Below Average Rainfall in the Southern Basins



BELOW AVERAGE RAINFALL IN THE SOUTHERN BASINS (WHERE IS THE EVIDENCE?)


 


In the document called the ‘Southern Basins Prescribed Wells Area Groundwater Monitoring Status Report 2002’ (DWLBC Report) by SCOTT EVANS October 2002, it states that the three rainfall stations selected “as representative of the rainfall pattern throughout the area” are Port Lincoln Post Office (18070), Big Swamp (18017) and Sleaford (18137)(see copy from page 5 below titled ‘CLIMATE’).

 

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The average (mean) rainfall from the Official Bureau of Meteorology (BOM) website (up to this current year 2013) for the three rainfall stations (mentioned above in the document) are tabled below.

 

Port Lincoln (Post Office)(18070)(bear im mind this station closed in 2002)

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Big Swamp (180170)

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Sleaford (Westmere) (18137)

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The figures (above) of the average monthly and annual rainfall from the official BOM website (2013) have been superimposed in red on the table below by us. The figures in black are from the 2002 Government document by Scott Evans (mentioned above).

 

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Conclusion——From Government documentation (BOM) there is NO evidence whatsoever of rainfall trending below average from 2002 to 2013.

 

So why are the groundwater levels continually going down?

 

It is quite simple. They have over-extracted to such a point that the water levels in at least one case and maybe more have fallen over 8 metres (see graph immediately below).image011

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This means that any “rainfall recharge” has to go through a larger depth of DRY SOIL to reach the aquifer. Therefore it gets absorbed before it reaches the water-table; consequently we are NOT seeing the rapid and “effective recharge” that the basins used to achieve when the water was far closer to the surface (when ONE good winter would fill the Basin).

At the present rate of extraction we believe we will NEVER see the Basins restored unless there are far greater rainfall events and less or no extraction.

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