Farm cadastral data were sourced from Victorian Department of 
Sustainability and Environment (DSE). Measures of water 
supplied to farms in the period, January to April 2009, were 
sourced from the Victorian Water Register (VWR), maintained 
by DSE (http://www. waterregister.vic.gov.au/). Farm-scale data 
were aggregated to district (pod) scale for regional reporting 
purposes. 
Seven cloud-free images of Landsat 5 were acquired for the 
study (Table 1). The images were sourced from the USGS 
(http://earthexplorer.usgs.gov). The selection of images 
represented the traditional irrigation period during spring, 
summer and autumn seasons in northern Victoria (irrigation is 
not normally required in the period, June — August, when 
rainfall usually exceeds evaporative demand). All images were 
radiometrically corrected prior to analysis. Digital numbers 
were converted into physical units of at-sensor-radiance, top-of- 
atmosphere (TOA) reflectance, and at-sensor brightness 
temperature to a 30 m spatial resolution, using the current 
equations available for Landsat-5 (Chander et al 2009). 
  
  
  
Acquisition Date | Scene (Path / Row) 
10 Oct 2008 94 / 85 
04 Nov 2008 93/85 
14 Jan 2009 94 / 85 
23 Jan 2009 93/85 
13 Apr 2009 93/85 
20 Apr 2009 94/85 
08 May 2009 92/85 
  
  
  
Table 1. Landsat 5 TM images used in the study. 
3. RESULTS 
Spatial distribution of CWR showed significant variation at 
pod-level during Jan-Apr 2009 (Figure 1). Large parts of 
Pyramid-Boort and Torrumbarry areas in the west had CWR 
under 1000ML. Higher numbers of CWR (reaching up to 9440 
ML) were in Central Goulburn, Shepparton and Murray Valley 
irrigation areas. 
Total water supply at pod-level varied from near zero to over 
5000 ML during January-April 2009 (Table 2). Spatial 
distribution of TWS (Figure 2) showed similar pattern as of 
CWR (Figure 1). Parts of eastern Torrumabrry, Central 
Goulburn, Shepparton, and Murray Valley had fairly high water 
supply whereas large parts of Pyramid-Boort areas received 
very little water. 
The ratio of TWS and CWR ranged between near zero and 13 
(Table 2). TWS and CWR showed a strong relationship (Figure 
3), which supports the use of these data to underpin a 
benchmark. The regional distribution of the ratio showed a 
considerable spatial variation. Lower values (=1.0) where 
supply is near or below demand, were found in the eastern part 
of the Catchment. Pyramid-Boort and the western part of 
Torrumbarry irrigation area showed higher values of the CWR: 
TWS. Irrigation intensity (ML/ha) ranged between O0 and 20 
ML/ha. Western areas had higher irrigation intensities as well as 
those on the edge of the irrigation systems. A large part of the 
Catchment had water use <5 ML/ha in Jan-Apr 2009. 
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B8, 2012 
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia 
Crop Water Requirement (ML) 
   
   
  
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Murray catchment during January — April 2009. The line shows 
the relationship, TWS = CWR, where farm water supply and 
water demand are in approximate balance. 
    
   
   
  
  
  
  
  
   
  
  
  
  
  
  
   
   
  
   
  
  
  
  
   
     
  
  
   
  
  
  
  
   
  
  
   
  
  
  
  
   
   
  
   
   
  
  
  
  
   
   
  
   
  
   
    
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