## 41 Hutchins Drive

Portland, Maine 04102

www.woodardcurran.com T 800.426.4262

T 207.774.2112

F 207.774.6635

CMP O’Connor (222350) September 2009 Water Level Study 

# MEMORANDUM

TO: Roy Koster (CMP)

FROM: Josh Bowe, Geologist

DATE: September 15, 2009

RE: Water Level Study, O’Connor Company Superfund Site, Augusta, Maine

Woodard & Curran recently completed a groundwater level study at the O’Connor Superfund Site in Augusta, Maine. The study was conducted to evaluate the potential impact that blasting along Route 17 may have on the on-site bedrock groundwater plume.

On July 24, 2009 Josh Bowe (Woodard & Curran) deployed automated pressure transducers in two on-site monitoring wells (OW-202B and OW-302B) approximately three days prior to the initiation of the blasting. Manual water level readings were collected and transducers were programmed and installed in the twomonitoring wells. Transducers were programmed to collect water levels and temperature readings on a fiveminute interval. A barometric logger was deployed in OW-302B above the water table and the data from the logger was used to compensate wa ter level data for changes in ba rometric pressure . In addition, precipitation data were downloaded from the Augusta NOAA weather station ID# 170275 located at the Augusta Airport. Blasting on Route 17 adjacent to the O’Connor Site began on July 27 th 

## and W&C remobilized to the site on July 28 th 

## to download ambient water level data from the transducers and ensure proper operation. Blasting ceased near the site on July 29 th 

## and W&C mobilized to the site after blasting completion to download complete water level data sets . The transducers remained in place and recorded data through the month of August until their removal on September 3 rd 

## . Drilling and blasting logs were collected from D&C Construction to correlate blasting events to groundwater level and temperature data.

Attached to this memorandum are four time series graphs for OW-202B and OW-302B depicting groundwater level, groundwater temperature, and precipitation trends before, during, and after the blasting periods. In summary, Chart 1 for OW-202B and OW-302B show groundwater levels rising over the three day period prior to blasting. Groundwater levels steadily increased in response to a significant precipitation event on July 24 th 

## when the area received approximately 1.6 inc hes of precipitation. Groundwater levels generally remained steady while blasting was conducted July 27 th 

## through July 29 th 

## . Natural groundwater level cycles were observed in the two bedrock wells and are not attributed to blasting activities. After the blasting period, groundwater levels continued to rise after subsequent precipitation events on July 26 th 

## ,27 th



## , and July 31 st 

## . Groundwater level trends display a seasonal decrease during the month of August as a result of periods of reduced precipitation and limited recharge. Chart 2 for OW-202B and OW-302B display groundwater temperature trends for the period of record and indicate that groundwater temperatures remained steady and did not fluctuate greater than 0.1 degrees Celsius.

Based on the recorded groundwater data and observed natural water level trends, W&C concludes that blasting activities conducted adjacent to the O’Connor Superfund Site along the Route 17 corridor did not result in any significant or sudden changes in groundwater levels or temperatures. The transducers were removed from the on-site monitoring wells on September 3 rd



## .

cc: Roy Koster (CMP) Henri Vincent (W&C) Lori Moreau (W&C)

# CHART 1

Groundwater Levels at

OW-202B and OW-302BOW-202B Groundwater Level vs. Blasting Events and Daily Precipitation14151617181920212223247/24/09 7/28/09 8/2/09 8/6/09 8/11/09 8/15/09 8/20/09 8/24/09 8/29/09 9/2/09

Water Level (feet below measuring point)00.511.522.533.544.55 Daily Precipitation (inches)Groundwater LevelBlasting EventsDaily Precipitation (in)Route 17 Blasting EventsNatural CyclesOW-302B Groundwater Level vs. Blasting Events and Daily Precipitation18192021222324252627287/24/09 7/28/09 8/2/09 8/6/09 8/11/09 8/15/09 8/20/09 8/24/09 8/29/09 9/2/09

Water Level (feet below measuring point)00.511.522.533.544.55 Daily Precipitation (inches)Groundwater LevelBlasting EventsDaily Precipitation (in)Route 17 BlastingEventsNatural Cycles

# CHART 2

Groundwater Temperatures at

OW-202B and OW-302BOW-202B Groundwater Temperature vs. Blasting Events567891011121314157/24/09 7/28/09 8/2/09 8/6/09 8/11/09 8/15/09 8/20/09 8/24/09 8/29/09 9/2/09

Groundwater Temperature (C)Blasting EventsGroundwater TemperatureRoute 17 Blasting EventsOW-302B Groundwater Temperature vs. Blasting Events567891011121314157/24/09 7/28/09 8/2/09 8/6/09 8/11/09 8/15/09 8/20/09 8/24/09 8/29/09 9/2/09

Groundwater Temperature (C)Blasting EventsGroundwater TemperatureRoute 17 Blasting Events