The Murrumbidgee River - Hay to Maude Rural Floodplain Risk Management Study was undertaken by WMAwater. The Flood Study component comprising the establishment of a two dimensional hydraulic (TUFLOW) model of the rural floodplain was completed in 2009. The Floodplain Risk Management Study (FRMS) was completed in 2011 and the Floodplain Risk Management Plan was placed on Public Exhibition also in 2011. In March 2012, a flooding event of similar size to that of the 1974 event occurred on the Murrumbidgee River at Hay. In light of the fact that the 1974 event was selected as the design event for the assessment of floodplain works as part of the FRMS and that a relatively large amount of recorded information was available following the March 2012 event, validation of the hydraulic model to this recent event is warranted.

This memorandum comprises the following parts.

Part 1 includes verification of the TUFLOW model for the March 2012 event. The existing hydraulic TUFLOW model was re-run with March 2012 inputs and model results compared to observed flood behaviour. An assessment of the models performance is made though no re-calibration has be undertaken.

Part 2 includes updating the Flood Frequency Analysis at Hay Town to incorporate the recent flood.