record of decision for cleanup indian booster pump station u.s. … · 1999. 8. 30. · station in...

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Record of Decision for Cleanup Indian Booster Pump Station

U.S. Defense Energy Support Center ADECDatabaseRecord Key93-2101-215-01

INTRODUCTION

The Alaska Department of Environmental Conservation (DEC) developed this Record of Decision, which presents the selected remedy and supporting rationale for cleanup at the Indian Booster Pump Station site, located within the Chugach State Park near Indian, Alaska.

The Record of Decision was developed in accordance with State of Alaska regulations governing the protection of human health and the environment from hazardous substances (18 Alaska Administrative Code Part 75, Article 3 "Discharge Reporting, Cleanup, and Disposal of Oil and Other Hazardous Substances"). The Alaska Department of Natural Resources (ADN'R) participated in the development of the proposed plan and supports the selected cleanup remedy.

The Record of Decision will be added to the Indian Booster Pump Station documentation atthe Loussac Library in Anchorage during the summer of 1999 and will also be available forpublic review at the DEC ContaminatedSitesPrbgram office in Anchorage.

SITE INFORMATION

The Indian Booster Pump Station, a former U.S. Defense Energy Support Center (DES C) facility, is located within Chugach State Park. The site is approximately 25 miles southeast of Anchorage and one mile north of the community of Indian, located near the Indian Creek Trailhead at the end of Oceanview Road. Landowners in the area include the State of Alaska, the Municipality of Anchorage and local residents.

RECORD OF DECISION INDlA;.J BOOSTER PUMP STATION

• The site encompasses approximately thirty acres of land (Figure 1). The Indian Booster Pump Station was constructed in 1967 in conjunction with a pipeline to transport fuel from Whittier to Anchorage for use by military bases and other government agencies in Alaska. The Anny operated the pipeline until 1989, when operational responsibility was transferred to DESC.

The pipeline no longer is used to transfer fuel. It \vas retrofitted for natural gas transport in 1995 and leased by the Department of Defense to the Alaska Pipeline Company in September 1995 for a tenn of 33 years. ENSTAR Natural Gas Company currently uses the pipeline to transport natural gas.

The geology beneath the site consists of a 1 to 2 foot thick organic mat covering 20 to 60 feet of glacial!ill. The upper IOta 20 feet of the till have been reworked by glacial out wash streams, while the lower portion of till remains consolidated and dense. Two groundwater zones have been identified, an unconfined shallow zone located 10 to 20 feet below ground surface and a semi-confined deep zone located 20 to 60 feet below ground surface.

In 1993, the pipeline was shutdown by DESC after a valve failed causing a release of up to 35,700 gallons of fuel. Emergency response measures involved excavation of groundwater interception trenches and the use of rope mops, skimmers, and vacuum pumps to recover liquid fuel (free product). A groundwater treatment plant was constructed to treat the groundwater contaminated by dissolved fuel. The emergency response recovered more than 21,000 gallons of fuel and prevented the release from impacting the nearby creek or down-gradient residential wells

After the emergency response actions, several environmental investigations were undertaken. In addition to the 1993 north valve release, previous spills of various types of fuel occurred at the site. These other releases are believed to be associated with an explosion at the Booster Pump Station in 1969, a leaking underground storage tank (removed in 1990) at the Booster Pump Station, and maintenance and repair operations at the north and south pipeline relief valves.

Soil, on-site groundwater, residential drinking water, and Indian Creek were tested to detennine the extent and degree of impact caused by these releases. It was detennined that Indian Creek was not significantly affected by the releases. Also, no petroleum contaminants were detected in any of the down gradient residential drinking water wells tested, even though more than 500 samples were collected and analyzed from 1993 to 1999.

Subsurface soil within the site is significantly contaminated in the area of the north valve. Shallow groundwater within the site is significantly contaminated due to fuel leaching from the soiL On-site groundwater monitoring showed free-product and high diesel-range fuel concentrations in the shallow groundwater. The deep groundwater zone is less impacted, but still degraded due to the fuel spills.

2 RECORD OF DECISION INDIAN BOOSTER PUMP STATION

-r--------------------,--------------

• IDENTIFICATION OF CONTAMINANTS OF CONCERN

In soil, diesel range organic (DRO) hydrocarbons were identified as the primary contaminants of concern in subsurface soil. Due to limited sample collection and the uncertainty of actual chemical concentrations in the subsurface soil within the smear zone, benzene, toluene, ethylbenzene, xylenes, and polynuclear aromatic hydrocarbons are considered potential contaminants of concern in subsurface soil.

In groundwater, DRO is the primary contaminant of concern. Benzene is another contaminant of concern that was reported in several monitoring wells sampled in 1993. Due to the uncertainty of dissolved chemical concentrations in the groundwater near wells previously impacted by free product, toluene, ethylbenzene, xylenes, and polynuclear aromatic hydrocarbons are considered potential contaminants of concern in-groundwater.

EXTENT OF CONTAMINATION

The site characterization results indicated that DRO concentrations in the soil and groundwater exceed Method two Table B2 cleanup levels (18 AAC 75.341). The majority of fuel contamination is in subsurface soil within a "smear zone"located 1 0 to 20 feet below ground surface" The extent of the smear zone is bounded on the north and east sides by the pipeline and tothe west and south by Collection Trenches 2, 5,6, and 8 (Figure 2).

Leaching of the DRO in the smear zone impacts groundwater quality in the shallow and deep groundwater zones. The extent of contaminated shallow groundwater is graphically depicted on Figure 3. DRO was reported in a deep groundwater well onsite, which confirms a hydraulic connection between the shallow groundwater zone and the deep groundwater zone.

SUMMARY OF RISK ASSESSMENT

A risk assessment report was prepared to characterize the risks posed by fuel contamination to human health and the environment. DEC approved the report in November 1998. DRO exceeded risk-based screening levels and was retained for inclusion in the human health and ecological risk characterizations. The risk assessment indicated that the site does not exceed the cumulative carcinogenic risk threshold. However, at several monitoring wells, the estimated hazard index exceeded the cumulative noncarcinogenic threshold for the groundwater ingestion pathway.

Ecological Risk Assessment Summary: In the ecological risk assessment, terrestrial and aquatic habitats with associated receptors were evaluated for potential impact due to remaining contamination. The potential exposure of the spruce grouse, snowshoe hare, American dipper, coho (silver) salmon, and dolly varden to site contaminants was evaluated. Based on the site conditions, potential of exposure to contaminants by ecological receptors was considered to be


• relatively small. The majority of the impacted soil at the site is at depth,and contaminated groundwater would be significantly diluted prior to mixing with surface water.

Human Health Risk Assessment Summary: The human health risk assessment showed that the groundwater contamination in the shallow and deep groundwater zones exceeded DEC cleanup levels for DRO, chiefly by the ingestion exposure pathway. For humans, complete pathways occur for the ingestion, inhalation, or dermal contact pathways if future park activities disturb the smear zone such that contaminated soil is redistributed to the surface. The smear zone is located within subsurface soil, approximately 10 to 20 feet beneath the ground surface, between high and low groundwater levels where contamination tends to stick or smear to soil.

CLEANUP l,EVELS

The soil and groundwater cleanup levels for the siteare based on values listed inTable Bl and Table B2 of 18 AAC 75.341 (see Table 1 below).

Table 1: Soil and Groundwater Cleanup Levels

Soil Groundwater Contaminant (mg/kg) (mg/I)

Diesel Range Organics (DRO) 250 1.5 I Benzene 0.02 0.005

Ethylbenzene 5.5 0.7 Toluene 5.4 .. 1.0 Xylenes (Total) 78 10.0 Acenaphthene 210 2.2 Anthracene i 4,300 11.0

i Benzo(a)anthracene 6 0.001 ! Benzo(b )fluoranthene 20 0.001

Benzo(k)fluoranthene 200 ,

0.01 Benzo(a)p yrene 3 0.0002 Chrysene 620 0.1 Dibenzo( a,h )anthracene 6 0.0001 Fluorene 270 1.46 Ideno( 1 ,2,3-c,d)pyrene 54 0.001 Naphthalene 43 1.46 Pyrene 1,500 1.1

4 RECORD OF DECISION INDIA1\ BOOSTER PUMP STATION

I

,. POINTS OF COMPLIANCE

Soil

A point of compliance for soil is an area where soil cleanup levels must be attained. The points of compliance for soil include the surface and subsurface soil in the vadose zone across the entire site. "Vadose zone" is defined at 18 AAC 78.995.

Groundwater

A point of compliance for groundwater is an area where groundwater cleanup levels must be attained. Alternative points of compliance for groundwater were identified in accordance with 18 A.~C 75.345 (e).

Three types of a1ternative points of compliance (APOC) will be monitored for compliance with the groundwater cleanup levels. The alternative points of compliance wells are listed in Table 2 below, and depicted in Figure 2. Type-l monitoring wells are located on the down-gradient edge of the plume. Type-2 monitoring wells are located within the plume area. Type-3 monitoring wells are located between Indian Creekand the plume.

Table 2 Groundwater Alternative Points of Compliance

APOCType Monitoring Well Location Type-l .. MW-5D MW-6 MW-7MW-13 MW-19MW-23 MW-34 MW-42A , , , , ; , , Type-2 MW-PH" MW-21 MW-22D MW-27DMW-30 MW-37 MW-38 MW-43 A

MW-44A MW-45A, MW-46A'MW-47A, MW-48DA ' , , Type-3 I MW-8, MW-ll, MW-16 ..

A - Monitoring well tobe installed.

Type-! points of compliance are located at the perimeter of the site, down-gradient of the existing DRO contamination, on hydrologic flow paths between the source area of contamination and human receptors. Type-l wells are expected to continue to meet cleanup levels, but will be monitored to verify that contaminant migration does not ocCur beyond the boundaries of the perimeter monitoring well network.

Type-'2 points of compliance are wells located within different parts of the existing groundwater contaminant plume. These wells will be monitored to evaluate the progress bfnatural attenuation processes, to confirm that the plume concentrations are stable or decreasing and to determine when cleanup levels are reached.


Type-3 points of compliance are wells located down-gradient of the site between the source areas of contamination and Indian Creek. These wells will be monitored to confirm that groundwater will not cause a violation of the 18 AAC 70 surface water quality standards for Indian Creek.

COMPARATIVE ANALYSIS OF ALTER'\fATIVES

Four altematives were evaluated for cleanup of the Indian Booster Pump Station Site as shown below.

Altemative # 1 1\atural Attenuation with Institutional Controls: Natural attenuation is the reduction in the concentration and mass of a hazardous substance and its breakdown products, due to naturally occurring physical, chemical, and biological processes without human intervention. These processes include dispersion, diffusion, sorption, retardation, and biological degradation. Groundwater would be tested and monitored at the site without further active characterization or cleanup measures, unless there is an unacceptable increase in contaminants. An institutional control would prevent access to subsurface soil and prevent installation of water wells at the site. Cleanup levels using only natural attenuation are estimated to be achieved in approximately 20 years. Estimated costs == $580,000.

Altemative #2 ~ Natural Attenuation, Additional Characterization, and Limited Excavation: This altemative includes natural attenuation with institutional controls,conducting additional characterization in the area of monitoring well MW-22, and the excavation, removal, and thermal treatment of approximately 1,000 cubic yards of soil in the area of monitoring well MW-26. The excavation of soil in the area of monitoring well MW -26 should also improve the quality of the groundwater at monitoring well MW -17. Following the excavation of the soils, the area would be recontoured and revegetated to the Chugach State Park Superintendent's satisfaction. Cleanup levels using this option are estimated to be achieved in approximately 18 years. Estimated costs $765,000.

Altemative#3 .~ Air Sparging/Soil Vapor Extraction: This altemative would include the installation of an air sparginglsoil vapor extraction unit near monitoring wells MW -22 and MW-26. Air sparging involves the injection of air into the subsurface below the groundwater table, which changes the fuels in the soil into a vapor fonn. The vapors are then removed from the soil with vapor extraction wells. Also, air sparging increases the amount of dissolved oxygen in groundwater, which increases the potential for biological decomposition of contaminants. Cleanup levels using this option are estimated to be achieved in approximately 20 years. Estimated costs"" S855,000.

Altemative #4 - Groundwater Pump & Treat: This alternative would include the installation of product recovery wells near monitoring wells MW-22 & MW-26. Pumped water would be treated using a mobile groundwater treatment system. A groundwater pump and treat system involves the pumping and treating of groundwater utilizing a mobile treatment plant and recovery wells. The pumped groundwater is processed through an activated carbon unit to

6 RECORD OF DEC1SION INDIAN BOOSTER PUMP STA nON

r remove the dissolved hydrocarbons. Treated water can either be re-injected or surface discharged. Cleanup levels using this option are estimated to be achieved in approximately 20 years. Estimated costs = $930,000.

ADEC uses five criteria to evaluate alternatives for site cleanup. The next section evaluates the four alternatives for the Site against these criteria.

1. Practicability. Are the alternatives capable of being designed, constructed and implemented in areliable and cost effective manner? Which of the alternative(s) are the most cost effective?

Alternative 2 would be easily implemented and would accelerate the natural attenuation process (alternative 1). Although alternative 3 & 4 can be designed, constructed, and implemented, the effectiveness of remediation of the residual contamination is questionable. Based on the soil type, groundwater recharge rates, and the chemical properties of old fuel, alternatives 3 & 4 may be unreliable. Alternative 2 would be the most cost-effective remedy for addressing residual contamination in the area of monitoring well MW -26 and would provide more infonnation that may either validate or invalidate a natural attenuation option in the vicinity of monitoring well MW-22.

2. Protectiveness: How well does each alternative protect human health, safety, and welfare or the environment, both during and after construction?

Alternatives 1, 2, 3, and 4 would protect human health, safety,welfare, and the environment. Due to the planned excavation, removal, and treatment of contaminated soil, alternative #2 is the most proactive remedy for the protection of human health, safety, welfare, and the environment.

3. Regulations: Will the alternative comply with all state and federal regulations?

All ofthe alternatives (1-4) will comply with applicable state and federal regulations.

4. Short- and long-tenn effectiveness.

Alternative 1 is estimated to reach cleanup goals in 20 years. Alternative 2 is estimated to reach cleanup goals inI8 years. Alternatives 3 & 4 are estimated to reach cleanup goals in 20 years. Some of the potential adverse impacts include: alternative 2 ~ increased truck traffic during excavation effort, transport of contaminated soil to Anchorage for treatment, and additional drilling activities in 1999; and alternatives 3 & 4 - routine site visits for system O&Mand additional drilling activities in 1999.


5. Public Input: Have significant comments received from the community been considered?

DEC has met regularly with representatives of the community throughout the site investigation. Many community concerns were addressed during the site characterization, risk assessment, and development of cleanup alternatives. Community representatives supported alternative 2. DEC has considered concerns expressed during the public meeting at the Valley Bible Chalet in Indian on June 17. 1999. Members of the public were concerned with future water monitoring practices, road maintenance, traffic and safety issues, dust control, scheduling of truck traffic, and contingencies to prevent groundwater migration of contaminants. No written or other public comments were received during the public comment period.

DESCRIPTION OF THE SELECTED CLEANUP ACTION

Based on the information generated from the site characterization, risk assessment, comparative analysis of alternatives, and the interim cleanup actions performed, DEC selected Alternative 2 (Natural Attenuation, Additional Characterization, and Limited Excavation) as the cleanup remedy for the Indian Booster Pump Station site. The site cleanup remedy must be conducted or supervised by a qualified person and must meet the cleanup operation requirements of 18 AAC 75.360.

The selected cleanup remedy includes monitored natural attenuation, the excavation of approximately 1,000 cubic yards of soil near monitoring wellMW -26, and re-vegetation of the excavated area. It also includes installation of eight new monitoring wells, including one to be installed between monitoring well MW -22 and the pumphouse, and one to be installed between monitoring well MW -22 and the former south pipeline valve.

The selected cleanup remedy includes limited institutional controls to restrict access to groundwater and to limit the ADN'R's ability to excavate soil in certain areas. Long-term groundwater monitoring will be conducted to determine when cleanup levels are attained and to ensure that contaminants do not migrate beyond the perimeter monitoring well network points of compliance. A brief summary of the selected cleanup remedy follows. More specific technical details of the cleanup remedy are provided in June 3, 1999 Site Management Plan.

Treatment ofnRO~Contaminated Soil

Approximately 1,000 cubic yards of DRO-contaminated subsurface soil will be excavated and thermally treated at an approved off-site treatment facility. Field screening instruments will be used to segregate contaminated soil from uncontaminated soil. Contaminated soil will not be stockpiled; it will be loaded directly into dump trucks that will haul the material as a covered load to an approved soil treatment facility.

8 RECORD OF DECISION INDIAN BOOSTER PU:\1P STATION

Gronndwater .. Monitoring

Groundwater monitoring will be employed to confinn that contaminant migration does not cause unacceptable risk to human health or the environment and to evaluate the effectiveness of natural attenuation. Three categories of wells will be monitored with different perfonnance objectives. The monitoring program will be evaluated annually to detennine if changes to sarnpling locations or sampling frequencies are appropriate.

Institutional Controls

Institutional controls will limit human and ecological exposure to contaminated soil and groundwater. A Public Drinking Water Supply well was installed up-gradient of the site to provide drinking water and to service anticipated future land uses.

ADEC and ADNR have signed a Memorandum of Agreement (MOA) to create an institutional control in accordance with 18 AAC 75.375. The purpose of theMOA is to provide notice of residual contamination, to protect human health, safety and welfare by minimizing potential exposure pathways to contaminated soil or contaminated groundwater, and to preserve the integrity of site cleanup activities or improvements. .

The MOA includes the following controls:

1. a Groundwater Development Control Area that restricts groundwater development within approximately eleven (11) acres of land.

2. An Excavation Control Area that requires prior DEC notification for any excavation or soil disturbance to a depth of greater than [our feet below ground surface within approximately 5.5 acres ofland.

3. Provisions for the ADNR, to beartheresponsibility for costs associated with removal or treatment of soil contamination if encountered at a d epth greater than 10 feet below the ground surface within the Excavation Control Area.

4. Notification of holders of existing or future utility easements, pennits, or rights-of-way across the Control Areas of the restrictions placed on soil excavation or the use of groundwater.

The groundwater development and soil excavation restriction areas are discussed in detail and the boundaries of the control areas are depicted in a figure in the MOA (see Appendix A).

PUBLIC INVOLVEMENT

Throughout the site investigation and developrnent of cleanup alternatives, DEC met on a monthly basis with community and municipal representatives,ADNR, DESC, and environmental consultants to discuss site issues and to addressconcems ofthe cornmunity.The public has been encouraged to participate during the site characterization process, the risk assessment process,

9 RECORD OF DECIS]ON lNDlAN BOOSTER PUMP STATION

and through the selection of the cleanup remedy for this site. DEC provided the public an opportunity to comment on the Proposed Plan for the cleanup of the Indian Booster Pump Station site during the 30-day comment period held from June 7 to July 6, 1999. Two informational meetings, one at the Loussac Library in Anchorage and one at the Valley Bible Chalet in Indian, were held to discuss this Proposed Plan and to answer questions. DEC, ADNR, and DESC representatives were present at each meeting. The informational meetings provided an opportunity for interested parties to submit written or verbal comments on the Proposed Plan.

RESPONSIVENESS SUMMARY FOR THE RECORD OF DECISION FOR CLEANUP ACTION AT THE INDIAN BOOSTER PUMP STATION SITE, INDIAN, ALASKA

This section summarizes and responds to comments made during the public comment period following issuance of the Proposed Plan. No written comments were received during the comment period from June 7 to July 6, 1999.

During the informational meeting held June 17, 1999 in Indian, some issues of concern were expressed by members of the pUblic. DEC believes it is important to respond to these concerns. The foHowing concerns and responses summarize the issues discussed at the informational meeting.

Concern: A community member expressed concern that residential well sampling will be discontinued and felt that the frequency of residential well sampling should be increased, not decreased.

Response:

Residential wells have been sampled several times each year since the August 1993 spill occurred without any indication of petroleum contamination attributable to sources associated with the Indian Booster Pump Station site. Recentperimeter monitoring well results indicates that the contaminated groundwater plume is not migrating beyond the site boundaries. Eight new groundwater wells will be installed at the site as part of the cleanup action, including one well tobe installed outside of the site boundaries closer to residential areas at the Chugach State Park boundary. Groundwater from existing and new wells will be sampled to determine compliance withcIeanup levels and to monitor for contaminant migration. A monitoring plan will be developed with specific contingencies in place if future sampling indicates that contaminant migration has or might occur.


Concern: A community member expressed concern about safety of children and other pedestrians during the cleanup activities.

Response: The contractor will infonn all drivers to drive slowly and safely and to beware of children, pets, and pedestrians, particularly along Oceanview Drive. The contractor will provide written notification to residents along the road withinforn1ation about the project schedule. The notification letter will also identify the name and phone number of a contact person for residents tocaH if they have questions or concerns during the project activities.

Concern: A community member expressed concern that truckers may stage vehicles on or near private property and disturb residents with the noise or fumes of idling trucks.

Response: The contractor will infonn drivers not to stage vehicles on private property along Oceanview Drive and will attempt to schedule trucks ina manner that minimizes disturbances to residents.

Concern: Community members expressed concern about the amount of dust and the need for additional road maintenance due to truck traffic during cleanup activities.

Response: The contractor will utilize a watering truck to minimize dust levels and will perfonn needed road maintenance until cleanup project construction activities are complete and site-related heavy equipment and trucks are moved off the site. The Chugach State Park Superintendent indicated that some leftover asphalt material from another area of the park

. might be available for road maimenancework in the future, contingent on adequate state funding.

Concern: A community member requested that natural plants and berry bushes be used at the site for restoration purposes.

Response: Natural vegetation, including blueberry, spruce, hemlock, birch, and shrubs will be used to re~vegetate portions of the site, as directed by the Chugach State Park Superintendent.

11 RECORD OF DECISION INDIAN BOOSTER PU.\1P STATION

REVIEW OF CLEANUP ACTION AFTER SITE CLOSURE

Gnder section 18 AAC 7S.380(d)(I) of the site cleanup rules, DEC may require additional action ifnew information is discovered which leads DEC to make a determination that the cleanup is not protective of human health, safety, and welfare, or the environment. Therefore, after cleanup activities are completed in accordance with this Record of Decision, the site may be reopened for further action if the cleanup is not protective of hUman health, safety, and welfare or the environment.

STATE OF ALASKA DEP ARTMEJ\T OF ENVIRONMENTAL CONSERVATION DIVISION OF SPILL PREVENTION AND RESPONSE

By: .) /7cr;:..L '!Ai Date--'4-~ ___ ,1999. ~

Manager, Contaminated Sites Remediation Program

12 RECORD OF DECISION I~DIAN BOOSTER peMP STATION

RECORD OF DECISION

INDIAN BOOSTER PUMP STATION

AERIAL PHOTO OF SITE VICINITY

LEGEND

•

~ MH-1 EXCAVATION

{ MW45

PROPOSED NEW MONITORING WELL LOCATION (TO BE INSTALLED)

CREEK GAUGE STATION LOCATION

- -------- ENSTAR NATURAL GAS PIPELINE

EXCAVATION LOCATION

EXISTING MONITORING WELL LOCATION

~ TRENCH LOCATION

. ,- ,- ,- ,- ,- ,. GROUNDWATER DEVELOPMENT CONTROL AREA BOUNDARY

- - - EXCAVATION CONTROL AREA BOUNDARY

CLASSP o WATER W~LL

PERIMETER NETWORK (TYPE 1 A

INTERIOR NETWORK (TYPE 2 APOC)

CREEK PROTECTION NETWORK (TYPE 3 APOC)

FREE PRODUCT NETWORK

SENTRY WELLS

DECOMMISSIONED WELLS

---------------------

E

N --= I w

0 100 200 !

APPROXIMATE SCALE IN FEET

400

R

---

RECORD OF DECISION

INDIAN BOOSTER PUMP STATION

ON-SITE GROUNDWATER MONITORING NETWORKS lf1"

I GROUP I FIGURE 2

220

200 -180 ::::: en E

160 -0 Z

140 0

120 ~ ~

100 Z W (.)

80 Z 0 (.)

60 0 0::

40 C

20

0 COLOR SCALE

LEt ~D --..... DEPTH OF GROUNDWATER BELOW

C'o "-... GROUND SURFACE (FEET) • DASHED WHERE INFERRED

• MONITORING WELL LOCATION

o MONITORING WELL GROUND SURFACE LOCATION

~ CREEK GAUGING STATION LOCATION

SHALLOW GROUNDWATER OCCURRANCE ORO CONCENTRATIONS (OCTOBER 1996)

Sample Location ORO (ma/n

CG-3 0.062

CG-4 0.0513

CG-5 0.0557

MW-2 0.129

MW-4 0.385 MW-5 0.138

MW-6 0.08

MW-7 0.242

MW-8 0.0664

MW-9 0.124

MW-10 0.0564

MW-11 0.0514

MW-12 0.077

MW-13 0.088 MW-14 0.09

MW-15 0.304 MW-16 0.103

Sample Location

MW-17

MW-18 MW-19

MW-20 MW-21

MW-22 MW-23 MW-26

MW-27 MW-28

MW-29R MW-30

MW-31 MW-34 MW-37 MW-38 MW-PH

ORO (mg/I)

212 0.104

0.078 0.094 0.66

100 (10/93\

0.161

245 0.0558 7.101

0.0872 1.27

0.253

0.17 0.386 99.5

3.1 2

CG = CREEK GAUGE MW = MONITORING WELL

ORO = Diesel Range Organ ics mg/I = Milligrams per Liter

NOT TO SCALE

RECORD OF DECISION INDIAN BOOSTER PUMP STATION

RESIDUAL CONTAMINANT LOCATION

DAMES & MOORE

~ I GROUP I

JOB NO: 09807'():!&-1eo DRAWN: ELK

DATE: JULY 1999 FILE: FIG03.DWG FIGURE 3

MEMORANDUM OF AGREEMENT

BETWEEN

THE ALASKA DEPARTMENT OF NATURAL RESOURCES

AND

THE ALASKA DEPARTMENT OF ENVIRONMENTAL CONSERVATION

This Memorandum of Agreement (MOA) is made between the State of Alaska, Department of Natural Resources, Division of Parks and Outdoor Recreation (hereinafter, "Parks") and the State of Alaska, Department of Environmental Conservation, Division of Spill Prevention and Response (hereinafter, "DEC"). DEC is the state agency which conducts, oversees, and approves activities associated with a discharge of oil or hazardous substances under the authority of AS 46.03, AS 46.04, and AS 46.09 and the regulations promulgated thereunder. Parks manages Chugach State Park under the authority of AS 41.21.120-41.21.125.

Purpose: This MOA creates an institutional control, see 18 AAC 75.375 (am 1122/1999), to provide notice of residual contamination; to protect human health, safety and welfare by minimizing potential exposure pathways to residual contaminated soil or contaminated groundwater; and to preserve the integrity of site cleanup activities or improvements. This MOA restricts groundwater development and soil excavation, thereby minimizing the potential risk to the public or to site workers of ingesting or contacting residual contaminated soil or contaminated groundwater. The conditions and restrictions set forth herein are to prevent the possibility that the property described below is developed, used, maintained or operated in a manner incompatible with the Indian Booster Pump Station Site Management Plan and to protect against uses of the property that are unsuitable in light of the Final Indian Booster Station Risk Assessment Report.

The Property: This MOAapplies to the Groundwater Development Control Area, containing 11 acres more or less, and the Excavation Control Area, containing 5.5 acres more or less, as described in the Indian Booster Pump Station Site Management Plan, herein referred to as the "Property," located partially within the S1I2 of the NW1I4 and the N1I2 of the SW1I4 ofs~ction 32, Township 11 North, Range 1 West, Seward Meridian, Alaska. See attached Figure 4 (Excavation and Groundwater Control Areas), Indian Booster Pump Station Site Management Plan dated June 3,1999.

Background: A jet fuel discharge of approximately 35,700 gallons occurred on August 3, 1993 from the Defense Fuel Supply Center (DFSC) Whittier to Anchorage pipeline at valve #7 near the Indian Booster Station in the vicinity of Indian, Alaska (ADEC spill #93-2101-215-01). DFSC operated the pipeline across Chugach State Park within right-of-way ADL # 32606. The discharge occurred within the Chugach State Park, near Indian Creek. DFSC responded to the discharge and reported recovering over 22,000 gallons of jet fuel. Residual petroleum remains in subsurface soil and groundwater at a depth of 10 to 20 feet below the ground surface.

DFSC conducted a site characterization and a risk assessment that indicated a significant risk to human health exists from contamination left in place should someone install drinking water wells and humans subsequently ingest contaminated groundwater. Therefore, the Indian Booster Pump Station Site Management Plan calls for cleanup actions and long-term groundwater monitoring until such time as either DEC approved cleanup levels are attained or DEC approves the termination of groundwater monitoring.

General Provisions:

1. This MOA shall automatically be terminated and be without further force or effect upon the execution by DEC and Parks of a Release of Memorandum of Agreement;

2. Nothing herein shall be deemed to ~reate in any third party the right to enforce this MOA; and

3. Nothing herein shall be deemed to limit the State's authority to bring an action against a third party under either State or federal law. Furthermore, this MOA does not limit in anyway the State's authority to require further cleanup actions by Defense Energy Support Center (DESC, formerly the DFSC) or any other responsible party should contamination be encountered.

MEMORANDUM OF AGREEMENT BETWEEN THE ALASKA DEPARTMENT OF NATURAL RESOURCES AND THE ALASKA DEPARTMENT OF ENVIRONMENTAL CONSERVATION PAGE 2

Parks agrees:

1. The conditions and restrictions set forth herein remain in force until such time as DEC and Parks execute a Release of Memorandum of Agreement;

2. To notify DEC immediately of any observed environmental problems, such as sheen on surface water, odors, stressed vegetation, or stains, believed to be associated with the jet fuel discharge;

3. To not drill any groundwater well within the bounds of the Property unless specifically authorized in writing by DEC;

4. To not disturb the groundwater monitoring system unless specifically authorized in writingby DEC;

5. To not excavate or otherwise disturb soil to a depth of greater than four feet below the ground surface without first notifying DEC's Contaminated Sites Remediation Program by telephone, fax, e-mail or memorandum seven days before commencing the activity (Parks will notify DEC within 24 hours should Parks, its contractors', agents, employees, and authorized representatives, encounter any petroleum-contaminated soil at any depth during excavation or other soil disturbance. In the case of an emergency requiring an immediate response, Parks may immediately begin to employ necessary action provided Parks notifies DEC in writing within 24 hours of commencing work and that Parks takes necessary steps to reestablish the DEC-approved groundwater monitoring system, should it be damaged.);

6. To bear the responsibility for any costs associated with removal or treatment of soil contamination if encountered at a depth greater than 10 feet below the ground surface during any excavation or soil disturbance activity caused or overseen by Parks, its contractors, agents, employees, and authorized representatives;

7. To provide DEC, its contractors, agents, employees, and authorized representatives, with full and unhindered access to the Property;

8. To notify holders of any existing or future utility easements, permits, or rights-of-way across the Property of the restrictions placed on soil excavation or disturbance activities and on the use of groundwater as well as the need to protect the groundwater monitoring system;

9. To maintain posted copies of this MOA at the two buildings located on the Property (the former pump house and the former groundwater treatment plant);

MEMORANDUM OF AGREEMENT BETWEEN THE ALASKA DEPARTMENT OF NATURAL RESOURCES AND THE ALASKA DEPARTMENT OF ENVIRONMENTAL CONSERVATION PAGE 3

10. To maintain any signs posted by the DESC (formerly DFSC) around the boundaries of the Groundwater Development Restriction Area or the Excavation Restriction Area; and

11. To request in writing that the Department of Natural Resources, Land Records Information Section depict this MOA on the land, mineral, and water estates of all State land status plats that include section 32, Township 11 North, Range 1 West, Seward Meridian, Alaska.

DEC agrees:

1. To advise and assist Parks in the interpretation and implementation of the Indian Booster Pump Station Site Management Plan and other site-related documents as well as the applicable provisions of 18 AAC 75 and 18 AAC 78.

STATE OF ALASKA DEP AR TMENT OF ENVIRONMENT AL CONSERVATION DIVISION OF SPILL PREVENTION AND RESPONSE

Manager, Contaminated Sites Remediation Program

STATE OF ALASKA DEPARTMENT OF NATURAL RESOURCES DIVISION OF PARKS AND OUTDOOR RECREATION

,1999.

B~~£ m Str 0

Date: 3 ~ ,1999. Director .

Attachment: Figure 4 (Excavation and Groundwater Control Areas), Indian Booster Pump Station Site Management Plan, dated June 3, 1999.

MEMORANDUM OF AGREEMENT BETWEEN THE ALASKA DEPARTMENT OF NATURAL RESOURCES AND THE ALASKA DEPARTMENT OF ENVIRONMENTAL CONSERVATION ..t. PAGE 4

LEGEND

_,_I_I_I_I_laI GROUNDWATER DEVELOPMENT CONTROL AREA BOUNDARY

EXCAVATION CONTROL AREA BOUNDARY

Q CREEK GAUGE STATION LOCATION

ENSTAR NATURAL GAS PIPELINE

EXCAVATION LOCATION

~ MONITORING WELL LOCATION

~ TRENCH LOCATION

E N 1-__

w

400 100 200 _

APPROXIMATE SCALE IN FEET

SITE MANAGEMENT PLAN

INDIAN BOOSTER PUMP STATION DAMES & MOORE

EXCAVATION AND [Dr M[ GROUNDWATER CONTROL 0'

AREAS I GROUP I FIGURE4

record of decision for cleanup indian booster pump station u.s. … · 1999. 8. 30. · station in...

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