Calibration and verification of the Lower Taieri Plains groundwater model
Holmes, Gillian Margaret
Groundwater hydrologists often use computer-based numerical models to predict the behaviour of groundwater systems due to their complexity. The overall goal of the present study was to further refine the previously developed Lower Taieri Plains groundwater model through the use of calibration and verification. Hydrological and climatic input data for the model were obtained for the period 1990 to 2000. Groundwater levels in five bores throughout the Lower Taieri Plains and drain flows in the Main Drain and Contour Channel were selected as calibration and verification targets. Calibration was undertaken using a trial and error approach on both a steady-state and transient version of the model. The calibrated steady-state model produced a Level 1 calibration for the groundwater levels in the Janefield bore and drain flows in Main Drain and Contour Channel, and a Level 2 calibration for the groundwater levels in the remaining four bores. In the calibrated transient model, a Level 1 calibration was produced for the Harley and Janefield bores, a Level 2 for the Donnelly bore, a Level 3 for the Outram bore and a Level 4 for the drain flows in Main Drain and Contour Channel. The steady-state model used in verification poorly simulated the target groundwater levels and drain flows, with the exception of the Janefield bore, for which a Level 1 verification was produced. Due to the poor simulations, the model could not be deemed verified. The transient model used in verification also poorly simulated the verification targets and, therefore, was not deemed as verified. The results of the calibration and verification imply that there are still many uncertainties associated with the model, due to the lack of information regarding its input parameters. Therefore, there are many opportunities for future research to further improve its capability to simulate the Lower Taieri Plains groundwater system.
Advisor: Murray, Dave; Richards, Kat
Degree Name: Master of Science
Degree Discipline: Geography
Publisher: University of Otago
Research Type: Thesis