Site Report: HEA Seldovia Power Plant

Site Name:	HEA Seldovia Power Plant
Address:	268 Winifred Avenue, Seldovia, AK 99663
File Number:	2331.38.002
Hazard ID:	4010
Status:	Cleanup Complete
Staff:	No Longer Assigned, 9074655229 dec.icunit@alaska.gov
Latitude:	59.439444
Longitude:	-151.713611
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.

Site Chronology
IC / Closure Details
Documents
Associated Sites

Problems/Comments

Petroleum hydrocarbon soil contamination observed during excavation of water line at site. Preliminary soil sampling indicates contamination as high as 32,900 ppm DRO. Further assessment planned for Spring of 2004. Interim removal action in 2005 reduced the remaining soil contaminant levels to below the ingestion & inhalation cleanup levels. The migration to GW pathway is the only remaining contaminant pathway, even though the GW is not used as a DW source. The site is served by the City of Seldovia public water system.

Action Information

Action Date	Action	Description	DEC Staff
1/7/2004	Site Characterization Report Approved	Reviewed 25 November 03, Soil Sampling Report.	Donald Seagren
1/8/2004	Site Added to Database	DRO contamination.	Alyce Hughey
1/8/2004	Site Ranked Using the AHRM	Initial ranking.	Donald Seagren
1/8/2004	GIS Position Updated	Using Figures 1 and 2 from a Site Characterization Work Plan from Environmental Management Inc., dated January 2004, in conjunction with TopoZone Pro and the KPB Parcel Lookup, entered the coordinates for this site. Metadata includes No Topo Basemap, TopoZone Pro Street Map, 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
1/8/2004	Update or Other Action	File number assigned and entered into Fileroom and CS Databases.	Alyce Hughey
1/12/2004	Update or Other Action	Reviewed Phase II draft work proposal. Provided comments to consultant for development of Phase II work plan.	Donald Seagren
1/14/2004	Update or Other Action	After discussion with Duane Parlow, HEA, standard cost recovery notification letter issued. LC requested form Juneau.	Donald Seagren
1/26/2004	Site Characterization Workplan Approved	Approved, with minor change, the Phase II Site Assessment Work Plan.	Donald Seagren
3/4/2004	Site Characterization Report Approved	Reviewed preliminary assessment letter. Approved leaving contaminated soils under slab so that HEA can continue with installation of generators. Corrective action plan to be developed. Final written decision to be issued upon review of final assessment report.	Donald Seagren
5/24/2004	Update or Other Action	MW appears to be installed into a perched aquifer. It has dropped 30" during recent dry spell. Will install additional MW's and a deep MW through bedrock to find true GW depth. Report to follow in July. HEA re-designed the power plant to fit the footprint of the pad to leave the contaminated soil available for remediation.	Donald Seagren
6/1/2004	Update or Other Action	Discussed with Larry Helgeson. Submit characterization report. Submit addendum when MWs installed. Stockpile excavated soils and backfill with clean gravel. Either test soils as excavated, or at a later time. Especially important for contaminated soils from under slab. Work plan to be submitted.	Donald Seagren
6/21/2004	Interim Removal Action Approved	Reviewed and approved work plan for trenching in potentially contaminated soils. Requested field screening and lab samples from trench through concrete slab to determine contaminant levels beneath slab.	Donald Seagren
6/28/2004	Site Characterization Report Approved	Reviewed initial site characterization report. Additional MWs to be drilled in August in conjunction with other planned site work. GW flow direction and site specific cleanup levels will be determined after completion of the additional work.	Donald Seagren
8/9/2004	Update or Other Action	Discussed proposed MW installations with Larry Helgeson. Also discussed Envirotech and that they are not currently approved as a soil treatment facility by the CS program. Envirotech is in the process of submitting a package for approval.	Donald Seagren
8/16/2004	Update or Other Action	Approved work plan to install additional MWs and dig test pits to further assess extent of contamination.	Donald Seagren
8/16/2004	Update or Other Action	Reviewed Soil & GW sampling report for additional site characterization. Soil under slab is contaminated with DRO above cleanup levels. Excavated soil stored on site in super sacks. GW contaminated slightly above Table C for DRO & Benzene. requested work plan for treatment of stockpiled contaminated soil.	Donald Seagren
12/2/2004	Interim Removal Action Approved	Approved interim removal action of approximately 200 cubic yards of highly contaminated soils containing DRO > 10,000 mg/kg. The contaminant plume is stable and not contaminating the groundwater. The groundwater is not used as a drinking water source. This interim removal action will reduce the risk to human health and the environment. Further corrective action measures and monitoring will be required to achieve full site closure.	Donald Seagren
5/18/2005	Update or Other Action	Reviewed and approved work plan for removal of highly contaminated soils and upgrade to MW 2 as interim corrective action measures.	Donald Seagren
10/4/2005	Update or Other Action	Reviewed the Interim Soil Removal and GW monitoring report dated 20 September 05. 115.11 tons of the most highly contaminated soil on the site was thermally remediated at ASR in Anchorage. MW2 was upgraded and all MWs sampled. The most highly contaminated soil was removed down to bed rock as an interim measure to reduce risk to human health and the environment. No contaminated GW, exceeding ADEC cleanup levels, was found in any of the MWs. LTM will continue.	Donald Seagren
11/3/2005	Institutional Control Record Established		Donald Seagren
11/3/2005	Conditional Closure Approved	The interim removal action reduced contaminant levels below the inhalation and ingestion levels. Based on site use, it was felt that these levels will be protective of human health and the environment. HEA is required to file a notice of environmental contamination with the recorders office. A long term GW monitoring plan will also be developed & implemented. Site closure will be approved when soil migration to groundwater cleanup levels in Tables B1 & B2 and GW cleanup levels in Table C are met throughout the site.	Donald Seagren
11/16/2005	Long Term Monitoring Established	Approved long term monitoring program. MW 1-3 will be sampled each event. MW-4 to be decommissioned. Semi annual monitoring events for the first two years or the program. The data will be reviewd at the end of 2 years and changed to annual if no evidence of contaminant migration is observed.	Donald Seagren
7/7/2006	Update or Other Action	Reviewed the monitoring report dated June 06. 2 MWs exceeded the cleanup level for DRO. However this result may be skewed due to a low recharge rate for these 2 MWs. Collecting the samples required multiple bailings, which stirred up bottom sediments. The samples were cloudy, not clear, indicating possible interference from the stirred up sediments. During the fall sampling event, low flow sampling techniques will be utilized. Duplicate filtered samples will be taken and analyzed if the low flow sampling does not appear to provide useable results. ADEC regulations require unfiltered samples. However by comparing the filtered with unfiltered sample results we will be able to determine the amount of interference, if any, attributable to the stirred up sediments.	Donald Seagren
12/4/2006	Update or Other Action	Reviewed 06 monitoring report.DRO below ADEC cleanup levels in October. DRO contamiantion decreased in all 3 wells from June to October. BTEX ND in October. Benzene was detected in June samples, but below ADEC clenaup levels. The water table had risen since the June sampling event, most likely the result of excessive amounts of rain in October. Next sampling event will be in 2007	Donald Seagren
4/12/2007	Exposure Tracking Model Ranking		Donald Seagren
7/11/2007	Update or Other Action	Reviewed monitoring report. MW2 was damaged and repaired but not sampled due to low recovery rate after purging. All parameters in MW1 & MW3 were ND. LTM to continue.	Donald Seagren
12/3/2007	Update or Other Action	Reviewd November 07 monitoring report. ll parameters below ADEC cleanup levels indicating that the remaining soil contamination is not migrating off site. The LTM program will continue. After consultation with the consultant for Homer Electric, the LTM may be revised.	Donald Seagren
1/15/2008	Update or Other Action	reviewed December 07 monitoring report. Based on the accumulated data showing that contamination is not migrating off-site, ADEC approved reducing the frequency of sampling from semi-annual to annual and eliminating MW3 from the sampling program.	Donald Seagren
6/12/2008	Update or Other Action	Site transferred from Don Seagren to Paul Horwath per Linda Nuechterlein.	Alyce Hughey
12/4/2008	Update or Other Action	Reviewed the Monitoring Well Sampling Report, dated November 2008 from Environmental Management Incorporated for Paul Horwath and provided him with a summary for his review and oversight. Site conditions remain stable. BETX showed undetected and DRO is detecting, but remains below the groundwater cleanup levels. At the time of the monitoring event, dewatering activities was being conducted for the new utility lines being placed down the center of Alder Street and Anderson Way. Future monitoring events is needed in order to depict the current site conditions.	Alyce Hughey
11/18/2009	Document, Report, or Work plan Review - other	Reviewed the Monitoring Well Sampling Report, dated September 2009 from Environmental Management Incorporated for Paul Horwath. Site conditions are remaining stable. All the analytes tested in MW-1 tested undetected during this monitoring event. MW-2 was not tested due to insufficient amount of water in the well to supply a sample. Monitoring wells MW-1 and MW-2 should continue to be sampled according to the current Long Term Groundwater Monitoring Plan. The redevelopment of MW-2 is recommended for some time during the spring of 2010.	Alyce Hughey
1/28/2011	Document, Report, or Work plan Review - other	Reviewed the Monitoring Well Sampling Report, dated December 2010, from Environmental Management Incorporated. During the October 10, 2010 groundwater sampling event taken from MW-1, laboratory analytical results detected DRO at 0.581 mg/L, which is below the groundwater cleanup levels. MW-2 was not tested, but was redeveloped. The water purged from the well had an orange discoloring to it. During the 2008, 2009, and 2010 samplings, MW-2 has produced orange discolored water from the well. It is being recommended that MW-2 be re-installed due to the insufficient amount of water historically and the discoloring of the groundwater.	Alyce Hughey
9/14/2011	Document, Report, or Work plan Review - other	Reviewed the Monitoring Well Sampling Report, dated August 2011, from Environmental Management Incorported. The June 20, 2011 groundwater sampling event detected DRO at 0.391 mg/L, which is below the groundwater cleanup levels. MW-2 was not tested because it was damaged. The no-purge HYDRA Sleeve sample collected from MW-1 was collected above the screened zone, and should have been collected within the screened zone of the well; therefore, the sample results may be slightly biased.	Alyce Hughey
12/28/2012	Document, Report, or Work plan Review - other	Reviewed the Monitoring Well Decommissioning, Installation and Sampling Report, dated October 2012, from environmental Management Incorporated. In July of 2012 monitoring wells MW-2, MW-3 and MW-4 were decommissioned. A replacement well (MW-2R) was installed to replace the damaged MW-2. Groundwater samples were collected from MW-1 and MW-2R with DRO at 0.453 mg/L and 1.2 mg/L and Benzene at 0.00052 mg/L and 0.00073 mg/L respectively, using a HydraSleeve.	Alyce Hughey
10/2/2013	Document, Report, or Work plan Review - other	Reviewed the Monitoring Well Sampling Report, HEA Gerald Willard Generation Power Plant, dated August 2013, prepared by Environmental Management Incorporated. On August 8, 2013 groundwater samples were collected from MW-1 with no analytes detected in the sample collected; however, the duplicate sample collected from MW-1 detected DRO at 0.494 mg/L. MW-2R was also sampled with detections of benzene at 0.000535 mg/L and DRO at 0.581 mg/L. A HydraSleeve groundwater sampler was used to collect the groundwater samples.	Alyce Hughey
10/7/2013	Exposure Tracking Model Ranking	Final site ranking, preparatory to removal of institutional control and long term monitoring, with ADEC's ETM completed for source area id: 74984 name: ast	Paul Horwath
10/11/2013	Institutional Control Record Removed	Following the completion of site cleanup actions performed at this site from 2003 to 2013, residual soil contamination remained in the surface and subsurface soil, but the concentrations do not exceed the ADEC Method Two, Table B2, Under 40 inch Zone, 'Ingestion' soil cleanup level for DRO. Long-term groundwater monitoring was performed from 2005 until 2013, until it was determined that contamination was not migrating, and concentrations have remained below the ADEC groundwater cleanup levels since 2006. ADEC has determined that residual contamination no longer poses an unacceptable risk to human health or the environment. Therefore, we are issuing this Cleanup Complete determination with the following conditions: 1. Any proposal to transport soil or groundwater off-site requires ADEC approval in accordance with 18 AAC 75.325(i). The excavation of soil on this property in the south/southwest and eastern portions of the property may expose contaminated soil requiring proper safety, management, and disposal practices. Any person(s) excavating soil or moving soil or groundwater from this property shall contact ADEC and shall provide for the proper handling, treatment, and disposal of any contaminated media encountered in accordance with all applicable ADEC regulations at that time. 2. The two remaining groundwater monitoring wells must now be properly decommissioned. This determination is in accordance with 18 AAC 75.380 and does not preclude ADEC from requiring additional assessment and/or cleanup action if future information indicates that this site may pose an unacceptable risk to human health or the environment. The Homer Electric Association remains liable for any additional assessment and/or cleanup action(s), should ADEC impose such a requirement.	Paul Horwath
10/11/2013	Long Term Monitoring Complete	Long-term groundwater monitoring was performed from 2005 until 2013, until it was determined that contamination was not migrating, and concentrations have remained below the ADEC groundwater cleanup levels since 2006. The two remaining groundwater monitoring wells MW-1 and MW-2R must now be properly decommissioned in accordance with ADEC's November 2011 Monitoring Well Guidance. A work plan which identifies proposed decommissioning procedures must be provided for ADEC review and approval, prior to implementation of those procedures.	Paul Horwath
11/5/2013	Update or Other Action	Paul Horwath approved for the decommissioning of two groundwater monitoring wells, MW-1 and MW-2R. The wells are planned for decommissioning on November 6, 2013.	Alyce Hughey
1/2/2014	Update or Other Action	On November 6, 2013, monitoring wells MW-1 and MW-2R were decommissioned according to the ADEC approved November 4, 2013 Monitoring Well Decommissioning Work Plan.	Alyce Hughey
2/17/2017	Site Characterization Workplan Approved	Issue conditional approval of a work plan for contaminated soil handling and disposal, to occur during construction excavation planned at this HEA facility during the 2017 field season.	Paul Horwath
8/28/2017	Update or Other Action	Reviewed a construction excavation project for conflicts with this closed site. Issue ADEC authorization to proceed with the work, based on condition that excavation of diesel contaminated soil must be reported to ADEC.	Paul Horwath
5/11/2018	Offsite Soil or Groundwater Disposal Approved	Approved the offsite transport and disposal of a waste soil stockpile, consisting of less than 10 cubic yards. No evidence of petroleum contamination was identified during the excavation of these soils. Soils were excavated from locations outside the boundaries of the "site".	Paul Horwath

Action Date

Action

Description

DEC Staff

1/7/2004

Site Characterization Report Approved

Reviewed 25 November 03, Soil Sampling Report.

Donald Seagren

1/8/2004

Site Added to Database

DRO contamination.

Alyce Hughey

1/8/2004

Site Ranked Using the AHRM

Initial ranking.

Donald Seagren

1/8/2004

GIS Position Updated

Using Figures 1 and 2 from a Site Characterization Work Plan from Environmental Management Inc., dated January 2004, in conjunction with TopoZone Pro and the KPB Parcel Lookup, entered the coordinates for this site. Metadata includes No Topo Basemap, TopoZone Pro Street Map, 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

1/8/2004

Update or Other Action

File number assigned and entered into Fileroom and CS Databases.

Alyce Hughey

1/12/2004

Update or Other Action

Reviewed Phase II draft work proposal. Provided comments to consultant for development of Phase II work plan.

Donald Seagren

1/14/2004

Update or Other Action

After discussion with Duane Parlow, HEA, standard cost recovery notification letter issued. LC requested form Juneau.

Donald Seagren

1/26/2004

Site Characterization Workplan Approved

Approved, with minor change, the Phase II Site Assessment Work Plan.

Donald Seagren

3/4/2004

Site Characterization Report Approved

Reviewed preliminary assessment letter. Approved leaving contaminated soils under slab so that HEA can continue with installation of generators. Corrective action plan to be developed. Final written decision to be issued upon review of final assessment report.

Donald Seagren

5/24/2004

Update or Other Action

MW appears to be installed into a perched aquifer. It has dropped 30" during recent dry spell. Will install additional MW's and a deep MW through bedrock to find true GW depth. Report to follow in July. HEA re-designed the power plant to fit the footprint of the pad to leave the contaminated soil available for remediation.

Donald Seagren

6/1/2004

Update or Other Action

Discussed with Larry Helgeson. Submit characterization report. Submit addendum when MWs installed. Stockpile excavated soils and backfill with clean gravel. Either test soils as excavated, or at a later time. Especially important for contaminated soils from under slab. Work plan to be submitted.

Donald Seagren

6/21/2004

Interim Removal Action Approved

Reviewed and approved work plan for trenching in potentially contaminated soils. Requested field screening and lab samples from trench through concrete slab to determine contaminant levels beneath slab.

Donald Seagren

6/28/2004

Site Characterization Report Approved

Reviewed initial site characterization report. Additional MWs to be drilled in August in conjunction with other planned site work. GW flow direction and site specific cleanup levels will be determined after completion of the additional work.

Donald Seagren

8/9/2004

Update or Other Action

Discussed proposed MW installations with Larry Helgeson. Also discussed Envirotech and that they are not currently approved as a soil treatment facility by the CS program. Envirotech is in the process of submitting a package for approval.

Donald Seagren

8/16/2004

Update or Other Action

Approved work plan to install additional MWs and dig test pits to further assess extent of contamination.

Donald Seagren

8/16/2004

Update or Other Action

Reviewed Soil & GW sampling report for additional site characterization. Soil under slab is contaminated with DRO above cleanup levels. Excavated soil stored on site in super sacks. GW contaminated slightly above Table C for DRO & Benzene. requested work plan for treatment of stockpiled contaminated soil.

Donald Seagren

12/2/2004

Interim Removal Action Approved

Approved interim removal action of approximately 200 cubic yards of highly contaminated soils containing DRO > 10,000 mg/kg. The contaminant plume is stable and not contaminating the groundwater. The groundwater is not used as a drinking water source. This interim removal action will reduce the risk to human health and the environment. Further corrective action measures and monitoring will be required to achieve full site closure.

Donald Seagren

5/18/2005

Update or Other Action

Reviewed and approved work plan for removal of highly contaminated soils and upgrade to MW 2 as interim corrective action measures.

Donald Seagren

10/4/2005

Update or Other Action

Reviewed the Interim Soil Removal and GW monitoring report dated 20 September 05. 115.11 tons of the most highly contaminated soil on the site was thermally remediated at ASR in Anchorage. MW2 was upgraded and all MWs sampled. The most highly contaminated soil was removed down to bed rock as an interim measure to reduce risk to human health and the environment. No contaminated GW, exceeding ADEC cleanup levels, was found in any of the MWs. LTM will continue.

Donald Seagren

11/3/2005

Institutional Control Record Established

Donald Seagren

11/3/2005

Conditional Closure Approved

The interim removal action reduced contaminant levels below the inhalation and ingestion levels. Based on site use, it was felt that these levels will be protective of human health and the environment. HEA is required to file a notice of environmental contamination with the recorders office. A long term GW monitoring plan will also be developed & implemented. Site closure will be approved when soil migration to groundwater cleanup levels in Tables B1 & B2 and GW cleanup levels in Table C are met throughout the site.

Donald Seagren

11/16/2005

Long Term Monitoring Established

Approved long term monitoring program. MW 1-3 will be sampled each event. MW-4 to be decommissioned. Semi annual monitoring events for the first two years or the program. The data will be reviewd at the end of 2 years and changed to annual if no evidence of contaminant migration is observed.

Donald Seagren

7/7/2006

Update or Other Action

Reviewed the monitoring report dated June 06. 2 MWs exceeded the cleanup level for DRO. However this result may be skewed due to a low recharge rate for these 2 MWs. Collecting the samples required multiple bailings, which stirred up bottom sediments. The samples were cloudy, not clear, indicating possible interference from the stirred up sediments. During the fall sampling event, low flow sampling techniques will be utilized. Duplicate filtered samples will be taken and analyzed if the low flow sampling does not appear to provide useable results. ADEC regulations require unfiltered samples. However by comparing the filtered with unfiltered sample results we will be able to determine the amount of interference, if any, attributable to the stirred up sediments.

Donald Seagren

12/4/2006

Update or Other Action

Reviewed 06 monitoring report.DRO below ADEC cleanup levels in October. DRO contamiantion decreased in all 3 wells from June to October. BTEX ND in October. Benzene was detected in June samples, but below ADEC clenaup levels. The water table had risen since the June sampling event, most likely the result of excessive amounts of rain in October. Next sampling event will be in 2007

Donald Seagren

4/12/2007

Exposure Tracking Model Ranking

Donald Seagren

7/11/2007

Update or Other Action

Reviewed monitoring report. MW2 was damaged and repaired but not sampled due to low recovery rate after purging. All parameters in MW1 & MW3 were ND. LTM to continue.

Donald Seagren

12/3/2007

Update or Other Action

Reviewd November 07 monitoring report. ll parameters below ADEC cleanup levels indicating that the remaining soil contamination is not migrating off site. The LTM program will continue. After consultation with the consultant for Homer Electric, the LTM may be revised.

Donald Seagren

1/15/2008

Update or Other Action

reviewed December 07 monitoring report. Based on the accumulated data showing that contamination is not migrating off-site, ADEC approved reducing the frequency of sampling from semi-annual to annual and eliminating MW3 from the sampling program.

Donald Seagren

6/12/2008

Update or Other Action

Site transferred from Don Seagren to Paul Horwath per Linda Nuechterlein.

Alyce Hughey

12/4/2008

Update or Other Action

Reviewed the Monitoring Well Sampling Report, dated November 2008 from Environmental Management Incorporated for Paul Horwath and provided him with a summary for his review and oversight. Site conditions remain stable. BETX showed undetected and DRO is detecting, but remains below the groundwater cleanup levels. At the time of the monitoring event, dewatering activities was being conducted for the new utility lines being placed down the center of Alder Street and Anderson Way. Future monitoring events is needed in order to depict the current site conditions.

Alyce Hughey

11/18/2009