Modelling Accuracy Uncertainties Impact Mapping: Difference between revisions
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* The level of uncertainty/inaccuracy in the input data, especially uncertainties in hydrological inflows (which can be considerable) and topography.
* Whether the model is calibrated, and if calibrated, the range of calibration events and quantity/quality/type of calibration data. A model well calibrated to a range of flood events will be much more accurate than an uncalibrated model. More information on calibration can be found in <u>[https://www.tuflow.com/Download/Publications/October2016_FMA_Newsletter_HuxleyRyan.pdf Flood Modelling: How Accurate is Your Model?]</u> or an Australian Water School webinar <u>[https://www.tuflow.com/library/webinars/#maximise_accuracy Maximising Hydraulic Model Accuracy]</u>.
* Has the model’s sensitivity to changes in uncertain parameters (
* The scale of the hydraulics. ±10mm would be a large error margin for a flume model flowing 10cm deep, but is negligible for a deep river system flowing 10m or more deep. It’s important to think about the error margin as a percentage (not an absolute amount) of the depth/flow in the main flow paths.
* The suitability of the software being used for the application, whether a 1D or 2D solution, how the equations are solved, and whether any key terms in the equations are omitted. For example, for non-complex (i.e. slow moving) flows, terms such as the sub-grid turbulence (commonly known as eddy viscosity) can be omitted, however, this can be an essential term for faster, complex flow hydraulics.
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