Publication Date

5-2022

Series Number

426

Publisher

Department of Primary Industries and Regional Development

City

Perth

ISSN

1039-7205

Abstract

This report documents the procedures used to identify suitable locations for irrigation development in the Pilbara region. It is the first study to investigate the potential for irrigated agriculture across the Pilbara. We used a desktop analysis to ascertain water availability and spatial data modelling to determine the potential of the land and soil resource to support irrigated agriculture. This study was part of the Pilbara Hinterland Agricultural Development Initiative (PHADI).

We used existing rangeland land inventory information augmented with digital spatial environmental data, in a process known as map disaggregation, to create soil and landform maps that had a quantified soil type prediction at every location on the ground. Soil type predictions were divided into 3 ‘irrigation suitability’ classes to identify areas most capable of supporting irrigation. We identified 3 landscape-scale constraints likely to preclude the development of irrigation in this extreme climate: inland flooding and inundation, water erosion and coastal inundation. We used proprietary data from Landgate and new datasets that were developed during this project to identify areas at heightened risk of these hazards and then excluded these areas from assessment. The assessment identified:

  • 2.1 million ha of class A1 land (8% of the PHADI area); Class A1 land has soil and landform characteristics that are rated as highly suited to irrigation making up more than 70% of its area
  • other small areas with significant good land for irrigation, which should be able to support smaller-scale irrigation developments if water supplies can be secured.

The water assessment reviewed all publicly available data and information to assess potential water resources in the Pilbara that could support irrigated agriculture. Specifically, the water assessment reviewed:

  • the volume of water that was available in areas with allocation limits
  • mining areas having surplus dewater not used for mining operations or environmental purposes
  • other sources of water potentially available, including underdeveloped non-target aquifers
  • surface water flows that could be captured and stored through managed aquifer recharge systems.

The review identified 10 prospective areas that, combined, could have 100–120 GL/y of water resources available to support irrigated agriculture. Together, these 10 sites cover 5,000–12,000 ha across the Pilbara, with individual areas from 250–500 ha up to possibly 3,000 ha. These areas should be investigated in greater detail for water supply, water quality, landform and soil characteristics.

All prospective irrigation development, particularly large precinct-type development, must thoroughly assess social, environmental and economic impacts and consequences – we summarise some key considerations of these aspects in this report. Proponents considering smaller-scale development would benefit from considering these aspects early in their planning and should be aware of the regulatory processes that must be complied with.

Number of Pages

54

Keywords

land and water resources, irrigated agriculture, spatial data modelling, land capability, Pilbara

Disciplines

Agriculture | Natural Resources Management and Policy | Remote Sensing

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