Mapping potential groundwater recharge and flow pathways in the Darling floodplain by integrating 3D hydrogeophysical and geomorphic maps with hydrodynamic and hydrogeochemical data  

Authors / CoAuthors

Gow, L.J. | Halas, L. | Lawrie, K. | Brodie, R.S. | Gibson, D. | Magee, J. | Clarke, J. | Tan, K.P. | Somerville, P.

Abstract

In many floodplain landscapes in Australia, surface-groundwater interactions are poorly understood. There is limited mapping of recharge and discharge zones along the major river systems, and only generalised quantification of hydrological fluxes based on widely spaced surface gauging stations. This is compounded by a lack of temporal data, with poor understanding of how surface-groundwater interactions change under different rainfall, river flow and flood regimes. In this study, high resolution LiDAR, in-river sonar, and airborne electromagnetic (AEM) datasets (validated by drilling) have been integrated to produce a detailed 3-Dimensional map of surface geomorphology and hydrogeology. These maps enable potential recharge zones in the river and adjacent landscape to be identified and assessed under different flow regimes. These potential recharge zones and groundwater flow pathways were then compared against the spatial continuity of (and presence of) 'holes' in near-surface and deeper aquitard layers derived from the AEM. These 3D mapping constructs provide a framework for considering groundwater processes. Hydrochemistry data, allied with hydraulic data from a bore monitoring network, demonstrate the importance of recharge during significant flood events. In many places, the AEM data also affirm the spatial association between fresher groundwater resources and sites of river/floodplain leakage. At a more localised scale, hydrogeochemical data allows discrimination of lateral and vertical fluxes. Overall, this integrated approach provides an important conceptual framework to constrain hydrogeological modelling, and assessments of sustainable yield. The constructs are also invaluable in an assessment of managed recharge options and locations.

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nonGeographicDataset

eCat Id

73542

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• External PublicationAbstract

( Theme )

• groundwater

( Theme )

• Airborne Electromagnetics

( Theme )

• hydrogeology

Australian and New Zealand Standard Research Classification (ANZSRC)

• Earth Sciences

• Published_Internal

Publication Date

2012-02-15T00:00:00

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Creative Commons Attribution 4.0 International Licence    

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