Site Report: Riviera Terrace

Site Name:	Riviera Terrace
Address:	3307 Boniface Parkway, Anchorage, AK 99504
File Number:	2100.38.409
Hazard ID:	4078
Status:	Cleanup Complete - Institutional Controls
Staff:	IC Unit, 9074655229 dec.icunit@alaska.gov
Latitude:	61.189167
Longitude:	-149.773333
Horizontal Datum:	WGS84

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

Widespread soil and groundwater contamination at the site resulted from releases from an underground piped fuel oil storage and distribution system that included a 25,000-gallon underground storage tank formerly located in the northeast corner of the 29.5-acre mobile home park property. The heating fuel system was reportedly installed in the late 1960s to early 1970s, with heating oil from the main 25,000-gallon tank piped to individual mobile homes. The site includes portions of two residential lots north of the northeast area of the property. Solvent contamination was documented in near-surface soil adjacent to the garage door of the mobile home park maintenance shop.

Action Information

Action Date	Action	Description	DEC Staff
9/30/1985	Update or Other Action	Report to ADEC by Mgr. of Riviera Terrace noting that "This is an old spill, perhaps as much as 20 years old". Suspect oil tank spill at Space #64 adjacent to Chester Creek. "Old fuel spill adjacent to Chester Crk. Slight sheen washing into crk during high water". Crowley Services conducted cleanup by trenching and using sorbents. (Note that this report is an appendix to the Phase II Report dated 12/20/2004).	Eileen Olson
10/2/1985	Update or Other Action	Date of Crowley Services cleanup report rec'd by the Dept. on October 4, 1985. Release described as a "stove oil seepage problem from an out-of-service line draining into the nearby creek bank. NOTE THAT THIS REPORT IS AN APPENDIX TO THE PHASE II REPORT dated 12/20/2004.	Eileen Olson
5/24/2004	Update or Other Action	DEC received a fax on May 24, 2004 from environmental consultant TERRASAT that included a copy of a 1992 ADEC letter documenting that the on-site water well was sampled for VOCs, and that the well was in compliance. Also attached was a copy of the 1998 Annual Drinking Water Quality report for the property that also showed that the water well was in compliance for VOCs.	Eileen Olson
6/4/2004	Update or Other Action	Date of report "Phase I Environmental Site Assessment for Riviera Terrace Trailer Court, Anchorage, Alaska" dated June 4, 2004 and prepared by TERRASAT Inc.(Note that this report was submitted as an appendix to the Phase II report dated 12/20/2004).	Eileen Olson
12/20/2004	Update or Other Action	Date of "Phase II Environmental Site Assessment, Riviera Terrace Trailer Court, Anchorage, Alaska" dated December 20, 2004 and prepared by TERRASAT Inc. ADEC rec'd this report on January 24, 2005. The report includes the Phase I and 1985 spill reports in the appendices.	Eileen Olson
1/24/2005	Meeting or Teleconference Held	Staff met with Spinell Homes representative and environmental consultant. During meeting consultant submitted a cover letter from owner notifying DEC of investigation results (that is, that contamination by petroleum hydrocarbon was found); submitted phase I and II environmental site assessment reports respectively dated June 4, 2004 and December 20, 2004, and submitted an affidavit from a person with personal knowledge of the fuel system and environmental history of the property.	Eileen Olson
3/7/2005	Site Added to Database	DRO.	Sarah Cunningham
3/11/2005	GIS Position Updated	TopoZone Pro. NAD27.	Sarah Cunningham
6/22/2006	Offsite Soil or Groundwater Disposal Approved	Approved request dated 6/21/2006 to transport soil to Alaska Soil Recycling for thermal treatment and approved post-treatment sampling for BTEX and DRO.	Eileen Olson
7/20/2006	Update or Other Action	Rec'd plan dated 7/17/2006.	Eileen Olson
7/31/2006	Update or Other Action	Approved "Workplan, Remediation Activities in Identified Contaminated Areas, Riviera Trailer Park, Anchorage, Alaska" dated July 17, 2006. Consultant BGES proposed conducting two phases of field work to include removing contamination and sources of contamination in two impacted areas of the site, and to install four monitoring wells in the shop area. As part of the work a 200-foot long section of abandoned fuel pipeline in the shop building will be investigated for leaks and removed. BGES also proposes to install prepacked monitoring wells using a backhoe, and to sample the wells after purging three well volumes but otherwise without developing the wells. The Department approved the well locations and had no objection to this type of installation and sampling methodology if the wells recharge adequately and otherwise function and if the soil that is excavated to install the wells is used to backfill the excavations. ADEC also requested an evaluation of the status of on-site drinking water wells and comments on the recommendations of the previous consultant.	Eileen Olson
12/15/2006	Site Visit	Site visit by staff: Consultant reports that contaminaton removed successfully in the southeastern/southcentral portion of the large tank area excavation and still plans to drill several soil borings to the southwest and west of the excavation. In addition, one or two of the borings will be completed as monitoring wells, one to the west of the excavation along the fence outside of a gated area, and a second well may be installed south or southwest of the first well. Still planned is the installation of monitoring wells in the northeastern corner of the yard and in the southern portion of the yard (to monitor groundwater flow at a point close to the creek), and in the central portion of the tank excavation, where contamination is expected to be the greatest. A well may also be installed near the northeast corner of the shop building. Depending upon the results of the soil borings, the feasibility of conducting additional excavation will be assessed and will depend on the lateral extent of remaining contamination, in consideration of the fact that contamination remains along the north wall of the excavation.	Eileen Olson
12/28/2006	Meeting or Teleconference Held	Meeting with consultant, owner and excavation contractor regarding site status and expectations with respect to evaluating adjacent properties that may be impacted by contamination originating on the Riviera Terrace site. To date approximately 2000 cubic yards of soil has been excavated and transported to ASR, with the highest levels of contaminants encountered in tank excavation soils at approximately 11,000 mg/Kg DRO and 0.363 mg/Kg benzene. Three newly installed wells have not been sampled yet.	Eileen Olson
2/15/2007	Update or Other Action	Update from consultant by telephone regarding site work. Work will resume Tuesday Feb. 20th and will entail placing borings on adjacent property.	Eileen Olson
2/21/2007	Meeting or Teleconference Held	Briefly met with consultant BGES who provided update on ongoing work. Two borings completed on adjacent property to north of large tank excavation. The closest boring is nine feet from the former center of the tank, and no contamination is evident in that boring based on field instruments and observations. Lab analysis is in progress. Additional borings are in progress, and will include borings along the buried fuel piping system.	Eileen Olson
2/27/2007	Update or Other Action	Pre-approval granted, with conditions, to transport soil that had yet to be excavated, to Anchorage Regional Landfill (ARL). Consultant had requested use of field screening using DEXIL PetroFlag for analysis. ARL would not accept that methodology in lieu of analysis. Conventional screening and analysis done.	Eileen Olson
3/28/2007	Update or Other Action	Referral of Informal Cost Recovery memorandum prepared by staff and sent to AG.	Eileen Olson
5/11/2007	Update or Other Action	Rec'd electronic copy of "Draft Report for Riviera Terrace Trailer Park". Consultant expects monitoring well sampling to be done May 14th and final report to be submitted week of 21st through 25th.	Eileen Olson
7/2/2007	Update or Other Action	ADEC review letter issued with subject line: Requirements for Conditional Site Closure status and review of "Remediation Activities in Identified Contaminated Areas, Riviera Trailer Park, Anchorage, Alaska" dated June 2007	Eileen Olson
7/6/2007	Meeting or Teleconference Held	ADEC staff met with owner and consultant regarding next steps to achieve conditional site closure status or to otherwise document site conditions in a manner that will demonstrate compliance with ADEC requirements. (10-11 a.m.)	Eileen Olson
8/28/2007	Update or Other Action	Rec'd "Groundwater Monitoring and Additional Site Evaluation Report" by BGES dated August 2007.	Eileen Olson
2/6/2008	Update or Other Action	Sent letter requesting groundwater monitoring of the six wells at the site.	Eileen Olson
4/14/2008	Update or Other Action	Received "Quarterly Groundwater Monitoring Report" dated April 2008.	Eileen Olson
5/30/2008	Exposure Tracking Model Ranking	Initial ranking with ETM completed.	Eileen Olson
6/6/2008	Exposure Tracking Model Ranking	A new updated ranking with ETM has been completed.	Eileen Olson
7/9/2008	Institutional Control Record Established	Institutional Control in the form of a deed notice required with conditional closure document, ROD and NEC dated 7/9/2008.	Eileen Olson
7/9/2008	Cleanup Complete Determination Issued	Issued conditional closure letter with attached Record of Decision and Notice of Environmental Contamination. Soil and groundwater contamination remains in site soil and groundwater at concentrations above applicable cleanup levels. Groundwater monitoring is required.	Eileen Olson
8/28/2008	Institutional Control Update	Received groundwater monitoring plan for two monitoring events. Plan includes decommissioning of MW5 as requested by ADEC. Approved plan with condition that only the first of the two sampling events is approved, with comments or approval to be provided regarding the second sampling event by Sept. 15, 2008.	Eileen Olson
10/1/2008	Institutional Control Update	ADEC received two page letter report 'Report of September 2008 Monitoring Well Sampling Results" showing DRO exceeded groundwater cleanup level in two wells and MW-5 weas decommissioned as required in the ROD on 9/16/2008.	Eileen Olson
2/4/2009	Institutional Control Update	Received report dated January 10, 2009 (mistakenly dated 2008) titled "Report of 2008 Monitoring Well Sampling Results" documenting monitoring well sampling events that took place on 9/10/08 and 12/12/08. The two monitoring events in late 2008 were required by the Record of Decision (ROD) for the site issued on July 9, 2008. Results show decreasing concentrations of DRO and benezene in groundwater sampled in 2007 and 2008. The report includes the request that groundwater monitoring be reduced from quarterly to twice-yearly.	Eileen Olson
4/7/2009	Institutional Control Update	ADEC letter sent reviewing "Report of 2008 Monitoring Well Sampling Results.” The review letter summarized the report findings and approved the request to reduce monitoring well sampling frequency from quarterly to twice-yearly sampling.	Eileen Olson
7/13/2009	Institutional Control Update	Received letter report "July 2009 Updated well Sampling Findings" dated 7/13/2009 that reports first bi-annual sampling event results for seven monitoring wells at the site.	Eileen Olson
11/11/2009	Institutional Control Update	Report "October 2009 Updated Well Sampling Findings" received, dated November 5, 2009, documenting the second bi-annual sampling event. Key findings: No analyte concentration was detected above the 18 AAC 75 regulatory limits at any well. Consultant recommends and requests that beginning in 2010 sampling be reduced to annual as provided in the ADEC Record of Decision for the site when DRO and Benzene concentrations show a continued trend of decline.	Eileen Olson
11/16/2009	Institutional Control Update	Review letter for report received 11/11/2009 approving request to reduce sampling from bi-annual to annual based on declining contaminant concentrations in accordance with conditions of Record of Decision.	Eileen Olson
9/8/2010	Institutional Control Periodic Reporting	DEC received letter report with subject line "June 2010 Updated Well Sampling Findings" prepared by TERRASAT and dated July 14, 2010. The email accompanying report submitted requests that the site be closed due to the continual declining trend in hydrocarbon concentrations.	Eileen Olson
10/23/2013	Document, Report, or Work plan Review - other	ADEC approved TERRASAT workplan dated October 21, 2013 for removing surface-stained soil, investigating an area outside of the onsite shop, and further evaluating hydrocarbon contamination discovered associated with an abandoned heating oil line west of trailer 120 at the edge of Riviera Way. In the past contamination west of trailer 120 was not fully delineated due to roadway conflicts. Work is scheduled for October 24th. Approval required that report includes photographs and field notes.Proposed work to be done in support of effort by owner to change status from closure with institutional controls (ICs) to closure without ICs.	Eileen Olson
10/23/2013	Offsite Soil or Groundwater Disposal Approved	Approved transport and thermal remediation of soil to be excavated based on site characterization results with post-treatment analysis for for DRO, RRO, GRO and BTEX.	Eileen Olson
12/9/2013	Update or Other Action	ADEC acknowledged to Alaska Soil Recycling (ASR) that soil received in October and November 2013 was to be comingled for treatment with responsibility for the soil transferred to ASR according to the bonding requirements of 18 AAC 75.365.	Eileen Olson
7/2/2014	Document, Report, or Work plan Review - other	ADEC conditionally approved workplan dated 6/27/2014 for investigation and cleanup of remaining contamination; objective is to achieve clean closure without institutional controls.	Eileen Olson
7/2/2014	Exposure Tracking Model Ranking	Initial ranking with ETM completed for source area id: 75052 name: Heating oil system releases	Eileen Olson
7/17/2014	Document, Report, or Work plan Review - other	ADEC conditionally approved the “Work Plan – Riviera Terrace Mobile Home Park – Shop Door Characterization” dated July 17, 2014.	Eileen Olson
7/30/2014	Site Visit	Site visit by Josh Barsis during sampling of area south of shop door.	Joshua Barsis
8/18/2014	Site Visit	Received call from consultant advising ADEC that a water main was hit the previous Friday (8/15/2014) while excavating exploratory trench 8b in a contaminated area, and oil-contaminated water was encountered. Also received a call from spill response (Spill Prevention and Emergency Response Program - PERP) staff Mark Sielaff who had been on site on 8/15/2014 in response to a complaint of strong diesel odors by a resident of a mobile home located immediately south of the excavation and water main break area. PERP staff followed up with photographs sent by email on 8/20/2014. Visited site and spoke to mobile home resident (space 13A); noticeable fuel odor outside of mobile home but owner noted odor was very strong when breeze was blowing his way.	Eileen Olson
8/20/2014	Update or Other Action	ADEC received spill notification form from consultant. Form states that Peterbuilt construction discovered contaminated soil on 8/9/14 and reported to the onsite manager. Consultant became aware of the contamination on 8/11/14. One characterization sample was taken at space 13A 6 ft. below ground surface for DRO/RRO and GRO/VOCs. Results were pending at the time of the notification.	Eileen Olson
10/15/2014	Document, Report, or Work plan Review - other	Reviewed and did not grant approval for incomplete report and plan dated Oct. 9, 2014 to transport remediated soil to Alaska Soil Recycling for thermal treatment. Requested that the stockpile, for which the contaminants of concern are PCE and other VOCs, be re-screened and resampled, and additional information including the biocell/stockpile dimensions provided.	Eileen Olson
10/21/2014	Document, Report, or Work plan Review - other	Reviewed three revised workplans dated and received October 20th and October 21st 2014; requested additional revisions, including locations of vent pipes within stockpile. Approved consultant request to sample only for VOCs since previous sampling confirmed that petroleum hydrocarbon levels are elevated, and the stockpiled soil will be thermally treated once it is confirmed that no VOCs exceed hazardous waste (RCRA) levels. Final plan version submitted after COB this date.	Eileen Olson
10/22/2014	Document, Report, or Work plan Review - other	Approved final revised workplan dated 10/22/2014. Provided response by email to questions regarding number of field screening samples required. Noted that all field screening samples need to be collected a minimum of 18 inches from the stockpile surface (sides or top). Requested that copies of field notes be provided to ADEC before sampling takes place.	Eileen Olson
11/10/2014	Exposure Tracking Model Ranking	Initial ranking with ETM completed for source area id: 79697 name: Surface releases south side of shop	Eileen Olson
11/12/2014	Document, Report, or Work plan Review - other	Approved Contaminated soil transport and treatment approval form dated Nov. 10, 2014 for 40 CY soil to be thermally treated at ASR; accompanied by "Request to Transport Soil from Shop Door Area Remediation Cell to ASR for Remediation - Second Request" dated Nov. 8,2014. The 'second request' is in reference to the initial request made in a plan dated Oct. 9th that was not approved. Pre-treatment of excavated soil stockpiled soil was done to remove low-level chlorinated solvents; stockpile sampling completed in late October 2014 had results of non-detect for chlorinated solvents.	Eileen Olson
12/30/2014	Update or Other Action	Acknowledged notification from Alaska Soil Recycling that total tonnage of petroleum impacted soil received from site between July 16 and October 31, 2014 was 6,337.81 tons. Total for year to date is 10,640.36 tons.	Eileen Olson
4/13/2015	Meeting or Teleconference Held	ADEC met with TERRASAT representatives to discuss work plan; work plan submitted during meeting.	Eileen Olson
4/21/2015	Document, Report, or Work plan Review - other	Partial approval of work plan dated 4/7/2015 rec'd during 4/13/2015 meeting titled "Work Plan for cleanup and On-site Bioremediation of Contaminated Soil and Characterization of Soil to Remain in the Ground...(etc.)". Approved placement of lined biopile a minimum of 100 feet from community water well, allowing construction of the biopile cell prior to completion of plan review.	Eileen Olson
4/23/2015	Update or Other Action	Consultant TERRASAT provided a utility map showing proposed utility corridors for Bella Vista Phase I construction (Bella Vista Phase I is north of Chester Creek). Excavation for utilities in areas where contamination has been documented during past investigations will be monitored by environmental consultant.	Eileen Olson
5/1/2015	Document, Report, or Work plan Review - other	ADEC review comments provided for work plan received April 7, 2015 with revisions made on this date including modifications to biopile design (no piping to be installed to aerate soil)and an increase in the estimated quantity of soil to be treated in the biocell to 1,400 cubic yards; . ADEC's comments included requests for additional information and plan modifications, and the reminder that ADEC cannot consider allowing contaminated soil to remain in place until ADEC has received and reviewed the site characterization report.	Eileen Olson
6/3/2015	Document, Report, or Work plan Review - other	ADEC approved plan to conduct site characterization and construct biopile (re plan dated April 7, 2015 and revised plan submitted May 7, 2015); plan revisions include using rototilling and an air knife to aerate the biopile; increasing volume of soil to be remediated from 1,230 cubic yards (CY)(est.) to 1,400 CY (est.); providing stockpile sampling details to ensure sampling throughout pile; and providing estimated contaminant concentrations in soil to be remediated (average DRO levels are 788 mg/kg with a maximum concentration of 2,160 mg/kg). Additional comments on plan to be provided concurrent with review of characterization report for work completed 2014 to date (report to be submitted within week).	Eileen Olson
6/16/2015	Update or Other Action	ADEC received "Site Characterization and Cleanup" report electronically, in part on 6/8/2015 with appendices provided 6/16/2015. Notified consultant that report will be reviewed before ADEC provides any additional comments on the plan received on 4/7/2015 with revisions made 5/7/2015.	Eileen Olson
6/3/2016	Site Visit	Site visit following report by consultant that contaminated soil encountered during excavation for roadbed within subdivision development that will replace mobile home park. No observable contamination at surface of ~20 cy soil stockpile.	Eileen Olson
5/16/2018	Institutional Control Update	ADEC approves of the decommissioning of all remaining groundwater monitoring wells (M2-M7) following an evaluation of groundwater analysis results. DRO, GRO, RRO, BTEX, and PAHs in groundwater are now all below groundwater clean up levels.	Kara Kusche
6/11/2018	Institutional Control Compliance Review	IC compliance review conducted. Staff changed from Eileen Olson/Kara Kusche to IC Unit. Closure/IC Details updated to reflect the conditions established in the 7/9/2008 Record of Decision. Reminder system set for future compliance reviews to occur every three years. It does not look like the NEC was ever recorded.	Kristin Thompson
10/25/2022	Document, Report, or Work plan Review - other	Reviewed a work plan which proposes sampling the soil included in a phytoremediation treatment cell, often referred to as a biopile. This biopile was constructed prior to the site being closed and is included in the institutional control requirements. There is about 1,070 cubic yards of soil in the biopile. The proposed sampling contaminants includes DRO, RRO, VOCs, and SVOCs. A sand auger will be used for sampling in order to protect the established vegetation and mycorrhizae. Screening samples will be collected at 18” deep, 3’, and about 5’ below top of the pile. The pile is about 6’ thick. Nine confirmation samples will be collected from the locations of the highest PID readings. This work plan is approved with a couple of minor modifications.	Evonne Reese

Action Date

Action

Description

DEC Staff

9/30/1985

Update or Other Action

Report to ADEC by Mgr. of Riviera Terrace noting that "This is an old spill, perhaps as much as 20 years old". Suspect oil tank spill at Space #64 adjacent to Chester Creek. "Old fuel spill adjacent to Chester Crk. Slight sheen washing into crk during high water". Crowley Services conducted cleanup by trenching and using sorbents. (Note that this report is an appendix to the Phase II Report dated 12/20/2004).

Eileen Olson

10/2/1985

Update or Other Action

Date of Crowley Services cleanup report rec'd by the Dept. on October 4, 1985. Release described as a "stove oil seepage problem from an out-of-service line draining into the nearby creek bank. NOTE THAT THIS REPORT IS AN APPENDIX TO THE PHASE II REPORT dated 12/20/2004.

Eileen Olson

5/24/2004

Update or Other Action

DEC received a fax on May 24, 2004 from environmental consultant TERRASAT that included a copy of a 1992 ADEC letter documenting that the on-site water well was sampled for VOCs, and that the well was in compliance. Also attached was a copy of the 1998 Annual Drinking Water Quality report for the property that also showed that the water well was in compliance for VOCs.

Eileen Olson

6/4/2004

Update or Other Action

Date of report "Phase I Environmental Site Assessment for Riviera Terrace Trailer Court, Anchorage, Alaska" dated June 4, 2004 and prepared by TERRASAT Inc.(Note that this report was submitted as an appendix to the Phase II report dated 12/20/2004).

Eileen Olson

12/20/2004

Update or Other Action

Date of "Phase II Environmental Site Assessment, Riviera Terrace Trailer Court, Anchorage, Alaska" dated December 20, 2004 and prepared by TERRASAT Inc. ADEC rec'd this report on January 24, 2005. The report includes the Phase I and 1985 spill reports in the appendices.

Eileen Olson

1/24/2005

Meeting or Teleconference Held

Staff met with Spinell Homes representative and environmental consultant. During meeting consultant submitted a cover letter from owner notifying DEC of investigation results (that is, that contamination by petroleum hydrocarbon was found); submitted phase I and II environmental site assessment reports respectively dated June 4, 2004 and December 20, 2004, and submitted an affidavit from a person with personal knowledge of the fuel system and environmental history of the property.

Eileen Olson

3/7/2005

Site Added to Database

DRO.

Sarah Cunningham

3/11/2005

GIS Position Updated

TopoZone Pro. NAD27.

Sarah Cunningham

6/22/2006

Offsite Soil or Groundwater Disposal Approved

Approved request dated 6/21/2006 to transport soil to Alaska Soil Recycling for thermal treatment and approved post-treatment sampling for BTEX and DRO.

Eileen Olson

7/20/2006

Update or Other Action

Rec'd plan dated 7/17/2006.

Eileen Olson

7/31/2006

Update or Other Action

Approved "Workplan, Remediation Activities in Identified Contaminated Areas, Riviera Trailer Park, Anchorage, Alaska" dated July 17, 2006. Consultant BGES proposed conducting two phases of field work to include removing contamination and sources of contamination in two impacted areas of the site, and to install four monitoring wells in the shop area. As part of the work a 200-foot long section of abandoned fuel pipeline in the shop building will be investigated for leaks and removed. BGES also proposes to install prepacked monitoring wells using a backhoe, and to sample the wells after purging three well volumes but otherwise without developing the wells. The Department approved the well locations and had no objection to this type of installation and sampling methodology if the wells recharge adequately and otherwise function and if the soil that is excavated to install the wells is used to backfill the excavations. ADEC also requested an evaluation of the status of on-site drinking water wells and comments on the recommendations of the previous consultant.

Eileen Olson

12/15/2006

Site Visit

Site visit by staff: Consultant reports that contaminaton removed successfully in the southeastern/southcentral portion of the large tank area excavation and still plans to drill several soil borings to the southwest and west of the excavation. In addition, one or two of the borings will be completed as monitoring wells, one to the west of the excavation along the fence outside of a gated area, and a second well may be installed south or southwest of the first well. Still planned is the installation of monitoring wells in the northeastern corner of the yard and in the southern portion of the yard (to monitor groundwater flow at a point close to the creek), and in the central portion of the tank excavation, where contamination is expected to be the greatest. A well may also be installed near the northeast corner of the shop building. Depending upon the results of the soil borings, the feasibility of conducting additional excavation will be assessed and will depend on the lateral extent of remaining contamination, in consideration of the fact that contamination remains along the north wall of the excavation.

Eileen Olson

12/28/2006

Meeting or Teleconference Held

Meeting with consultant, owner and excavation contractor regarding site status and expectations with respect to evaluating adjacent properties that may be impacted by contamination originating on the Riviera Terrace site. To date approximately 2000 cubic yards of soil has been excavated and transported to ASR, with the highest levels of contaminants encountered in tank excavation soils at approximately 11,000 mg/Kg DRO and 0.363 mg/Kg benzene. Three newly installed wells have not been sampled yet.

Eileen Olson

2/15/2007

Update or Other Action

Update from consultant by telephone regarding site work. Work will resume Tuesday Feb. 20th and will entail placing borings on adjacent property.

Eileen Olson

2/21/2007

Meeting or Teleconference Held

Briefly met with consultant BGES who provided update on ongoing work. Two borings completed on adjacent property to north of large tank excavation. The closest boring is nine feet from the former center of the tank, and no contamination is evident in that boring based on field instruments and observations. Lab analysis is in progress. Additional borings are in progress, and will include borings along the buried fuel piping system.

Eileen Olson

2/27/2007

Update or Other Action

Pre-approval granted, with conditions, to transport soil that had yet to be excavated, to Anchorage Regional Landfill (ARL). Consultant had requested use of field screening using DEXIL PetroFlag for analysis. ARL would not accept that methodology in lieu of analysis. Conventional screening and analysis done.

Eileen Olson

3/28/2007

Update or Other Action

Referral of Informal Cost Recovery memorandum prepared by staff and sent to AG.

Eileen Olson

5/11/2007

Update or Other Action

Rec'd electronic copy of "Draft Report for Riviera Terrace Trailer Park". Consultant expects monitoring well sampling to be done May 14th and final report to be submitted week of 21st through 25th.

Eileen Olson

7/2/2007

Update or Other Action

ADEC review letter issued with subject line: Requirements for Conditional Site Closure status and review of "Remediation Activities in Identified Contaminated Areas, Riviera Trailer Park, Anchorage, Alaska" dated June 2007

Eileen Olson

7/6/2007

Meeting or Teleconference Held

ADEC staff met with owner and consultant regarding next steps to achieve conditional site closure status or to otherwise document site conditions in a manner that will demonstrate compliance with ADEC requirements. (10-11 a.m.)

Eileen Olson

8/28/2007

Update or Other Action

Rec'd "Groundwater Monitoring and Additional Site Evaluation Report" by BGES dated August 2007.

Eileen Olson

2/6/2008

Update or Other Action

Sent letter requesting groundwater monitoring of the six wells at the site.

Eileen Olson

4/14/2008

Update or Other Action

Received "Quarterly Groundwater Monitoring Report" dated April 2008.

Eileen Olson

5/30/2008

Exposure Tracking Model Ranking

Initial ranking with ETM completed.

Eileen Olson

6/6/2008

Exposure Tracking Model Ranking

A new updated ranking with ETM has been completed.

Eileen Olson

7/9/2008

Institutional Control Record Established

Institutional Control in the form of a deed notice required with conditional closure document, ROD and NEC dated 7/9/2008.

Eileen Olson

7/9/2008

Cleanup Complete Determination Issued

Issued conditional closure letter with attached Record of Decision and Notice of Environmental Contamination. Soil and groundwater contamination remains in site soil and groundwater at concentrations above applicable cleanup levels. Groundwater monitoring is required.

Eileen Olson

8/28/2008

Institutional Control Update

Received groundwater monitoring plan for two monitoring events. Plan includes decommissioning of MW5 as requested by ADEC. Approved plan with condition that only the first of the two sampling events is approved, with comments or approval to be provided regarding the second sampling event by Sept. 15, 2008.

Eileen Olson

10/1/2008

Institutional Control Update

ADEC received two page letter report 'Report of September 2008 Monitoring Well Sampling Results" showing DRO exceeded groundwater cleanup level in two wells and MW-5 weas decommissioned as required in the ROD on 9/16/2008.

Eileen Olson

2/4/2009

Institutional Control Update

Received report dated January 10, 2009 (mistakenly dated 2008) titled "Report of 2008 Monitoring Well Sampling Results" documenting monitoring well sampling events that took place on 9/10/08 and 12/12/08. The two monitoring events in late 2008 were required by the Record of Decision (ROD) for the site issued on July 9, 2008. Results show decreasing concentrations of DRO and benezene in groundwater sampled in 2007 and 2008. The report includes the request that groundwater monitoring be reduced from quarterly to twice-yearly.

Eileen Olson

4/7/2009

Institutional Control Update

ADEC letter sent reviewing "Report of 2008 Monitoring Well Sampling Results.” The review letter summarized the report findings and approved the request to reduce monitoring well sampling frequency from quarterly to twice-yearly sampling.

Eileen Olson

7/13/2009

Institutional Control Update

Received letter report "July 2009 Updated well Sampling Findings" dated 7/13/2009 that reports first bi-annual sampling event results for seven monitoring wells at the site.

Eileen Olson

11/11/2009

Institutional Control Update

Report "October 2009 Updated Well Sampling Findings" received, dated November 5, 2009, documenting the second bi-annual sampling event. Key findings: No analyte concentration was detected above the 18 AAC 75 regulatory limits at any well. Consultant recommends and requests that beginning in 2010 sampling be reduced to annual as provided in the ADEC Record of Decision for the site when DRO and Benzene concentrations show a continued trend of decline.

Eileen Olson

11/16/2009

Institutional Control Update

Review letter for report received 11/11/2009 approving request to reduce sampling from bi-annual to annual based on declining contaminant concentrations in accordance with conditions of Record of Decision.

Eileen Olson

9/8/2010

Institutional Control Periodic Reporting

DEC received letter report with subject line "June 2010 Updated Well Sampling Findings" prepared by TERRASAT and dated July 14, 2010. The email accompanying report submitted requests that the site be closed due to the continual declining trend in hydrocarbon concentrations.

Eileen Olson

10/23/2013

Document, Report, or Work plan Review - other

ADEC approved TERRASAT workplan dated October 21, 2013 for removing surface-stained soil, investigating an area outside of the onsite shop, and further evaluating hydrocarbon contamination discovered associated with an abandoned heating oil line west of trailer 120 at the edge of Riviera Way. In the past contamination west of trailer 120 was not fully delineated due to roadway conflicts. Work is scheduled for October 24th. Approval required that report includes photographs and field notes.Proposed work to be done in support of effort by owner to change status from closure with institutional controls (ICs) to closure without ICs.

Eileen Olson

10/23/2013

Offsite Soil or Groundwater Disposal Approved

Approved transport and thermal remediation of soil to be excavated based on site characterization results with post-treatment analysis for for DRO, RRO, GRO and BTEX.

Eileen Olson

12/9/2013

Update or Other Action

ADEC acknowledged to Alaska Soil Recycling (ASR) that soil received in October and November 2013 was to be comingled for treatment with responsibility for the soil transferred to ASR according to the bonding requirements of 18 AAC 75.365.

Eileen Olson

7/2/2014

Document, Report, or Work plan Review - other

ADEC conditionally approved workplan dated 6/27/2014 for investigation and cleanup of remaining contamination; objective is to achieve clean closure without institutional controls.

Eileen Olson

7/2/2014

Exposure Tracking Model Ranking

Initial ranking with ETM completed for source area id: 75052 name: Heating oil system releases

Eileen Olson

7/17/2014

Document, Report, or Work plan Review - other

ADEC conditionally approved the “Work Plan – Riviera Terrace Mobile Home Park – Shop Door Characterization” dated July 17, 2014.

Eileen Olson

7/30/2014

Site Visit

Site visit by Josh Barsis during sampling of area south of shop door.

Joshua Barsis

8/18/2014

Site Visit

Received call from consultant advising ADEC that a water main was hit the previous Friday (8/15/2014) while excavating exploratory trench 8b in a contaminated area, and oil-contaminated water was encountered. Also received a call from spill response (Spill Prevention and Emergency Response Program - PERP) staff Mark Sielaff who had been on site on 8/15/2014 in response to a complaint of strong diesel odors by a resident of a mobile home located immediately south of the excavation and water main break area. PERP staff followed up with photographs sent by email on 8/20/2014. Visited site and spoke to mobile home resident (space 13A); noticeable fuel odor outside of mobile home but owner noted odor was very strong when breeze was blowing his way.

Eileen Olson

8/20/2014

Update or Other Action

ADEC received spill notification form from consultant. Form states that Peterbuilt construction discovered contaminated soil on 8/9/14 and reported to the onsite manager. Consultant became aware of the contamination on 8/11/14. One characterization sample was taken at space 13A 6 ft. below ground surface for DRO/RRO and GRO/VOCs. Results were pending at the time of the notification.

Eileen Olson

10/15/2014

Document, Report, or Work plan Review - other

Reviewed and did not grant approval for incomplete report and plan dated Oct. 9, 2014 to transport remediated soil to Alaska Soil Recycling for thermal treatment. Requested that the stockpile, for which the contaminants of concern are PCE and other VOCs, be re-screened and resampled, and additional information including the biocell/stockpile dimensions provided.

Eileen Olson

10/21/2014

Document, Report, or Work plan Review - other

Reviewed three revised workplans dated and received October 20th and October 21st 2014; requested additional revisions, including locations of vent pipes within stockpile. Approved consultant request to sample only for VOCs since previous sampling confirmed that petroleum hydrocarbon levels are elevated, and the stockpiled soil will be thermally treated once it is confirmed that no VOCs exceed hazardous waste (RCRA) levels. Final plan version submitted after COB this date.

Eileen Olson

10/22/2014

Document, Report, or Work plan Review - other

Approved final revised workplan dated 10/22/2014. Provided response by email to questions regarding number of field screening samples required. Noted that all field screening samples need to be collected a minimum of 18 inches from the stockpile surface (sides or top). Requested that copies of field notes be provided to ADEC before sampling takes place.

Eileen Olson

11/10/2014

Exposure Tracking Model Ranking

Initial ranking with ETM completed for source area id: 79697 name: Surface releases south side of shop

Eileen Olson

11/12/2014

Document, Report, or Work plan Review - other

Approved Contaminated soil transport and treatment approval form dated Nov. 10, 2014 for 40 CY soil to be thermally treated at ASR; accompanied by "Request to Transport Soil from Shop Door Area Remediation Cell to ASR for Remediation - Second Request" dated Nov. 8,2014. The 'second request' is in reference to the initial request made in a plan dated Oct. 9th that was not approved. Pre-treatment of excavated soil stockpiled soil was done to remove low-level chlorinated solvents; stockpile sampling completed in late October 2014 had results of non-detect for chlorinated solvents.

Eileen Olson

12/30/2014

Update or Other Action

Acknowledged notification from Alaska Soil Recycling that total tonnage of petroleum impacted soil received from site between July 16 and October 31, 2014 was 6,337.81 tons. Total for year to date is 10,640.36 tons.

Eileen Olson

4/13/2015

Meeting or Teleconference Held

ADEC met with TERRASAT representatives to discuss work plan; work plan submitted during meeting.

Eileen Olson

4/21/2015

Document, Report, or Work plan Review - other

Partial approval of work plan dated 4/7/2015 rec'd during 4/13/2015 meeting titled "Work Plan for cleanup and On-site Bioremediation of Contaminated Soil and Characterization of Soil to Remain in the Ground...(etc.)". Approved placement of lined biopile a minimum of 100 feet from community water well, allowing construction of the biopile cell prior to completion of plan review.

Eileen Olson

4/23/2015

Update or Other Action

Consultant TERRASAT provided a utility map showing proposed utility corridors for Bella Vista Phase I construction (Bella Vista Phase I is north of Chester Creek). Excavation for utilities in areas where contamination has been documented during past investigations will be monitored by environmental consultant.

Eileen Olson

5/1/2015

Document, Report, or Work plan Review - other

ADEC review comments provided for work plan received April 7, 2015 with revisions made on this date including modifications to biopile design (no piping to be installed to aerate soil)and an increase in the estimated quantity of soil to be treated in the biocell to 1,400 cubic yards; . ADEC's comments included requests for additional information and plan modifications, and the reminder that ADEC cannot consider allowing contaminated soil to remain in place until ADEC has received and reviewed the site characterization report.

Eileen Olson

6/3/2015

Document, Report, or Work plan Review - other

ADEC approved plan to conduct site characterization and construct biopile (re plan dated April 7, 2015 and revised plan submitted May 7, 2015); plan revisions include using rototilling and an air knife to aerate the biopile; increasing volume of soil to be remediated from 1,230 cubic yards (CY)(est.) to 1,400 CY (est.); providing stockpile sampling details to ensure sampling throughout pile; and providing estimated contaminant concentrations in soil to be remediated (average DRO levels are 788 mg/kg with a maximum concentration of 2,160 mg/kg). Additional comments on plan to be provided concurrent with review of characterization report for work completed 2014 to date (report to be submitted within week).

Eileen Olson

6/16/2015

Update or Other Action

ADEC received "Site Characterization and Cleanup" report electronically, in part on 6/8/2015 with appendices provided 6/16/2015. Notified consultant that report will be reviewed before ADEC provides any additional comments on the plan received on 4/7/2015 with revisions made 5/7/2015.

Eileen Olson

6/3/2016

Site Visit

Site visit following report by consultant that contaminated soil encountered during excavation for roadbed within subdivision development that will replace mobile home park. No observable contamination at surface of ~20 cy soil stockpile.

Eileen Olson

5/16/2018

Institutional Control Update

ADEC approves of the decommissioning of all remaining groundwater monitoring wells (M2-M7) following an evaluation of groundwater analysis results. DRO, GRO, RRO, BTEX, and PAHs in groundwater are now all below groundwater clean up levels.

Kara Kusche

6/11/2018

Institutional Control Compliance Review

IC compliance review conducted. Staff changed from Eileen Olson/Kara Kusche to IC Unit. Closure/IC Details updated to reflect the conditions established in the 7/9/2008 Record of Decision. Reminder system set for future compliance reviews to occur every three years. It does not look like the NEC was ever recorded.

Kristin Thompson

10/25/2022

Document, Report, or Work plan Review - other

Reviewed a work plan which proposes sampling the soil included in a phytoremediation treatment cell, often referred to as a biopile. This biopile was constructed prior to the site being closed and is included in the institutional control requirements. There is about 1,070 cubic yards of soil in the biopile. The proposed sampling contaminants includes DRO, RRO, VOCs, and SVOCs. A sand auger will be used for sampling in order to protect the established vegetation and mycorrhizae. Screening samples will be collected at 18” deep, 3’, and about 5’ below top of the pile. The pile is about 6’ thick. Nine confirmation samples will be collected from the locations of the highest PID readings. This work plan is approved with a couple of minor modifications.

Evonne Reese

Contaminant Information

Name	Level Description	Media	Comments
DRO	> Table C	Groundwater
DRO	Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation	Soil

Name

Level Description

Media

Comments

DRO

> Table C

Groundwater

DRO

Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation

Soil

Control Type

Type

Details

Requirements

Description	Details
Advance approval required to transport soil or groundwater off-site.	Standard condition.
Groundwater Use Restrictions	The installation of groundwater wells or use of groundwater, other than use of the existing on-site drinking water wells for any purpose is prohibited without the approval of ADEC.
New Construction Restrictions	If construction of buildings for human occupation is planned within 100 feet of the contaminated soil associated with the former 10,500-gallon UST, a workplan must be submitted to ADEC to evaluate the potential for indoor vapor intrusion.
When Contaminated Soil is Accessible, Remediation Should Occur	If the remaining contaminated soils become accessible, for example through removal of mobile homes or other structures, ADEC must be notified before work begins. Any future assessment and/or cleanup activities shall be conducted by a qualified environmental consultant in accordance with applicable ADEC regulations, including following a workplan previously approved of by ADEC.
Movement or use of contaminated material (including on site) in a manner that results in a violation of the water quality standards is prohibited (18 AAC 70)	Standard condition.
Other	The landowner shall report to ADEC every three (3) years to document any changes in land use or ownership at the site.

Description

Details

Advance approval required to transport soil or groundwater off-site.

Standard condition.

Groundwater Use Restrictions

The installation of groundwater wells or use of groundwater, other than use of the existing on-site drinking water wells for any purpose is prohibited without the approval of ADEC.

New Construction Restrictions

If construction of buildings for human occupation is planned within 100 feet of the contaminated soil associated with the former 10,500-gallon UST, a workplan must be submitted to ADEC to evaluate the potential for indoor vapor intrusion.

When Contaminated Soil is Accessible, Remediation Should Occur

If the remaining contaminated soils become accessible, for example through removal of mobile homes or other structures, ADEC must be notified before work begins. Any future assessment and/or cleanup activities shall be conducted by a qualified environmental consultant in accordance with applicable ADEC regulations, including following a workplan previously approved of by ADEC.

Movement or use of contaminated material (including on site) in a manner that results in a violation of the water quality standards is prohibited (18 AAC 70)

Standard condition.

Other

The landowner shall report to ADEC every three (3) years to document any changes in land use or ownership at the site.

Decision document - Cleanup Complete with ICs

No associated sites were found.

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Alaska Department of Environmental Conservation

Site Report: Riviera Terrace

Site Chronology

IC / Closure Details

Documents

Associated Sites

Problems/Comments

Action Information

Contaminant Information

Control Type

Requirements

Decision document - Cleanup Complete with ICs

Missing Location Data

State of Alaska Department of Environmental Conservation