The pesticide diuron from urban and agricultural runoff is detected at concentrations above current water quality guidelines in the Great Barrier Reef (GBR) marine environment. We quantified the load of the pesticide diuron entering GBR waters using the GBR-Dynamic SedNet catchment model. After comparison of simulated distributions with observations at 11 monitoring sites we determined a half-life of diuron in GBR marine waters of 40 days. The 1 km resolution eReefs marine model (GBR1: version GBR1_H2p0_Cq3pe1_Dhnd) was nested inside the 4 km eReefs marine model (GBR4: version GBR4_H2p0) to achieve stable and reliable boundary forcing. Diuron only enters the marine model from the catchments. Diuron at the ocean boundaries is set to 0 and if diuron leaves the 1km model boundary it does not return. The simulation period is from January 2016 to July 2018. The GBR1 hydrodynamic model was forced by wind, atmospheric pressure gradients, surface heat fluxes and evaporation / precipitation fluxes, tides, and waves and calculates temperature, salinity, elevation and offshore currents, integrating on a 1.2 second barotropic time step. The hydrodynamic model calculates the mean volume flux through model cell faces over a 1-hour period (Herzfeld et al., 2016) that are used in a transport model to disperse diuron. The transport scheme was a flux-form semi-Lagrangian advection scheme that applies the fluxes in steps determined by the Lipschitz stability criterion, with a maximum of 1 hour time step. Each model cell contains their own value of diuron based on the hydrodynamics, and so diuron fluctuates hourly in each cell. The eReefs marine model represents freshwater input from 16 rivers located in the GBR. For rivers with freshwater input, GBR1 uses a river boundary condition where freshwater was discharged in a brackish surface plume. This boundary condition provides realistic plume dynamics and avoids excessive offshore transport caused by overestimating the density difference between freshwater plumes and seawater (Herzfeld, 2015, Baird et al., 2017). For the remaining minor rivers, diuron enters GBR coastal waters as loads as a surface flux (Figure 1B). Rivers containing high diuron loads that enter as surfaces fluxes were the Murray, Mossman, Proserpine and Burrum and Plane (very high risk). Some river catchments in GBR-SedNet do not contain diuron loads, (Normanby, Fitzroy, Calliope, Boyne, Styx, Shoalwater and Waterpark) as diuron was not one of the pesticides used or generally found within these catchment areas during frequent monitoring of all pesticides. Individual river plume dispersal was quantified using conservative tracers. A river tracer was specified as a unit concentration in each river flow (e.g., 1 kg m-3). Therefore, a model grid cell with 0.20 concentration of river water will be composed of 20 % river water, and 80 % water that comes either from another river/s or the ocean. Each river has a unique tracer that was individually advected and diffused using a conservation flux-form scheme based on hourly-averaged 3D velocity fields. Similarly, the diuron tracer has a time-varying river concentration in μg L-1 specified by the SedNet catchment model and was advected and diffused in a similar manner to the river tracers.
This dataset has been superseeded by GBR4_H2p0 (2010-09 to present) and it was removed from the NCI fx3 project and THREDDS server in April 2024. An archive copy has been retained by the custodians, and access can be arranged on request. Results from version 1.85 of the 4 km resolution regional-scale hydrodynamic model of the great Barrier Reef (GBR4). It was forced with BlueLink OceanMAPS data on the open boundaries and Bureau of Meteorology model ACCESS-R for surface atmospheric data. The tide was introduced through 22 constituents derived from the global CSR tide model, and 22 river boundaries incorporated measured stream flow and temperature data from QLD DNRM's gauging stations. This model version was published for reference in the SIEF report from January 2016, but was later discovered to have been forced with incorrect (multiplicative error) rainfall levels, and the 2015 results contain salinity errors. This model configuration and associated results dataset may be referred to as "GBR4_H1p85" according to the eReefs simulation naming protocol.
This dataset has been superseeded by GBR4_H2p0_B2p0_Chyd_Dcrt(2010-12 to 2016-10) and then by GBR4_H2p0_B3p1_Cq3b_Dhnd (2010-04 to 2019-04) and it was removed from the NCI fx3 project and THREDDS server in April 2024. An archive copy has been retained by the custodians, and access can be arranged on request. Results from version 924 of the 4km-resolution regional-scale biogeochemistry and sediments model of the Great Barrier Reef (GBR4), forced by version 2.0 of the 4km-resolution hydrodynamic model and with Furnas relationships for wet and dry tropics rivers as catchment inputs.
SUPERSEDED: This dataset has been superseded by "eReefs GBR1 hydrodynamics v2.0" (GBR1_H2p0) and it was removed from the NCI fx3 project and THREDDS server in April 2024. An archive copy has been retained by the custodians, and access can be arranged on request. Results from an early version of the 1km-resolution shelf-scale hydrodynamic model of the Great Barrier Reef (GBR1). This version of the model was forced by version 1.85 of the eReefs GBR 4 km resolution hydrodynamic model, and the results were made available for comparison purposes only. This model configuration and associated results dataset may be referred to as "GBR1_H1p71" according to the eReefs simulation naming protocol.
SUPERSEDED: This dataset has been superseeded by GBR4_H2p0_B2p0_Chyd_Dcrt(2010-12 to 2016-10) and then by GBR4_H2p0_B3p1_Cq3b_Dhnd (2010-04 to 2019-04) and it was removed from the NCI fx3 project and THREDDS server in April 2024. An archive copy has been retained by the custodians, and access can be arranged on request. This is the eReefs GBR 4 km resolution Biogeochemistry (BGC) and Sediments model data version 926. It is based on the eReefs GBR 4 km Hydrodynamic SHOC model data for physical properties plus a sediment transport model for predicting the fate of suspended fine sediments and a biogeochemical model for water column and benthic production, water quality and nutrient cycling. It includes a spectrally resolved light model and is forced by a wave model to calculate resuspension rates of particulate matter
DEPRECATED: This dataset has been superseded by GBR1_H2p0_B3p2_Cfur_Dnrt Results from an early version of the 1km-resolution shelf-scale biogeochemical model of the Great Barrier Reef (GBR1). This version of the model was forced by version 1.85 of the eReefs GBR 1 km resolution hydrodynamic model, and made several improvements to the v926 (B1p0) model for: more accurate optical calculations; Normanby – particulate and dissolved loads corrected; Sediment tracer “Dust” added; Oxygen mass conservation part of diagnostics. This model configuration and associated results dataset may also be referred to as "GBR4_H1p71_B1p9_Cfur_Dnrt" according to the eReefs simulation naming protocol, but that protocol was not codified until after this dataset was superseeded, so it is usually referred to by the v924 identifier.
SUPERSEDED: This dataset has been superseeded by GBR4_H2p0_B3p0_Chyd_Dcrt (2010-12 to 2018-10) and then by GBR4_H2p0_B3p1_Cq3b_Dhnd (2010-12 to 2019-04) and it was removed from the NCI fx3 project and THREDDS server in April 2024. An archive copy has been retained by the custodians, and access can be arranged on request. 4km-resolution Biogeochemical model version 2.0, forced by version 2 of the Hydrodynamic model and `best available forcing`¹, deployed as `catchment real time` (6 month lag for SOURCE Catchments model). ¹ best available forcing: ○ 2011-06-30 to 2014-06-30: P2R SOURCE Catchments; ○ 2014-07-01 to 2016-10-30: Empirical SOURCE Catchments; ○ 2016-10-31 onwards: Furnas relationships for wet and dry tropics rivers.
SUPERSEDED: This dataset has been superseded by GBR4_H2p0_B3p0_Cpre_Dcrt (2010-12 to 2018-01), and then by GBR4_H2p0_B3p1_Cq3p_Dhnd (2010-12 to 2019-04), and it was removed from the NCI fx3 project and THREDDS server in April 2024. An archive copy has been retained by the custodians, and access can be arranged on request. 4km-resolution Biogeochemical model version 2.0, forced by version 2 of the Hydrodynamic model using SOURCE Catchments – Pre-Industrial catchment cover and deployed as `catchment real time` (6 month lag for SOURCE Catchments model).
This dataset has been superseded by GBR4_H2p0_B3p1_Cq3b_Dhnd (2010-12 to 2019-04), and it was removed from the NCI fx3 project and THREDDS server in April 2024. An archive copy has been retained by the custodians, and access can be arranged on request. 4km-resolution Biogeochemical model version 3.0, forced by version 2 of the Hydrodynamic model and `best available forcing`¹, deployed as `catchment real time` (6 month lag for SOURCE Catchments model). ¹ best available forcing: ○ 2011-06-30 to 2014-06-30: P2R SOURCE Catchments; ○ 2014-07-01 to 2016-10-30: Empirical SOURCE Catchments; ○ 2016-10-31 onwards: Furnas relationships for wet and dry tropics rivers.
SUPERSEDED: This dataset has been superseeded by GBR4_H2p0_B3p1_Cq3p_Dhnd (2010-12 to 2019-04) and it was removed from the NCI fx3 project and THREDDS server in April 2024. An archive copy has been retained by the custodians, and access can be arranged on request. 4km-resolution Biogeochemical model version 3.0, forced by version 2.0 of the Hydrodynamic model and by SOURCE Catchments with pre-industrial catchment cover, deployed as `catchment real time` (6 month lag for SOURCE Catchments model).