Bungendore Groundwater Model
Client: Hydroilex on behalf of Palerang Council
Year: 2005-2006
Project Reference: 05032
WRL Technical Report: Bungendore Regional Groundwater Flow Model - Historic Rainfall Variability and Uncertainty Analysis (2006/02)
Bungendore is a small town located south of Lake George, heavily dependant on groundwater for town water supplies and irrigation. Hydroilex was engaged by Palerang Council to undertake a regional evaluation of the Lake George catchment and associated groundwater system, to determine the hydrogeological controls, and likely sustainable yield of the aquifer. WRL was subsequently commissioned by Hydroilex to analyse the hydrogeological data provided and develop a groundwater model for the Turallo Creek catchment. The catchment is 172 km2 and comprised of fractured rock highlands overlain by alluvium in the lowlands.
Significant quantities of data are required to successfully develop, calibrate and run a groundwater model; including pumping data, water level data, geology, land use and rainfall, well construction details, bore logs and hydraulic conductivity. WRL compiled and quality checked the available data to firstly create a conceptual model of the aquifer. GIS maps of the land use, topography, geology and hydraulic conductivity were created for use within the model.
WRL developed the numerical model using the FEFLOW code to create a 3D finite element mesh and assign material properties to the model domain. The groundwater model was calibrated over the short time frame of 4 years for which data was available, with calibration focusing on hydraulic conductivity and rainfall recharge to the model.
WRL’s model has had a significant impact on the future development of water supplies in the Bungendore area. WRL concluded that rainfall recharge is lower than expected in the catchment, at just 1% of rainfall. Usage was shown to be at or near the sustainable yield during low rainfall periods such as 2002-2004. Sensitivity analysis of the model was completed to demonstrate the accuracy and potential variation in model results. Based on the results of the model, WRL recommended great caution in the further development of the catchment and a program of data collection to reduce the uncertainty of the model.
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