flood plume from the Burdekin catchment can extend as far north as Cairns in high runoff years ( Brinkman et al ., 2014 ; Waterhouse et al ., 2016 ).
Within the Burdekin basin there are several large catchments , and there are now multiple lines of evidence showing that the Bowen-Broken-Bogie catchment , which is downstream of the Burdekin Falls Dam , is the dominant source of sediment and particulate nitrogen to the GBR ( Lewis et al ., 2015 ; Bartley et al ., 2014 ). This catchment has some of the highest sediment concentrations and one of the highest per-hectare sediment loads of any catchment draining to the GBR lagoon ( Dougall et al ., 2013 ), and these erosion rates are estimated to be ~ 7.5 times higher than natural ( Bartley et al ., 2015 ). The Upper Burdekin also has high sediment yields , with current rates being ~ 3.6 times higher than natural , and there are some areas that have erosion rates that are as high as the Bowen-Broken-Bogie on a per hectare basis ( Bainbridge et al ., 2014 ; Bartley et al ., 2015 ). Despite ~ 75 % of the fine sediment generated in the Upper Burdekin being trapped in the BFD , the large area (~ 30,000 km2 ) and high rainfall in the Upper Burdekin means that the overall contribution of the ecologically significant sediment fraction (< 16 µ m ) to the marine system can be on par with the Bowen in some years ( Bainbridge et al . 2016 ).
Within the Bowen-Broken-Bogie ( BBB ) Catchment , sediment is delivered from a relatively small proportion of the area which has vulnerable soils that are well‐connected to the stream network . These are primarily where subsoil is exposed in scalds , rills and gullies ( Brooks et al . 2016 ; Wilkinson et al . 2014 , 2015a ). These features can be identified in the landscape , but the critical gap in our understanding is the effectiveness of erosion remediation options for controlling these sources of sediment at property and subcatchment scales .
This report provides further information on the characteristics of the BBB Catchment that are relevant to the design of the Burdekin MIP .
1.2 Scope and Objectives of this Synthesis Report
Objective : To complete a comprehensive Synthesis Report for the Bowen-Broken-Bogie catchment utilising extensive existing biophysical , land management practice , social and economic data . It will be used in conjunction with feasibility studies to inform decision making around the best location and mix of actions to reduce sediment loads .
Outcomes : The Synthesis Report will :
• establish a 2017 baseline biophysical , land management practice , social and economic data for the catchment ;
• provide key findings for each catchment to inform prioritisation of investment , best location and actions for project design ; and
• list knowledge and data gaps .
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