New geomorphic and surface-materials mapping approaches for hydrogeological investigations in the Darling River NSW, Australia  

Authors / CoAuthors

Halas, L. | Magee, J. | Lawrie, K.C. | Pain, C.F. | Clarke, J.D.A.

Abstract

Geomorphic landscape features and associated surface materials are fundamental to groundwater recharge processes as they form the first layer through which surface water passes before it becomes groundwater. Different surface materials exhibit different water-holding capacity and hence permeability characteristics. In the Broken Hill Managed Aquifer Recharge project, surface-materials mapping in conjunction with geomorphic mapping, has assisted hydrogeological investigations, including recharge predictions, salinity hazard and the identification of potential infiltration basins. Prior to landform identification, LiDAR DEM data was levelled using trend surfaces to eliminate regional slope (~20m). As a consequence of this, an ArcGIS interactive contour tool could be used to identify specific breaks in elevation associated with landform features. Multivariate image analysis of elevation, high resolution SPOT and Landsat-derived wetness further enhanced the contrast between geomorphic elements to confirm mapping boundaries. While specific landforms can be characterised by particular surface materials, these sediments can vary within a single geomorphic feature. Consequently, SPOT multispectral satellite imagery was used to identify surface materials using principal component analysis and unsupervised classification. This approach generated 20 classes; each assigned a preliminary cover/landform attribute using SPOT imagery. Field data (surface and borehole sample, and observations at shallow pits) were used to refine the classification approach. Interactive mapping using a de-trended DEM provided a rapid, effective and accurate alternative to time consuming manual landform digitisation. The combination of these two new products - surface-materials and geomorphic maps - has assisted in the identification of potential recharge sites and naturally occurring infiltration sites.

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nonGeographicDataset

eCat Id

73664

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Keywords

• GA PublicationAbstract

( Theme )

• hydrogeology

( Theme )

• geomorphology

( Theme )

• marine

Australian and New Zealand Standard Research Classification (ANZSRC)

• Earth Sciences

• Published_Internal

Publication Date

2012-02-16T00:00:00

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Australian Government Security ClassificationSystem    

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Creative Commons Attribution 4.0 International Licence    

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unknown

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geoscientificInformation

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