Reduced order emulation of distributed hydraulic models

Young, Peter and Leedal, David and Beven, Keith and Szczypta, Camille (2009) Reduced order emulation of distributed hydraulic models. In: 15th IFAC Symposium on System Identification, 2009. IFAC. ISBN 978-3-902661-47-0

Abstract

Water level predictions made with hydraulic models are uncertain and evaluating this uncertainty using Monte Carlo ensemble prediction is computationally very expensive. In this paper we show how a reduced order Dynamic Model Emulator (DME) can be used to reproduce, with high accuracy, the outputs of a large and complex 1-D hydraulic model (HEC-RAS) at specied cross-sections along the Montford to Buildwas reach of the River Severn in the U.K, together with estimates of uncertainty in the predictions. This emulation model is obtained by the application of Dominant Mode Analysis (DMA), involving the identication and estimation of nonlinear State-Dependent Parameter (SDP) transfer function models, using data generated by dynamic experiments conducted on the HEC-RAS model. The paper shows how this `nominal' DME is able to emulate the distributed hydraulic model for a nominal set of its physically-dened parameters and it presents initial results from a complete DME that emulates the HEC-RAS model over a user-dened region of its parameter space.