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Water Level Assessment Introduction
Page 2


Natural Recharge Is Minimal and Slow
  • Few Places For Recharge To Grande Ronde Basalt
      • Few places where interflow zones outcrop
      • The interflow zones are thin
      • Shallow basalt zones don’t leak to deep zones
  • Only Natural Source: Precipitation
      • Winter/spring runoff
      • Small in magnitude compared with pumping
  • Long distances to wells à extremely slow process


 Water Levels



Existing Groundwater Supplies In The Deep Basalt Are Not Reliable Or Sustainable In The Long-Term 

(Lower Grande Ronde) 

Continuing to Deepen Wells Into the Lower Grande Ronde Is Only A Temporary Solution 

(Declines in Water Levels and Pumping Yields) 



Last Updated ( Thursday, 19 March 2009 )
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