07 Nov Tony Bigwood
Since August 2014 Tony has been the Director Efficiency Measures Section, established to manage the $1.8 billion Water for the Environment Special Account and design and implement infrastructure projects that sustain businesses in the Murray – Darling Basin while also recovering environmental water. Prior to this, Tony worked for two decades in natural resource and environmental management areas across the Australian government including forest management, Great Barrier Reef issues and environmental assessment.
Implementing An Offset: More Than A Mass Balance Equation
“Offsets” represent a new way to remediate degraded stream systems. Increasing demands are placed on point source water treatment with burgeoning population growth. With water treatment costs rising with each additional kilogram of nutrient to be removed, “offsetting” the treatment cost and required plant upgrades by securing nutrients elsewhere in the catchment forms the basis of the Queensland Government’s nutrient offset policy (Flexible options for managing point source water emissions: A voluntary market-based mechanism for nutrient management)
Improving the condition and stability of degraded streambank locations provides a range of ecosystem services including improved water quality and habitat values and increased resilience in the face of high flow events, reducing sediment export and helping to protect infrastructure and agricultural land from flood damage.
Whilst a simple mass balance equation, with a safety factor, forms the basis for determining the extent of remediation works that represent a quantum of nutrient or sediment being compensated for, a large array of factors underpins the successful implementation of an offset project. This paper explores the contributing components that lead to the successful implementation of a riparian restoration offset project.
A case study on Laidley Creek where more than two kilometres of restoration works have been conducted will be used to outline the implementation of the policy and the contributing factors that led to site selection and the adopted implementation strategy. These factors include the maturity of intergovernmental, industry and landholder relationships, riparian and catchment condition assessment, sediment source investigations, reach process understanding, ecological restoration fundamentals, trust and sufficient flexibility to apply adaptive management principles.
In addition to the sediment and nutrient retention, the investment provides public good benefits in terms of improved water quality in the Brisbane River and Ramsar listed Moreton Bay, and reduced downstream water treatment costs.