Targeting for pollutant reductions in the Great Barrier Reef river catchments
Introduction
Internationally there is increasing pressure to protect coral reefs from climate change, agricultural pollutant run-off and coastal development, resulting in a number of integrated coastal management plans (Thia-Eng, 1993; Gibson et al., 1998; Meliadou et al., 2012; Tabet and Fanning, 2012). In Australia the declining health of the Great Barrier Reef (GBR) has resulted in specific management actions focused on agriculture as identified under the Reef Water Quality Protection Plan (Reef Plan) (State of Queensland, 2013). There have been large investments over the past decade by the Australian and Queensland governments in changing farm management practices through incentives, regulation, market based instruments and extension. The two main industries of focus for improvements in farm Best Management practices (BMP) are sugarcane for dissolved inorganic nitrogen (DIN) run-off and grazing for sediment run-off (Carroll et al., 2012). However the increase in the adoption of BMP’s to date has been slow despite the high level of investment across the GBR. For example high risk grazing management practices still cover 36% of grazing land, while sugarcane has 32% of cane lands managed using high risk management practices for pollutant run-off (State of Queensland 2016).
Internationally there have various approaches to changing farm management practices to reduce non-point source pollution (Logan, 1993; Ripa et al., 2006; Baumgart-Getz et al., 2012), along with methods for identifying the most cost effective outcomes for multiple objectives and with limited budgets (Claassen et al., 2008). Similarly, the complexity of managing large diverse catchments (adjacent catchments to the GBR cover 424,000 km2) which have objectives that can be translated from a catchment framework to a paddock scale action has proved challenging (Lu et al., 2004; Doole et al., 2013; Gurnell et al., 2016). The Great Barrier Reef Water Quality Protection Plan identified priority pollutants and industries to target based on loads entering the marine environment (Reef Plan 2013). On-ground incentive funding has been allocated to landholders through catchment-level natural resource management groups to improve awareness and make changes in management activities. However the scale, industries, process and parameters used to design programs and allocated funding has varied significantly between groups (Beher et al., 2016; Beverly et al., 2016; Star et al., 2017).
The need for prioritisation of where and how to achieve pollutant reductions in the GBR is driven by three critical factors. First, there is high heterogeneity in the performance of different management practices in different places based on geographic and biophysical parameters (Newburn et al., 2005; Bryan and Crossman, 2008), which underpin variations in benefits for the GBR per dollar spent, particularly when the time to achieve benefits is factored in (Bainbridge et al., 2009; Star et al., 2011). Second, the different management practices vary in effectiveness at reducing pollutants, costs, time lags to be effective (Meals et al., 2010; Bartley et al., 2014), adoption rates by landholders (Feather and Amacher, 1994; Greiner et al., 2009; Greiner and Gregg, 2011; Rolfe and Gregg, 2015; Rolfe and Harvey, 2017) and risks of success or interruptions (Prokopy et al., 2008; Doole and Pannell, 2011; Rolfe and Gregg, 2015; Star et al., 2015a, 2015b). Third, the effect of reductions on the most important marine assets varies significantly across the six major catchments (Waterhouse et al., 2017; de Valck and Rolfe, 2018).
Earlier funding schemes took limited account of the variations in benefits from farm management changes, focusing on flat rate grant schemes and engagement with multiple landholders. Since those initial design stages, there have been large improvements regarding the science information, economic costs and farm management factors which allows a more systematic approach to prioritisation then was possible in the past (Waterhouse et al., 2017). This improved information also reveals that none of the potential management changes achieve the high benefit, high effectiveness and low cost priorities together (Rolfe and Windle, 2011; Waterhouse et al., 2017), forcing an appraisal of which combinations are preferred (Naidoo et al., 2006). The resource budget is not sufficient to do everything, forcing some level of selection (Paton et al., 2004; Brodie et al., 2012; Star et al., 2012). An important addition to the scientific knowledge is that there are large variations in levels of exposure on marine assets by different river systems, meaning that it is important to go beyond end-of-catchment targets in prioritising water quality improvements (Brodie et al., 2017). This paper presents a prioritisation approach for improving water quality into the Great Barrier Reef which integrates improved science and cost information and aligns to the information collected in the Reef Plan Report Cards (2013-14), allowing an improved consistency in approach across regions. It presents a prioritisation across all 47 individual river catchments in the Great Barrier Reef catchment, covering the industries of sugarcane and grazing. The focus at the catchment level and only two industries is necessary to keep the analysis tractable while still demonstrating how priorities can be set.
The prioritisation approach presented here is a much more comprehensive and internationally relevant approach to improving water quality than simply targeting investments by action or pollutant, allowing a more strategic and efficient program design. It applies a cost-effectiveness analysis framework, similar to those used to evaluate major water quality proposals in Europe (Balana et al., 2011). The scale of assessment across all catchments and key industries accounts for the critical biophysical, social and economic parameters which more commonly accounted for in individual or separate approaches (Brodie et al., 2003; Ruitenbeek et al., 1999; Coiner et al., 2001; Roebeling et al., 2009; Cools et al., 2011; Doole, 2012; Star et al., 2013). The contribution of this paper to the literature is to demonstrate how scientific, economic and uncertainty information can be combined in a cost-effectiveness analysis to identify the most effective options for water quality improvements.
Section snippets
Background and study area
The GBR covers two thirds of the coast of Queensland or 35,000 km2 (Gordon, 2007). There are six catchments that enter into the GBR, all which have a number of sub-catchments: Cape York at the most northern, Wet Tropics, Burdekin Dry Tropics, Mackay-Whitsunday, Fitzroy and the Burnett Mary at the most southern part of the GBR system (Fig. 1). Under Reef Plan (2013) a number of targets were set which include a 20% reduction in Total Suspended Sediments (TSS) and a 40% reduction in pesticides and
Methods
The method applied in this analysis uses an economic framework of cost effectiveness to evaluate pollutant reductions from the priority pollutants and industries set under Reef Plan (State of Queensland, 2013). The intermediate benefits in this analysis are the loads of pollution reduced, while the final benefits account for the reduced risk to the health of the GBR. The exercise does not involve a benefit cost analysis as the value of improvements in reef health are not available in monetary
Results
A large number of potential actions were evaluated, including 235 different sediment reduction actions and 57 different DIN reduction actions. This complicates the presentation of results.
Discussion
This paper integrates relevant data to prioritise investments to improve reef health by integrating a number of biophysical, agronomic and economic factors into a cost-effectiveness framework. Novel aspects of the methodology are that it incorporates spatial analysis and risk and adoption factors have been considered. It provides insights into achieving cost effective outcomes over large areas and between industries highlighting the capacity for pollutant reductions.
The approach addresses a
Conclusions
Policy makers often find it challenging to develop programs and allocated funding to improve water quality where there are complex and lagged relationships between changes in upstream management actions and benefits to downstream users. The framework described in this paper provides an improved approach for the evaluating the relationships between policy actions, investments and expected environmental benefits.
The case study application highlights that current science and monitoring data
Acknowledgment
The authors would like to acknowledge the Queensland Office of the Great Barrier Reef who funded this research.
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