Use of a coastal biogeochemical model to select environmental monitoring sites

A method for the spatial selection of sites for a coastal environmental monitoring system is described. The study was completed in southeastern Tasmania, Australia, but the method can be applied in all regions with validated biogeochemical models. A 3-dimensional coupled hydrodynamic, sediment and biogeochemical model with high spatial and temporal resolution was validated against observations collected throughout 2002 and found to capture the essential features of the biogeochemical dynamics of the system. The model was used to predict the possible quantitative environmental impact of a projected increase in fish farming activity in the region. Integrated impacts of fish farm waste on labile nitrogen, phosphorus, chlorophyll and dissolved oxygen concentrations in the water column were spatially ranked to identify the most likely places to detect environmental change due to fish farming activities. Priority sites were found to be grouped in the Huon Estuary and northern part of the D'Entrecasteaux Channel consistent with the residual northward current in the region. The final monitoring program synthesized model and field understanding to ensure adequate spatial and temporal sampling of the region.

Research Highlights
► A biogeochemical model is used to inform the spatial selection of coastal environmental monitoring sites.
► A coupled 3D hydrodynamic, sediment and biogeochemical model of an estuary and marine channel is validated against observations.
► Scenario simulations quantify the possible future water quality impact of an expanding fish farming industry and the most impacted locations are identified for environmental monitoring.
► Priority monitoring sites identified by the modelling study are consistent with the residual circulation.
► The final monitoring system array is constructed from a synthesis of model and field understanding of regional water quality dynamics.