COMMITMENT & INTEGRITY 

DRIVE RESULTS 

41 Hutchins Drive T 800.426.4262 

Portland, Maine 04102 T 207.774.2112 

www.woodardcurran.com F 207.774.6635 

May 3,2013 

Roy Koster, P.E. 

Manager - EH&S Compliance 

Central Maine Power Company 

83 Edison Drive 

Augusta, ME 04330 

Superfund Records Center 

SITE: O' (Onr\Or 

BREAK: TZ ~ 

OTHER: ZJiT^To 

i SDMS DocID 552560 

Re: O'Connor Company Superfund Site, Augusta, Maine 

Observation of Disturbed Soil Condition and Recommendations 

Dear Mr. Koster, 

As you requested, I accompanied you on a visit to the O'Connor Company Superfund site, April 30, 

2013, to examine an unusual disturbance of surficial soil. The disturbance first observed during a recent 

routine inspection by Central Maine Power can be broadly characterized as holes in the ground. The 

presence of holes raised question about cause, such as erosion, settlement, or animals. 

The area exhibiting the unusual soil disturbance is perhaps 500 square feet of grassed field positioned 

immediately downhill of the Designated Area's eastern margin. Within the disturbed area are multiple 

small holes best described as tunnels. Some tunnels are just beneath the dead vegetation from last 

growing season while other tunnels are at shallow depth in the soil. As shown in the attached photos, it 

was possible to probe into the tunnels with a metal measuring tape. At entrances to a few tunnels were 

larger voids on the order of 6 to 8 inches in width, height and depth. 

Upon seeing the situation and subsequently sharing photographic information with a colleague we have 

concluded the soil disturbance was caused by animals, likely voles or similar small rodents. Woodard & 

Curran is currently involved with a landfill site in Massachusetts where a vegetated final cover is 

exhibiting a nearly identical occurrence. There, voles were the confirmed cause. The single difference 

at the O'Connor site is the large holes near the tunnel entrances. We speculate the larger holes are the 

result of coyotes or another animal digging for a meal. 

Understanding the O'Connor site's remedy includes a clean protective soil layer covering contaminated 

soil; it is desirable to maintain the integrity of the covering soils. Although the vole tunnels we observed 

are outside the site's Designated Area where contaminated soils persist, it is possible that the animals 

will expand their habitation to other portions of the site, including the Designated Area. Therefore, it is 

desirable to eradicate the voles before the colony expands and the Designated Area is also affected. 

The existing coyote holes should be filled with soil to eliminate tripping hazards and reduce possibility of 

erosion. The vole tunnels can be left as-is to recover through collapse or fill with vegetation roots. 

In conclusion, Woodard & Curran recommends that CMP take an active approach to remove the vole 

colony. A professional exterminator should be contacted for additional guidance and made aware other 

wildlife is evidently present. Maintain the frequency of site inspections; being cognizant the vole tunnels 

are most visible when the grass is first emerging in early spring. No additional course of action beyond 

the routine inspections and maintenance appears necessary. 
WOODARD 

&CURRAN 

We hope you find the opinions useful for providing a solution to a potential problem. If there are further 

questions or need for assistance, please contact me at 1-800-426-4262 or email 

pporada(5)woodardcurran.com. Thank you for the opportunity to assist CMP with this issue. 

Sincerely, 

WOODARD & CURRAN INC. 

Paul Porada, P.E. 

Vice President 

PJP 

226630.13 

Enclosures: Photos 

cc: Terry Connelly, US EPA 

Claudia Sait, Maine DEP 

CMP (226630) 

2013.05.03 Letter.Docx 

2 May 3,2013 
Affected Area, Boundary Highlighted 

Remnants of animal burrow in soil surface and beneath vegetation. 

CMP (226630) 

2013.05.03 Letter.Docx 

3 May 3,2013 
CM

P (226630) 

2013.05.03 Letter.Docx 

4 May 3,2013 
Larger size hole dug at 

entrance to a burrow. Roughly 

hemispherical in shape, 6 to 8 

inches diameter. Note 

excavated soil on ground 

between hole and boots. 

CMP (226630) 

2013.05.03 Letter.Docx 

5 May 3,2013