Model CalibrationAn OverviewVictorian 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 OutlineData Collection

◦What, Where, How?◦Monitoring Specifications◦SCADA Data◦Monitoring Contractors◦Data Review

Workshop OutlineModel Calibration

◦Calibration Specifications◦Event Selection◦Proof of Calibration◦What if Model Won’t Calibrate

Workshop OutlineWrap Up

◦Lessons learned◦Future Workshops

Data CollectionWhat? Where? How?

◦What do we measure◦Where do you place monitors◦How do you arrange monitoring

Specifications◦Monitoring Tolerances◦Capabilities of Modelling Equipment

Data CollectionSCADA Data

◦Operational requirements vs modelling requirements

◦Accuracy◦Calibration of monitors◦How is data recorded◦Can data be downloaded

Data CollectionContractors

◦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

CalibrationSpecification

◦Calibration tolerances◦Consistency with data accuracy◦Reporting requirements

Event Selection◦Time series vs event based◦Peak events

CalibrationProof of Calibration

◦Calibration plots◦Statistical comparison

What if Calibration cannot be Achieved?◦Data anomalies◦System anomalies

Wrap-upWhat have we learnt from today

Future Workshop Topics