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Effective and efficient pathways for investment in improved water quality in the Great Barrier ReefSearch fields
Description and method logicMethod purpose
Effective and efficient pathways for investment in improved water quality in the Great Barrier Reef (GBR) [1] provides a quantitative assessment of the most cost-effective catchment management actions in 46 basins within the GBR catchment and a data visualisation tool to support the comparison of investment scenarios.
The method aimed to:
SummaryThe effective and efficient pathways for investment in improved water quality in the Great Barrier Reef methodology (the method) was driven by the outputs of the Paddock to Reef models (P2R)[3] and integrated with cost and efficacy data to identify the groups of actions needed to achieve the target load reductions for the three key contaminant sources considered of major impact to the reef. P2R modelling provided the modelled annual baseline load for dissolved inorganic nitrogen (DIN), fine sediment, and pesticides (5 PSII herbicides). Target load reductions were based on the Ecologically Relevant Targets (ERTs) established in the Reef 2050 Water Quality Improvement Plan (WQIP), which investigated the most cost-effective policy solution sets to reduce the impacts associated with sediment and nitrogen run-off across key GBR catchments.
The method used previous modelling results to evaluate the cost effectiveness of different management response pathways, and how they contributed towards the achievement of the ERTs. ERTs[4], which are basin-specific pollutant load reductions for DIN, fine sediment, and pesticides, were set for 46 catchments within the Great Barrier Reef based on the Reef 2050 WQIP[5], previous work in the Burdekin WQIP[6] and the Scientific Consensus Statement[7]. Key contaminant sources were attributed to a specific land use type and pollution source for each of the modelled sub-catchments. For the scenarios looking at changes in practices, (e.g. moving practice from High (score of D) to Moderate- (score of C), C to Moderate-Low (score of B) and B to Lowest-risk (score of A)), the most recent estimates for percentage of land within each basin being managed with practices at different water quality risk states were applied. Ten policy solution sets (intervention types) were investigated, including seven solution sets from the 2016 Reef Costings Study[8] and three additional interventions that were identified as being potentially significant (horticulture and grains, major point sources (Wastewater Treatment Plants - WWTPs) and pesticides). The final solutions investigated were: 1. Practice change – Cane 2. Practice change – Grazing 3. Practice change – Pesticides 4. Practice change – Irrigation 5. Practice change – Horticulture (bananas) 6. Catchment remediation – Gullies 7. Catchment remediation – Streambanks 8. Catchment remediation – Treatment Systems 9. Point source WWTP management 10. Land use change. The solution sets evaluated the above-mentioned practices using the minimum compliance standards baseline for cane, grazing and bananas and based on the findings of the 2017 Scientific Consensus Statement. Each of the solution sets were individually modelled to allow comparisons of cost-effectiveness between options and to establish efficient investment pathways – the investment required to mitigate one unit of pollution (e.g. $/kg DIN). Because each solution set has different types of costs (establishment/capital, refurbishment, operations and maintenance, and opportunity costs) and different timings of costs, the cost effectiveness for each solution set required costs to be discounted to present value terms. Based on the information available, for each solution set and each relevant cost category parameters, ‘low-’ (best), ‘more likely-’ (e.g. true costs), and ‘high-‘ (worst) cost parameters were established. These parameters became the input parameters for the Cost-effectiveness Analysis (CEA) modelling. Monte Carlo simulations were undertaken for all major input parameters and for each individual solution set. Monte Carlo simulation performs risk analysis by using different input parameters and their distribution bounds in multiple iterations to find the range and probabilities of outputs of interest. When multiple solution sets are compared, this analysis then provides insight into the degree of confidence that two alternative solution sets have different levels of efficiency. For example, where there is no cross-over between the 90% confidence interval range of CEA, it is very likely that the CEA of one solution set is superior to the other. The output of the Monte Carlo simulations can be used to gain insight into which input parameters of the CEA calculations (e.g. capital costs, efficacy estimates) have the greatest impact on the estimates of CEA. A Solution Statement was also produced for each solution set outlining their scope and extent, the management actions they contained, the costs and efficacy of those actions, the necessary assumptions and limitations used and a summary of the relevant results. Method logic
A summary of the process used in the effective and efficient pathways for investment in improved water quality in the Great Barrier Reef methodology was as follows:
All costs were estimated in real terms and discounted to a present value using agreed discount rates. A discount rate of 7.0% (real) was used, with sensitivity analysis at 4.0% and 10% (real) as per the Queensland Treasury guidelines. A 30-year time frame was used for the analysis of each solution set with costs for 5-year investments (cash costs) and 15-year (net present value) quantified to assist with scenario and investment pathway development. The cost categories included for each solution set were dependent on the specific elements of that solution set. Where information on the geographical differentiation of solution set efficacy or costs was available, this was also included into the modelling for each of the reporting areas. In all cases, a range of values for the different costs were modelled to establish the most likely, 5th percentile and 95th percentile using a Monte Carlo analysis with 20,000 iterations. An assessment of each of the final solution sets were also assessed against the non-cost risks to capture the impact of non-cost risks on the CEA. The detailed modelling outputs from the solution sets are then input into the Reef Planning and Investment Tool, a scenario development and data visualisation tool. Criteria groupings of the method
The effective and efficient pathways for investment in improved water quality in the Great Barrier Reef method incorporates a range of criteria, including:
Data required
For the method, the following data are required:
To use the Reef Planning and Investment Tool, the following data are required:
Resources requiredExpertise required
For the method, the following expertise is required:
To use the Reef Planning and Investment Tool, the following expertise is required:
Materials required
For the method, the following materials are required:
To use the Reef Planning and Investment Tool, the Reef Planning and Investment Tool software and database management software for storing the outputs generated by each scenario are required. Method outputsOutputs
Uses
Criteria by category
Physical and chemicalEconomicManagement and planningReviewRecommended userDecision-makers, investors in Reef water quality improvement projects.
Strengths
Limitations
Case studiesSolution Statement 01: Practice Change - Sugarcane fertiliserIn Alluvium 2019. Effective and Efficient Pathways for Investment in Improved Water Quality in the Great Barrier Reef: Final Report. A report for the Great Barrier Reef Foundation, Brisbane.
Solution Statement 02: Practice Change - GrazingIn Alluvium 2019. Effective and Efficient Pathways for Investment in Improved Water Quality in the Great Barrier Reef: Final Report. A report for the Great Barrier Reef Foundation, Brisbane.
Solution Statement 03: Practice Change - PesticidesIn Alluvium 2019. Effective and Efficient Pathways for Investment in Improved Water Quality in the Great Barrier Reef: Final Report. A report for the Great Barrier Reef Foundation, Brisbane.
Solution Statement 04: Practice Change - Sugarcane (Irrigation)In Alluvium 2019. Effective and Efficient Pathways for Investment in Improved Water Quality in the Great Barrier Reef: Final Report. A report for the Great Barrier Reef Foundation, Brisbane.
Solution Statement 05: Practice Change - Horticulture (bananas)In Alluvium 2019. Effective and Efficient Pathways for Investment in Improved Water Quality in the Great Barrier Reef: Final Report. A report for the Great Barrier Reef Foundation, Brisbane.
Solution Statement 06: System Repair - Gully remediationIn Alluvium 2019. Effective and Efficient Pathways for Investment in Improved Water Quality in the Great Barrier Reef: Final Report. A report for the Great Barrier Reef Foundation, Brisbane.
Solution Statement 07: Catchment Remediation - StreambanksIn Alluvium 2019. Effective and Efficient Pathways for Investment in Improved Water Quality in the Great Barrier Reef: Final Report. A report for the Great Barrier Reef Foundation, Brisbane.
Solution Statement 08: Catchment remediation - Treatment SystemsIn Alluvium 2019. Effective and Efficient Pathways for Investment in Improved Water Quality in the Great Barrier Reef: Final Report. A report for the Great Barrier Reef Foundation, Brisbane.
Solution Statement 09: Upgrading Sewage Treatment PlantsIn Alluvium 2019. Effective and Efficient Pathways for Investment in Improved Water Quality in the Great Barrier Reef: Final Report. A report for the Great Barrier Reef Foundation, Brisbane.
Solution Statement 10: Land use changeIn Alluvium 2019. Effective and Efficient Pathways for Investment in Improved Water Quality in the Great Barrier Reef: Final Report. A report for the Great Barrier Reef Foundation, Brisbane.
LinksReferences
Last updated: 14 April 2021 This page should be cited as: Department of Environment, Science and Innovation, Queensland (2021) Effective and efficient pathways for investment in improved water quality in the Great Barrier Reef, WetlandInfo website, accessed 30 August 2024. Available at: https://wetlandinfo.des.qld.gov.au/wetlands/resources/tools/assessment-search-tool/effective-and-efficient-pathways-for-investment-in-improved-water-quality-in-the/ |