Table 2 . Estimated sediment reductions ( tonnes ) from projects completed in the LDC Project to date . Project type
Proportion of total project area
Hillslope and Streambank Sediment ( t )
Gully Sediment ( t )
Total Sediment ( t )
Proportion of total reduction
GLM Wire & Water 49 % 2,831 2,831 26.8 % Revegetation 10 % - - 0.0 % Grader Project 24 % 1,383 1,383 13.1 % Erosion control 13 % 54 54 0.5 % Streambank 2 % 237 237 2.2 % Gully 3 % 528 5,536 6,064 57.4 %
Total |
5,034 |
5,536 |
10,570 |
% of Total |
48 % |
52 % |
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Figure 3 . Total fine sediment reduction by project type and erosion source . Inset shows the proportion of the total project area for each project type 2019 - 2021 .
Sediment reduction estimates were calculated using two methods :
1 ) Hillslope and streambank erosion management projects : the pollutant reduction component of the Alluvium / GBRF investment tool ( Alluvium , 2019 ); and
2 ) Gully erosion management projects - the Reef Trust Gully Toolbox method ( Wilkinson et al ., 2019 ).
The LDC Water Quality Report 2019 ( Waterhouse et al ., 2019 ) highlighted that a number of assumptions underlay these calculations , therefore , these figures should be treated as the best available estimate of sediment reductions to date .
Hillslope and streambank erosion management projects : The pollutant reduction component of the Alluvium / GBRF investment tool has been used to calculate the estimate fine sediment reductions from each of the projects completed in the LDC Project to date . To undertake this , Alluvium used the Paddock to Reef catchment model results from the
2016 Reef Report Card ( as reported in 2018 ) which provided annualised pollutant load results for each sub catchment in the Burdekin Dry Tropics NRM region . These results are presented as both generated ( at the sub-catchment ) and delivered ( applying a delivery ratio representing that which reaches the end of catchment ) mean annual loads . Using the delivered results , Alluvium use the
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