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 
     
SATELLITE-BASED MEASUREMENTS FOR BENCHMARKING REGIONAL 
IRRIGATION PERFORMANCE IN GOULBURN-MURRAY CATCHMENT 
M. Abuzar*? *, A. McAllister?, D. Whitfield?, K. Sheffield * 
Future Farming Systems Research Division (FFSR), Department of Primary Industries (DPI) 
* FFSR, DPI, 32 Lincoln Square North, Carlton, VIC 3053, Australia 
® FESR, DPI, 255 Ferguson Road, Tatura, VIC 3616, Australia 
KEY WORDS: Remote Sensing, agriculture, application, image, satellite, temperature 
ABSTRACT: 
Irrigation has a significant impact on regional water resources in south-eastern Australia. It is therefore important that objective 
assessments of the current use of water are undertaken on a routine basis. New remote sensing technologies now provide an 
opportunity to assess and monitor water use at farm and catchment scales. This study demonstrates the use of satellite-based 
estimates of evapotranspiration (ET) and NDVI (Normalised Difference Vegetation Index) in irrigation performance indicators that 
relate crop water use to crop water requirement (CWR) in the Goulburn-Murray Irrigation Region of South-Eastern Australia. The 
METRIC energy balance algorithm (Allen et al 2007) was used to derive ET estimates from Landsat satellite data. 
1. INTRODUCTION 
Irrigation dominates agriculture in the Goulburn-Murray 
Irrigation Region of south-eastern Australia. The Catchment, 
located in Victoria, Australia, between 35° 06' and 36° 42" S 
latitudes, and 143° 18' and 146° 01' E longitudes accounts for 
an area of about 68,000 sq km, and includes the key irrigation 
areas of Central Goulburn, Shepparton, Rochester-Campaspe, 
Pyramid-Boort, Murray Valley and Torrumbarry. It is one of the 
most important agricultural regions in Australia with major 
irrigation-based industries that include dairy, horticulture and 
viticulture enterprises. 
Irrigated agriculture consequently has a major impact on 
available water resources in the region, and the sustainable 
management of the increasingly limited water resource requires 
repeated objective assessments of irrigation water use (supply) 
in relation to the demand for water, set by crop type, crop water 
requirement (CWR), crop area and seasonal weather conditions 
(evaporative demand + rainfall). This study demonstrates the 
use of Satellite Remote Sensing to support comprehensive, 
affordable irrigation water use assessments, and improved 
irrigation management in the Catchment. 
The study focused on a fundamental indicator of irrigation 
performance, namely the relationship between farm total crop 
water use (‘water supply’, TWS) and crop water ‘demand’, 
measured as CWR. Comparisons of TWS in relation to CWR 
rapidly identify issues of under- and over-supply of irrigation 
water on farms. 
2. METHODS 
The study compared measures of TWS and CWR in the 
irrigation season 2008-09. Landsat satellite images for 2008-09 
were used to identify areas of active irrigation, and to derive 
estimates of CWR. Pixel-scale estimates of CWR were derived 
from the standard equation: 
  
* : . > oii 
Corresponding and presenting author: mohammad.abuzar@dpi.vic.gov.au 
CWRp = 2. (Kc ETr-R) (1) 
where Kc was the crop- and field-specific ‘crop coefficient” 
appropriate to the irrigated field, ETr was ‘alfalfa’ ‘tall-crop’ 
reference crop evapotranspiration (Allen et al 2006), and R was 
‘effective’ rainfall (McAllister et al 2009). The summation in 
Equation 1 depended on crop, and was extended over the 
seasonal duration of active irrigation of a crop. Field-scale and 
farm-scale estimates of CWR were derived by integrating values 
of CWR, over pixels-within-fields and fields-within-farms, 
respectively. 
Meteorological data appropriate to the calculation of ETr and R 
were sourced from SILO website 
(http://www .longpaddock.qld.gov.au/silo/) for two locations 
(Shepparton and Swan Hill). ^ NDVI-dependent crop- and 
region-specific estimates of Kc (Whitfield et al 2011) were used 
to make pixel-specific estimates of Kc for use in Equation 1. 
Crop- and region-specific estimates of Kc made according to 
Whitfield et al (2011) were based on relationships that 
described the dependence of satellite-derived rates of ET on 
associated measures of NDVI. Satellite measures of ET and 
NDVI were made using a variant of the METRIC method 
(Allen et al 2007) that used the empirical relationship of 
Teixeira et al (2009) to describe surface roughness as a function 
of NDVI and surface albedo. 
Horticulture in the Goulburn-Murray Irrigation Region is 
dominated by long-lived perennial plantings. Land use and 
crop types on horticultural fields are therefore relatively stable 
over time. The areal extent of fields within horticultural farms 
and associated crop type were sourced from land use maps 
provided by Shepparton Preserving Co. (SPC). 
By contrast, both annual and perennial pastures are important 
on irrigated dairy farms. Seasonal variations in satellite-derived 
representations of the VIT space, which describes land surface 
temperature as a function of NDVI (Abuzar et al 2008), were 
used to categorise irrigated dairy fields into annual and 
perennial classes.