SKM: Pinehaven Flood Model Report and Flood Maps

SKM (now Jacobs) fed the ‘flow’ outputs from the flawed and unreliable MWH ‘rainfall-runoff’ model into SKM’s flood model, and prepared flood maps (2010) showing where they predict flooding will occur. A major error later became apparent in SKM’s ‘future case scenario’ (Vol1 pp14-16, 31-32).

The Beca audit (2015) acknowledged the error as a “major issue” and advised that the future development modelling be reviewed. Jacobs reworked the model (2016) and the Beca auditor stated (in 2017) that Jacobs had corrected the error. However, R J Hall & Associates Ltd (2019) found that Jacobs had not actually addressed the error, that it was unresolved, and concluded that there are “substantive discrepancies” in SKM’s flood model and flood maps, and that “the flood modelling … should be … corrected before any reliance is placed upon it as the baseline modelling for assessing post-development runoff of future Guildford development in the upper Pinehaven catchment.”