# OPERATIONS AND MAINTENANCE PLAN

O’CONNOR COMPANY SUPERFUND SITE AUGUSTA, MAINE



# 222350 Central Maine Power Company October 2009 

# woodardcurran.com

CO MMITMENT & INTE G RITY DRIVE RE SU LT SCentral Maine Power (222350.00) i October 27, 2009 Operations and Maintenance Plan Woodard & Curran 

## TABLE OF CONTENTS

SECTION PAGE NO.



### 1. INTRODUCT ION................................................................................................................... ............. 1-1
1.1 Site Setting ................................................................................................................... ..................1-1 1.2 History of Contaminatio n and Remedi ation ....................................................................................1-2 1.3 Current Co nditions............................................................................................................. .............1-5 1.4 Purpose of the O perations and Main tenance Plan.........................................................................1-7


### 2. RECORD KEEPING AND REPORTING............................................................................................ 2-1

3. NORMAL OPERATIONS AND MAINTE NANCE ............................................................................... 3-1
3.1 Inspections .................................................................................................................... .................3-1 3.2 Soil Sampling .................................................................................................................. ...............3-1 3.3 Routine Maintenance............................................................................................................ ..........3-2 3.4 Repairs ...........................................................................................................................................3-4


### 4. ASSESSMENT OF SITE CONDITIONS............................................................................................. 4-1

5. OPERATIONAL SA FETY PLAN........................................................................................................ 5-1

6. GLOSSARY OF ACRONYMS........................................................................................................... . 6-1

7. REFERENC E LIST................................................................................................................. ............ 7-1



## LIST OF FIGURES

FIGURE PAGE NO. Figure 1 Site Loca tion Map.............................................................................................................. ............ 1-3 Figure 2 Site Fe atures .................................................................................................................. ............... 1-4 Figure 3 Revised Si te Plan .............................................................................................................. ............ 1-6 Figure 4 Designated Area Soil Sa mpling Locations .................................................................................... 3-3



## APPENDICES

Appendix A: 2009 Site Photographs Appendix B: O’Connor Inspection Checklist Appendix C: Monitoring Well Decommissioning ProceduresCentral Maine Power (222350.00) 1-1 October 27, 2009 Operations and Maintenance Plan Woodard & Curran 

## 1. INTRODUCTION

1.1 SITE SETTING
The F. O’Connor Site (Site) consists of approximately 23 acres within a 28-acre property owned by Central Maine Power Company (CMP) and is located on U.S. Route 17 approximately three miles east of the Kennebec River in Augusta, Maine. The location of the property is shown on Figure 1 and the Site features are shown on Figure 2. The surrounding area is generally rural. The property is bordered on the east and southeast by Riggs Brook, a small northerly flowing tributary of the Kennebec River, on the north and west by woodlands, and on the south by Route 17. The property south of Route 17 is generally wooded. A residence abuts the CMP property along its western boundary. The land at the Site was used as farmland un til the 1950s when the F. O’Connor Company established a salvage yard and transformer recycling operation at the Site. The Maine De partment of Environmental Protection (MEDEP)-designated Hazardous Substance Site consists of the same 23 acres within the 28-acre property.

The Site is located on a ridge that transects the Site in a generally northeast-southwest direction. An access road splits the Site from southwest to northeast. North and west of the road, the Site is relatively level, with a low swampy area known as the Upland Marsh. East and south of the road the topography slopes sharply toward Riggs Brook, with a change in elevation of approximately 50 feet. Three water bodies are located on the Site, all of which were created by operations of the F. O’Connor Company and later reconstructed as a part of the source control work. The approximately 2-acre Upland Marsh drains to a channel th at flows to the Upper and Lower Lagoons and on to the Riggs Brook wetlands. Figure 2 shows these features and site topography.
The overburden soils at the Site generally consist, from surf ace to depth, of glacial marine silts and clays, glacial till, and bedrock. The clay tends to be absent only in areas of shallow bedrock. Bedrock drilling completed during site investigations indicated mostly competent rock with very few recognizable fractures. Bedrock outcrops are found in the areas of transformer work area (TWA) I and III (see Figure 2).

The principal groundwater migration pathwa y on the Site is a discrete zone within the till along the top of the bedrock surface. Groundwater flow from the Upland Marsh (a la rge recharge basin) is confined and channeled through the bedrock trough in the bedrock saddle centered immediately northeast of the Upper Lagoon. The bedrock flow regime has very little water in storage. The vertical permeability of the bedrock is believed to be very low, creating a “quasi” perched condition of the overburden groundwater flow system. At the southeastern end of the Site, near Riggs Brook, the potentiometric surface of the bedrock groundwate r is above the ground surface. MW-106B in this area is a free-flowing artesian well.Central Maine Power (222350.00) 1-2 October 27, 2009 Operations and Maintenance Plan Woodard & Curran 

### 1.2 HISTORY OF CONTAMINATION AND REMEDIATION
The F. O’Connor Company operated a sa lvage yard for the dismantling and recycl ing of electrical transformers and capacitors on the Site from the early 1950s until the late 1970s. This resulted in drippage and spillage of oil to the ground, principally in the vicinity of the TWAs. Soil and groundwater contamination primarily consisted of polychlorinated biphenyls (PCBs) with some volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs), and inorganics. Potential sources of contamination that were identified on the Site included three TWAs, scrap piles, oil storage tanks, and two lagoons in stalled to help control oil migration from the Site (see Figure 2).

In September 1991, CMP, an identified potentially responsible party (PRP) at the Site, signed a Consent Order with the United States Environmental Protection Agency (USEPA) to undertake an investigation and remediation of the Site. CMP also acquired ownership of the Si te from the F. O’Con nor Company in 1992.

The Remedy for the Site was initially described in the Record of Decision (ROD) (USEPA, 9/89) and Consent Decree (USEPA, 9/3/91), and was modified in the Explanation of Significant Differences (ESD) (USEPA, 7/20/94). The Remedy included two components, Source Control (SC) and Management of Migration (MOM). On April 26, 1996 USEPA separated the Riggs Brook component of the MOM by creating a third operable unit (OU-3). The Site was therefore broken down into three operable units:

• OU-1 Source Control

• OU-2 Management of Migration

• OU-3 Riggs Brook2500 0 2500 5000



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# ---- ------ BAR SCALE 1" = 100' CHECK GRAPHIC SCALE BEFORE USING DAlE: OCIDBER 2009 SCALE: AS NOTED FIGURE2Central Maine Power (222350.00) 1-5 October 27, 2009 Operations and Maintenance Plan Woodard & Curran The Source Control Remedial Action (SCRA) at OU-1 was completed in November 1997, and included the excavation and off-site disposal of 20,000 tons of soil and sediment with PCB concentrations greater than 10 parts per million (ppm). Another 3,000 tons, with PCB levels less than 10 ppm, were consolidated on site in one three- to four-acre area, identified as the Designated Area (See Figure 2). Approximately 24,000 cubic yards of clean soil (PCBs less than 1 ppm) were imported to the Site to restore the excavated area to approximate the original grade and to provide a 12-inch soil cover over the entire Designated Area. Site restoration also included re-establishing drainage patterns to achieve discharges to Riggs Brook similar to those that existed prior to remediation of the Site, restoration of on-site wetlands, including the establishment of compensatory wetlands, and removal of the perimeter fence (W&C, 1998).

The Amendment to the Consent Decree, September 2003 and its Appendix II Remedial Design/Remedial Action (RD/RA) 2003 Statement of Work (SOW) (USEPA, 9/18/03) re quired that the 25-sided Designated Area be simplified to a 10-sided area. This 10-sided Designated Area has been surveyed and permanent markers have been placed on site to make the Designated Area easier to recognize while in the field. The current site topography following the SCRA as well as the Revised 10-sided Designated Area is shown on Figure 2.

The MOM operable unit (OU-2) addresses groundwater quality and the potential migration of contaminants on the Site. Groundwater at the Site has been monitored since 1996, and a number of monitoring wells on the Site continue to be sampled for groundwater quality. The 1989 ROD was amended in September 2002 following an evaluation of the technical practicability of restoring the groundwater within a reasonable time period. The ROD Amendment (USEPA, 9/02) changed the remedy for groundwater and designated a Technical Impracticability (TI) zone for OU-2. The TI zone for OU-2 is shown on Figure 3.

The Riggs Brook operable unit (OU-3) addresses sediment and biota quality along Riggs Brook. In accordance with the 1989 ROD and the 1991 SOW, ten years (1996-2005) of annual sediment sampling have been completed and biota sampling, also required by the ROD, was completed in 1997 and 2000.



### 1.3 CURRENT CONDITIONS
Based on the five-year site review completed in September 2007, the Site remains a mix of forest and open field, bordering the Riggs Brook wetland, and unchanged since the 2002 five-year review. The open fields encompass the formerly contaminated areas and the three reconstructe d wetlands on the Site (Upland Marsh, Upper Lagoon, and Lower Lagoon). The Site is not actively used by CMP. Surrounding land uses include low-density residential, light agricultural, fields, and forest.

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FREE PRODUCT OIL MONITORING LOCATION

LONG TERM MONITORING LOCATION

DECOMMISSIONED MONITORING WELLS

DESIGNATED AREA MARKERS

- SURVEYED BY EPRO 2002

- ·- ·-·-·-·- REVISED 10-SIDED DESIGNATED AREA

SUPERFUND SITE BOUNDARY**~** TOPOGRAPHIC INFORMATION IS APPROXIMATE. TOPOGRAPHIC INFORMATION HAS BEEN COMPILED FROM ORIGINAL SITE PLAN AND 1999 SURVEY OF REMEDIATED AREA



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FIGURE3Central Maine Power (222350.00) 1-7 October 27, 2009 Operations and Maintenance Plan Woodard & Curran Natural resources on the Site include both terrestrial and aquatic habitats. Riggs Brook is not navigable in the vicinity of the Site, but large wetland areas in the Riggs Brook watershed have been mapped by the MEDEP. The Riggs Brook wetlands are considered to be shrub swamps, consisting of a mix of woodlands and emergent aquatic vegetation and peat.

Site inspections have concluded that vegetation at the Site is well developed, and drainage channels are in good condition, and functioning as designed. Annual mowing was not routinely performed in the first 10 years after Source Control to allow the vegetation to establish itself. Howe ver, the TWA II area was mowed to facilitate access to the wells. In 2006 and 2007, the entire Designated Area, with the ex ception of the steep slopes east of TWA II, was mowed. Future mowing at the Site will be conducted in accordance with this Operations and Maintenance (O&M) Plan. Minor ruts in the access road were filled in 2003; otherwise the access road is in good repair. A vehicle barrier gate across the access road was installed in 2003 (see Figure 2).

Monitoring conducted in 2007 to evaluate wetland ve getation survival and general wetland system recovery, measured slightly less acreage and less vegetative cover than was recorded prior to remediation, yet the function and value acreage has increased. The restored wetlands have developed wet meadow communities comprised of a dominance of wetland species with a mixture of old-field upland species, which is consistent with the characteristics of natural communities. In addition to the wetland species, the 2007 monitoring identified hydric soil conditions and evidence of hydrology. The wetland communities pr ovide potentially diverse habitat for aquatic and wetland dependant species.

Photographs taken in 2009, showing the Site conditions and features (Upland Marsh, lagoons, access road, vehicle barrier gate, culverts, representative boundary markers, etc.) are located in Appendix A.



### 1.4 PURPOSE OF THE OPERATIONS AND MAINTENANCE PLAN
This O&M Plan has been prepared for Operable Units OU-1 and OU-2. Sediment and biota sampling have been completed at OU-3 and there is no additional monitoring proposed for OU-3.

This O&M Plan has been prepared in accordance with the Section 4.e (6) of the Revised Statement of Work (RSOW) (USEPA, 10/20/94) for the Site. The purpose of this O&M Plan is to define those operations, monitoring andmaintenance activities that will be performed to ensure the long-term continued effectiveness of the SCRA and longterm monitoring of the Site. The draft O&M Plan was originally submitted as part of the SCRA Work Plan 100 Percent Remedial Design (CMP, 7/9/96), and has been updated several times since. The O&M plan will be reviewed and updated as necessary coincident with the five-year reviews. By performing Site maintenance and monitoringCentral Maine Power (222350.00) 1-8 October 27, 2009 Operations and Maintenance Plan Woodard & Curran activities in a timely manner as outlined in this plan, the potential for major repairs and long-term costs will be
reduced.

Wetland compliance monitoring required as a part of the 100% remedial design for the SCRA was conducted five times between 1998 and 2007, and has been completed.Central Maine Power (222350.00) 2-1 October 27, 2009 Operations and Maintenance Plan Woodard & Curran 

## 2. RECORD KEEPING AND REPORTING
The O&M activities associated with the SCRA and long-term monitoring at the Site were initiated in 1998 upon completion of the SCRA. Inspections of the Site have been conducted semi-annually, at the same time as the groundwater monitoring events. Beginning in 2008, groundwate r monitoring is conducted annually in April, but site inspections continue to be conducted semi-annually in the sp ring and the fall. An inspec tor familiar with the Source Control 100 Percent Remedial Design, the O&M requirements, and the monitoring requirements will perform each inspection for the Site. The information from each inspection will be recorded on the inspection checklist provided in Appendix B, as well as any site photographs.

Following each of the inspection visits, necessary maintenance or repairs will be scheduled and performed as required. The inspection checklists, along with a letter report describing any routine maintenance or repairs that were or will be completed will be forwarded to USEPA and MEDEP within a month of the inspection. This letter report will also address any non-routine maintenance or repairs that are proposed.

The RD/RA SOW, Appendix II of the 2003 Amendment to the Consent Decree, stated that as long as contamination remains which prevents unrestricted use of the Site, five-year reviews shall be performed to evaluate the effectiveness of the implemented cleanup plan. Consequently, it is anticipated that maintenance and inspections will continue for an extended period of time. As part of the five-year process, the O&M Plan will be reviewed and revised as necessary to incorporate significant changes in the operations and maintenance procedures and frequencies. USEPA and MEDEP will be given the opportunity to co mment on any proposed changes to the O&M Plan and USEPA’s concurrence, after opportunity for MEDEP revi ew and comment, will be obtained before implementing any proposed changes.

Contact names, addresses and phone numbers for reporting are as follows.
Mr. Terrence Connelly USEPA Region 1 1 Congress Street Suite 1100 (Mail Code HBT) Boston, MA 02114-2023 (617) 918-1373

Ms. Claudia Sait Maine Department of Environmental Protection Bureau of Remediation and Waste Management State House Station #17 Augusta, ME 04333-0017 (207) 287-7713 Roy Koster Central Maine Power Environmental Compliance Department 83 Edison Drive Augusta, ME 04336 (207) 626-9574Central Maine Power (222350.00) 3-1 October 27, 2009 Operations and Maintenance Plan Woodard & Curran 

## 3. NORMAL OPERATIONS AND MAINTENANCE
Normal operations, monitoring and maintenance for the Site have consisted of and will continue to consist of Site inspections, soil sampling and routine maintenance and repairs to the soil cover and drainage systems when necessary. The purpose of the monitoring and maintenance program is to identify and correct any damage that may occur to the soil cover or drainage syst ems that could interfere with the prope r functioning of these systems or the protectiveness of the SCRA. If damage is identified during an inspection, corrective maintenance or repairs will be implemented.



### 3.1 INSPECTIONS
For each inspection, the following general information and observations will be noted.

a. Inspector(s) Name(s);

b. Date, time, and weather conditions;

c. Condition of monitoring wells;

d. Observed erosion, sloughing, or settlement of surface soils within the Designated Area;

e. Observed erosion or rutting of access road soils;

f. Observed animal burrow holes;

g. Condition of culverts, drainage channels, and Designated Area permanent markers;

h. Condition of Upland Marsh, and reconstructed lagoons; and

i. Any other obvious changes to the condition of the Site. Inspections will be conducted semi-annually in the spring and fall, and in the event of a major storm (such as two inches or more rainfall within a 24-hour period) that co uld produce erosion, an additional site inspection will be conducted. Following each of the inspection visits, necessary maintenance or repairs will be scheduled and performed as required.



### 3.2 SOIL SAMPLING
As a part of operations and maintenance for the Site , every five years coincident with the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) -required five-year reviews, samples will be collected of the soil cover that was placed on the Designated Area in 1997. The purpose of sampling the soil cover is to demonstrate that concentrations of total PCBs remain less than 1 ppm. Using the surveyed locations on the 30-Central Maine Power (222350.00) 3-2 October 27, 2009 Operations and Maintenance Plan Woodard & Curran foot sampling grid that was established during the SCRA, and additional gr id nodes added where necessary to fill in the 10-sided Designated Area, soil samples will be collected at 10 random locations, within the 10-sided Designated Area, to be representative of the soil cover (see Figure 4).

The 10 random points will be marked in the field prior to sampling. A composite soil sample will be collected from each sampling location from a depth of approximately 8-12 inches below ground surface. The soil will be homogenized and the sample collected and analyzed for PCBs using Method 8082. If PCBs are found to exceed 1 ppm, the data will be reviewed with MEDEP and USEPA to determine if additional action is required.

A detailed discussion can be found in the O’Connor Company Superfund Site Quality Assurance Project Plan Amendment (W&C, 4/17/07). This QAPP Amendment wi ll be revised for future five-year reviews.



### 3.3 ROUTINE MAINTENANCE
Mowing. Non-wetland areas of the Designated Area will be mowed as necessary during the summer months to prevent the growth of trees and shrubs, and the perimeter of the access road shall be mowed as necessary to maintain access. Based on past experience, it is expected that this mowing will occur once each summer. The need to increase the frequency of mowing will be determined based upon the rout ine inspections and the height of the vegetation in the early fall during annual mowing. Any trees and shrubs observed to be growing on the steep slope between Points C, D, E, and F of the Designated Area will be cut down individually, as mowing this slope creates a potential safety issue for the mower.

Drainage. If inspections of culverts and drainage channels show evidence of debris accumulation or damage, activities to unclog or repair these drainage pipes and c hannels shall be scheduled. It is important that all drainage systems are operating properly in order to prevent erosion or slope failure along the lagoon dikes, resulting in expensive repairs and possible environmental damage.

If normal maintenance requires the removal of sediment or debris from drainage channels, the work shall be performed with typical equipment used for that purpose, taking care not to dam age the surface of the cover system or any other site features. If maintenance of the drainage channels requires excavation greater than 12 inches, the USEPA and MEDEP will be notified prior to the start of the maintenance activity.

Surface Soils. The Site surfaces shall be inspected for deficiencies in the soil layer overlying the Designated Area. Deficiencies may be evident as excessive erosion, surface water ponding, depressions, animal burrow holes, vehicle ruts, or other abnormalities. Large obstructions that may restrict the movement of water (from rainfall, snowmelt, etc.) from migrating into and through the soil cover shall be removed.**~**

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## LEGEND:

PTA DESIGNATED AREA MARKERS

- SURVEYED BY EPRO 2002

- ·- ·-·-·-·- REVISED 10-SIDED DESIGNATED AREA

SUPERFUND SITE BOUNDARY

NOTES: 1. TOPOGRAPHIC INFORMATION IS APPROXIMATE. TOPOGRAPHIC INFORM A llON HAS BEEN COMPILED FROM ORIGINAL SITE PLAN AND 1999 SURVEY OF REMEDIATED AREA.

2. FOR SIMPLIFICATION, GROUNDWATER AND OIL MONITORING LOCATIONS, GEOPROBE, SURFACE WATER SAMPLING LOCATIONS ARE NOT SHOWN ON THIS FIGURE.

80' SAMPLING GRID FOR SOURCE CONTROL REMEDIAL ACTION (FIGURE 5 W&C SOURCE CONTROL REMEDIAL ACTION REPORT SEPT 2. 1998)

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FIGURE4Central Maine Power (222350.00) 3-4 October 27, 2009 Operations and Maintenance Plan Woodard & Curran If animal burrow holes are observed during site inspections, efforts will be made to remove the animals from the Site,
and the burrow holes will be filled.
Monitoring Wells. In accordance with the Management of Migration Groundwater Monitoring Program Sampling and Analysis Plan (SAP), Volume I of II, Revision 4 (W&C, December, 1996), the co ndition of monito ring wells has been checked during each groundwater monitoring event, and will continue to be checked during the annual April groundwater monitoring events.
In summary, the monitoring and extraction wells will be observed for the following:

• Check the well for proper identification and location;

• Observe the well for evidence of settlement of the casing, and condition of the surface seal;

• Calculate the percentage of well screen that is free of sediment for each well, to determine if the well requires rehabilitation; and

• Check security of the well.
Detailed procedures for well rehabi litation are described in Section 5 a nd Table 4 of the SAP (W&C, December, 1996).
Based on USEPA’s approval of CMP’s monitoring well decommissioning request (dated June 14, 2007), 18 wells and 7 piezometers were decommissioned during the summ er of 2008 (see Figure 3). Procedures for well decommissioning are outlined in Appendix C.



### 3.4 REPAIRS

Erosion. The most common repair will likely be erosion or ve getation damage. Eroded areas shall be filled with soil and seeded. A layer of mulch or an erosion control blanke t shall be provided as necessary to protect these areas until vegetation is established.
Drainage Ways. Erosion of the drainage channels will be repair ed in a manner that will ensure long-term resistance to possible future erosion. These measures may include re-grading and seeding, installation of erosion control blankets, or construction of riprap surfaces in areas requiring more permanent slope protection.

The operation of the outlet pipes of the Upland Marsh, Upper Lagoon, and Lower Lagoon is important in the establishment and long-term success of the restored wetlands. If damage to the outlet pipes of the Upland Marsh or lagoons occurs, repairs shall be made as soon as possible following discovery. All repair activities shall be reviewedCentral Maine Power (222350.00) 3-5 October 27, 2009 Operations and Maintenance Plan Woodard & Curran and approved by a qualified engineer. The suspected caus e of the damage and all work performed as part of the repairs will be documented in the following site inspection report.

Surface Soils . Settlement in the Designated Area can be tolerated provided the integrity of the cover soil remains intact. Vegetated areas of the Designated Area that may have experienced some settlement are still considered protective, due to the stabilizing effect of the vegetation. However, if erosion or rutting of soil in the Designated Area is observed, the area must be refilled with soil and reseeded to maintain the required cover soil depth. If erosion or rutting on the access road is observed, the road must be repaired by filling the ruts or eroded areas such that the elevation of the access road remains equal to or higher than the vegetated portion of the Designated Area. This will ensure that the thickness of clean soil in the access road is greater than the minimum requirement over the Designated Area.

Monitoring Wells . If well rehabilitation measures other than pumping out the accumulated silt as described in the SAP (W&C, December, 1996) are to be undertaken, USEPA an d MEDEP shall be notified prior to the start of the
work.Central Maine Power (222350.00) 4-1 October 27, 2009 Operations and Maintenance Plan Woodard & Curran 

## 4. ASSESSMENT OF SITE CONDITIONS
All normal maintenance and repairs shall be conducted as necessary and included in the inspection letter report with an evaluation and assessment of site conditions and any observed changes at the Site. Prior to conducting any repairs that are determined to be major (excavation to a depth of 12 inches or greater), the USEPA and MEDEP would be notified. In addition, the location of any ident ified problems or maintenance and repair issues shall be shown on the figure included in Appendix B, and included with the inspection report.

It was noted above that the groundwater monitoring program is being performed under the Management of Migration Groundwater Monitoring Program Sampling and Analysis Plan (SAP), Volume I of II, Revision 4 (W&C, December, 1996). This program, whose objective is to track dissolved PCBs and VOCs, while not an O&M activity, will be performed at the same time as the spring site inspection and this serves as a cross-reference to that program. The monitoring shall be performed until it has been determin ed by USEPA, after opportunity for review and comment by MEDEP, that the groundwater in the overburden soils and in the bedrock has achieved the performance standards
set in the 1989 ROD and 2002 ROD Amendment.

The 1989 ROD included temporary institutional controls as a part of the overall remedy. The 1994 ESD modified this to make the institutional controls permanent. CMP and ME DEP signed a restrictive covenant which was recorded in the Kennebec County Registry of Deeds on September 13, 2002. Compliance with this covenant, while not an O&M activity, will be confirmed at the same time as the spring site inspection and this serves as a cross-reference to that
covenant.Central Maine Power (222350.00) 5-1 October 27, 2009 Operations and Maintenance Plan Woodard & Curran 

## 5. OPERATIONAL SAFETY PLAN
All inspections and maintenance work shall be performed in conformance with the Site Health and Safety Plan (CMP, 7/9/96), and well decommissioning shall be performed in accordance with the supplemental Health and Safety Form (W&C, 4/15/08). Requirements of the Occupational Safety and Health Act (OSHA) 29 CFR provide the basic safety requirements that shall be followed for all activities at the Site.

Maintenance and inspection activities present many opportunities for physical injury to occur. This Site contains steep slopes and riprap drainage structures which could make otherwise normal activities more unpredictable and dangerous. Equipment use at this Site should be done with care. Wearing the proper protective clothing and sturdy boots and using common sense can prevent many injuries.Central Maine Power (222350.00) 6-1 October 27, 2009 Operations and Maintenance Plan Woodard & Curran 

## 6. GLOSSARY OF ACRONYMS

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act

CMP Central Maine Power Company

ESD Explanation of Significant Differences

MEDEP Maine Department of Environmental Protection

MOM Management of Migration

O&M Operations and Maintenance

OSHA Occupational Safe ty and Health Act

OU Operable Unit

PCBs Polychlorinated biphenyls

ppm Parts per million

PRP Potentially Responsible Party

RD/RA Remedial Design/Remedial Action

ROD Record of Decision

RSOW Revised Statement of Work

SAP Sampling and Analysis Plan

SC Source Control

SCRA Source Control Remedial Action

SOW Statement of WorkCentral Maine Power (222350.00) 6-2 October 27, 2009 Operations and Maintenance Plan Woodard & Curran SVOC Semi-volatile organic compound

TI Technical Impracticability

TWA Transformer Work Area

USEPA United States Environmental Protection Agency

VOC Volatile organic compoundCentral Maine Power (222350.00) 7-1 October 27, 2009 Operations and Maintenance Plan Woodard & Curran 

## 7. REFERENCE LIST
CMP, 1996. Source Control (SC) 100 Percent Remedial Design, O’Connor Company Superfund Site, Augusta, Maine; July 9, 1996.
CMP, 6/14/2007. Letter from Ray Kost er, CMP to Terrence Connelly, USEPA, RE: O’Connor Company Superfund Site Monitoring Well Decomm issioning Request, 2007.
TRC Engineering, LLC, 2007. Wetland Restoration Monitoring Report for the O’Connor Company Superfund Site, Augusta, Maine; Prepared for Central Maine Power Company; Augusta 24, 2007.

TSA, 1996. Wetlands Construction and Monitoring Report, 100 Percent Remedial Design , O’Connor Company Superfund Site, Augusta, Maine. The Smart Associat es, Environmental Consultants, Inc. Concord; New Hampshire, 1996.

USEPA, 1989. Record of Decision Summary ; U.S. Environmental Protection Agency, Region 1, Boston, Massachusetts; September 1989.

USEPA, 1991. Consent Decree – United States of America, Plaint iff v. Central Maine Power Company, Defendant; September 3, 1991.
USEPA, 7/20/94. Explanation of Significant Differences , O’Connor Company Superfund Site, Augusta, Maine; July 20.
USEPA, 10/20/94. Remedial Design/Remedial Action Revised Statement of Work , O’Connor Company Superfund Site, Augusta, Maine; October 20.
USEPA, 9/02. Record of Decision Amendment Operable Unit 2 , F. O’Connor Company Superfund Site; U.S. Environmental Protection Agency, Region 1, New England; September.
USEPA, 9/18/03. Amendment to Consent Decree - United States of America v. F. O’Connor Company Superfund Site, et. al , in the United States District for the District of Maine; September 18.

Woodard & Curran, 1996. Management of Migration Groundwater Monitoring Program Sampling and Analysis Plan, O’Connor Superfund Site; December 1996 with Amendments.

Woodard & Curran, 1998. Final Source Control Remedial Action Report , O’Connor Company Superfund Site, Augusta, Maine; September 1998.

Woodard & Curran, 2002. Technical Impracticability Evaluation for OU-2 Management of Migration , O’Connor Company Superfund Site, Augusta, Maine; June 2002.
Woodard & Curran, 4/17/07. O’Connor Company Superfund Site Quality Assurance Project Plan Amendment

, O’Connor Company Superfund Site, Augusta, Maine; April 17.Central Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan Woodard & Curran 

# APPENDIX A: 2009 SITE PHOTOGRAPHSCentral Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan Culvert inlet by Route 17

Access road looking southCentral Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan Access road looking north

Eastern slopeCentral Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan Culvert inlet under access roadCentral Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan Designated area markerCentral Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan Outlet- Upper Lagoon

Lower LagoonCentral Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan O’Connor beaver dam along Upland Marsh edge - June 25, 2009

Transformer work area (TWA) wellsCentral Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan Outlet pipe- Lower LagoonCentral Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan Outlet pipe- Upper LagoonCentral Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan Upland Marsh

Upper LagoonCentral Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan Vehicle barrier gateCentral Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan Woodard & Curran 

# APPENDIX B: O’CONNOR INSPECTION CHECKLISTCentral Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan 

## O’Connor Inspection Checklist

Inspector: Date: Weather: Time:



## MONITORING/OBSERVATION WELLS

Well Casing Well Locks Condition Erosion Comments

MW 104B MW 106A
MW 106B
MW 501
MW 502
MW 503
MW 507A
MW 508B OW 201B OW 202B OW 302B

RW 101 Follow Up Action Required:Central Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan 

## Designated Area

Boundary Markers Condition Comments PTA PTB PTC PTD PTE PTF PTG PTH PTI PTJ Follow Up Action Required:



## Surface Soils

CONDITION L OCATION ( MARK ON ATTACHED MAP )

Excessive Settlement - Ponding

Erosion Rills

Vegetation – Stressed or Sparse

Animal Burrows

Tree and Shrub Encroachment on Designated AreaCentral Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan 

## Access Road

Feature Condition Comments Excessive Rutting Erosion, Sloughing of Shoulders Other Follow Up Action Required:



## CULVERTS AND SU RFACE DRAINAGE

Location Condition Comments Upland Marsh Culvert – Primary Upland Marsh Culvert – Overflow Upper Lagoon Culvert Outlet Swale Upper to Lower Lagoon Lower Lagoon Culvert Outlet Drainage Lower Lagoon to Riggs Brook Follow Up Actions Required:



## UPLAND MARSH AND LAGOONS

Location Feature Condition Comments Side Slopes Upland Marsh Vegetation Side Slopes Upper Lagoon Vegetation Side Slopes Lower Lagoon Vegetation Follow Up Actions Required:Central Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan 

## INSTITUTIONAL CONTROLS

Covenant Compliance Comments No use of groundwater beneath the Property has occurred during the past year without prior written approval of MEDEP No activity which might disrupt remedial or monitoring measures has occurred during the past year without prior written approval of MEDEP CMP or subsequent owner has maintained the Property during the past year in a condition adequate to ensure continued compliance with all applicable cleanup standards, and to ensure the ongoing adequacy of the remediation implementedCentral Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan 

## OTHER OBSERVATIONS/RECOMMENDED ACTIONS

CHECK HERE IF ADDITIONAL INFORMATION IS ATTACHED

Inspector’s Signature Date:Central Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan..l.tGtHD.:i+FREEPROOUC'TatWOHilORJNClOCAllClHALONelERWIIONITOAINClOCAll()lI+C£CIJWISSIONm'IIW.SI1-PTADESlCNAlEDMI£AIIARICERS-SUII\€lminIBYEPRORE'ilsm1o-SI!IEIIDESl()l"lEDAA£A---SUPERAJN)S1EBOUIIOARYla'OGRAPitCtif<HIAliONISAI'I'ROlGIIAlLla'OGRAPitCtifORIIAllClHHASBt:ENCCloll'ti.EI>,_ORJGIIW..SI'IEPlANNIO1118tSUR'>£YRDIEiliAlEDM£Az'j/a..0wIiii,Q/wIena:Central Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan Woodard & Curran 

# APPENDIX C: MONITORING WELL DECOMMISSIONING PROCEDURESCentral Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan APPENDIX C:
MONITORING WELL DECOMMISSIONING PROCEDURES

The State of Maine has not published guidelines or po licies specifically concerning the abandonment of groundwater monitoring wells at hazardous waste sites. However, the Maine Department of Human Services, Bureau of Health has issued Well Drillers and Pump Installers Rules (10-144 Chapter 232), that contain guidance detailing the abandonment of drinking water wells (Chapter 5). The objective of the Chapter 5 rules is to ensure that abandonment of wells is completed in a manner appropriate to prevent potential entry of contaminants into groundwater. Ch apter 5 of 10-144 Chapter 232 (Abandonment of Wells) is attached, and was utilized in the development of this monitoring well decommissioning plan.
Monitoring wells proposed to be decommissioned at the O’Connor Company Superfund Site in Augusta, Maine will be handled in two ways, depending on whether the well is located inside of or outside of the designated area at the Site. The designated area is a three- to four-acre area containing soil contaminated with PCBs less than 10 parts per million beneath a 12-inch clean soil cover. It is proposed that monitoring wells within the designated area be grouted in place, and terminated at 6-inches below grade (within the top 12-inches of clean cover soil) to avoid disturbance of potentially PCB-impacted soils in the designated area. For wells located outside of the designated area, an attempt will be made to remove the existing well
construction materials.

Monitoring well decommissioning procedures are described in detail below:

Monitoring wells within the designated area

• Measure well depth and compare to as-built depth; clear any obstructions in the well.

• Pump via the tremie pipe method (i.e., bottom of well to top), a neat cement/bentonite grout mixture into the well or open borehole.

• Fill the well pipe with the grout material to approximately 6-inches below ground surface.

• Groundwater that is displaced during the well grouting procedure will be allowed to runoff to the ground surface, except at well OW-301B. Based on historic sampling results, displaced groundwater from this well will be containerized and sampled for off-site disposal.

• Remove the well’s protective casing (standpipe). For bedrock wells OW-204B and OW-301B, the well casing above ground surface is the protective casing.Central Maine Power (222350.00) October 27, 2009 Operations and Maintenance Plan • Terminate the well approximately 6-inches below grade (using an internal cutting tool, if necessary to minimize disturbance of soil), followed by ground surface restoration to surrounding conditions (i.e., topsoil consistent with the existing Site cover soils).
Monitoring wells outside of the designated area

• Measure well depth and compare to as-built depth; clear any obstructions in the well.

• If possible, remove the existing well construction materials (e.g., screen, riser, steel casing) by directly lifting/pulling the material from the ground using the drill rig, while intermittently grouting the hole. Limit the length of well material pulled between grouting to prevent collapse prior to grouting, estimated to be two feet. Push out the bottom of the well and pump via the tremie pipe method (i.e., bottom of well to top), a neat cement/bentonite grout mixture into the well or open borehole.

• Fill the borehole with the grout material.

• Groundwater that is displaced during the well grouting procedure will be allowed to runoff to the ground
surface.

• Remove the well’s protective casing (standpipe).

• Terminate the well approximately 3 feet below grade; apply a minimum of one to two feet of concrete following by ground surface restoration to surrounding conditions (i.e., topsoil).

• All extracted well materials will be disposed of or recycled in accordance with applicable regulations.
A record of decommissioning activities will be completed and maintained, including removal and sealing methods, date, depth sealed, and quantity of sealing material used. The monitoring well decommissioningactivities will be performed by a registered driller in the State of Maine. Woodard & Curran will provide onsite oversight and documentation of the abandonment ac tivities, including a letter report summarizing the work performed. All work will be conducted in accordance with the Supplemental Health & Safety Plan (April, 2008).