dry season cattle breached the exclusion fence and grazed down the area which exposed tunnels at the gully head. The site that is recorded as not receiving maintenance to the reshaping in Figure 16 is Site 13. It has a small area of revegetation on near level ground that is stable, however the maintenance that was required at this site has been recorded under the rock chute category. The two highly disturbed sites that required maintenance were on sloped landforms.
All six rock chutes required maintenance and are likely to require maintenance into the future. This is despite the moderate wet seasons since construction. Anecdotal evidence suggests there has been limited engagement of these rock chutes; water has not yet flowed down one, four appear to have had small flows and one has been fully engaged during high rainfall events( Site 13). Site 13’ s chute received timely repairs by the landholder( in-kind). Four chutes have suffered from gradual erosion of the abutments and two of these also have erosion immediately upslope
of the crest( Figure 17). Two sites( Sites 22 and 9) received maintenance to the erosion around the rock chute in 2024. Five of the six chutes are in the highly erodible Sodosol soil type.
The sixth rock chute( Site 24) is in Downs country Vertosol soil, a‘ soft’ erodible cracking clay. Maintenance is not required to this structure, but it has proved difficult to keep engaged. Site 24’ s chute is situated downslope of a series of low-grade diversion banks to safely discharge runoff to the gully floor. However, the flows are bypassing the chute; cutting through a wing bank and emptying in the gully channel a little further upstream of the chute. The failed wing bank was repaired in 2024 with a new design. However, the wall was again breached in the same place early in the 2024 / 25 wet season. Soil from the bank has built up immediately above the chute, further reducing the likelihood of the chute taking runoff. Refer to Figure 32 for more information on these works.
Site 9 Site 10
November 2022
December 2022
Site 13
April 2023 July 2023
Site 22 Rock chute 1
Site 22 Rock chute 2
Head cut above chute
April 2023
April 2023
Figure 17. The five rock chutes at small-scale sites on highly erodible Sodosol soils. All have active erosion that will require continued maintenance to be effective.
NQ DRY TROPICS 29