GIS methods for rapid landform and surface material mapping: application for recharge assessment  

Authors / CoAuthors

Halas, L. | Pain, C.F. | Magee, J. | Wallace, L. | Gow, L. | Lawrie, K.C.

Abstract

Several different techniques have recently been developed to rapidly map and characterise surface landforms and materials for groundwater recharge studies in Australia. In this example, in the Darling Floodplain of western New South Wales, regional landform mapping was carried out primarily using Google Earth imagery with hill-shaded LiDAR DEM and SPOT images as visual guide and some field validation. A second, more detailed map (compiled: 1:25,000; final usable scale: 1:30,000) included landform elements such as borrow pits, individual scrolls and oxbow lakes was compiled using LiDAR DEM. Prior to landform delineation, the LiDAR DEM required levelling to eliminate tilting in the landscape, by subtracting the floodplain trend surface from the DEM. This is particularly important in floodplains and river profiles where there can be as much as a 20 m difference between the upper and lower reaches. A best-fit trend surface, which provides an average estimation of change in slope along a single plane, was required to level the data. Once the LiDAR was levelled, an interactive contour tool in ArcGIS was used to generate graphic outlines of particular features at identified breaks in elevation using hill-shading, e.g. channel banks and dune bases. Slope and 3-D DEM visualisation also facilitated identification of these breaks. Further editing was required to assemble line work, convert it into polygons, and assign landform attributes. A greater number of landform classes were developed at this finer scale than for the regional scale. In many cases, specific landforms are characterised by particular surface materials, though sediment type can vary within a single landform class. SPOT imagery has been used to delineate surface materials. In summary, the combination of the two datasets - landforms and surface materials - has allowed for the identification of potential recharge site

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nonGeographicDataset

eCat Id

71330

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Keywords

• External PublicationConference Paper

( Theme )

• landforms

( Theme )

• DEM

( Theme )

• remote sensing

( Theme )

• geomorphology

Australian and New Zealand Standard Research Classification (ANZSRC)

• Earth Sciences

• Published_Internal

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2010-01-01T00:00:00

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Australian Government Security ClassificationSystem    

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Creative Commons Attribution 4.0 International Licence    

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geoscientificInformation

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