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A Feasibility Assessment of Irrigated Agriculture on the Keep River Plains



A Feasibility Assessment of Irrigated Agriculture on the Keep River Plains


Short, M. A; Yin Foo, D; Tickell, S; Northern Territory. Department of Environment and Natural Resources, Water Resources Division


E-Publications; E-Books; PublicationNT; Technical Report ; 46/2019




Keep River Plains


A project was commenced in 2016 to undertake the additional scientific investigations required to better assess these risks prior to any expenditure of Australian Government, NT Government or private sector funds on future irrigation development and associated infrastructure. This assessment of the feasibility of irrigated development into the Ord Stage 3 – Keep River Plains has encapsulated a broad range of earth science disciplines. These include the areas of geology, geomorphology and soil, hydrology, hydrogeology, hydrogeochemistry, ecology (springs and potential GDEs), geophysics and the specialisation areas of remote sensed data acquisition.


Made available by via Publications (Legal Deposit) Act 2004 (NT).

Table of contents

1 Executive summary -- 2 Introduction -- 2.1 Technical background -- 2.2 Project objectives -- 2.3 Project scope -- 2.4 Project reporting milestones -- 2.5 Report exclusions -- 2.6 Feasibility assessment approach -- 2.7 Previous assessments -- 2.7.1 Salinity -- 2.7.2 Soils -- 2.7.3 Flooding -- 3 Salinity hazard -- 3.1 Methodology -- 3.2 Salinity risk scores -- 3.2.1 Soils -- 3.2.2 Groundwater -- 3.3 Salinity hazard map -- 3.4 Salinity hazard mapping limitations -- 4 Flood inundation potential -- 4.1 Rainfall-runoff modelling -- 4.2 Water observations from space -- 4.3 Flood inundation potential limitations -- 5 Land Capability assessment -- 5.1 Border Creek and Keep River Plains -- 5.2 Upper Knox Creek Plain -- 5.3 Land capability assessment limitations -- 6 Feasibility of irrigated agriculture -- 6.1 Summary -- 6.1.1 Upper Knox Creek Plain -- 6.1.2 Lower Border Creek Plain -- 6.1.3 Upper Keep River Plain -- 6.1.4 Lower Keep River Plain -- 6.2 Technical recommendations -- 7 Glossary -- 8 List of Abbreviation -- 9 References




Irrigated agricultuire; Groundwater

Publisher name

Northern Territory Government

Place of publication



Technical Report ; 46/2019


52 pages : colour maps ; 30 cm.

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Attribution International 4.0 (CC BY 4.0)

Copyright owner

Northern Territory Government



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Page content

A Feasibility Assessment of Irrigated Agriculture on the Keep River Plains Department of Environment and Natural Resources 29 November 2019 Page 20 of 52 3 Salinity hazard The following methodology is based on the method used to produce previous ORIA salinity hazard maps (Lawrie et al., 2009a & b) but includes additional datasets because of the assessments produced by this project (Table 2-1). This section presents an assessment of these new datasets with the aim of producing a relative risk rating of the salinity hazard for the Keep River Plains. The assessment relies on spatial data (measured, modelled and qualitative) relating to soils and hydrogeology the sources of the datasets are presented in Table 3-1. Table 3-1. Data sources for the layers used to produce the salinity hazard map Report Salinity hazard layer/s Carnavas & Burgess (2019) Lower Keep River Plain soil salinity Lower Keep River Plain soil drainage potential Carnavas et al. (2019) Lower Border Creek and Upper Keep River Plains soil salinity Lower Border Creek and Upper Keep River Plains soil drainage potential Harris-Pascal et al. (2019) Depth to watertable Shallow groundwater salinity Presence/depth to Milligans Formation Note: A salinity hazard map was not produced for the Knox Creek Plain area because there are data gaps from the new assessments for both soils (low resolution sampling) and groundwater (poorly constrained AEM and NMR data). 3.1 Methodology Each of the spatial layers described in Table 3-1 have been assigned a relative risk score depending on their measured or assessed spatial distribution. The higher the risk score (four being the highest), the higher the likelihood for induced salinisation of land as a consequence of irrigated agriculture. Salinity risk score layers for each of the five datasets consist of approximately 4 ha pixels covering the Upper and Lower Keep River Plains, as well as the Lower Border Creek Plain. The five layers were then combined into a final salinity hazard layer by adopting the median salinity risk score for each pixel as the indicative salinity hazard risk. This produced a layer that had pixel values ranging from one (low risk) to four (high risk). 3.2 Salinity risk scores The classes, value ranges and categories associated with each salinity risk score are presented in Table 3-2. The rationale for assigning each salinity risk score is briefly described in the following sections.