Final LDC WQ Report | Page 76

Pre-treatment data was collected at this site on both the control and treatment sites in the 2020-21 wet season . The location of the water quality monitoring sites , land condition and terrain analysis surveys are shown on Figure 27 .

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 .

Vegetation The vegetation data collection commenced at this site in February and May 2021 for the hillslopes and gullies . It is important to note that the hillslope vegetation surveys are in the upper part of the catchments of both gullies ( Figure 31 ) as this will enable assessment of future change in the proportion of vegetation that may influence the rainfall and runoff entering the gully site . At the end of the 2020-21 wet season , there was not a significant difference in the hillslope % cover , between the treatment and control sites , but there was a difference in biomass . There was not any difference between the % cover and biomass on the gully channel or walls , however , there was a difference in landscape condition between the control and treatment sites . The treatment site is dominated by buffel grass and large tussocks , and the control site is dominated by Urochloa ( Sabi grass ) which has a much lower basal area in comparison . It is useful to have these baseline conditions established so that the change in metrics once the treatments and management are implemented at the site can be assessed .

The land condition at the control and treatment site varies , with the treatment site having a lower proportion in ‘ D ’ Condition ( 52 % ‘ C ’ Condition , 48 % ‘ D ’ Condition ) compared to the control site ( 17 % ‘ B ’ Condition , 22 % ‘ C ’ Condition and 61 % ‘ D ’ Condition ).

Water Quality Outcomes

Water monitoring infrastructure was installed in February 2021 therefore only a partial rainfall record was collected for the wet season ., There was ~ 208 mm of rainfall at the treatment site , and ~ 204 mm at the control site for the period measured .

Fortunately , several runoff events were captured in March and April with 19 samples processed for TSS and 9 for TN at the treatment site . Only 3 samples were analysed for TSS at the control site ( Figure 32Figure 32 ). All samples can be considered as pre-treatment . There was no statistical difference between the TSS

76