Temporal trends of groundwater levels in the Condamine catchment 2007-2013

Temporal trends of groundwater levels in the Condamine catchment 2007-2013

Over 500 hydrographs of monitoring bores, located in the Condamine Catchment, were reviewed, analysed and clustered. Results indicate that the consistent trend of declining water levels occurred for several decades in most parts of the Condamine catchment and ceased in the late 2000s. In most bores in the Condamine catchment, current groundwater levels are higher by 1.5 – 8.5 m than the levels recorded in
2010. In other bores, groundwater levels stabilized since 2007. These trends are a cumulative result of (1) enhanced recharge during summer 2007/08 and summer 2010/11 flood events, and (2) restriction on water pumping in the CGMA.
The bore hydrographs testify to the conceptual mechanism of recharge and interconnections between aquifers in the catchment: (1) Diffuse recharge occurs over the eastern and south-eastern rims of the catchment, (2) the elevated water table introduce higher fluxes toward the Condamine floodplain, and (3) the enhanced lateral fluxes combined with restricted pumping lead to stable water levels in the floodplain.
The current hydrological situation thus represents a step toward sustainable use of the groundwater resources. Nevertheless, the lateral fluxes from the eastern recharge zones are not constant and may decrease again should another drought period will take place in the Darling Downs region. It is suggested to keep the water allocation process in place and also to incorporate the effect of water table elevation in the eastern recharge areas, in the water allocation announcement equation.

Copyright 2014 University of Southern Queensland. This publication is copyright. It may be reproduced in whole or in part for the purposes of study, research, or review, but is subject to the inclusion of an acknowledgment of the source. Report prepared for CRDC project 11-12FRP00044 (DNRM, USQ and UNSW)