Underground Storage Tank Cleanup Fund - ECAP Success Story

Claim 6680 - UNOCAL #7005, CHEVRON FACILITY NO. 306578


Site: Unocal #7005, Chevron Facility No. 306578 (T0601300323)
Address: 1823 Main Street N. Walnut Creek, Contra Costa County
CUF Priority Assigned: D
CUF Amount Paid: $466,029
Years Open Prior to ECAP: 30
ECAP Start Date: 6/17/2019
Case Closed: 11/4/2021


  Impediments to Closure Prior to ECAP

  • Groundwater Criteria - Not Met
  • Petroleum Vapor Intrusion to Indoor Air - Not Met
  • Direct Contact and Outdoor Air - Not Met
  • General Criteria - Not Met

  Impediments to Closure After CSM/JET Meetings

  • Groundwater Criteria - Met
  • Petroleum Vapor Intrusion to Indoor Air - Not Met
  • Direct Contact and Outdoor Air - Met
  • General Criteria - Not Met

  Case Overview

The site is the location of a former commercial petroleum fueling facility and currently developed as a Target garden center. An unauthorized release was reported in March 1990. An unknown volume of contaminated soil was excavated to a depth of 12 feet below ground surface (bgs) beneath the former USTs and seven feet bgs beneath the former dispensers in May 1991 during the removal of three gasoline USTs.

Groundwater extraction was conducted between February 1995 and January 1999, which removed 5.5 million gallons of contaminated groundwater.

Batch groundwater extraction was conducted intermittently between March 2005 and November 2005, which removed 13,500 gallons of impacted groundwater. High vacuum dual phase extraction was conducted between January and February 2015, which removed 2,095 pounds of total petroleum hydrocarbons as gasoline (TPHg) and 396,140 gallons of contaminated groundwater. Multi-phase extraction (MPE) was conducted between August 2019 and November 2019, which removed 3,541.6 pounds of TPHg and 1,002,410 gallons of contaminated groundwater. Since 1990, 11 groundwater monitoring and two extraction wells were installed and monitored.

  Region 2
San Francisco Bay Regional Water Quality Control Board

How Did ECAP Help?

  • ECAP staff facilitated a series of meetings to discuss the Low Threat Case Closure Policy (LTCP) and remaining impediments to closure.
  • ECAP staff assisted in establishing remediation goals and technology to address remaining impediments.
  • ECAP staff helped evaluate remediation data and optimize the remediation system during system operation.
  • ECAP staff helped promote communication between all parties involved in project.


  • Collaboration between all parties (6 stakeholders-Lead Regulatory Agency, Fund Staff, Claimant, Property Owners, Developers, and Consultants)
  • Implementation of effective remediation technology that resulted in expedited case closure
  • After joining ECAP the case was closed in 874 days (2.4 years)