Figure 24 . Location of the Mt Pleasant ( left ) and the Treatment and Control gullies . The location of the installed treatment structures and monitoring equipment / locations are shown . ........................................... 67 Figure 25 . Mt Pleasant Treatment gully site setup ( A and B ). The same system was set up at the control site . ( C ) is the control site during an event in March 2021 and ( D ) is the treatment site in March 2021 . ............... 68 Figure 26 . ( A ) TSS concentration and ( B ) TN concentrations at Mt Pleasant for the 2019-20 and 2020-21 wet seasons . ............................................................................................................................................................. 69 Figure 27 . Location of Strathbogie site ( left ) and the Control and Treatment gullies . The location of the treatment structures and monitoring equipment / locations are shown . .......................................................... 70 Figure 28 . Images of the rehabilitation site at the Strathbogie Treatment gully taken during the 2019-20 wet season . ............................................................................................................................................................... 71 Figure 29 . Strathbogie Control and Treatment results for ( A ) Rainfall ( B ) runoff ( C ) Total Suspended Sediment ( TSS ) loads ( t / y ), and ( D ) TSS in t / ha and ( E ) Total Nitrogen ( TN ) loads ( kg / y ) and ( F ) TN in kg / ha . No loads data is presented in 2017 / 18 due to instrument issues . ................................................................................... 74 Figure 30 . ( A ) TSS concentration and ( B ) TN concentrations at Strathbogie for four wet seasons . ................. 75 Figure 31 . Location of the Havilah ( left ) and the Treatment and Control gullies . The location of the installed treatment structures and monitoring equipment / locations are shown . .......................................................... 76 Figure 32 . ( A ) TSS concentration and ( B ) TN concentrations at Havilah for the 2020-21 wet season . ............. 77 Figure 33 . Map showing the location of the small scale gully remediation sites ( green stars ). ...................... 82 Figure 34 . Overview of the map of the BBB showing the distribution of hotspots of active gullying . ............. 84 Figure 35 . Map of the BBB focal area showing the 17 identified clusters . ....................................................... 85 Figure 36 . Example of the high resolution semi-automated mapped gullies based on LiDAR data , compared to the underlying 100m x 100m grid gully density map previously available for prioritisation . Source : Brooks et al . ( 2018 ). ........................................................................................................................................................... 87 Figure 37 : Example of gullies mapped with a soft margin ( not all of which is currently eroding ) and a hard margin ( the actively eroding part ). .................................................................................................................... 88 Figure 38 : Fine sediment yield curve depicts a small number of high yielding gullies contributing 30 % of the catchment fine sediment yield ( yellow bar ). ..................................................................................................... 89 Figure 38 . The cost-effectiveness framework for the LDC Project split into six steps . Source : Star et al . ( 2019 ). ........................................................................................................................................................................... 93 Figure 39 . A schematic diagram of two paired project sites showing the road drainage structures , location of monitoring equipment in the mitre drain , and direction of flow ( photo taken December 2020 ) ( Fruition Environmental , 2021 ). ....................................................................................................................................... 94 Figure 40 . Rising Stage Sampler assembly and water level data logger installation . ........................................ 95 Figure 41 . Concentration of suspended sediment < 20μm for each respective RSS sample between December 2020 and April 2021 .. ........................................................................................................................................ 96 Figure 42 . Predicted fine sediment reductions and project areas for all projects completed in the LDC Project in the Bowen Broken Bogie sub-catchments . ................................................................................................. 102 Figure 43 . BBB sub-catchment fine sediment ( t / ha / y ) from the Source Catchments model estimates . The red line shows the rate for the whole BBB catchment ( 1.44t / ha / yr ) for comparison . ......................................... 103 Figure 44 . Fine sediment average annual ( t / y ) contributions by erosion type for each BBB sub-catchment ( end of stream , from Source Catchment model estimates ). ........................................................................... 104 Figure 45 . Fine sediment average annual ( t / y ) contributions by land use for each BBB sub-catchment from the Source Catchment model estimates . ........................................................................................................ 104
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