Coastal wetland rehabilitation first-pass prioritisation for blue carbon and associated co-benefits

Abstract

Context The Australian Government has developed a methodology for payment for carbon services provided by blue carbon ecosystems that focuses on avoided emissions and carbon additionality resulting from tidal restoration of coastal wetlands. Aims This study is a first-pass prioritisation for tidal restoration of coastal wetlands in New South Wales (NSW). Methods A pixel-based approach was applied using readily available datasets, with particular focus on watersheds above in-stream tidal barriers. Key results Many sites were identified, to investigate in detail, opportunities to restore tidal flows to coastal wetlands. More were associated with the broad coastal floodplains of northern NSW than narrower floodplains of southern NSW. Conclusions Information is needed about the location, ownership, land tenure, structure, condition and height of in-stream and over-land flow barriers, particularly in the context of rising sea levels. Decisions about managing in-stream drainage and flood mitigation infrastructure should be made cognisant of opportunities to increase blue carbon, and provide associated co-benefits, including mitigating other deleterious impacts from coastal wetland drainage. Implications Decision support tools for evaluating economic and environmental costs and benefits of tidal barriers will assist decision-makers assessing future proposals to repair or remove aging barriers, or create new tidal barriers.