Post on 15-Oct-2020
Groundwater
Contamination in the
Rialto-Colton Basin
RWQCB, Santa Ana Region
July 17, 2012
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Overview
– Early investigations
– Two source areas
• County/Stonehurst
• 160-acre site
– Agency roles
– County groundwater remedy
The Problem
• Perchlorate detected in 1997
• Some wells shut down in 2002
• First Regional Board orders issued
in 2002
• Investigation of sources and
extent of contamination
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Regional Board Role
• Lead agency for County
groundwater remedy
• Lead agency for Stonehurst site
• Investigation of 160-acre site until
2008; proposed CAO
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County Groundwater Remedy
• CAO adopted in 2003 and revised
in 2004
• Requires cleanup and
replacement water
• Treatment system for Rialto #3
and two additional extraction wells
• Began operation in 2006
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