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Site Report: Swanson River P&S Yard

Site Name: Swanson River P&S Yard
Address: Mi. 17.5 Swanson River Rd, Sterling, AK 99672
File Number: 2334.38.017
Hazard ID: 452
Status: Active
Staff: Peter Campbell, 9072623412 peter.campbell@alaska.gov
Latitude: 60.752778
Longitude: -150.853889
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

7/1/88, area of hydrocarbon odor discovered in drainage down gradient from P&S yard at Swanson River Field. Release occurred before 1986. The contamination extends from the P&S Yard, to the Eastern groundwater seeps and into the wetlands. The Xylene detected is from spillage at above ground storage tank facility storing Xylene and petroleum field chemicals. The spill area is estimated to cover 25,000 square feet. Reported 7/1/88 by Jim Ives, ARCO; when other sampling was being done. Various monitoring and limited remediation technologies have been tried. LTM and air sparging with sub-surface discharge of treated water to adjacent leachfield on-going. Bentonite slurry wall surrounds the site to control infiltration of water through remaining contaminant plume. Slowly the area inside the wall is being de-watered. Plans are being developed for the next phase of remediaiton in 2006.

Action Information

Action Date Action Description DEC Staff
3/1/1991 Update or Other Action (Old R:Base Action Code = RARR - Remedial Action Report Review (CS)). Reviewed a remedial action report. Former Staff
4/17/1991 Update or Other Action (Old R:Base Action Code = RAPR - Remedial Action Plan Review (CS)). Approved construction/implementation of water remediation unit - water is to be remediated via an air-stripping tower and discharged on site. Former Staff
8/5/1991 Update or Other Action (Old R:Base Action Code = RAU - Remedial Actions Underway (General)). Began groundwater remediation. Former Staff
1/1/1992 Site Added to Database Former Staff
3/13/1992 Site Number Identifier Changed Reckey # changed as per Kenai District office. Former Staff
8/24/1992 Update or Other Action (Old R:Base Action Code = RAPR - Remedial Action Plan Review (CS)). Reviewed additional site assessment plan and discussed it in a meeting with the RP and consultant on 6/22/94. Plan was approved in the meeting. Written approval pending ADEC receipt of revised plan. Former Staff
8/23/1993 Meeting or Teleconference Held Reviewed monthly update on progress of work. Attended meeting with RP and landowner and involved regulatory agencies to discuss progress and direction for future work. Former Staff
9/9/1993 Update or Other Action (Old R:Base Action Code = RAPR - Remedial Action Plan Review (CS)). Reviewed monthly report on progress of remediation and improvements to the remediation plan. Former Staff
10/4/1994 Update or Other Action (Old R:Base Action Code = RAPR - Remedial Action Plan Review (CS)). Reviewed monitoring/remedial action report Former Staff
11/23/1994 Interim Removal Action Approved Review monitoring / progress report. Donald Seagren
6/15/1995 Site Ranked Using the AHRM Initial ranking. Action code added because it wasn't when the site was originally ranked. Donald Seagren
7/12/1995 Update or Other Action (Old R:Base Action Code = RAPR - Remedial Action Plan Review (CS)). Review and approve remediation work plan for additional contaminated soils removal and remediation. Donald Seagren
8/30/1995 Update or Other Action (Old R:Base Action Code = RECN - Site Reconnaissance (CS)). Met with representatives of UNOCAL and Geoengineers to inspect on-going remediation activities and discuss changes to remediation plan. Donald Seagren
1/11/1996 Update or Other Action (Old R:Base Action Code = RARR - Remedial Action Report Review (CS)). Reviewed quarterly GW monitoring and sampling report. Donald Seagren
5/1/1996 Long Term Monitoring Established Reviewed a quarterly GW monitoring report. Donald Seagren
5/23/1996 Cleanup Plan Approved (Old R:Base Action Code = RAPA - Remedial Action Plan Approval). Reviewed 1995 Soil Remediation Report. Donald Seagren
6/3/1996 Update or Other Action Reviewed various monitoring reports, site characterization reports, etc. for the P&S Yard as well as other Swanson River sites. Attended a meeting with Chevron, UNOCAL, USFWS, and BLM to discuss progress at the field and plans for future cleanup and remediation activities. Donald Seagren
8/9/1996 Update or Other Action Reviewed work plan addendum for additional site assessment and remediation work. Discussed the plan with UNOCAL and issued approval. Donald Seagren
9/5/1996 Update or Other Action Site inspection to observe and discuss on-going remediation and further site characterization work. Further work included installation of additional monitor wells, installation of air sparging trench, and further excavation and bio-piles. Donald Seagren
12/11/1996 Update or Other Action Reviewed work plan for ecological risk assessment. Sent comment letter to Unocal. Donald Seagren
4/7/1997 Update or Other Action Reviewed an ecological risk assessment work plan. Discussed it with a risk assessment manager. Sent a conditional approval letter. Donald Seagren
6/11/1997 Update or Other Action Traveled to Anchorage for an annual agency meeting concerning status of environmental activities at the site as well as other sites in the rest of the field. Donald Seagren
6/1/1998 Cleanup Plan Approved (Old R:Base Action Code = RAPA - Remedial Action Plan Approval). Reviewed and approved 1998 remediations workplan after discussions with USFWS, GeoEngineers and Unocal. Donald Seagren
6/5/1998 Update or Other Action Reviewed GW monitoring report. Donald Seagren
8/19/1999 Update or Other Action reviewed GW monitoring report Donald Seagren
9/21/1999 Meeting or Teleconference Held Site inspection with USFWS, Unocal, OilRisk Consultants to discuss progress on wetlands. Final soil cleanup in summer 2000 followed by final contouring/construction of wetland cells and seeding/planting. Also discussed tank settings and flare stacks Donald Seagren
9/24/1999 Update or Other Action Reviewed GW monitoring report Donald Seagren
12/6/1999 Update or Other Action Reviewed GW monitoring report #91 Donald Seagren
12/28/1999 Update or Other Action Reviewed GW monitoring report #92 Donald Seagren
1/3/2000 Update or Other Action Reviewed 1999 Annual Report: P&S Yard Soil Remediation; Sent letter to Unocal concerning inappropriate use of RBCL's for attaining cleanup levels. RBCL's were never accepted and use should be discontinued in future reports. Cleanup levels in Amend. 5 of COBC are the only acceptable cleanup levels for the site. Donald Seagren
2/9/2000 Update or Other Action Reviewed GW monitoring Report #94 Donald Seagren
3/7/2000 Meeting or Teleconference Held Met with John Beitia (Unocal) and Jim Frates (USFWS) to discuss final plans for created wetlands at site. Discussed final contouring, plantings, etc. Donald Seagren
4/25/2000 Update or Other Action Reviewed revised Wetlands construction and planting plan. No comments. Will defer to BLM and USFWS. Called John Beitia and left a message telling him so. Waiting to talk to Jim Frates, KNWR Donald Seagren
6/26/2000 Update or Other Action Returned phone call from John Beitia. Discussed continuing excess GW concerns with John Beitia and Jim Frates. Had to construct temporary holding pond during final contouring and planting of wetland cells. Pump and treat system still running at maximum flow rate for permit. Donald Seagren
6/30/2000 Update or Other Action Site inspection with Jim Frates and John Beitia. Contouring and planting going well. Should be completed within 2 weeks. Treatment system turned back down from max allowable under permit. Project looks good Donald Seagren
7/21/2000 Update or Other Action Review monitoring report #99 ADEC wastewater permit #9623-DB002 Donald Seagren
8/22/2000 Update or Other Action Review monitoring report #100 ADEC wastewater Permit #9623-DB002 Donald Seagren
9/13/2000 Update or Other Action Site inspection with Unocal, EPA/R10, and Alaska Harvester Inc. Discussed continuing xylene problem, possible causes and solutions, including modification of the engineered wetlands. Donald Seagren
9/20/2000 Meeting or Teleconference Held Site inspection with Chevron, Unocal, USFWS to discuss possible changes to lower cells to capture contaminated water that may be missed by the cells , but captured by the recovery system. Will allow to stabilize then evaluate. Sheen (petroleum or natural organic????) seen on pond 6. Water levels appear lower than a week ago. Donald Seagren
10/4/2000 Update or Other Action Reviewed monitoring report #101: discussed possible additional remediation alternatives with John Hammelman Donald Seagren
10/6/2000 Update or Other Action Reviewed soil remediation report to compare with COBC cleanup levels. Soil still exceeds cleanup level for xylene Donald Seagren
10/11/2000 Site Characterization Workplan Approved Reviewed and approved workplan for installation of microwells to further determine sources of GW contamination after discussing concerns with John Hammelman Donald Seagren
10/24/2000 Update or Other Action Reviewed Monitoring Report #102, contamination still high in influent to system Donald Seagren
10/25/2000 Update or Other Action Site inspection with Jim Frates, USFWS. Met with Dave Brailey. Preliminary data shows an apparent pocket of contamination in the area of MW3. Final decision on approach will come after review of final report Donald Seagren
12/5/2000 Update or Other Action Reviewed Monitoring report #103 Donald Seagren
12/26/2000 Update or Other Action Reviewed monitoring report 104 Donald Seagren
2/20/2001 Update or Other Action Review monitoring report # 105 and exceedance report Donald Seagren
3/8/2001 Update or Other Action Reviewed wastewater permit exceedance report. Donald Seagren
3/8/2001 Update or Other Action Review monitoring report #107 for February 2001. Influent xylenes still high 58,900 ppb Donald Seagren
3/8/2001 Update or Other Action Review and approve work plan for monitor well installation in Ponds 1,2 &3 of constructed wetlands Donald Seagren
3/8/2001 Update or Other Action Review Microwell Installation Report Donald Seagren
3/20/2001 Update or Other Action Site inspection during the installation of the 6 pond MW in the first 3 ponds. One MW had installation problems and wasn't installed completely, but may still be serviceable. Will have to wait until after spring thaw to determine. Ponds frozen solid to the bottom Donald Seagren
5/14/2001 Site Characterization Workplan Approved Reviewed and approved work plan for installation of additional micro wells to further delineate the groundwater contaminant plume in order to take corrective steps to make the wetlands more efficient Donald Seagren
5/17/2001 Update or Other Action Site inspection with Jim Frates, USFWS. Met with Dave Brailey and determined locations for new micro wells. Met with Baldwin's and discussed survival of plantings from last year and additional plantings for this year. Still a bit too early to determine survivability. Will go back out in a couple of weeks when things green up. Donald Seagren
6/11/2001 Update or Other Action Review monitoring report 109 Donald Seagren
6/14/2001 Update or Other Action Site inspection with USFWS, Unocal, Chevron and Dave Brailey Donald Seagren
7/24/2001 Update or Other Action Provided project updates to Folley and Pearson as background for their meeting on Friday. Briefed Alan Kukla on GW remediation as background for his review and renewal of the non-domestic wastewater permit. Donald Seagren
7/27/2001 Meeting or Teleconference Held Site meeting with USFWS, Unocal and consultants to review plans for further remediation at the P&S Yard. Walked site to allow USFWS to determine the extent of excavation. Donald Seagren
8/2/2001 Update or Other Action Reviewed Swanson River sediment sampling report. Donald Seagren
8/3/2001 Update or Other Action Reviewed June 2001 monitoring report. Donald Seagren
8/23/2001 Meeting or Teleconference Held Site meeting with Unocal, Chevron, OilRisk Consultants, USFWS, and Interfluve, Inc. to discuss how to proceed to best define remaining contamination, excavate and remediate and re-vegetate site. Donald Seagren
9/10/2001 Update or Other Action Reviewed analytical data from ponds and Swanson River. Approved de-watering ponds 4,5,6 once wastewater disposal permit is in place. Requested updated work plan for site so we aren't dealing with it piecemeal through various e-mails. Need a written document to tie together all things agreed to in various meetings. Donald Seagren
9/17/2001 Update or Other Action Reviewed July 2001 monitoring Report # 112. Donald Seagren
9/25/2001 Update or Other Action Review GW monitoring report. Donald Seagren
10/16/2001 Update or Other Action Discuss Non-Domestic WW concerns and possible solutions with Cammy Taylor of AOCG. Donald Seagren
10/22/2001 Update or Other Action Reviewed Department letter to Unocal regarding non-issuance of non-domestic wastewater permit for GW treatment system. Provided comments to Alan Kukla. Donald Seagren
11/26/2001 Update or Other Action Reviewed monitoring report # 114 - Permit # 9623-DB002 Donald Seagren
11/26/2001 Site Characterization Workplan Approved Reviewed and approved Soil Boring and Surface Sampling Work Plan. Approval includes the addition of RRO and PAH sampling to the proposed fill area across the road from the P&S Yard. Donald Seagren
11/26/2001 Update or Other Action Discussed Non-Domestic WasteWater disposal permits with Oren Wolley (EH). Requested renewal request from John Hammelman. Pump and treat system will be covered under new general permit currently being re-written by Oren. De-watering of the ponds will be covered by CS program, assuming the pond water remains clean, below Table C MCLs. Donald Seagren
12/17/2001 Update or Other Action Review monitoring report #115. Donald Seagren
1/7/2002 Update or Other Action Coordinate with SW program in Anchorage concerning site background and AOGC injection well request by Unocal. Donald Seagren
1/23/2002 Update or Other Action Review monitoring report #116. Donald Seagren
1/24/2002 Update or Other Action Review monitoring report #117. Donald Seagren
3/4/2002 Update or Other Action Review Monitoring report #118. Donald Seagren
4/24/2002 Meeting or Teleconference Held Annual meeting with ADEC, USFWS, BLM, Unocal and Oil Risk Consultants to discuss 01 work and workplans for 02. Donald Seagren
4/29/2002 Update or Other Action Review monitoring report # 119 Donald Seagren
5/2/2002 Site Characterization Workplan Approved Reviewed and approved workplan for 14 additional soil borings and 1 MW to assist in developing plan for containment wall around entire site. Donald Seagren
5/14/2002 Meeting or Teleconference Held Site inspection of soil boring work. Donald Seagren
5/28/2002 Update or Other Action Reviewed monitoring report. Donald Seagren
7/2/2002 Proposed Plan Reviewed and approved plan for installation of cut off wall during the summer of 2002. Proposed cut off wall will isolate the P&S Yard contamination and allow for dewatering and remediation of the contaminated soils. Donald Seagren
8/5/2002 Meeting or Teleconference Held Site inspection with Unocal, Dave Briley, USFWS to observe current site conditions, discuss options and provide direction for Unocal meeting. Donald Seagren
8/8/2002 Update or Other Action Reviewed Report of 2001 Environmental Work. Donald Seagren
8/9/2002 Update or Other Action Telephone conversation with John Hmmelman. Unocal internal meeting decided to go with the cut off wall plan. Project will go out to bid. Due to lateness of the season and potential for freezing weather to affect the integrity of the cutoff wall, the project may need to be postponed until 2003. Donald Seagren
8/21/2002 Update or Other Action Reviewed monitoring report July 2002. Donald Seagren
8/28/2002 Update or Other Action Site walk through with Unocal staff, consultants, USFWS and contractor for installation of cut off wall. Contract to be awarded this week. Construction can start in two weeks and be completed, weather permitting, prior to freeze up. Donald Seagren
10/1/2002 Update or Other Action Reviewed August 02 monitoring report. All discharge/treatment through constructed wetlands. No discharge through permitted system. Xylenes and Ethylbenzene continue to exceed cleanup levels in influent. Donald Seagren
10/3/2002 Update or Other Action Site inspection with John Hammelman during recovery trench installation. Cutoff wall installation should be completed this weekend. Donald Seagren
10/10/2002 Update or Other Action Reviewed and approved workplan for MW installation to replace MWs lost during cut off wall installation. Donald Seagren
12/2/2002 Update or Other Action Reviewed October 02 monitoring report. Drastic reduction in influent Xylene concentration from past norms. Now at 1,000 PPB where previously it averaged >40,000 PPB. The cutoff wall may be effective. Donald Seagren
2/10/2003 Update or Other Action Reviewed December 02 monitoring report. Xylene drop in lat monitoring report was an anomaly. Larry Acomb, Geosphere, Inc. latest consultant. Donald Seagren
4/23/2003 Meeting or Teleconference Held Annual meeting to discuss 2002 work and 2003 plans. Donald Seagren
4/29/2003 Site Characterization Report Approved Reviewed 2002 Site Investigation Report. Donald Seagren
6/9/2003 Update or Other Action Reviewed April 2003 monitoring report. Donald Seagren
6/9/2003 Update or Other Action Reviewed final Report of 2002 Environmental Work. Donald Seagren
8/13/2003 Meeting or Teleconference Held Agency (BLM, USFWS, ADEC) meeting with Unocal field staff and Bob Shipley, new Unocal Remediation & Abandonment Mgr. to discuss outstanding environmental issues and what will be accomplished yet this year. Basically lost a summer's work/progress with waiting for Unocal to change mgr's. Donald Seagren
8/27/2003 Meeting or Teleconference Held Agency meting (ADEC, USFWS,BLM) meeting to discuss outstanding issues at SRF and to bring newer staff up to date on field history. Donald Seagren
9/11/2003 Meeting or Teleconference Held Meeting with USFWS/ADEC/Unocal and consultants to discuss G&I project, pilot restoration project and P&S yard site cleanup, recovery trench improvements and leach filed re-build. Donald Seagren
9/22/2003 Meeting or Teleconference Held Meeting with Unocal/BLM/USFWS to discuss project status/update. Also discuss grind and inject, gravel removal and restoration projects. Donald Seagren
10/8/2003 Meeting or Teleconference Held Agency/Unocal meeting at SRF. Action item lit discussion. Site inspection of P&S Yard, pilot remediation project, gravel pit restoration. Donald Seagren
10/22/2003 Meeting or Teleconference Held Kick off meeting for leach field re-build project. Project to begin on Monday, 27 October 03. It is estimated to take about 8 (12hour) days. Donald Seagren
11/14/2003 Update or Other Action Treatment system leach field reconstruction completed. Line from collection trenches to conex upgraded and re-insulated. Donald Seagren
1/13/2004 Update or Other Action Review 2003 Drain Filed Reconstruction Report. Donald Seagren
4/28/2004 Update or Other Action File number assigned and entered into the Fileroom DB and CS DB. Alyce Hughey
5/18/2004 Update or Other Action Approved Unocal's request to discontinue sediment monitoring in wetlands downgradient of P&S yard, with 2 stipulations - sediment sampling required for closure & the Department can reimpose sediment sampling at any time, based on site specific data. Donald Seagren
8/11/2004 Update or Other Action Telephone call from Bob Shipley. Hot xylene (5700ug/l) sample from wetlands. Will re-sample and attempt to determine source of contamination of sample. If re-sample comes out hot, additional assessment & corrective action will be required. Donald Seagren
9/2/2004 Update or Other Action Reviewed June & July 04 monitoring report and August 04 Wetlands Monitoring report. Issues will be discussed further at the 29 September agency meeting. Wetlands will be monitored monthly until freeze-up. Donald Seagren
11/2/2004 Update or Other Action Discussed sampling with Scott Thorsell. 2 influent samples from latest sampling event have been lost/broken in transit to lab. It is being checked further. Approval given to conduct next sampling event next week and not have to re-sample influent samples. Effluent samples were received in good shape. Sampling reports may be combined. Sampling report will provide further information/discussion on missing influent samples. Donald Seagren
12/2/2004 Update or Other Action Reviewed September 04 monitoring report. Continued slow decrease in contaminant levels. No change in risk to human health or the environment. Donald Seagren
12/16/2004 Update or Other Action Reviewed October & November 04 monitoring reports. Influent vials broken for October sampling. Influent samples shows continued slow decreasing trend, but still above COBC cleanup levels for ethylbenzene and xylene. Treated effluent all below cleanup levels. Draft site corrective action plan to be submitted to agencies for review at January meeting. Donald Seagren
2/1/2005 Update or Other Action Reviewed and commented on the DRAFT Treated Groundwater Disposal Plan, SRF P&S Yard. This plan will replace the Non-Domestic Wastewater Disposal Permit that is to be cancelled by the Water Program. The revised plan will be discussed and finalized at the meeting on 17 February. Donald Seagren
2/17/2005 Update or Other Action Reviewed January 05 monitoring report. Upset due to faulty heating element caused exceedances. The problem was corrected which brought the treated effluent to below the cleanup standards in the COBC. Donald Seagren
3/11/2005 Update or Other Action Reviewed & approved Treated GW Disposal plan. This work plan replaces the non-domestic WW disposal permit that was cancelled by the water program. The water program is no longer issuing disposal permits when a discharge is regulated by a contaminated sites corrective action plan, to avoid duplication of efforts. Donald Seagren
3/22/2005 Update or Other Action Reviewed February 05 monitoring report. Initial treated effluent samples exceeded cleanup levels for Xylenes. System was inspected and appeared to be working correctly. Re-sampling showed treated effluent samples to be below cleanup levels. Donald Seagren
5/6/2005 Update or Other Action Soil boring work plan approved. This is for preliminary work in roadway prior to re-locating cutoff wall this summer. Donald Seagren
6/20/2005 Update or Other Action Reviewed road way assessment report. One hit of xylene above COBC cleanup levels but below ADEC Table B cleanup levels. Re-location of cut off wall approved. Donald Seagren
6/27/2005 Update or Other Action Reviewed May & June 05 monitoring reports. Discussed exceedances, remedies and improvements to future reports with Scott Thorsell. Also discussed coordination of site inspection to look at re-veg plots and cutoff wall re-location project. Donald Seagren
8/10/2005 Meeting or Teleconference Held Agency meeting and site inspection; RECON will start moving for relocating slurry wall on 22 August 05. Work to begin on 29 August 05. Examined wetlands seeps and determined new surface water monitoring and well point locations. The changes should give better data on any contamination downgradient of the slurry wall that may be entering the wetlands that leads to the Swanson River. Donald Seagren
8/11/2005 Update or Other Action Reviewed the May through June 05 Wetland monitoring report. changes to the monitoring program were made at the field inspection on 10 August 05 to improve the quality and consistency of the data. Donald Seagren
8/23/2005 Update or Other Action Review and approve work plan for repair of the slurry wall. Work is scheduled to begin the week of 29 August 05. Donald Seagren
8/26/2005 Update or Other Action Verbally approved the use of water from ponds 1&2 as make up water for the slurry wall repair project. Scott Thorsell will sample the ponds. The work plan called for use of water in ponds 3 - 6 but currently there is not enough water in those ponds for the project needs, so ponds 1 & 2 will be utilized as needed. Donald Seagren
9/1/2005 Update or Other Action Site inspection during repair to the slurry wall. Progress is going well. Daily updates are being submitted by Unocal. It is anticipated that the wall repair work will be complete this weekend. Final capping, contouring and replacement of any MWs will be completed following the repairs. Unocal and their consultant are on site constantly to monitor the project. Donald Seagren
9/6/2005 Update or Other Action Repair of cut off wall completed. Gave verbal approval to store excess bentonite mix in pond 1 for the winter with the concurrence of BLM & USFWS. The mixing pond has steep sides that would be a hazard to humans and wildlife if left open. The pond has sloping sides that would be less of a hazard. The mix would be available for capping material as the project moves into the next phase next year. Donald Seagren
10/4/2005 Update or Other Action Reviewed August 05 monitoring report. Contaminant levels appear stable. No change to risk to human health or the environment. Wetlands monitoring results will be submitted under a separate report. Donald Seagren
10/7/2005 GIS Position Updated Using Figure 1 and 2 from a Site Characterization Report Unocal P&S Yard, from Geo Engineers, dated May 10, 1996, 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 1:10,000, Coordinate Datum NAD83. High degree of confidence in accuracy of location. Alyce Hughey
10/7/2005 Update or Other Action Reviewed the wetlands sampling report dated 8 August 05. It ppears that due to low water levels, the accuracy of the analytical results from sampling point W-1 is being affected by biogneic material. Samples from futher in the wetlands are not detecting any contamination exceeding cleanup levels. Modification of the sampling plan was discussed during a recent site inspection. A work plan is being developed to modify the existing sampling plan. Donald Seagren
10/7/2005 Update or Other Action The work plan for the well point installatin is approved. Due to fluctuating water levels at sampling point W1, the quality of hte data is suspect. It is thought that the addition of ground water and surfce water sampling points further out will provide more accurate data and a better picture of existing site conditions. Donald Seagren
11/28/2005 Update or Other Action Reviewed the Fall 05 wetland sampling report and the October 05 monitoring report. All contaminant levels within acceptable limits with no change in the riskl to human health or the environment. A new MW established int eh wetlands indicated xylene @ 8.29 mg/l which is between Table C levels (10 mg/l) and the COBC cleanup level of 0.2 mg/l. Surface water samples did not exhibit any contamination exceeding cleanup levels. This is the first sample for W-1P. It will be watched over time to establish any trends. Donald Seagren
11/29/2005 Update or Other Action Reviewed the 2005 restoration inspection report. The report summarizes the 3 year pilot project and provides recommendations for continued monitoring and future site restoration projects. The bottom line is that gravel alone is a poor substrate for most revegetation. Soill ammendments to increase water holding capacity and nutrient additons are required for a sucessful site restoration projects. Non-native invasive species should be removed so that they do not exclude native species. Donald Seagren
12/7/2005 Meeting or Teleconference Held Annual field summary meeting was held in ADEC offices in Soldotna. Summarized assessment, remediation, monitoring and abandonment work conducted in 2005 as well as tentative plans for 2006. Direction is currently in flux due to Chevron purchasing Unocal. Another meeting will be held in the Spring to cover plans for 06 in more detail. Donald Seagren
12/22/2005 Update or Other Action Reviewed November 05 monitoring report. the treatment system continues to operate under normal conditions, although the pumping rate for November was less than previous months. It is not certain at this time if the reduced pumping rate is a result of dewatering associated with the extension of he slurry wall in September. The system will continue to be monitored. All the effluent disposed of in the leach fiels was below the COBC cleanup levels. Donald Seagren
3/13/2006 Update or Other Action Reviewed February & March 06 monitoring reports. Influent remains above COBC cleanup levels for Ethylbenzene and Xylene. Treated water, discharged to the adjacent leachfield meets both aDEC cleanup levels and the COBC cleanup levels. No significant change to the risk to human health or the environment. Donald Seagren
8/1/2006 Update or Other Action Reviewed June 06 monitoirng report. Xylene effluent level (337 mg/l) exceeds COBC cleanup levels of 200 mg/l but is well below Table C cleanup levels of 10,000 mg/l. No lab QA/QC checklist included with the report. Reminded Unocal of the lab data quality tech memo and the checklist to be included with all reports. Donald Seagren
8/9/2006 Update or Other Action Reviewed June & July 06 monitoring reports. Treated effluent samples blelow cleup standards. Inffluent samples continue to be over the clenaup levels. No appreciable change to the risk to human health & the environment. Donald Seagren
8/9/2006 Update or Other Action Reviewed June & july 06 wetlands montiroing reports. Consituents are non detect or well below clenaup levels. the cut off wall and capture/treatment system is not allowing contaminant migration into the wetlands. risk to human thealth and the environment is low. Donald Seagren
10/10/2006 Update or Other Action Reviewed August & September 06 Wetlands Monitoring report. W-1P (well point in wetlands to sample groundwater) exceeded Table C levels for Benzene, ethylbenzene and Xylene. Requested an explanation for the exceedance snince previous sampling events wee all below Table C cleanup levels. Donald Seagren
1/2/2007 Update or Other Action Reviewed wetlands monitoring report. Due to freezing winter conditions, this was the last sampling event for the wtlands until after breakup in 07. Monitoring results wre comparable to previous sampling event. No apprciable change to risk to human helath or the environment. Donald Seagren
2/5/2007 Update or Other Action Reviewed December 06 and January 07 monitoring reports. Seasonal low water conditions prevailed during both months. The low flow and cold temperatures caused a short down time during December 06. The down time was used for system maintenance and cleaning of the collection trench pumps and water level sensors. Treated effluent samples continute to be between the COBC cleanup levels for Xylene (200 ug/l) and Table C cleanup levels of 10, 000 ug/l. The 05 work plan was approved using Table C cleanup levels. The USFWS has been contacted about trying to change the COBC cleanup levels to Table C. Donald Seagren
3/5/2007 Exposure Tracking Model Ranking Intitial Ranking Complete for Source Area: 71431 (Autogenerated Action)
7/20/2007 Update or Other Action Reviewed May & June 07 monitoring reports. No significant change in risk to human health and the environment. Donald Seagren
10/1/2007 Update or Other Action Reviewed August 07 monitoring report and wetlands monitroing report. Discussed with Scott Thorsell of Chevron. Water levels were generally low throughout the summer of 07. Wetlands monitroing indicated some crrep of ethyl benxzene and xylenes into the wetlands that exceed clenaup levels. CH2MHill is conducting a feasability assessment to try to determine the best approach to go forward to complete the site cleanup. The concern in the wetland is to stop contaminant migration without damaging the wetlands area. Monitor wells further downstream shwo that the contaminants are not reaching the Swanson River. Donald Seagren
4/1/2008 Site Characterization Workplan Approved Approved Work Plan to Collect Data to Develop an Interim Soil Cleanup Level, dated 6 March 08 Max Schwenne
6/11/2008 Update or Other Action 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
10/3/2008 Site Characterization Workplan Approved Approved a September 2008 OilRisk Consultants work plan to fill in data gaps identified at the P&S Yard. The work plan also contained assessment activities previously approved in the OilRisk Consultants Work Plan to Collect Data to Develop an Interim Soil Cleanup Level, dated 6 March 08. Don Fritz
1/28/2009 Site Characterization Workplan Approved On January 12, 2009, ADEC received a work plan titled “Request for additional sampling, P&S Yard Data Gaps Drilling Program”. This work plan was also submitted by Dave Brailey. This work plan proposes installing six additional soil borings at specified locations in order to obtain additional soil samples. The additional soil samples are needed in order to identify a total xylene concentration that corresponds to the Compliance Order by Consent cleanup level (200 µg/L) concentration for leachate using EPA’s Synthetic Precipitation Leaching Procedure (SPLP, Method 1312). Don Fritz
7/9/2009 Meeting or Teleconference Held Phone conversation with Scott Thorsell regarding wastewater disposal, Discussed with Paul, determined that they needed to work with Alan Kukla for discharges outside of P&S Yard perimeter Don Fritz
7/22/2009 Document, Report, or Work plan Review - other Reviewed September 2007 P&S Yard Wetlands Sampling report by Dave Brailey Don Fritz
9/15/2009 Cleanup Plan Approved August 19, 2009, work plan was submitted by Scott Thompson (Coffman Engineers) on behalf of Chevron North America Exploration and Production. On August 28th, Scott Thompson delivered additional information to our office concerning the design package, including a letter from you, a technical memorandum prepared by Greg Jones (GV Jones & Associates, Inc.), wastewater checklists, and engineered drawings titled P & S Yard GTS Drain Field Replacement. The engineered drawings were signed and sealed by Greg Jones. Work plan approved Don Fritz
10/21/2009 Site Visit Site visit to the P&S Yard with Scott, Scott, Claire, and Dave Brailey. Don Fritz
10/23/2009 Update or Other Action Phone call with Scott Thompson regarding sewer rock gradation variation. Review submittal, follow-up conversation with Monica and then Paul regarding sewer rock gradations, and regulatory background. Research infiltrator concerns on line and send e-mail to Scott Thompson approving gradation and asking about burial depth. Don Fritz
12/24/2009 Site Characterization Report Approved Review 2nd quarter 2009 P&S groundwater monitoring results. Left phone message with Dave Brailey requesting chain of custody form. Don Fritz
1/26/2010 Meeting or Teleconference Held Contaminated Sites staff participated in a teleconference with staff from Chevron, their consultants, and staff from the Waste Water Program. Chevron is pursuing a wastewater discharge permit in preparation for temporary dewatering activities the Swanson River P&S Yard to facilitate soil excavation activities next summer. Chevron conducted an excavation dewater air stripping system pilot test this summer, however, they were unsuccessful in meeting the standard discharge permit levels (10µg/L total aromatic hydrocarbons). Chevron requested consideration of a 0.2 mg/L discharge limit on xylene to match their Compliance Order by Consent requirement. Wastewater staff advised that the permit would require meeting the 10µg/L total aromatic hydrocarbon limit, but that the point where Chevron needed to meet this criteria was flexible. Chevron was agreeable to this approach. Don Fritz
2/22/2010 Site Characterization Report Approved Review of the 3rd quarter and 4th quarter P&S Yard monitoring reports prepared by Dave Brailey. Don Fritz
4/7/2010 Site Characterization Workplan Approved On March 22, 2010, the Kenai Area Office of the Alaska Department of Environmental Conservation (ADEC) received the Work Plan for Soil Boring and Piezometer Installation for the Swanson River P&S Yard site near Sterling, Alaska. This work plan was prepared by Dave Brailey (OilRisk Consultants) on behalf of Chevron North America Exploration and Production. Based upon our review of your work plan and a phone call with Scott Thompson, the plan is hereby approved contingent upon compliance with the following conditions: Don Fritz
4/13/2010 Update or Other Action Review of the Interim Soil Cleanup Level Analysis report. Phone call with Earl Crapps regarding wet weight analysis results. Don Fritz
5/12/2010 Meeting or Teleconference Held Contaminated Sites staff met with staff from Chevron, the USF&WS, and Oilrisk Consultants regarding work plans for the Swanson River P&S Yard for the upcoming field season. Chevron’s Environmental staff have received concurrence from Chevron management to undertake an aggressive soil remediation effort beginning this field season. Chevron will be providing a work plan in the near future to dewater the soils within the slurry wall, attempt to identify where groundwater is still entering the slurry wall, and to begin excavating impacted soils so that they can be land farmed within the slurry wall Don Fritz
6/23/2010 Update or Other Action Finish reviewing 2010 cleanup plan and review consent order to determine how the 2 mg/L xylene cleanup level was adopted. Teleconference with Scott Thorsell, Scott Thompson, and Dave Brailey to review issues with the P&S yard work plan and availible options. Don Fritz
6/24/2010 Meeting or Teleconference Held Telecon with Claire, Scott Thompson, and Dave Brailey regarding the placement of "clean soils" outside of the slurry wall, even though they exceed the 1.5 mg/kg cleanup level site specific for the site. Claire agreed with the movement of the soils. Further discussed random systematic sampling and the use of field screening versus collecting more samples. Don Fritz
6/28/2010 Update or Other Action Review 2010 work plan and Application for Temporary Use of Water that was sent by Michael Walton to various state employees. Don Fritz
9/21/2010 Site Visit Site visit to inspect current site remediation efforts. Paul Horwath
5/11/2011 Site Visit Site visit by ADEC staff to inspect current site remediation efforts. Don Fritz
5/17/2012 Cleanup Plan Approved ADEC reviewed Chevron's 2012 Cleanup Plan and approved the proposed plan. ADEC and Chevron discussed several minor comments/concerns with the plan, including: 1. Section 3.0 Cleanup Overview. While this comment is not applicable to this year’s activities, we discussed the department’s willingness to entertain not utilizing a liner between impacted material to be landfarmed and the backfilled soils that will in the future be placed in the western extent of the excavation. Our belief is that if the lift is placed onto the backfilled soils, or previous lifts, during warm, dry weather conditions, the relatively rapid volatilization of the contaminants should preclude the infiltration of contaminated leachate to underlying soils. This possibility may warrant further evaluation by Chevron. 2. Section 4.2 Screening and Landfarming of 2011 Excavation Spoils. The department sought clarification regarding the handling of the soils once a lift is determined to be treated. You indicated that once a lift was determined to be treated, the lift would be removed and stockpiled in the treated soils area, after which a new lift of impacted soils would be constructed. 3. Section 4.5 Backfilling Operations. We discussed the concern whether the aquitard could be compromised while grading it to provide positive drainage. You indicated that while the aquitard has been shown to be rather thick, Chevron shared this concern, and intended to keep the shaping of the aquitard to a minimum. We agree with this position. 4. Section 6.4 Field Quality Assurance. We discussed that the department was willing to reduce the number of field duplicates for soil samples to one duplicate for each 25 primary samples. ADEC approved the plan to begin dewatering the excavation in preparation for this summer’s activities, and routing the treated water through the infiltration gallery at the top of the hill until Chevron receive the ADEC wastewater permit. Don Fritz
9/3/2013 Site Characterization Workplan Approved Work plan prepared by AECOM to investigate beneath the Swanson River Road surface adjacent to the P&S Yard site in an effort to further delineate xylene-impacted soils. The work will involve bringing a truck-mounted environmental drilling rig out to the site, advancing soil borings in the roadway and collected both soil and groundwater samples. Work will occur in September (Fritz). Alyce Hughey
4/29/2014 Cleanup Plan Approved Don Fritz approved the 2014 Remediation Work Plan-Pipe and Supply Yard for the Swanson River P&S Yard site. This work plan was submitted by Brian Kelly (AECOM Environment) on behalf of Chevron Environmental Management Company. Based on our review of the work plan, an April 25, 2014 meeting with individuals representing Chevron, AECOM, CH2MHILL, BLM, and USF&WS) phone calls and with Brian Kelly on April 29, 2014, and the April 29, 2014 e-mail communication from Brian Kelly addressing the comments by the department regarding the work plan. Alyce Hughey
5/1/2014 Site Characterization Workplan Approved Peter Campbell approved the 2014 Subsurface Investigation Work Plan, dated April 2014, prepared by AECOM Environment based on the review of the work plan and information presented in meeting on April 25, 2014. Alyce Hughey
7/28/2014 Site Visit Site visit to discuss the results of the summer drilling investigation and review remediation progress. Peter Campbell
7/31/2014 Document, Report, or Work plan Review - other Review 2nd 1/4 2014 Monitoring Results for the P&S Yard Groundwater Treatment System, Swanson River Field Peter Campbell
9/8/2014 Document, Report, or Work plan Review - other Received 2014 Subsurface Investigation Report dated August, 2014 Report discusses the results of drilling soil borings and wells on the east and west side of the site. Recommendations include discontinuing excavation of Cell 6 and leaving soils in place that appear not to be impacted. Peter Campbell
9/11/2014 Meeting or Teleconference Held Chevron, AECOM and CH2MHill met with ADEC to discuss the 2014 Subsurface Investigation Report, Impacted soil under the main road may be treated with air sparging rather than land farming. Excavation next year may stop short of removing all of the soil inside of the slurry wall depending on field screening results. AECOM will develop a work plan to define the plan. Peter Campbell
11/3/2014 Document, Report, or Work plan Review - other Review 3rd Quarter Monitoring Results for the P&S Yard Groundwater Treatment System. Submitted by AECOM for Chevron. Dated 10/28/2014 Peter Campbell
11/4/2014 Meeting or Teleconference Held Chevron, AECOM, CH2MHill, ADEC, BLM and FWS met to discuss the potential of formally changing the soil cleanup level prescribed in the Compliance Order by Consent. BLM's risk assessor has determined that an updated risk assessment would be required from the original 1990's document. Chevron reiterated their intent to develop a work plan for remediating soils Impacted soil under the main road may be treated with air sparging rather than land farming. Excavation next year may stop short of removing all of the soil in Cell 6 depending on soil boring, laboratory and field screening results. AECOM will develop work plans for the 2015 field season. Peter Campbell
2/2/2015 Document, Report, or Work plan Review - other Review 4th Quarter Monitoring Results for the P&S Yard Groundwater Treatment System. Submitted by AECOM for Chevron. Dated 1/29/2015. Average pumping rate is 12,000 gallons per day from the treatment cell. There have been no exceedances for monitored compounds since 2011. Peter Campbell
3/18/2015 Document, Report, or Work plan Review - other Review the Final 2014 Remediation Report for the Pipe and Storage Yard soil remediation project. Over two million four hundred thousand gallons of water was removed from within the containment wall and processed for discharge. A total of 17, 621 cubic yards (CY) of material was excavated during the 2014 field season. 21, 095 CY of soil were screened, 15,656 cy land farmed and 20,207 backfilled into the lined cell. Groundwater monitoring in the wetlands downgradient of the treatment cell is showing a declining trend in the xylene concentrations at 3.87 mg/l with a cleanup level of 0.2 mg/l. Xylene was not detected in surface water samples downstream from the site. The 2015 field season should include completion of completion of the excavation work in cell 5 and the installation of an air sparging system under the roadway on the west side of the site. Peter Campbell
4/28/2015 Document, Report, or Work plan Review - other Review of the 1st Quarter 2015 Monitoring Results for the Treatment System. Effluent samples indicate that the roughly 115,000 gallons of treated water discharged to the subsurface leach field met the groundwater cleanup levels. Peter Campbell
4/29/2015 Update or Other Action Review and approval of the 2015 Remediation Work Plan. This summer, remaining xylene contamination on the eastern end of the containment cell will be removed and land farmed. In addition, an air sparging system will be installed on the western side of the site to treat soils under an active roadway. Peter Campbell
6/8/2015 Document, Report, or Work plan Review - other Received Supplemental Ecological Risk Evaluation for the Pipe and Supply Yard Xylene Site, Swanson River Field, Alaska. Peter Campbell
7/2/2015 Update or Other Action Letter sent to chevron requesting they install a groundwater monitoring network sufficient to assess the groundwater contaminant plume and address the fate of the slurry wall. Peter Campbell
7/2/2015 Update or Other Action USFWS risk assessor requested that the new risk assessment be revised to include an inhalation exposure pathway for soil dwelling mammals. Peter Campbell
7/24/2015 Document, Report, or Work plan Review - other Review 2014 Wetland Annual Report for the P&S Yard. The report summarized monthly sampling for the summer of 2014 between June and October. The well point down gradient of the treatment cell (W1-P) was below surface water cleanup standards (2.0 mg/L) except for October at 3.81 mg/L. The surface water samples were non-detect for 2014. Peter Campbell
8/11/2015 Site Visit Site visit to observe wetland conditions, excavation work and the status of the air sparge system installation. The field crew was on site to conduct groundwater monitoring. Peter Campbell
9/8/2015 Site Visit Site visit with USFWS to observe backfill conditions and discuss options for long term groundwater and surface water monitoring, and access to the site. Observe air-sparge installation progress. Peter Campbell
10/1/2015 Site Visit Active site excavation and soil remediation has been completed. Backfill of the treatment cell has left no water storage capacity inside of the slurry wall that surrounds the treatment cell. Recent rainfall caused surface water ponding that threatened to overflow the slurry wall. Pumping and engineering controls kept the water from breaching the berm. Surface water testing indicated that the water had no detectable xylene concentrations. Additional testing of the surface water will be conducted as the water is managed until freezing conditions prevail. The air saprge system installation is progressing and initial operation testing is scheduled to begin October 12, 2015. Peter Campbell
10/1/2015 Document, Report, or Work plan Review - other Review 3rd Quarter 2015 Monitoring Results for the P&S Yard Groundwater Treatment System. Report summarizes water monitoring results. Influent and effluent water sample results were below ADEC cleanup levels. BTEX Influent levels have been trending downward since 2010. the highest influent sample was 606 ug/l. Effluent samples were all non-detect. Peter Campbell
10/15/2015 Site Visit End of season site visit. Surface water discharge discontinued to the swail. All dewatering is to the leach field. Testing is starting on the air sparge system. The water discharge line was not completed this field season. Dewatering from the air sparge will not be possible, so the system will be run at low volume until next spring when the water discharge line can be installed. Peter Campbell
1/13/2016 Update or Other Action Reviewed and approved the Final Groundwater Monitoring Program for the P&S Yard dated December 15, 2015. This document was a work plan for the installation of twelve new monitoring wells to establish a well network. There are six new proposed wells for the wetlands east of the treatment cell. Peter Campbell
1/13/2016 Document, Report, or Work plan Review - other Review 4th Quarter 2015 Monitoring Results for the P&S Yard Groundwater Treatment System. Report summarizes water monitoring results. Influent and effluent water sample results were below ADEC cleanup levels. BTEX Influent levels have been trending downward since 2010. Peter Campbell
2/5/2016 Update or Other Action Review 2015 Wetland Annual Report. Down gradient well point results demonstrate an overall decline of xylene concentrations, indicating that treatment and natural attenuation are effective. A water sample was collected from beneath the ice in the wetlands. Sample results were non-detect. Peter Campbell
3/18/2016 Document, Report, or Work plan Review - other Received photo documentation of the monitoring well installation project in the wetlands from March. Peter Campbell
8/29/2016 Update or Other Action Review 2nd Quarter 2016 Monitoring Results for the P&S Yard Groundwater Treatment System. Report summarizes water monitoring results. Influent and effluent water sample results were below ADEC cleanup levels. BTEX Influent levels have been trending downward since 2010. The highest influent result for xylene was 0.465 mg/L (June 2016). Effluent from the treatment system was 0.006 mg/L. The cleanup level for xylene is 10 mg/L. Peter Campbell
11/10/2016 Document, Report, or Work plan Review - other Review the 2015 Remediation Report for the Swanson River Field P & S Yard site. Soil remediation within the slurry wall appears to have met Chevrons goals for soil treatment. Groundwater monitoring will now be used to determine if the cleanup level is protective to groundwater. Chevron is using air sparging on soils under the roadway to attempt to clean soil impacts west of the site. The State has requested a work plan to increase monitoring and address impacts to the wetlands and surface water east of the site. Peter Campbell
3/13/2017 Update or Other Action Reviewed Remediation Status Update for the air sparge system The system has been shut down since December 12, 2017. The scheduled February 2017 sample event was canceled due to weather. Sampling postponed until frost is out of the ground. Peter Campbell
4/6/2017 Document, Report, or Work plan Review - other Review 4th Quarter 2016 Monitoring Results for the P&S Yard Groundwater Treatment System. Report summarizes water monitoring results. Influent and effluent water sample results were below ADEC cleanup levels. BTEX Influent levels have been trending downward since 2010. Peter Campbell
7/12/2017 Document, Report, or Work plan Review - other Review the 2016 Wetland Annual Report. Groundwater results from WP-1, the monitoring well nearing the wetlands, exceeded the groundwater cleanup level for xylenes between May and October 2016. Ethyl benzene also exceeded cleanup levels in May and June 2016. Creek surface water samples exceeded water quality cleanup standards at location W-1E in May and June of 2016. The furthest down gradient water sample did not have any exceedances. Peter Campbell
8/9/2017 Document, Report, or Work plan Review - other Review the 2016 Well Installation and Groundwater Monitoring Report. Draft letter to Chevron with a request that Chevron map iron staining in the creek and collect surface water samples in area of iron staining to determine if there is a correlation to contamination entering the surface water. New monitoring wells TW-6 and TW-7 have elevated levels of BTEX. In response ADEC has required that surface water at the eastern end of the slurry wall be sampled for BTEX. Peter Campbell
10/19/2017 Update or Other Action Groundwater Treatment System 3rd Quarter Report. No water was treated or discharged to the leach field during the 3rd 1/4 because the system was shut down for the winter and dewatering has been completed for the project. Peter Campbell
4/12/2018 Document, Report, or Work plan Review - other Groundwater Treatment Report received from AECOM. The system was shut down in 2016, no water has been treated or discharged since that time. Peter Campbell
5/9/2018 Document, Report, or Work plan Review - other Reviewed the 2017 Annual Groundwater and Wetland Monitoring Report. Three monitoring wells installed in the interior of the slurry wall have had elevated levels (above groundwater cleanup levels) of ethyl benzene and xylene. TW-6 had 0.201 mg/l xylene in September and TW-7 had 0.319 mg/l xylene. Concentrations of groundwater in the surface water, which is now overflowing the slurry wall on the east side into the wetland, were non-detect for TAH in July and September 2017, as were surface water samples collected between the slurry wall and the wetlands. TW-13, which is outside of the slurry wall and down gradient from treated soils had 0.256 mg/l in the groundwater. Monitoring well W-1P which is a monitoring well adjacent to the surface water and a surface water compliance point had xylene at 0.598 mg/l, TAH at 0.601 and TAqH at 0.602. The air sparge system on the west side slurry wall has been off since 2016. Monitoring well TW-2 and TW-3 have elevated levels of ethyl benzene and xylene. In 2017 well TW-3 was sampled in April (xylene 27.9 mg/l), July (xylene 20.8 mg/l) and September (xylene 0.347 mg/l). Peter Campbell
5/10/2018 Document, Report, or Work plan Review - other Reviewed the Addendum to 2017 GW and Wetland Monitoring WP Five new wetland surface water sample locations added (W-4, W-5, W-6, W-7 and W-8) down gradient from the slurry wall. Two ponded surface water sample locations were added inside of the slurry wall at the southeastern end of the slurry wall (PSW1 and PSW-2) to measure water quality overtopping the slurry wall. Peter Campbell
6/19/2018 Document, Report, or Work plan Review - other Review and approve the 2018 Addendum to the 2017 Groundwater and Wetland Monitoring Work Plan. Peter Campbell
6/19/2018 Document, Report, or Work plan Review - other Review and approve the 2018 Remediation Work Plan. Peter Campbell
8/2/2018 Document, Report, or Work plan Review - other Letter to Chevron re: 2017 Annual Groundwater and Wetland Monitoring Report. Letter corrects the cleanup level for wetland well W-1P as the as the Alaska Water Quality Standard of TAH and TAqH. Letter states that water leaving the treatment cell must meat groundwater cleanup standards. Peter Campbell
3/13/2019 Meeting or Teleconference Held Meet with Chevron and consultant to discuss results of 2018 work. Peter Campbell
6/13/2019 Meeting or Teleconference Held Meeting held with Chevron, BLM, USFWS, ADEC and a new consultant to discuss outstanding issues. 1:Surface water quality, ground water impacts and residual soil impacts on the eastern side of the site, outside of the slurry wall. 2: Water quality from the interior of the slurry wall. 3: Air sparge operation and water quality on the west side of the site in the "bathtub". 4: What will site closure look like? Fate of slurry wall and seeding of the site? Peter Campbell
9/19/2019 Document, Report, or Work plan Review - other Review and approve the 2019 Site Investigation and Monitoring Work Plans. Plan covers surface and ground water sampling. Repair and operation of the air sparge system. Removal of surplus equipment. There has been a change of consultants on the site so the plan calls for a comprehensive evaluation of data, the identification of data gaps, and a plan to develop remedial alternatives and a recommended approach to site closure. Peter Campbell
10/25/2019 Document, Report, or Work plan Review - other Review the 2018 Remediation Program report which covered the installation of monitoring wells at the western side of the treatment cell, the installation of 19 piezometers in the eastern wetland, and sampling of site monitoring wells and surface water. Piezometers installed in the wetlands east of the site are impacted above cleanup levels and did not define the north and south extent of impact. There are unusual benzene impacts in the central area of piezometers. Surface water quality as measured in well WP-1 is improving with time, but still above cleanup levels for TAH and TAqH. The interior landfarm monitoring wells show a declining trend in contaminant levels, approaching cleanup goals. The air sparge system under the roadway is in operation. Peter Campbell
12/11/2019 Meeting or Teleconference Held Meeting held with Chevron, their consultant, USFWS, BLM and ADEC. This was a strategy session to discuss the path forward for site closure. Remaining issues include the fate and duration of operation for the air sparging system on the west side of the site in the roadway area. The fate of the slurry wall surrounding the landfarm. One topic of discussion was to remove a 200 foot section of the eastern slurry wall and replace it with permeable reactive barrier. Chevron was not prepared to discuss surface water contamination and wetland impacts at the western side of the site. The regulatory agencies agreed that this was a high priority and that other site closure issues were secondary to resolving surface water impacts. Peter Campbell
3/23/2020 Update or Other Action Due to the pandemic and travel restrictions, the wetland field investigation scheduled for this spring has been postponed. Site conditions require frozen ground access, so drilling will be delayed till at least late fall. Peter Campbell
6/22/2020 Document, Report, or Work plan Review - other Review and approve the Work Plan for 2020 Activities with no modifications. Peter Campbell
6/26/2020 Document, Report, or Work plan Review - other Receive the groundwater treatment system report for the 2nd 1/4 of 2020. The system remains shut down. Peter Campbell
7/29/2020 Document, Report, or Work plan Review - other Review the 2019 Swanson River P&S Yard Annual Report. 2019 was a very dry year, which affected water levels in many of the wells and piezometers at the site. Many of the piezometers in the eastern wetlands were dry and not able to be sampled. Air sparge operations are continuing in the western site under the road bed where xylene concentrations around TW-3 remain elevated. Peter Campbell
12/17/2020 Meeting or Teleconference Held Meeting with consultant and Chevron to discuss a summary of field work and what a work plan will look like for 2021. New wells were installed within the slurry wall with good water quality results. The wetland delineation of the xylene plume was incomplete due to the extent of the plume. Drilling and delineation of the plume will continue in the spring. Peter Campbell
3/8/2021 Meeting or Teleconference Held Meeting with new Chevron project manager to discuss work plans and site status. Peter Campbell
3/8/2021 Meeting or Teleconference Held Meeting with new Chevron project manager to discuss work plans and site status. Peter Campbell
6/29/2021 Document, Report, or Work plan Review - other ADEC 2021 Work Plan Approval Peter Campbell
8/11/2021 Document, Report, or Work plan Review - other Review the 2020 report. Peat wetland soils downgradient of the landfarm area have been impacted by xylenes. Groundwater discharges to surface water, impacting wetland surface water. Previous investigations have failed to investigate mineral soils below the peat. ADEC has requested a modification of the 2021 work plan drilling to include an investigation of these deeper soils. Peter Campbell
9/24/2021 Document, Report, or Work plan Review - other Analytical testing indicates that the air sparge system has been effective in reducing xylene levels in the western containment area. Xylene levels along the north half of the containment area (TW-1 and TW-2) appear to have been effectively remediated to levels below the cleanup level. TW-3 continues to show xylene levels above the cleanup level. A review of the analytical data indicates that the contamination within the landfarm continues to attenuate and the air sparge system appears to be effective within the air sparge area. Surface water sampling in the wetlands area continues to show elevated levels of xylene. The analytical data from the soil sampling in the landfarm containment indicates that soil concentrations are below cleanup levels. Dissolved concentrations of xylenes in groundwater samples exceeded the OBC cleanup level in wells. The analytical data from the soil sampling in the wetlands area indicates detectable concentrations of ethylbenzene and xylene. Ethylbenzene concentrations ranged from ND to a maximum concentration of 98.2 mg/kg at BH-11. Xylene concentrations ranged from ND to 829 mg/kg at BH-23. Additional sampling will be conducted in 2021 to further delineate the lateral extent of soil impacts in the wetlands area east of the landfarm. Peter Campbell
10/26/2021 Document, Report, or Work plan Review - other Review and approve Amendment #1 to the 2021 work plan requested by ADEC. Primary concern was sampling deeper in the subsurface on the eastern edge of the wetland plume to determine if xylene may have migrated vertically and moved under the silt. Peter Campbell
7/18/2022 Document, Report, or Work plan Review - other Review 2022 work plan which includes the operation of the western air sparge system, annual monitoring of wells within the slurry wall, wetland borings and surface water sampling. Wetlands characterization work is being conducted to assess the extent of impacts to areas east of the slurry wall and west of the surface water. Peter Campbell
5/26/2023 Offsite Soil or Groundwater Disposal Approved Approval to transfer and dispose of 15 gallons of investigation derived waste soil to U.S. Ecology. Peter Campbell
9/1/2023 Update or Other Action Receive the groundwater treatment system report for the 3rd 1/4 of 2023. The system remains shut down. Peter Campbell
12/27/2023 Update or Other Action Receive the groundwater treatment system report for the 4th 1/4 of 2023. The system remains shut down. Peter Campbell

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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