Salinity situation statement Tweed River and Gnowergerup Brook

Salinity situation statement: Tweed River & Gnowergerup Brook WRT 41 Water Resource Technical Series
Scenario 3 — 59% strategic trees
It was considered necessary to analyse the salinity levels if the response units releasing the
highest salt loads per hectare were planted. So response units with salt loads greater than
2000 kg/ha were selected for ‘planting’ with trees and response units with salt loads smaller
than 2000 kg/ha were not planted (Fig. 34). This equated to 59% of the cleared area getting
‘plantations’.
In 2030, projected salinities in the Tweed River and Gnowergerup Brook would be reduced to
1861 mg/L and 2154 mg/L respectively, representing salinity reductions of 1289 mg/L and
2482 mg/L TDS respectively compared to the ‘base case’ scenario.
Figure 34 Response units selected for planting in ‘59% strategic trees’
The predicted salt loads, salinities and flows for the response units in 2030 are shown in
Figures 35, 36, 37 respectively.
When response units (numbers 10, 11, 13, 21 and 37) with high salt loads (above
3000 kg/ha) were planted with trees, salt loads were reduced to less than 500 kg/ha
(Fig. 35). There is also a reduction in response unit salinity, which can be seen by comparing
the predicted salinity in 2030 (Fig. 36) to the ‘base case’ (Fig. 28).
38 Department of Water