTEMS
Introduction • What is Calibration? • Getting the model to reproduce observed hydraulic conditions (Virtual representation of real systems) • Need observed data to calibrate to. • Observed data should represent extreme conditions • Model parameters are adjusted until modelled data matches observed data • Can’t calibrate the entire network • Can only calibrate elements of the network
Introduction • Water Network Model Calibration: • Observed Pressure Including Tank and Reservoir Levels. • Observed Flows and Pump Operation • Need peak demand conditions to test network hydraulics. • Models generally calibrated to peak summer conditions.
Introduction • Sewer Network Model Calibration: • Observed flows (Velocities and Depths) • Observed Pump Operation • Peak flow conditions generally associated with rainfall induced flows • Need to monitor rainfall concurrently with flows • Models need to be calibrated to dry weather first • Then rainfall runoff routing is used to calibrate rainfall contribution
Workshop Outline • Data Collection • What, Where, How? • Monitoring Specifications • SCADA Data • Monitoring Contractors • Data Review
Workshop Outline • Model Calibration • Calibration Specifications • Event Selection • Proof of Calibration • What if Model Won’t Calibrate
Workshop Outline • Wrap Up • Lessons learned • Future Workshops
Data Collection • What? Where? How? • What do we measure • Where do you place monitors • How do you arrange monitoring • Specifications • Monitoring Tolerances • Capabilities of Modelling Equipment
Data Collection • SCADA Data • Operational requirements vs modelling requirements • Accuracy • Calibration of monitors • How is data recorded • Can data be downloaded
Data Collection • Contractors • Who is out there • Are they any good • Data Review • How do you know you are getting good data • Data checks • Data consistency • Error accumulation
Calibration • Specification • Calibration tolerances • Consistency with data accuracy • Reporting requirements • Event Selection • Time series vs event based • Peak events
Calibration • Proof of Calibration • Calibration plots • Statistical comparison • What if Calibration cannot be Achieved? • Data anomalies • System anomalies
Wrap-up • What have we learnt from today • Future Workshop Topics