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Site Report: Swanson River Tank Setting 1-9

Site Name: Swanson River Tank Setting 1-9
Address: Mi. 17.5 Swanson River Rd, Sterling, AK 99672
File Number: 2334.38.019
Hazard ID: 448
Status: Active
Staff: Peter Campbell, 9072623412 peter.campbell@alaska.gov
Latitude: 60.719722
Longitude: -150.862778
Horizontal Datum:NAD83

We make every effort to ensure the data presented here is accurate based on the best available information currently on file with DEC. It is therefore subject to change as new information becomes available. We recommend contacting the assigned project staff prior to making decisions based on this information.

Problems/Comments

Petroleum contamination of soil and groundwater beneath this flare stack due to past releases of petroleum products. Light non-aqueous phase liquid (LNAPL) recovery and annual groundwater monitoring on-going. Contaminant plume appears stable and not expanding. Under current site conditions, risk to human health and the environment is minimal. Due to oil field infrastructure, major excavation and remediation of the contaminated soil is not feasible. Cleanup will occur when the pad is abandoned.

Action Information

Action Date Action Description DEC Staff
5/23/1990 Update or Other Action (Old R:Base Action Code = SI - Site Investigation). Arco sent in Phase II Investigation Report. All locations investigated except 1-9 have glacial drift which strongly limited the vertical/horizontal migration of hydrocarbons in subsurface soils. At 1-9 tank setting, permeable coarse grained soils have allowed hydrocarbons to migrate substantially in the subsurface soils/groundwater. Former Staff
11/1/1991 Update or Other Action (Old R:Base Action Code = TOTH - Treatment, Other). Results of Bioventing treatability test provided to the Department. Former Staff
7/15/1992 Update or Other Action (Old R:Base Action Code = TAS - Treatment Alternative Study (CS)). ARCO submitted results of evaluation remediation alternatives for SRF. Report identified numerous potential remediation methods for the contaminated soil and groundwater. Report concluded that in-situ bioventing was the optimum alternative for soil remediation, and disposal of contaminated groundwater at class II wells was optimum method for mitigating contaminated groundwater concern. Former Staff
8/24/1992 Update or Other Action (Old R:Base Action Code = RAPR - Remedial Action Plan Review (CS)). ADEC provided conditional approval of bioventing pilot study. Former Staff
12/6/1993 Site Added to Database Petroleum contamination. Site broken out of Swanson River Field Tank Setting that was formerly inclusive of all Swanson River Field Tank Setting sites. Former Staff
12/6/1993 Site Ranked Using the AHRM Initial ranking. Former Staff
9/20/2000 Meeting or Teleconference Held Meeting at the oil field with Unocal, Chevron, USFWS to discuss past sampling results, improvements to sampling this year and approach to addressing problems. Will have meeting after this years monitoring report has been reviewed to discuss approach for the sites. Informed participants that in order to comply with USFWS regulations, Method 2 cleanup levels (Tables B and C) must be met, not 10 times or risk assessment. Donald Seagren
10/9/2000 Update or Other Action Re-reviewed the 1999 GW Monitoring Report. Final decision will wait until fall 2000 sampling event. At minimum, Unocal will have to determine extent of free product migration and begin free product recovery where needed. Donald Seagren
5/14/2001 Update or Other Action Reviewed 2000 monitoring report; discussed free product recovery work plan with John Hammelman. Donald Seagren
9/12/2002 Site Characterization Workplan Approved Review and approve Work Plan for Monitoring Well Installation. Coordinate with USFWS. Donald Seagren
4/23/2003 Meeting or Teleconference Held Annual meeting to discuss 2002 work and 2003 plans. Donald Seagren
4/29/2003 Update or Other Action Reviewed 2002 MW installation report. Donald Seagren
4/30/2004 Update or Other Action File number assigned and entered into the Fileroom DB and CS DB. Alyce Hughey
5/27/2004 Meeting or Teleconference Held Monthly progress meeting. Revised NAPL recovery plan to be submitted by 30 June 04. Donald Seagren
6/18/2004 Cleanup Plan Approved Reviewed and approved NAPL recovery plan Donald Seagren
3/21/2005 Update or Other Action Reviewed 2004 GW monitoring report. No appreciable change in the risk to human health or the environment. Donald Seagren
8/10/2005 Meeting or Teleconference Held Field agency meeting and site inspections. Examined belt skimmer in recovery well. Unocal is experiencing problems with the skimmer belt hanging up resulting in a shut down of the system. Unocal is exploring different methods of repairing the system. Sorbent pads have been placed in the recovery well while the problem is being corrected. They may go to a new skimmer system for 2006. Donald Seagren
10/7/2005 GIS Position Updated Using A Swanson River Layout Map, from Unocal, in conjunction with TopoZone Pro and the KPB Parcel Lookup, entered the coordinates for this site. Metadata includes No Topo Basemap, TopoZone Pro Street Maps, Black and White Aerial Photo, on a Medium Size Map, View Scale 1:24,000, Coordinate Datum, NAD83. Alyce Hughey
3/9/2006 Update or Other Action reviewed 05 monitoirng report. No significant change to risk to human health or the environment. Gw flow direction did change form SW to NW . Water table is extremely flat at thsi site. The change will be followed. It is thought to be an anomoly. Annual Monitoring and LNAPL recovery to continue. Donald Seagren
4/2/2007 Update or Other Action Reviewd 06 monitoring report. No significant change to risk to human helath or the environment. Annual monitoring and LNAPL recovery to continue Donald Seagren
5/7/2007 Exposure Tracking Model Ranking Donald Seagren
6/11/2008 Streamlined Cleanup Program Site transferred from Don Seagren to Paul Horwath per Linda Nuechterlein. On 6-30-08 transferred from Paul Horwath to Don Fritz per Paul Horwath. Alyce Hughey
9/28/2011 Document, Report, or Work plan Review - other Reviewed the 2010 Groundwater Monitoring Report: Swanson River Field Tank Settings and Flare Pits, dated July 2011, prepared by OilRisk Consultants. During the 2010 groundwater sampling event conducted in November through December, all twelve of the monitoring wells located at pad 1-9 were sampled for BTEX. Analytical results detected Benzene in five of the monitoring wells above the groundwater cleanup levels at concentrations of 0.0196 mg/L to 0.430 mg/L. Alyce Hughey
11/16/2011 Update or Other Action Site transferred from Don Fritz to Peter Campbell per Paul Horwath. Alyce Hughey
9/24/2015 Meeting or Teleconference Held Meeting discussing long term sampling strategy and filling data gaps. Plans for installing a new well down gradient from TS1-9B which has free product. Peter Campbell
9/18/2017 Document, Report, or Work plan Review - other Tank Setting 1-9 groundwater wells are monitored on a biennial and a four-year schedule. All viable wells are gauged during each sampling event. 2017 field activities include: Sample four wells for 8260C and PAH: TS1-9A, TS1-9C, TS1-9D, and FS1-9N. Five wells are sampled for 8260C every four years and will be sampled next in 2019: TS1-9U, TS1-9HH, FS1-9D, FS1-9I, and FS1-9M. Replace LNAPL-absorbent socks in two wells: TS1-9B and FS1-9F. If LNAPL is not observed, sample wells for PAH and 8260C. See 2017 Kenai Groundwater Monitoring Program Work Plan. Peter Campbell
11/7/2019 Document, Report, or Work plan Review - other Reviewed the 2017 Groundwater Monitoring Program Report. LNAPL was present in TS1-9D and FS1-9F. 200 ml of product was recovered from FS1-9F. Peter Campbell
3/25/2020 Document, Report, or Work plan Review - other Review the 2019 Groundwater Monitoring Report. No significant changes in the ground water contaminant plume. ADEC asked Hilcorp to honor data points when mapping groundwater flow. Peter Campbell
5/27/2021 Document, Report, or Work plan Review - other Review the Contaminated Soil and Water Management Plan for 2021 Flowline Installation and Inspection. Plan approved. Peter Campbell
7/21/2021 Document, Report, or Work plan Review - other 2021 Groundwater Monitoring Program Work Plan ADEC Approval Letter Peter Campbell
8/1/2022 Document, Report, or Work plan Review - other 2021 Groundwater Monitoring Program Report ADEC Report Plan Approval Peter Campbell
6/1/2023 Long Term Monitoring Workplan or Report Review Review and approve 2023 Groundwater Monitoring Program Work Plan Addendum Peter Campbell

Contaminant Information

Name Level Description Media Comments

Control Type

Type Details

Requirements

Description Details

No associated sites were found.

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State of Alaska Department of Environmental Conservation

P.O. Box 111800
Juneau, AK 99811-1800
Phone: 907-465-5066
Fax: 907-465-5245
TDD: 800-770-8973
Physical Location: 410 Willoughby