ACT Healthy Waterways Program Cost Benefit Analysis

About This Project

The ACT’s Environment, Planning and Sustainable Development Directorate engaged Mosaic Insights sister-company Natural Capital Economics (NCEconomics) to undertake an ex-post economic evaluation of the ACT Healthy Waterways program. This program was aimed at improving water quality in the ACT and downstream into the Murrumbidgee River system by reducing total nitrogen, total phosphorous and total suspended solids through water quality control infrastructure, encouraging behaviour change, and improving data and knowledge.

NCEconomics partnered with Alluvium and Mosaic Insights to investigate the benefits of investing in water quality improvements infrastructure, behaviour change programs and research activities. Infrastructure projects included the construction of wetlands, rain gardens, ponds and waterway restoration works. We followed an ecosystem services evaluation framework to scope the different benefits of the program. Identified key benefits included water quality improvement, amenity enhancement, improved recreation and physical activity stimulation, urban cooling and enhanced biodiversity.

Mosaic Insights conducted the urban heat modelling component using aerial images of the site before and after the ACT Healthy Waterways program infrastructure was built to conduct urban heat modelling.

NCEconomics undertook a cost-effectiveness analysis, a cost-benefit analysis and a regional economic impact assessment. The cost-effectiveness analysis provided information on the most effective assets to manage total nitrogen, total phosphorus and total suspended solids. The cost-benefit assessment indicated that the program was economically viable with a benefit-cost ratio greater than 1.

Our study provided the ACT Government with confidence that the program has led to multiple benefits across the ACT and nearby regions and that this was an economically viable undertaking. Our finding will be used to inform policy, support efficient resource allocation as well as provide enhanced understanding about the benefits of water sensitive urban design assets.