The design at Gully 1 involves the reshaping of complex gully networks which will form two stabilised , freedraining basins . The reshaping will involve bank battering and topography reshaping through cut and fill , and compaction earthworks operations . On-contour rock check dams will be constructed across the bed of the drainage basins to assist in slowing the flow of water and improving the soil condition by enhancing the deposition of fine sediment , nutrients , and seed . The design also includes reshaping three incised linear gullies and one gully scarp which will also be reshaped to create a free draining surface which is less undulated and ties into the existing surface . The existing earthen bund around the head of the gully will be reinforced to manage overland flows utilising excess cut from reshaping works . The reshaped surfaces will be treated including :
• application and incorporation of gypsum to all reshaped and disturbed surfaces ;
• spreading of topsoil stripped from the footprint of the works or borrowed from an alternative source on the property ;
• application and incorporation of mulch ; sowing or broadcasting of seed and application of fertiliser ; and
• application of coir net matting over the designated batters and upslope areas of the reshaped surfaces .
Images of the site before and after treatment are shown in Figure 19 .
Figure 19 : Before and after images of the Glen Bowen Treatment gully ( Image source : NQ Dry Tropics ). Gully # 2 ( LRP17-022 commonly referred to as Trial Site Three and completed in conjunction with Gully 4 ).
The actively eroding footprint of Gully 2 has a perimeter of about 1km , with an internal area of 1.1ha . The banks of the gully scarp are on average 2.5-3m high . The drainage lines within the gully all converge to a single drainage line discharging into the Bowen River . The Gully 2 remediation design consists of the following works :
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