2024 – Hydrologic Time Travel: An Enoggera Reservoir Case Study

Hugh Nguyen-Mallen

This case study tells a tale of two Enoggera Reservoir configurations due to upgrade works and two records of historic reservoir water level records. This hydrology case study at Enoggera Reservoir, Brisbane, demonstrates a proposed data harmonisation technique for two historic datasets to improve rainfall-runoff model calibration. The two datasets were initially considered unreconcilable. A reservoir routing model was used to transport one dataset backward in time to simulate the recorded storm events as if Enoggera Reservoir had never been upgraded. Now reconciled, a rainfall-runoff model was calibrated to 160 years of two records, rather than 30 years of contemporary logger data, greatly increasing confidence in its predictions. The calibrated and validated rainfall-runoff model was then transported forward in time using the upgraded Enoggera Reservoir conditions. This proposed technique can allow practitioners to make use of the long time series of data available at some dam sites that have previously been discarded due to the influence of the reservoir attenuation on the data.