• Site At-a-Glance

Hinkley Groundwater Remediation

PNL's Role

PNLís role on the Hinkley Groundwater Remediation Program is to provide an independent technical for the Hinkley Community. Acting in the role of the Independent Review Panel (IRP) Manager, PNL has been providing technical outreach to the Hinkley Community since February 2012. As outlined on the Water Board November 4, 2015 CAO, PNL scope of work includes the following tasks:

  • Task 1: An annual report and presentation to the Water Board on the independent consultantís effort within the Hinkley Community.
  • Task 2: A minimum of six newsletters each year to disseminate information to Hinkley residents.
  • Task 3: A minimum of four public meetings held in the Hinkley community.
  • Task 4: Availability for one on one communication with individuals or groups of Hinkley residents.
  • Task 5: Production of technical review, written comments and presentations to respond to Water Board orders, PG&E reports, USGS reports and other technical materials related to the chromium remediation.
  • Outside expert on matter(s) of greatest concern to the community.

Ongoing Activities

The current plume area is approximate 7.5 miles in length and 2.5 miles wide. The extent of the plume in the northern area is still debated and is being addressed by the Unites States Geological Survey (USGS). USGS is currently conducted a Cr6 background study to determine the extent of the Cr6 plume in the Hinkley Valley. The USGS background study is anticipated to be completed by 2019. On November 4, 2015 the Water Board adopted a comprehensive Cleanup and Abatement Order for the Hinkley Groundwater Remediation Program. Components of the Final Remedy includes the following remedial actions:

  • In Situ Reactive Zones (IRZs) to treat the highest Cr6 concentration at the core of the plume;
  • Agricultural Treatment Units (ATUs) to treat lower Cr6 concentration;
  • Hydraulic Control /Containment to ensure that the Cr6 plume is not migrating further north; and
  • Northwest Freshwater Injection (NWFI) System that ensures the Cr6 plume is not migrating to the western area of Hinkley.

Technical Milestones

  • 2004: Operations begin at Desert View Diary(DVD) Land Treatment Unit (LTU)
  • 2007: PG&E completes first Cr6 in groundwater background study
  • 2007: Operations begin at Central IRZ
  • 2008: Operations begin at Source Area IRZ
  • 2009: Operations begins at South Central Re-Injection Area (SCRIA) IRZ and Northwest Area Extraction Wells
  • 2010: NWFI System is operational
  • 2011: Operations begin at Gorman, Cottrell, and Ranch ATUs
  • February 2012: PNL get retained to provide technical outreach to the Hinkley Community
  • August 2010 to October 2012: PG&E submits Feasibility Study and Addendums to Water Board
  • June 2012: PG&E completes Replacement Water Supply Feasibility Study Report
  • 2013: Operations begins at Yang ATU
  • July 17, 2013: Water Board certifies Hinkley Groundwater Remediation Program Environmental Impact Report
  • March 12, 2014: Water Board adopts Waste Discharge Requirements (WDR) for Agricultural Treatment Units
  • July 1, 2014: States adopts Maximum Contaminant Level (MCL) for Cr6 in drinking water of 10 parts per billion
  • 2015: USGS Background Study begins
  • 2015: Operations begins at Community East and Fairview ATUs
  • November 4, 2015: Water Board adopt Comprehensive CAO for Hinkley Groundwater Remediation Program
  • December 18, 2015: Water Board approves the completion of the Supplemental Environment Project (SEP) for water to the Hinkley Elementary/Middle School

Stakeholder Relations

  • PNL works closely and has created a good working relationship with all key stakeholders (Hinkley Community, Water Board, PG&E and USGS) on the Hinkley Groundwater Remediation Program.
  • PNL provides project updates and information at www.HinkleyGroundwater.com.
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