Supplementary Table 1
	Number of locations	Number of repeats 
	260	2
	227	3
	51	4
	14	5
	17	6
	8	7
	8	8
	11	9
	4	10
	1	13
	Number of locations with repeat sample collection and analysis through time in the dataset 


Supplementary Table 2
	Depth 	Number of repeats	SD- δ18O ‰ 				SD- δ2H  ‰
	 	 	Mean	Median	5th percentile	95th percentile	Mean	Median	5th percentile	95th percentile
	1-30m 	213	0.28	0.01	0.01	1.08	2.02	1.02	0.14	6.83
	30-50m 	132	0.2	0.1	0	0.71	1.27	0.78	0.1	4.75
	50-300m 	247	0.16	0.1	0.01	0.51	0.86	0.56	0.07	2.1
	300-1000m 	9	0.08	0.07	0.01	0.14	0.52	0.42	0.14	1.06
	Mean, median, 5th and 95th percentiles of  standard deviation by depth intervals for all repeated sites during sampling. 


Supplementary Table 3
	Data Reference
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Supplementary Figure 1


Supplementary Figure 2
	Supplementary Figure 2. Semi-variograms (i.e. variance against distance) of sample δ18O data for the four depth intervals with optimised semi-variogram model fit.


Supplementary Figure 3
		Supplementary Figure 3 . δ2H  isoscapes for the four depth intervals described in the main text. Cells depicted in white indicate no information available in the current layer. Cells depicted in grey correspond to those with information available in a different depth interval.


Supplementary Figure 4
		Supplementary Figure 8 . NSW river catchment locations. 


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