Irrigation Intensification or Extensification Assessment Using Spatial Modelling in GIS

Yun Chen, Shahbaz Khan, Zara Paydar

Research output: Book chapter/Published conference paperConference paperpeer-review

14 Citations (Scopus)
67 Downloads (Pure)


Land suitability assessment (LSA) plays an important role in maintaining and developing land use on a spatial basis. It identifies the levels and geographical patterns of biophysical constraints and evaluates potential capacity of land and its sustainable use. This paper describes the evaluation of land suitability for intensification (achieving more per unit of inputs) or extensification (retiring unsuitable lands) in irrigated cropping within the framework of a research project carried out at in Macintyre Brook catchment, southern Queensland, Australia. It presents a spatial modelling procedure for the assessment of irrigated cropland suitability using available biophysical information in a GIS environment. Spatial data, including topography (25 m resolution DEM), soils and groundwater,were converted into grid layers which were classified into four suitable levels based on threshold values of evaluation criteria defined by experts. A weighting coefficient of each criterion was determined using GIS-based analytical hierarchy process (AHP). All criterion maps were integrated as inputs to a GIS-based LSA tool, a spatial weighted-linear model, built with ArcGIS 9.2 software. The modelling exercise revealed that the spatial model produced fine discrimination of land units and there was a good potential of land use by intensifying irrigation in areas classified as highly suitable for irrigated cropping to optimum utilisation. The model output includes a land suitability map which was then compared with the available catchment scale present land use map (50 m resolution) to decide the areas of irrigation intensification or extensification.Application of the methodology showed the significance of spatial modelling for detailed mapping purposes at a comparatively low cost. Results of the study indicated the usefulness of spatial modelling in assessment of land suitability and land-use planning. The resultant map can assist decision makers in ensuring that landsused according to their capacity to satisfy human needs for present and future generations, thus sustaining ecological and economic productivity of natural resources. Further modelling studies are being conducted for more detailed assessment of land use for different irrigated crops in this area.The investigation presented in this paper is a biophysical evaluation, the selection of criteria was largely limited by data availability, and the threshold values of criteria are subjective as well. It was carried out without considering the uncertainty in the input data and expert knowledge. It is recognised that more parameters are requiredin the assessment of land characteristics on a catchment system, particularly those related to the properties that govern runoff, salinity and irrigation. Therefore, the study only gives primary results based on topography, groundwater, and soil properties that affect the suitability classification of irrigated cropping.
Original languageEnglish
Title of host publicationAdvances and Applications for Management and Decision Making Land, Water and Environmental Management
Subtitle of host publicationIntegrated Systems for Sustainability MODSIM07
EditorsLes Oxley, Don Kulasiri
Place of PublicationChristchurch, New Zealand
PublisherModelling and Simulation Society of Australia and New Zealand
Number of pages7
ISBN (Electronic)9780975840047
Publication statusPublished - 2007
EventInternational Congress on Modelling and Simulation (MODSIM) - Christchurch, New Zealand
Duration: 10 Dec 200713 Dec 2007


ConferenceInternational Congress on Modelling and Simulation (MODSIM)
Country/TerritoryNew Zealand


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