08 Nov Mr Ed Beling
Ed is a principal marine scientist and chartered civil engineer. His career background and specialist skills lie in the fields of wastewater strategies, numerical modelling, effluent management and environmental impact assessments. Ed also heads up Intrawater which is a specialist consultancy dedicated to the provision of robust scientific and engineering advice to government agencies and water utilities.
Partha Susarla will also be presenting the paper. Partha is a strategic planning manager at Unitywater and has more than 28 years of experience in the strategic planning and delivery of water infrastructure projects in three countries (India, New Zealand and Australia)
Nutrient Offsetting In The Caboolture River – How Unitywater Is Planning To Maintain Environmental Values In A Catchment Facing Massive Population Growth
By 2041, the equivalent population in the Caboolture River catchment will increase by almost 120% to approximately 235,500. Under its regulatory provisions and its own charter, Unitywater must provide for this growth without causing environmental harm or worsening the condition of the river. With another pledge to reduce the cost of its services, Unitywater has developed a solution based on recycling and nutrient offsetting that will not only help reduce pollution in the waterway but also restore degraded sections of the river.
The concept of nutrient offsetting is still in its infancy in Queensland, but policies are now in place that allow the holder of point source licences to offset emissions targets elsewhere in the catchment. Fundamentally this provides utilities the potential to find a more cost effective “green” solution for their nutrient emissions relative to investing in expensive traditional “grey” infrastructure.
With respect to the Caboolture River, field analysis identified 15 riparian sites that were badly eroded, poorly vegetated and suitable for restoration. Further investigations determined that nearly 8 tonnes per year of nitrogen could be mitigated by the restoration works. Such volumes could significantly offset the need for sewage treatment plant upgrades, and when combined with an irrigation scheme, reduce the overall volume of nutrients entering the waterway over coming decades.
To establish the efficacy of these works, significant numerical modelling of the estuary was undertaken. Multiple scenarios were analysed to understand the potential impacts of each nutrient reduction action. Using the scenario results, “delivery” ratios were developed to present the equivalency of each action in terms of environmental outcomes.
The result of this work to date is that Unitywater now has nutrient credits included in its environmental licence, a business case to progress the riparian works and a mandate to improve the health of the Caboolture River.