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Accueil du site → Doctorat → Australie → The use of digital terrain modelling for development of hydrogeological conceptual models of the Nunijup Catchment in Southwest of Western Australia

Curtin University of Technology (2010)

The use of digital terrain modelling for development of hydrogeological conceptual models of the Nunijup Catchment in Southwest of Western Australia

Sharafi, Shahram

Titre : The use of digital terrain modelling for development of hydrogeological conceptual models of the Nunijup Catchment in Southwest of Western Australia

Auteur : Sharafi, Shahram

Université de soutenance : Curtin University of Technology.

Grade : Doctor of Philosophy (PhD) 2010

Résumé partiel
Despite past extensive research in the Kent River Catchment, little qualitative and quantitative assessment has been carried out for comparing each method of land classification used in this area. In the absence of a measureable assessment of each method, adopting a management technique presents a challenge to landholders as well as funding agencies to opt for the appropriate groundwork. This thesis is a case study that introduces the methodology of Relative Elevation Difference Model (REDM) technique to predict the groundwater levels and defines the hydrogeological characterisation of Nunijup sub-catchment within the Upper Kent River Catchment. This research compares the results of the REDM technique with Hydrogeomorphic Analysis of Regional Spatial Data (HARSD), and the GIS based Landmonitor techniques for landscape classification using Digital Elevation Model (DEM) and monitoring bores data. It aims at identifying the most accurate, reliable and cost effective landscape classification for the management of dryland salinity caused by shallow water tables. Using soil, rainfall, groundwater levels, hydrological and geological datasets, a finite difference groundwater flow model was constructed to affirm the suitability of the REDM method and predict the salinity impact on the study area for a period of 50 years. To model the pattern and extent of salinity and predict its future trends in the Kent River Catchment, a grid based GIS technique was used. DEM data were used for hydrological modelling of the study area and to calculate a number of physical attributes of the study area including elevation, slope, drainage pattern and the catchment area. These parameters were used to quantify the topographic and hydrologic characteristics of the Upper Kent River Catchment. The HARSD technique was used to map the areas with similar hydrologic and morphological patterns or Hydrogeomorphic Units (HGU) ; to predict the watertable depth, and to generate a groundwater map using ArcViewGIS software provided by Environmental Systems Research Institute Inc. (ESRI). The HARSD method is a generalised method of estimating groundwater levels at subcatchment scale with simplified geology. At the regional level, it produces a less accurate result due to increased geological complexity in the landscape particularly in the vicinity of shear zones, faults and dykes in addition to increased errors in the DEMs due to the larger study area. The Landmonitor project (1988-2000) produced a series of maps showing the areas of shallow water tables for the south-west agricultural region of Australia. The technique used in the Landmonitor project was utilised to identify the areas within 2 m height above the valley floors. While providing valuable information in elevated areas, the level of accuracy of Landmonitor technique decreases in the flat and plateau landscape and tends to overestimate the areas with shallow water tables in these areas. The REDM method was used to classify the catchment based on the height difference (or vertical distance) from the closest discharge point. It is based on topographical, hydrogeological and geomorphological characteristics of the catchment and enables an accurate identification and selection of the landscape units prone to shallow saline water tables.

Présentation

Page publiée le 30 novembre 2012, mise à jour le 6 juillet 2017