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 
RIPARIAN VEGETATION STATUS AND RATES OF WATER USE FROM SATELLITE 
DATA 
K. Sheffield ^ *, M. Abuzar?, D. Whitfield^, A. McAllister^, M. O'Connell" 
? Future Farming Research Division, Department of Primary Industries, Parkville, Victoria - (kathryn.sheffield, 
mohammad.abuzar) @dpi.vic.gov.au 
^ Future Farming Research Division, Department of Primary Industries, Tatura, Victoria - (des.whitfield, 
andy.mcallister, mark.oconnell) 9 dpi.vic.gov.au 
KEY WORDS: Ecosystem, Vegetation, Multitemporal, Landsat, Management 
ABSTRACT: 
Hydrology and water availability are key determinants of the health of riparian vegetation systems, and an understanding of the 
interactions between vegetation and hydrology is a prerequisite for the maintenance and improvement of these systems under 
managed water regimes. Changes to natural flooding cycles, caused by the regulation of river flows and irrigation activities, have 
changed the composition and amount of vegetation, and the distribution of species within riparian areas (Chong and Ladson, 2003; 
Lawrence and Colloff, 2008). The extent and frequency of flooding cycles are key issues for the health of riparian ecosystems under 
controlled water management regimes. This paper demonstrates the potential contribution of satellite-based measurements to an 
improved understanding of the changes in vegetation status of riparian systems, and, also, of their water requirement. 
Evapotranspiration (ET) and Normalised Difference Vegetation Index (NDVI) of the Barmah Forest were derived from satellite 
imagery over a number of years. NDVI provided a general measure of vegetation status and cover. ET measures provided an 
indication of the availability of water to the existing vegetation, and an assessment of areas under water-stress (Anderson et al., 
2012). Previous work has demonstrated that these indicators provide a comprehensive measure of riparian vegetation status 
(Sheffield et al., 2011), and estimates of vegetation water requirement (Whitfield et al., 2010a; Sheffield et al., 2011). This paper 
addresses changes in NDVI and ET rate of major vegetation classes in the Barmah Forest over the period, 1993 — 2008. Measures of 
ET and NDVI, analysed in conjunction with rainfall and river flow data, provided insights into the response of vegetation to changes 
in water availability, which may be used to evaluate impacts of management practices and water regime within riparian zones. 
1. INTRODUCTION 
1.1 Overview 
The physiological health and activity of riparian vegetation 
systems are heavily influenced by water availability and the 
hydrological processes that govern the distribution of water in 
time and space within those systems. The distribution and 
regeneration of plant species in riparian zones is also linked 
with water availability and factors such as frequency, timing, 
depth and duration of inundation during flood events. 
Inundation characteristics affect the distribution and abundance 
of riparian plant species in addition to a range of ecosystem 
functions and primary production within the riparian system 
(Chong and Ladson, 2003; MDBC, 2006; Stromberg et al., 
2006; Lawrence and Colloff, 2008; Sims and Colloff, 2012). 
Water availability in riparian areas is also affected by natural 
events such as drought, and human activities including the 
regulation of river flows and irrigation. Environmental flows 
are increasingly employed to maintain riparian areas in 
regulated river systems, where the volume and extent of 
flooding is controlled by regulators, pipes and culverts. Issues 
such as frequency, duration and extent of riparian flooding are 
most pronounced under limited water supply, when regional 
water managers are required to address the balance between 
commercial and environmental uses of water. 
  
* Corresponding author. 
The water management of riparian systems will be better 
informed by an improved understanding of rates of water use 
relative to water requirements. An improved understanding of 
where the water is required is needed to improve the availability 
of water to targeted species or geographic zones. Objective, 
affordable repeatable measurements of vegetation status and 
water use are the minimum required to support improved water 
management of riparian systems in Australia and elsewhere. 
The use of satellite-based assessments of water use to support 
resource management and monitoring is advocated by Anderson 
et al (2012). This paper aims to demonstrate the potential 
contribution of satellite-based remotely sensed data to improved 
understanding of water requirements and vegetation status 
within the Barmah Forest, Australia. This paper aims to 
evaluate the information extracted from remotely sensed data as 
we hypothesize that it will provide important monitoring 
opportunities in riparian ecosystems. 
Remotely sensed data additionally allow a retrospective 
assessment of the impact of past and current water management 
on vegetation status. The data can be used to appraise the 
effectiveness of 'environmental flows' and identify areas of 
riparian vegetation in decline. This type of information will 
contribute to a greater understanding of water requirements 
within riparian systems. The extensive spatial coverage of 
remotely sensed data allow riparian vegetation to be assessed 
across the landscape, a key consideration in the connectivity of 
riparian systems which is important to both species diversity