Author(s): T. J. Peterson; A. W. Western
Linked Author(s):
Keywords: Time series modelling; Groundwater hydrograph; Climate forcing; HARTT; Land use change
Abstract: For many decades, throughout much of Australia, considerable public investment has been made in establishing and monitoring groundwater bores. To improve the value extracted from this data set, this paper presents a new, and statistically robust, hydrograph analysis method. It extends an existing transfer function-noise model by inclusion of a derived soil moisture state variable. It allows simulation of a groundwater hydrograph using only climate forcing and does not resort to, as per the HARTT model, adoption of an unexplained temporal trend or an assumption of first order stationary climate forcing. Furthermore, the contribution from historic climate can be decomposed into that from various historic periods to provide novel insight into catchment dynamics, trends and lags. Four variants of this model, plus HARTT, were applied to eleven observation bores from a paired catchment reafforestation study in Great Western, Victoria. The findings include: (i) the inclusion of a soil moisture component in the model significantly increased the predictive performance compared to the original transfer function-noise model; (ii) decomposition of the hydrograph can provide significant insight into temporal trends and lags; and (iii) no model could estimate the groundwater head change from reafforestation with sufficient statistical confidence. Overall, this time series model is an advance in the technical methodology and in the utilisation of groundwater data.
Year: 2011