The next greatest reduction estimates were from the Glenmore Creek ( 15 %; includes the Mt Wickham large scale gully project ) and Broken ( 12 %) sub-catchments . All other sub catchments contributed less than 10 % to the total fine sediment reduction in the BBB catchment . This highlights the variation across the subcatchments , but also the dominance of the Bowen sub-catchment , largely reflecting the investment effort but also the types of projects that were funded .
Table 8 . Predicted fine sediment savings at the sub-catchment scale as a result of projects initiated by the LDC Project across all years of reportable practice change 2019 – 2021 ( as of June 2021 , generated by Alluvium , 2021 as in Q1 ).
Sub-catchment |
Project area ( ha ) |
|
|
Total Fine Sediment Reduction ( tonnes )
2019 2020 2021 TOTAL
|
Proportion of total |
Bogie |
19,904 |
493 |
199 |
- |
692 |
7 % |
Bowen |
7,894 |
108 |
2,490 |
3,505 |
6,102 |
58 % |
Broken |
10,005 |
324 |
27 |
934 |
1,285 |
12 % |
Glenmore Creek |
425 |
107 |
1,498 |
- |
1,605 |
15 % |
Little Bowen |
3,489 |
201 |
27 |
- |
228 |
2 % |
Pelican Creek |
7,951 |
93 |
405 |
- |
498 |
5 % |
Rosella Creek |
11,724 |
108 |
52 |
- |
160 |
2 % |
Total |
64,615 |
1,433 |
4,698 |
4,439 |
10,570 |
|
Figure 5 . Predicted fine sediment reductions for all projects completed in the LDC Project 2019 , 2020 and 2021 ( as at June 2021 ) in the Bowen Broken Bogie sub-catchments ( generated by Alluvium , 2021 ).
As noted above , the modelled fine sediment outputs using the Source Catchments model are expected to be different from the Alluvium tool project-scale estimates for several reasons , however , given the significant assumptions applied in the estimates from the Alluviumtool , the modellers considered these results to be reasonably comparable . The Source Catchments model also generated results for PP and PN , shown in Table 9 . These are based on the annualised average loads ( based on the total modelled load and divided by 3 years ). As per the Alluvium tool results for fine sediment , the Bowen sub-catchment generated the greatest
43