Storm Bay Modelling & Information System, TAS (2018-Current)

Fast Facts

Completed 2023.
Funding: FRDC 2017-215 for the Tasmanian Department of Primary Industry, Parks, Water and Environment.
Project Leader and Further Information: Dr. Karen Wild-Allen.

Project Objectives and Progress to Date

The objectives of the Storm Bay project were to evaluate the performance of a former CSIRO hydrodynamic model of Storm Bay; to characterise the primary sources of nutrients into Storm Bay from ocean currents, sediment resuspension, and river inputs; to deliver a new validated model of water quality in Storm Bay suitable for assessing future salmon farm expansion; and to provide an information system comprising model results, observations and synthesis analyses, with links to complimentary projects (e.g. monitoring program, decision support tools, seasonal predictions).

In the 4.5 year project a detailed assessment of an early Storm Bay hydrodynamic model was completed; new autonomous glider, benthic lander, mooring and field observations were made to characterise nutrients in the Bay; and the CSIRO hydrodynamic model was updated with a revised grid and process representation for sediment transport, biogeochemical cycling and spectral optics. Assessment of the model against observations showed that it reproduced observed water quality dynamics in Storm Bay with good skill and demonstrated that the model was fit for the purpose of simulating water quality impacts of future salmon farm expansion in Storm Bay.

Our findings show that Storm Bay has a general circulation, driven by river discharge, from northwest to southeast. In summer months inshore waters mix with sub-Antarctic waters from the southwest and eddies of East Australia Current water from the southeast; fronts that form between these water masses are highly dynamic and there is strong interannual variability. The largest source of nutrients into Storm Bay is from inflow of offshore deep ocean water seasonally modulated by the Zeehan and East Australia Current; river runoff, anthropogenic wastewater, salmon farm discharge and atmospheric input also contribute nutrients to Storm Bay.

Scenario simulations that explored future management of Storm Bay with additional fish farm leases suggest an increase in ambient nutrient, phytoplankton chlorophyll, and turbidity concentrations and a small decrease in bottom water oxygen and propagation of light to benthic habitat. A future scenario based on 2020 anthropogenic loads plus an additional 3ktN of fish farm waste in Storm Bay, showed an increase in the area classified as mesotrophic (medium nutrient, annual mean chlorophyll between 1-3 mg m^-3) from 34% in a Pre-Storm Bay development scenario, to 42% in this Post-Storm Bay development scenario, with a corresponding 8% reduction in oligotrophic area.

Observation of small and often localised changes in water quality in a naturally highly variable system is challenging. Continuous sensor systems provide additional insight to monthly monitoring programs whilst twin model simulations with- and with-out anthropogenic discharge have the potential to differentiate natural variability from anthropogenic impacts on water quality. A new project to support sustainable operation of the Storm Bay Modelling and Information System is in development.

Data Portal – https://stormbaymodelling.csiro.au/

The Storm Bay Modelling and Information Dashboard is operational and available to members of the public, stakeholders and researchers. The portal shows hindcast and near real time simulated circulation and water quality in Southeast Tasmania, a selection of observations, and publications. Project stakeholders and expert users can login to the site for direct access to model results and decision support tools.

Recent Presentations

Langlais C, Schaeffer A, Legresy B, Herzfeld M, Wild-Allen K (2019) Summer Intrusions into Storm Bay. Australian Marine Science Association Conference, Poster Abstract, Perth, July 2019.

Langlais C, Schaeffer A, Legresy B, Herzfeld M, Wild-Allen K (2021) Shelf break exchanges in South-East Tasmania and its impact on Storm Bay. Australian Meteorological & Oceanography Society online conference “Science for impact”, Oral presentation 12 Feb 2021.

Wild-Allen, K., Skerratt, J., Baird, M., Langlois, C. (2021) Quantifying the supply of nutrients to Storm Bay, southeast Tasmania, to evaluate the potential impact of expanding aquaculture on water quality. Oral presentation at Australian Marine Science Association Conference, July 2021.

Wild-Allen, K., Skerratt, J., Baird, M., Langlois, C. (2022) Digital twin simulations distinguish anthropogenic nutrient impacts from natural variability in a complex coastal ecosystem with salmon aquaculture. Abstract. ECSA59 Conference, Estuarine Coastal Shelf Association, Spain, September 2022.

Recent Publications

Langlais C, Herzfeld M, Griffin D, Wild-Allen K (2018) Assessment of the CSIRO Storm Bay Hydrodynamic Model Against Observations. FRDC 2017-215 Progress Report Work Package 1.1, CSIRO Oceans & Atmosphere, Hobart.

Wild-Allen K (2021, 2022) Storm Bay biogeochemical modelling and information system: supporting sustainable aquaculture in Tasmania. CSIRO Information Sheet, June 2021 & June 2022.

Wild-Allen, K., Andrewartha, J., Baird, M., Beardsley, J., Brewer, E., Bodrossy, L., Eriksen, R., Gregor, R., Griffin, D., Herzfeld, M., Hughes, D., Jansen, P., Langlais, C., Margvelashvili, N., Martini, A., McMahon, M., Revill, A., Rizwi, F., Skerratt, J., Schwanger, C., Sherrin, K., Frydman, S., Wild, D. (2023) Storm Bay Biogeochemical Modelling and Information System: supporting sustainable aquaculture in Tasmania (FRDC 2017-215) Final Report. CSIRO Oceans & Atmosphere, Hobart, March 2023.

Wild-Allen, K., et al., 2023 Storm Bay Biogeochemical Modelling and Information System: supporting sustainable aquaculture in Tasmania (FRDC 2017-215) Final Report Appendices Part 1. CSIRO Oceans & Atmosphere, Hobart, March 2023.

Near Real Time Model Results