FINAL BVSL PT Q4-06

Final Report of

Fourth Quarter 2006 Operation & Monitoring Report

Phase IIA Groundwater Remediation System Bitterroot Valley Sanitary Landfill

Ravalli County, Montana

July 2007

Bitterroot Valley Sanitary Landfill Fourth Quarter 2006 Phase IIA Operations & Monitoring Report

Tetra Tech July 2007 i

EXECUTIVE SUMMARY

The National Institutes of Health (NIH) initiated a third phase (Phase IIA) of groundwater remediation at the Bitterroot Valley Sanitary Landfill (BVSL) facility in 1997. The Phase IIA Groundwater Remediation System is designed to intercept and treat contaminated groundwater in the upper aquifer migrating from the BVSL. The purpose of this action is to promote restoration of the aquifer to allow support of its original uses including drinking, industry, and agriculture.

The NIH implemented a two-part interim remedial action (IRA) at the BVSL in 1993 and 1994 to remediate chloroform and other waste chemicals disposed of in the landfill during the period from 1981 to 1985. The IRA consisted of removing and treating soil and water from the source area that was contaminated by chloroform and other volatile organic compounds (VOCs). The groundwater treatment system installed during the IRA remediated approximately 9.2 million gallons of groundwater from 1994 through October 1997 (e.g., Phase I Groundwater Remediation). Treated effluent produced by the system was discharged at a land application discharge area under Montana Ground Water Pollution Control System (MGWPCS) permit MGWPCS-G1004 dated August 5, 1994.

The groundwater standard for chloroform of 60 micrograms per liter (µg/L) is presented in the numerical water quality standards published in Circular WQB-7 by the Montana Department of Environmental Quality (DEQ 1999). This standard is being exceeded in groundwater migrating from the former landfill area. Phase IIA groundwater remediation is intended to intercept this groundwater and reduce the amount of time necessary for groundwater downgradient of the former landfill to comply with the water quality standard for chloroform.

Major components of the Phase IIA system include four source area groundwater recovery wells, six groundwater interception wells, two downgradient demonstration monitoring wells, a water treatment system, treatment system monitoring components, and an outfall structure located in the North Channel of Bear Creek (Bear Creek). Treated effluent from the Phase IIA system is pumped from the treatment building to the Bear Creek outfall and discharged. The Montana Department of Environmental Quality (DEQ) stated in a letter from their Permits Section of the Water Protection Bureau dated November 10, 1997, to the CECRA Program Hazardous Waste Site Cleanup Bureau, that a Montana Pollution Discharge Elimination System (MPDES) permit would not be required if substantive requirements of CECRA (Section 75-10-721) were met. These substantive requirements consist of meeting discharge limits of non-detect (less than or equal to upstream background) at the required reporting values given in Circular WQB-7 (DEQ 1999). Tetra Tech, Inc. (Tetra Tech, formerly Maxim) prepared an operation, maintenance and monitoring plan to guide management of the Phase IIA system. After DEQ reviewed the Operation, Maintenance, and Monitoring Plan, Tetra Tech issued the document in June 1998. The document was updated in January 2007 to include changes and repairs to the system (Tetra Tech 2007).

The original system installed during 1998 included two source area groundwater recovery wells (R-1 and R-2) and six groundwater interception wells (R-3S through R-8D). Additional groundwater recovery wells R-9D and R-10 were added to the system during March 2000 and September 2004, respectively.

Tetra Tech July 2007 ii

Recovery well R-9D was installed in the vicinity of monitoring well BR-GW-36D as a result of additional aquifer characterization work completed during 1999 (Maxim 1999a, 1999b, and 2000b). During this characterization, monitoring wells were installed to delineate the extent of VOC-affected groundwater in the vicinity of monitoring well BR-GW-36D. Recovery well R-10 was installed in the vicinity of monitoring well BR-GW-41S because of the presence of relatively high chloroform concentrations in samples from this well during semi-annual groundwater monitoring events in 2004 (Maxim 2004a, 2004b). Before wells R-9D and R-10 were brought into full-time operation, batch tests were completed to demonstrate that the groundwater treatment system could effectively treat groundwater pumped from these wells in addition to water pumped from the other remediation wells operating at the site (Maxim 2000b, 2004c).

This report presents results of system operation for the third quarter (October through December) of 2006. Monthly monitoring was performed and water samples were taken from influent and effluent piping at the treatment system on January 8, 2006. Key findings from fourth quarter 2006 monitoring are presented below.

Key Findings

• The system recovered and treated approximately 9.0 million gallons of water during the quarter, bringing the cumulative volume of groundwater recovered and treated at the site (including 9.2 million gallons during the IRA from 1994-97) to approximately 362 million gallons.

• Approximately 83.1 percent of the influent water was delivered by four operating interception wells (R-4D, R-6D, R-7S and R-8D) on Meridian Road.

• Wells R-3S and R-5S were not operating during the quarter because of insufficient water in well casings.

• Problems affecting flow readings that are recorded by the SCADA system were caused by rotors of the flow meters becoming stuck in inlet piping of several wells and database errors.

Average flow readings were calculated using appropriate data respective of these system errors.

• During the fourth quarter many updates to the system were completed prior to the end of the current contract which included the following:

o The groundwater pump in well R-5S was replaced.

o The transfer pump and motor were replaced at the outlet of the air stripper sump.

o Mechanical flow meters were removed and piping was installed on the outfall and infiltration trench piping.

o Hangers for the air intake stack were replaced.

o The compression coupler on the discharge piping was repaired and adjusted.

Tetra Tech July 2007 iii o Replaced the float switch in the air stripper sump that activates the transfer pump.

o Cleaned and repaired blower, including replacing bearings.

o Replaced all galvanized piping on the inlet piping manifold with schedule 80 PVC.

o Adjusted all rubber gaskets on the air stripper trays.

o Replaced rotor paddles in the inlet flow meters.

• The system was shut down from December 20, 2006 until January 4, 2007. Influent and effluent samples were taken, on January 8, 2007, after the updates were complete and the system was restarted.

• The sample of treatment system influent (combined flow of all operating recovery/interception wells) collected in January exhibited a chloroform concentration of 21 µg/L, which is lower than the concentration of 24 µg/l measured during the previous year (Fourth Quarter, January 2006).

• Measurable concentrations of chloroform (24 µg/l), chloromethane (2.4 µg/l), cis-1,2-dichloroethene (2.4 µg/l), dichlorodifluoromethane (0.5 µg/l), tetrachloroethene (0.6 µg/l), and vinyl chloride (0.1 µg/l), were detected in the influent water sample. All VOCs were below applicable WQB-7 standards (DEQ 1999) in the system influent.

• Chloromethane (4.7 µg/l) was detected in the sample of treatment system effluent. Due to the increase from the influent to the effluent sample, Tetra Tech believes the result is a false positive error resulting from the use of out-of-date degraded hydrochloric (HCl) acid preservation during sampling. Influent and effluent will be retested in January 2007 with fresh HCl acid to confirm this hypothesis.

• Since activation in July 1998, the Phase IIA system has pumped 353 million gallons of contaminated groundwater, removing an estimated 79.5 kilograms (kg) of chloroform. Approximately 3.6 kg of chloroform was removed from treated groundwater in 2006.

Tetra Tech July 2007 iv

TABLE OF CONTENTS

EXECUTIVE SUMMARY............................................................................................................... I

1.0 INTRODUCTION

2.0 METHODS

2.1 SYSTEM OPERATION MONITORING

2.2 GROUNDWATER MONITORING

2.3 SAMPLING LOCATIONS, DATES AND ANALYSES

2.4 SYSTEM MAINTENANCE

3.0 RESULTS

3.1 SYSTEM OPERATION DATA

3.1.1 Flow Rates

3.1.2 Treated Water Volumes

3.2 GROUNDWATER ELEVATION

3.3 INFLUENT/EFFLUENT VOC DATA

3.4 CHLOROFORM MASS REMOVAL ESTIMATE

4.0 REFERENCES

LIST OF FIGURES

FIGURE 1 Location map FIGURE 2 Site Map FIGURE 3 Plan View System FIGURE 4 Water Level Wells FIGURE 5 Treatment Building Plan FIGURE 6 Flow Rate and Groundwater Elevation Graphs - Interception Wells FIGURE 7 Flow Rate and Groundwater Elevations Graphs - Source Area Wells FIGURE 8 Influent Chloroform Concentration Graph FIGURE 9 Chloroform Concentration Graph - Pumping Wells FIGURE 10 Chloroform Concentrations in Shallow Portion of Unit A, September/October 2006 FIGURE 11 Chloroform Concentration in Deep Portion of Unit A, September/October 2006 FIGURE 12 Chloroform Recovery Trends

Tetra Tech July 2007 v

LIST OF TABLES

TABLE 1 Monitoring Frequency and Parameters TABLE 2 Sampling Location and Dates TABLE 3 Fourth Quarter 2006 System Operation Data TABLE 4 Analytical Results For Groundwater Treatment System – Fourth Quarter 2006

LIST OF APPENDICES

APPENDIX A WATER LEVEL DATA

APPENDIX B ORGANIC WATER QUALITY DATABASE

APPENDIX C CHLOROFORM MASS RECOVERY ESTIMATE

Tetra Tech July 2007 1

1.0 INTRODUCTION

The National Institutes of Health (NIH) completed construction of the Phase IIA Groundwater Remediation System at the Bitterroot Valley Sanitary Landfill in June 1998. The landfill is located in Ravalli County, about one mile south of Victor, Montana (Figure 1), and received waste laboratory chemicals during the period of 1981 to 1985. NIH retained Tetra Tech, Inc. (Tetra Tech, Formerly Maxim Technologies) to design, construct, operate and monitor performance of the Phase IIA system under contract number 263-95-C-0252 between NIH and Tetra Tech. This work is being conducted voluntarily under the auspices of the Montana Department of Environmental Quality's (DEQ) Comprehensive Environmental Clean-up and Responsibility Act (CECRA).

The purpose of Phase IIA remediation is to promote restoration of the upper aquifer to its original uses including drinking, industry, and agriculture. The system has been operated on a nearly full-time basis since activation on July 10, 1998. A document titled Operation, Maintenance, and Monitoring Plan, Phase IIA Groundwater Remediation System was issued in June 1998, subsequent DEQ review and approval is used to guide activities described in this report. The document was updated in January 2007 to include changes and repairs to the system (Tetra Tech 2007). The site map and the layout of the Phase IIA Groundwater Remediation System are presented in Figures 2 and 3. The major system components include:

A groundwater recovery system consisting of four source area groundwater recovery wells (R- 1, R-2, R-9D and R-10) located at the former landfill, and six groundwater interception wells (R- 3S, R-4D, R-5S, R-6D, R-7S, and R-8D) located downgradient of the former landfill between U.S.

Highway 93 and Meridian Road.

A water treatment system including air stripper, forced draft blower, effluent discharge pump, batch tank, water piping, and exhaust stack.

System monitoring components including electronic and mechanical flow meters, a supervisory control and data acquisition (SCADA) system and an alarm interlock system.

Discharge piping leading from the treatment building to an outfall structure located in the North Channel of Bear Creek.

Each groundwater recovery and interception well is completed in the uppermost aquifer at the site, hereafter referred to as hydrostratigraphic Unit A (Maxim 2001). This unit is typically divided into two hydrogeologic regimes designated as the shallow and deep portions of Unit A. Wells R-3S, R-5S, and R- 7S are designed to intercept groundwater migrating from the landfill in the shallow portion of Unit A.

Wells R-4D, R-6D and R-8D are designed to intercept groundwater migrating from the landfill in the deep portion of Unit A. Well R-9D is used to recover groundwater near the source area from the deep portion of Unit A. Well R-10 is used to recover groundwater near the source area from both the shallow and deep portions of Unit A. Wells R-1 and R-2 were installed during NIH’s interim remedial action (IRA, Phase I Groundwater Remediation) in 1994 and are used to recover groundwater near the source area from the shallow portion of Unit A. All recovered groundwater is pumped to the groundwater treatment building through buried PVC piping. After air stripping, effluent is pumped from the treatment building to the outfall structure at Bear Creek for discharge.

Location and Vicinity Map

Victor, Montana

FIGURE 1

project/BVSL/loc

From USGS 7.5’ Victor Quad 1967

Feet 2000

Bitterroot Valley Sanitary Landfill

M O N T A N A Missoula

Victor

RAVALLI COUNTY

Groundwater Recovery/Interception Well Performance Monitoring Well Existing Buried Piping

R-7S,8D

R-5S,6D

GW-81S

GW-82D

R-3S,4D

R-2

Former Land Application Area

(MGWPCS-G1004)

R-1

R-9D

Existing power pole

Treatment BuildingFormer

Treatment Shed

Discharge Pipe to Bear Creek

Vacuum/Pressure Relief Valves

Outfall to Bear Creek

R-10

Source Removal Area project\BVSL\fig3july06

Phase IIA Groundwater Remediation System Bitterroot Valley Sanitary Landfill

Victor, Montana

FIGURE 3

From Montana Aerial Photography, Missoula, MT (March 1999)

N

0 Feet 200

Humdinger Lane

Pine Lane

North Channel Bear

Creek

M e rid ia n

R o a d

H ig h w a y

Dinger Lane

Tetra Tech July 2007 5

The DEQ stated in a letter from their Permits Section of the Water Protection Bureau to the CECRA Program Hazardous Waste Site Cleanup Bureau (dated November 10, 1997) that a Montana Pollution Discharge Elimination System (MPDES) permit would not be required for the system if substantive requirements of CECRA (Section 75-10-721) were met (Tetra Tech 2007). These substantive requirements consist of meeting discharge limits of non-detect (less than or equal to upstream background) at the required reporting values given in Circular WQB-7, Montana Numeric Water Quality Standards (DEQ 1999).

This report presents monitoring data collected during October, November, and December 2006.

Monitoring was performed in general accordance with methods described in Tetra Tech (2007).

Groundwater elevations measured in all site monitoring wells since 1998 and the verified database for water samples collected from the treatment system since July 1998 are contained in Appendices A and B, respectively. Appendix C of this report contains the assumptions and methods used to estimate chloroform recovery.

Tetra Tech July 2007 6

2.0 METHODS

Tetra Tech monitored the Phase IIA Groundwater Remediation System in accordance with the frequencies and parameters summarized in Table 1 and described in Maxim (1998). This section describes methods used to obtain system operation and performance monitoring data. Figures 2 and 3 show the location of project monitoring wells and the layout of the groundwater treatment system, respectively.

TABLE 1 Monitoring Frequency and Parameters

MONITORING ACTIVITY – FOURTH QUARTER 2006

MONTH Sample Influent

Effluent

Sample Pumping

Wells

Record Operating

Parameters

Remote System

Monitoring

Measure Water Levels

October √ √

November √ √

December √* √ √ √*

Notes:

indicates monitoring activity was performed.

* Samples were collected on January 8, 2007 due to system being shut down for updates.

2.1 SYSTEM OPERATION MONITORING

Following activation of the system on July 10, 1998, monitoring was conducted at frequent intervals (daily to weekly). After several weeks of operation, system monitoring was conducted at less frequent intervals (quarterly) as confidence was gained in the effectiveness and dependability of the system. During January 1999 through March 2000, Tetra Tech performed quarterly system monitoring. After addition of well R- 9D to the system, samples of treatment system influent and effluent water were collected on a more frequent basis from March through June 2000 and analytical results showed that VOCs continued to be removed by the treatment system (Maxim 2000a, b). On September 28, 2004, well R-10 was added to the Phase IIA system on a full time basis. Tetra Tech performed batch tests which demonstrated that the groundwater treatment system had capacity for the increased influent flow rate caused by addition of well R-10 (Maxim 2004c).

Tetra Tech performed monitoring of the treatment system during the quarter (Table 1). System operation was confirmed using the remote SCADA system. A list of operational parameters that are

Tetra Tech July 2007 7 being monitored is presented in Section 3.0 of Tetra Tech (2007). Routine monitoring activities completed during the fourth quarter of 2006 are presented as follows.

• Tetra Tech recorded system operation parameters including pressures, flow rates, and total treated water volumes during periodic site visits. Visual system inspections (i.e., pumps, piping, gauges, etc.)

were also completed to ensure proper operation.

• System operation parameters were electronically recorded at ten-minute intervals by the SCADA system. Parameters stored in the SCADA system computer were uploaded to the project database approximately once a week.

• Issues with data collected from the SCADA system were discovered. Data gaps in the system records, zero readings and inaccurate data are present in the tabular data files.

2.2 GROUNDWATER MONITORING

Groundwater elevations in wells located within the system’s area of influence were measured on January 8, 2007, the same day influent and effluent samples were collected, to provide a basis for determining the effect of remediation system operation on the groundwater flow system. Figure 4 shows the locations of these wells.

2.3 SAMPLING LOCATIONS, DATES AND ANALYSES

Table 2 lists water sample collection points for the fourth quarter of 2006. Water samples were collected from the treatment system influent and effluent piping on January 8, 2007. Locations of water sampling points in the treatment building are shown on Figure 5.

Each water sample was containerized and submitted under custody to Northern Analytical Laboratories, Inc. in Billings, Montana. The samples were analyzed for VOCs according to EPA method 524.2.

2.4 SYSTEM MAINTENANCE

The following summarizes system maintenance activities for the quarter.

• Routine system maintenance was performed monthly and consisted of cleaning the air intake screen, restoring clogged flow meters, and inspecting the Bear Creek outfall for obstructions.

• Wells R-3S and R-5S were not operating during the quarter because of insufficient water in well casings.

• Problems affecting flow readings that are recorded by the SCADA system were caused by rotors of the flow meters becoming stuck in inlet piping of several wells and database errors. Average flow readings were calculated using appropriate data respective of these system errors.

Tetra Tech July 2007 8

• During the fourth quarter many updates to the system were completed prior to the end of the current contract which included the following:

o The groundwater pump in well R-5S was replaced.

o The transfer pump and motor were replaced at the outlet of the air stripper sump.

o Mechanical flow meters were removed and piping was installed on the outfall and infiltration trench piping.

o Hangers for the air intake stack were replaced.

o The compression coupler on the discharge piping was repaired and adjusted.

o Replaced the float switch in the air stripper sump that activates the transfer pump.

o Cleaned and repaired blower, including replacing bearings.

o Replaced all galvanized piping on the inlet piping manifold with schedule 80 PVC.

o Adjusted all rubber gaskets on the air stripper trays.

o Replaced rotor paddles in the inlet flow meters.

Tetra Tech July 2007 10

TABLE 2 Sampling Location and Dates

FOURTH QUARTER 2006

CATEGORY WELL or

LOCATION

October November December

R-1 R-2

R-9

SOURCE AREA

RECOVERY WELLS

R-10 R-3S R-5S

SHALLOW

INTERCEPTION WELLS

R-7S

R-4D R-6D

DEEP INTERCEPTION

WELLS

R-8D

INFLUENT √*

AIR STRIPPER

EFFLUENT √*

NOTES:

Sample locations are designated “SP” on Figure 5 of this report.

√ Indicates sample was collected.

* Samples were collected on January 8, 2007 due to system being shut down for updates.

Source area recovery wells are located in the former landfill area.

Interception wells are located between Meridian Road and U.S. Highway 93, downgradient of the former landfill.

Blank cells indicate sample was not collected.

Tetra Tech July 2007 12

3.0 RESULTS

Monitoring data collected during the fourth quarter of 2006 are presented below.

3.1 SYSTEM OPERATION DATA

System operation data are summarized in Table 3. Other operation data, including pressure readings and valve settings for each pumping well, are stored in the project file at Tetra Tech’s Missoula, Montana office.

Trends in flow rates and groundwater elevation for each groundwater interception well and each source area recovery well are present in Figure 6 and 7, respectively. Key operational monitoring results are presented below.

3.1.1 Flow Rates

The target flow rate for each well is based on available drawdown and maximum pump capacity. The average flow rates presented in this section are calculated by averaging the flow rates measured at 10-minute intervals recorded by the SCADA system. Results of flow rate monitoring include:

• Wells R-3S and R-5S were not operating during the quarter because of insufficient water in well casings. Water elevations in these wells were measured on January 8, 2007. Water levels were comparable to levels in the fourth quarter of 2005. R-5 has not been in operation since January 2005, and R-3 shut down in August 1998. These low water conditions affecting the shallow interception wells appear to be a result of the cumulative effect of eight years of drought and continuous groundwater pumping.

• The pump in R-5S was replaced in October 2006 as par of the contract completion, to ensure a functioning pump when and/or if groundwater levels increase in the future.

• The average flow rate from the shallow interception well, R-7, was 14.0 gpm for the quarter. A normal range from this well for this time of year is 12 to 38 gpm.

• The combined average flow rate from deep interception wells R-4D, R-6D, and R-8D was 65.0 gpm, which is within the historical range of 60 to 70 gpm measured during the recent years.

• The combined average flow rate from wells R-1, R-2 and R-10 was 11.9 gpm. Pumps in these three wells operate independently on a cyclical pattern. Flows from the three wells are comparable to flows in recent years.

• The average flow rate from well R-9D was 4.2 gpm, which is near the average range of 5 to 6 gpm pumped from this well during recent years.

• Approximately 83 percent of the influent water was delivered by the four operating Meridian Road interception wells (R-4D, R-6D, R-7S and R-8D).

Tetra Tech July 2007 13

TABLE 3 Fourth Quarter 2006 System Operation Data

FLOW RATES (GPM)¹

CATEGORY WELL or

LOCATION

October November December Average²

FLOW

TOTAL3

(MG)

R-1/R-2/R-10* 11.6 12.2 11.8 11.9 23.41 SOURCE AREA

RECOVERY

WELLS R-9D** 4.3 4.2 4.2 4.2 16.35

R-3S 0 0 0 0.0 0.14

R-5S 0 0 0 0.0 21.98

SHALLOW

INTERCEPTION

WELLS

R-7S 14.0 14.0 14.0 14.0 51.62

R-4D 30.9 30.9 30.8 30.9 99.71

R-6D 22.0 22.0 22.0 22.0 88.16

DEEP

INTERCEPTION

WELLS

R-8D 12.5 11.8 12.0 12.1 59.04

BEAR CREEK DISCHARGE 102.3 103.1 103.0 102.5 353

NOTES:

NA - not applicable.

R-1/R-2/R-10* - water flowing from wells R-1 and R-2 was combined on March 17, 2000. Flow from R-10 was combined with R-1/R-2 piping on September 28, 2004.

R-9D** - well R-9D was activated on March 3, 2000.

¹ - Flow rates as instantaneous averages in gallons per minute (gpm) are recorded every ten minutes by the data acquisition system (SCADA), values shown are monthly averages when operating.

² - Values shown are monthly instantaneous averages that include intervals when discharge pump does not operate. The system discharges treated water to Bear Creek periodically at flow rates ranging from 0 to 225 gpm.

³ - Cumulative flow of water from individual well meters in millions of gallons (MG) since system activation on July 10, 1998.

The discharge total does not include 9.2 MG of water treated during the IRA.

4 - The difference in influent volume and discharge volume is due to an over estimation of individual well influent flow rates measured at the well head compared to the cumulative effluent flowing through a centralized flow meter.

Notes: (feet) - groundwater elevations are relative to an arbitrary site datum.

(gpm) - gallons per minute Flow Rate and Groundwater Elevation Graphs Groundwater Interception Wells

Phase IIA Groundwater Remediation System Bitterroot Valley Sanitary Landfill

Victor, Montana

FIGURE 6

R-3S

Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 DATE (Month-Year)

G R

O U

N D

W

AT

ER

E

LE

VA

TI

O

N (f ee t)

AV

ER

AG

E

FL

O

W R

AT

E

(g pm

R-5S

Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 DATE (Month-Year)

G R

O U

N D

W

AT

ER

E

LE

VA

TI

O

N (f ee t)

AV

ER

AG

E

FL

O

W R

AT

E

(g pm

R-7S

Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07

DATE (Month-Year)

G R

O U

N D

W

AT

ER

E

LE

VA

TI

O

N (f ee t)

AV

ER

AG

E

FL

O

W R

AT

E

(g pm

R-4D

Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07

DATE (Month-Year)

G R

O U

N D

W

AT

ER

E

LE

VA

TI

O

N (f ee t)

AV

ER

AG

E

FL

O

W R

AT

E

(g pm

860870880890900910920930940

Ja n-

A pr

-9

Ju l-9

O ct

-9

Ja n-

A pr

-9

Ju l-9

O ct

-9

Ja n-

A pr

-0

Ju l-0

O ct

-0

D ec

-0

A pr

-0

Ju l-0

O ct

-0

D ec

-0

A pr

-0

Ju l-0

S ep

-0

D ec

-0

A pr

-0

Ju l-0

S ep

-0

D ec

-0

M ar

-0

Ju n-

S ep

-0 4 0510152025303540

Relative Groundwater Elevation System Started July 10, 1998 Shutdown Study 4/28/04 - 9/28/04 Flow Rate

LEGEND

R-8D

Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 DATE (Month-Year)

G R

O U

N D

W

AT

ER

E

LE

VA

TI

O

N (f ee t)

AV

ER

AG

E

FL

O

W R

AT

E

(g pm

R-6D

Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 DATE (Month-Year)

G R

O U

N D

W

AT

ER

E

LE

VA

TI

O

N (f ee t)

AV

ER

AG

E

FL

O

W R

AT

E

(g pm

1099HYDcurrentq406

Notes: (feet) - groundwater elevations are relative to an arbitrary site datum (gpm) - gallons per minute

Piping for wells R-1 and R-2 were combined on 3/17/00; Flow from R-10 was combined with R-1 and R-2 on 9/28/04

Before July 2000, piping prevented measurement of depth to water in wells R-1 and R-2

Groundwater elevation shown for well R-9D on July 14, 2000 was measured while pump was not operating

Flow Rate and Groundwater Elevation Graphs Source Area Recovery Wells

Phase IIA Groundwater Remediation System Bitterroot Valley Sanitary Landfill

Victor, Montana

FIGURE 7

R-9D

Jan-00 Jul-00 Jan-01 Jul-01 Jan-02 Jul-02 Jan-03 Jul-03 Jan-04 Jul-04 Jan-05 Jul-05 Jan-06 Jul-06 Jan-07

DATE (Month-Year)

A V

E R

A G

E F

LO

W

R A

TE

(g pm

G R

O U

N D

W A

TE

R

E

LE

V A

TI

O

N (f ee t)

R-9D Pumping Rate Shutdown Study 3/28/04 - 9/28/04 R-9D Groundwater Elevation Recovery Well R-9D Activated 3/3/00

R-1, R-2 and R-10

Jan-

Jul-98 Jan-

Jul-99 Jan-

Jul-00 Jan-

Jul-01 Jan-

Jul-02 Jan-

Jul-03 Jan-

Jul-04 Jan-

Jul-05 Jan-

Jul-06 Jan-

DATE (Month-Year)

A V

E R

A G

E F

LO

W

R A

TE

(g pm

G R

O U

N D

W A

TE

R

E

LE

V A

TI

O

N (f ee t)

R-1 Pumping Rate R-2 Pumping Rate R-1 & R-2 (Combined Flow After 3/17/00) Phase IIA System Activated July 10, 1998 Shutdown Study 3/28/04 - 9/28/04 R-1/R-2/R-10 (Combined Flow After 9/28/04) R-1 Groundwater Elevation R-2 Groundwater Elevation

1099HYDcurrentq406

Tetra Tech July 2007 16

3.1.2 Treated Water Volumes

Electronic flow meters record the cumulative flow of water from each well as well as effluent discharge to Bear Creek (Figure 5). Since water was pumped through electronic flow meters during system validation and batch testing, total flows presented in Table 3 are determined by adding the cumulative flow passing each flow meter during the quarter and adding to the total flow reported during the previous monitoring.

Approximately 9.0 million gallons (MG) of treated groundwater were discharged to Bear Creek during the quarter. This total consists of approximately 7.5 MG of groundwater pumped from interception wells and

1.5 MG pumped from recovery wells. Since activation in July 1998, the Phase IIA system has pumped 353 MG of contaminated groundwater.

3.2 GROUNDWATER ELEVATION

Depth to water and groundwater elevations measured on January 8, 2007 and previous monitoring event are presented in Appendix A. Figure 6 presents groundwater hydrographs for groundwater interception wells R-3S through R-8D. Figure 7 presents groundwater hydrographs for groundwater recovery wells R-1, R-2, R-9D and R-10. Fourth quarter 2006 groundwater elevations are generally lower in the remediation wells in comparison to fourth quarter 2005 data.

3.3 INFLUENT/EFFLUENT VOC DATA

Tables 4 list the types and concentrations of VOCs that have been detected in Phase I and Phase IIA pumping wells and influent/effluent water samples on at least one occasion. A graph of chloroform concentrations in samples of treatment system influent (i.e., combined flow from wells R-1 through R-

10) is shown on Figure 8. Figure 9 presents chloroform concentration graphs for wells R-1 through R-

10. Appendix B contains VOC analytical results for samples collected since 1998. Interpretations of data presented in Figures 8 and 9 and Table 4 are presented as follows:

• The sample of treatment system influent (combined flow of all operating recovery/interception wells) collected in January exhibited a chloroform concentration of 21 µg/L, which is lower than the concentration of 24 µg/l measured during the previous year (Fourth Quarter, January 2006).

• Measurable concentrations of chloroform (24 µg/l), chloromethane (2.4 µg/l), cis-1,2-dichloroethene (2.4 µg/l), dichlorodifluoromethane (0.5 µg/l), tetrachloroethene (0.6 µg/l), and vinyl chloride (0.1 µg/l), were detected in the influent water sample. All VOCs were below applicable WQB-7 standards (DEQ 1999) in the system influent.

• Chloromethane was detected in the sample of treatment system effluent. Due to the increase from the influent (2.4 µg/l) to the effluent (4.7 µg/l) sample, Tetra Tech believes the result is a false positive error resulting from the use of out-of-date degraded hydrochloric (HCl) acid preservation during sampling. Influent and effluent will be retested in January 2007 with fresh HCl acid to confirm this hypothesis.

Tetra Tech July 2007 17

• While influent chloroform concentrations have varied during recent quarterly monitoring events (Figure 8), however overall chloroform concentrations in samples from system pumping wells continue to exhibit a decreasing trend (Figure 9).

Figures 10 and 11 present chloroform isocontours interpreted from groundwater data collected during the September/October 2006 semiannual monitoring event. Tetra Tech provided a discussion of these data in the September/October 2006 Semiannual Groundwater Monitoring Report (Tetra Tech 2006).

TABLE 4

ANALYTICAL RESULTS FOR GROUNDWATER TREATMENT SYSTEM - FOURTH QUARTER 2006

Phase IIA Groundwater Remediation System

Bitterroot Valley Sanitary Landfill

GROUNDWATER

PARAMETER TREATMENT SYSTEM

INF EFF**

01/08/07 01/08/07

Benzene 0.5 5 5

Chloroethane * * *

Chloroform 0.5 57 60 21 Chloromethane * 28 28 2.4 4.7

Dichlorodifluoromethane 1.0 1,400 1,400 0.5

Ethylbenzene 0.5 700 700

1,4-Dichlorobenzene 10 75 75

1,1-Dichloroethane 1.0 * *

1,2-Dichloroethane 0.5 3.8 4.0 c-1,2-Dichloroethene 0.5 70 70 2.4 t-1,2-Dichloroethene 0.5 100 100

Methylene Chloride 2.0 5 5

Naphthalene 10 28 28

Tetrachloroethene 0.5 5 5 0.6

Toluene 0.5 1,000 1,000

1,1,1-Trichloroethane 0.5 200 200

Trichloroethene 0.5 5 5

1,2,4-Trimethylbenzene * * *

1,3,5-Trimethylbenzene * * *

Total Xylenes 1.0 10,000 10,000

Vinyl Chloride 0.15 0.15 0.15 0.1

NOTES:

Phase IIA System activated July 10, 1998; Well R-9D activated March 3, 2000.

Samples analyzed by EPA method 524.2

All results in micrograms per liter (µg/l)

WQB-7 -- MDEQ's Circular WQB-7 Human Health Standards for groundwater. September, 1999.

" * " Not included in WQB-7

" ** " Indicates WQB-7 surface water standards apply since treated water is discharged to Bear Creek

Blank cell indicates results below practical quantitation limit

-- indicates parameter not measured/analyzed

WQB-7

Reporting

Limit

WQB-7

Standard

SW

WQB-7

Standard

GW

P&T Lab Data Q4_06

Tetra Tech July 2007 19

Jul-98 Dec-98 Jul-99 Dec-99 Jun-00 Dec-00 Jun-01 Dec-01 Jun-02 Dec-02 Jun-03 Dec-03 Jun-04 Dec-04 Jun-05 Dec-05 Jun-06 Dec-06

DATE

C hl or of or m

C on ce nt ra tio n (µ g/ l)

Influent Chloroform Concentration

System On

System Off

R-9D Activated March 2, 2000

Shutdown Study

R-10 Activated September 28, 2004

FIGURE 8 Influent Chloroform Concentration Graph

Victor, Montana

Chloroform Concentration Graph - Pumping Wells Phase IIA Groundwater Remdiation System

Bitterroot Valley Sanitary Landfill Victor, Montana

FIGURE 9

CHLOROFORM CONCENTRATIONS IN PUMPING WELLS

Jul-98 Jan-99 Jul-99 Jan-00 Jul-00 Jan-01 Jul-01 Jan-02 Jul-02 Jan-03 Jul-03 Jan-04 Jul-04 Jan-05 Jul-05 Jan-06 Jul-06 Jan-07

DATE (Month-Year)

W el ls R

-1 th ro ug h R

-8 D a nd

R -1

(µ g/ l)

W el l R -9

D o nl y

(µ g/ l)

R-1 R-2 R-3S R-4D R-5S R-6D R-7S R-8D System Activated R-10 R-9D

R-9D Activated (3-3-00)

System Activated (7-10-98)

R-10 Activated (9-28-04)

P&T Lab Data Q4_06

Tetra Tech July 2007 23

3.4 CHLOROFORM MASS REMOVAL ESTIMATE

Appendix C contains the estimated chloroform recovery results for the Phase IIA system. Important assumptions used to estimate chloroform recovery are also described in Appendix C. Third quarter data was used to estimate removal rates. Since activation in July 1998, the Phase IIA system has recovered an estimated 79.5 kilograms of chloroform from groundwater. In 2006 an estimated 3.6 kilograms of chloroform were removed. Figure 12 illustrates the general trends in chloroform recovery for the system.

1998 1999 2000 2001 2002 2003 2004 2005 2006

Year

C hl or of or m

R em ov ed

(k g)

Annual Removal Cumulative Removal

FIGURE 12 Chloroform Recovery Trends

Tetra Tech July 2007 24

4.0 REFERENCES

Maxim Technologies, Inc.®, 1999a. Summary of Results, Phase IIB Source Area Characterization, Bitterroot Valley Sanitary Landfill, Ravalli County, Montana. Document issued to the Montana Department of Environmental Quality and the National Institutes of Health. April.

_____, 1999b. Work Plan for Additional Aquifer Characterization, Bitterroot Valley Sanitary Landfill, Ravalli County, Montana. Document issued to the Montana Department of Environmental Quality and the National Institutes of Health. August.

_____, 2000a. Second Quarter 2000 Monitoring Report, Phase IIA Groundwater Remediation System, Bitterroot Valley Sanitary Landfill, Ravalli County, Montana. Report issued to Montana Department of Environmental Quality and the National Institutes of Health. July.

_____, 2000b. Construction and System Startup Report, Expansion of Phase IIA Groundwater Remediation System, Bitterroot Valley Sanitary Landfill, Ravalli County, Montana. Document issued to Montana Department of Environmental Quality and the National Institutes of Health. October.

_____, 2001. Semiannual Report, July 2001 Groundwater Monitoring, Bitterroot Valley Sanitary Landfill, Ravalli County, Montana. Report issued to Montana Department of Environmental Quality and the National Institutes of Health. October.

_____, 2004a. Semiannual Report, January 2004 Groundwater Monitoring, Bitterroot Valley Sanitary Landfill, Ravalli County, Montana. Report issued to Montana Department of Environmental Quality and the National Institutes of Health. March.

_____, 2004b. Semiannual Report, July 2004 Groundwater Monitoring, Bitterroot Valley Sanitary Landfill, Ravalli County, Montana. Report issued to Montana Department of Environmental Quality and the National Institutes of Health. September.

_____, 2004c. Construction and System Startup Report, Expansion of Phase IIA Groundwater Remediation System, Bitterroot Valley Sanitary Landfill, Ravalli County, Montana. Document issued to Montana

_____, 2006. Fourth Quarter 2005 Monitoring Report, Phase IIA Groundwater Remediation System, Bitterroot Valley Sanitary Landfill, Ravalli County, Montana. Report issued to Montana Department of Environmental Quality and the National Institutes of Health. January.

Montana Department of Environmental Quality, 1999 (DEQ). Circular WQB-7, Montana Numeric Water Quality Standards, Montana Department of Environmental Quality. September.

Tetra Tech, Inc., 2006. Semiannual Report, September/October 2006 Groundwater Monitoring, Bitterroot Valley Sanitary Landfill, Ravalli County, Montana. Report issued to Montana Department of Environmental Quality and the National Institutes of Health. December.

Tetra Tech July 2007 25

_____, 2007. Operation, Maintenance, and Monitoring Plan, Phase IIA Groundwater Remediation System, Bitterroot Valley Sanitary Landfill, Ravalli County, Montana. Report issued to the Montana Department of Environmental Quality and the National Institutes of Health. January. Revision of 1998 Operation, Maintenance, and Monitoring Plan.

APPENDIX A

WATER LEVEL DATA

FOURTH QUARTER 2006 OPERATION & MONITORING REPORT

PHASE IIA GROUNDWATER REMEDIATION SYSTEM

BITTERROOT VALLEY SANITARY LANDFILL

RAVALLI COUNTY, MONTANA

T8N, R20W, SECTION 31

WATER LEVEL DATA

BITTERROOT VALLEY SANITARY LANDFILL

Station Type Measuring Point Elevation (feet)

Date Depth to Water (feet) (1)

Water Elevation (feet)

Station ID

R-1 INTERCEPTION 982.41 4/6/2001 47.44 934.97

R-1 INTERCEPTION 982.41 1/4/2002 58.06 924.35

R-1 INTERCEPTION 982.41 1/31/2002 57.95 924.46

R-1 INTERCEPTION 982.41 4/19/2002 66.38 916.03

R-1 INTERCEPTION 982.41 7/10/2002 47.12 935.29

R-1 INTERCEPTION 982.41 1/14/2003 58.79 923.62

R-1 INTERCEPTION 982.41 7/7/2003 65.12 917.29

R-1 INTERCEPTION 982.41 1/22/2004 62.45 919.96

R-1 INTERCEPTION 982.41 4/28/2004 66.40 916.01

R-1 INTERCEPTION 982.41 4/29/2004 47.10 935.31

R-1 INTERCEPTION 982.41 5/5/2004 46.86 935.55

R-1 INTERCEPTION 982.41 5/12/2004 46.82 935.59

R-1 INTERCEPTION 982.41 5/19/2004 46.67 935.74

R-1 INTERCEPTION 982.41 5/26/2004 46.61 935.80

R-1 INTERCEPTION 982.41 6/9/2004 46.49 935.92

R-1 INTERCEPTION 982.41 6/23/2004 46.45 935.96

R-1 INTERCEPTION 982.41 7/16/2004 46.41 936.00

R-1 INTERCEPTION 982.41 1/7/2005 46.33 936.08

R-1 INTERCEPTION 982.41 5/26/2005 65.20 917.21

R-1 INTERCEPTION 982.41 7/18/2005 64.50 917.91

R-1 INTERCEPTION 982.41 10/4/2005 64.48 917.93

R-1 INTERCEPTION 982.41 1/13/2006 59.79 922.62

R-1 INTERCEPTION 982.41 6/28/2006 47.42 934.99

R-1 INTERCEPTION 982.41 9/25/2006 63.50 918.91

R-1 INTERCEPTION 982.41 1/8/2007 65.91 916.50

R-2 INTERCEPTION 989.61 4/6/2001 62.18 927.43

R-2 INTERCEPTION 989.61 1/4/2002 55.54 934.07

R-2 INTERCEPTION 989.61 1/31/2002 52.30 937.31

R-2 INTERCEPTION 989.61 4/19/2002 62.75 926.86

R-2 INTERCEPTION 989.61 7/10/2002 52.69 936.92

R-2 INTERCEPTION 989.61 1/14/2003 62.85 926.76

R-2 INTERCEPTION 989.61 7/7/2003 58.15 931.46

R-2 INTERCEPTION 989.61 1/22/2004 53.58 936.03

R-2 INTERCEPTION 989.61 4/29/2004 52.58 937.03

R-2 INTERCEPTION 989.61 5/5/2004 52.38 937.23

R-2 INTERCEPTION 989.61 5/12/2004 52.40 937.21

R-2 INTERCEPTION 989.61 5/19/2004 52.19 937.42

R-2 INTERCEPTION 989.61 5/26/2004 52.12 937.49

R-2 INTERCEPTION 989.61 6/9/2004 52.02 937.59

R-2 INTERCEPTION 989.61 6/23/2004 51.95 937.66

R-2 INTERCEPTION 989.61 7/16/2004 52.02 937.59

R-2 INTERCEPTION 989.61 1/7/2005 51.58 938.03

R-2 INTERCEPTION 989.61 5/26/2005 65.20 924.41

R-2 INTERCEPTION 989.61 7/18/2005 59.85 929.76

R-2 INTERCEPTION 989.61 10/4/2005 52.35 937.26

R-2 INTERCEPTION 989.61 1/13/2006 52.11 937.50

R-2 INTERCEPTION 989.61 6/28/2006 52.54 937.07

R-2 INTERCEPTION 989.61 9/25/2006 54.60 935.01

R-2 INTERCEPTION 989.61 1/8/2007 54.60 935.01

R-3S INTERCEPTION 955.49 1/15/1998 32.94 922.55

R-3S INTERCEPTION 955.49 7/7/1998 29.14 926.35

R-3S INTERCEPTION 955.49 7/16/1998 30.31 925.18

R-3S INTERCEPTION 955.49 7/23/1998 30.87 924.62

R-3S INTERCEPTION 955.49 7/30/1998 31.56 923.93

R-3S INTERCEPTION 955.49 8/6/1998 32.01 923.48

R-3S INTERCEPTION 955.49 8/10/1998 32.30 923.19

R-3S INTERCEPTION 955.49 8/17/1998 32.68 922.81

R-3S INTERCEPTION 955.49 8/24/1998 32.75 922.74

Elevations relative to project datumNotes: (-) Water Level above Measuring Point

(1) Depth below measuring point (>) Water Level Below Bottom of Casing

NA Not Accessible

G:\Environmental\BVSL\cad\Jan2006event\bvsl2k.mdb <Table_B_Water_L

Station Type Measuring Point Elevation (feet)

Date Depth to Water (feet) (1)

Water Elevation (feet)

Station ID

R-3S INTERCEPTION 955.49 8/31/1998 32.55 922.94

R-3S INTERCEPTION 955.49 9/15/1998 33.04 922.45

R-3S INTERCEPTION 955.49 12/11/1998 33.61 921.88

R-3S INTERCEPTION 955.49 1/8/1999 33.52 921.97

R-3S INTERCEPTION 955.49 5/19/1999 33.19 922.30

R-3S INTERCEPTION 955.49 7/12/1999 29.98 925.51

R-3S INTERCEPTION 955.49 10/7/1999 33.04 922.45

R-3S INTERCEPTION 955.49 1/4/2000 31.79 923.70

R-3S INTERCEPTION 955.49 5/19/2000 29.50 925.99

R-3S INTERCEPTION 955.49 7/10/2000 28.93 926.56

R-3S INTERCEPTION 955.49 1/8/2001 31.74 923.75

R-3S INTERCEPTION 955.49 4/6/2001 32.65 922.84

R-3S INTERCEPTION 955.49 7/9/2001 29.98 925.51

R-3S INTERCEPTION 955.49 1/4/2002 32.13 923.36

R-3S INTERCEPTION 955.49 1/31/2002 32.10 923.39

R-3S INTERCEPTION 955.49 4/19/2002 31.57 923.92

R-3S INTERCEPTION 955.49 7/11/2002 29.16 926.33

R-3S INTERCEPTION 955.49 1/14/2003 33.68 921.81

R-3S INTERCEPTION 955.49 7/7/2003 36.04 919.45

R-3S INTERCEPTION 955.49 1/12/2004 34.15 921.34

R-3S INTERCEPTION 955.49 4/28/2004 34.40 921.09

R-3S INTERCEPTION 955.49 4/29/2004 34.40 921.09

R-3S INTERCEPTION 955.49 5/5/2004 34.25 921.24

R-3S INTERCEPTION 955.49 5/12/2004 34.12 921.37

R-3S INTERCEPTION 955.49 5/19/2004 33.86 921.63

R-3S INTERCEPTION 955.49 5/26/2004 33.56 921.93

R-3S INTERCEPTION 955.49 6/9/2004 32.64 922.85

R-3S INTERCEPTION 955.49 6/23/2004 31.76 923.73

R-3S INTERCEPTION 955.49 7/16/2004 30.93 924.56

R-3S INTERCEPTION 955.49 1/7/2005 32.69 922.80

R-3S INTERCEPTION 955.49 5/26/2005 33.58 921.91

R-3S INTERCEPTION 955.49 7/18/2005 31.71 923.78

R-3S INTERCEPTION 955.49 10/4/2005 33.56 921.93

R-3S INTERCEPTION 955.49 1/13/2006 33.59 921.90

R-3S INTERCEPTION 955.49 6/28/2006 31.85 923.64

R-3S INTERCEPTION 955.49 9/25/2006 33.86 921.63

R-3S INTERCEPTION 955.49 1/8/2007 33.67 921.82

R-4D INTERCEPTION 955.31 1/15/1998 38.74 916.57

R-4D INTERCEPTION 955.31 7/7/1998 38.01 917.30

R-4D INTERCEPTION 955.31 7/16/1998 57.41 897.90

R-4D INTERCEPTION 955.31 7/23/1998 55.50 899.81

R-4D INTERCEPTION 955.31 7/30/1998 59.47 895.84

R-4D INTERCEPTION 955.31 8/6/1998 61.18 894.13

R-4D INTERCEPTION 955.31 8/10/1998 61.97 893.34

R-4D INTERCEPTION 955.31 8/17/1998 62.82 892.49

R-4D INTERCEPTION 955.31 8/24/1998 63.08 892.23

R-4D INTERCEPTION 955.31 8/31/1998 63.80 891.51

R-4D INTERCEPTION 955.31 9/15/1998 66.46 888.85

R-4D INTERCEPTION 955.31 12/11/1998 66.41 888.90

R-4D INTERCEPTION 955.31 1/8/1999 89.06 866.25

R-4D INTERCEPTION 955.31 5/19/1999 74.25 881.06

R-4D INTERCEPTION 955.31 7/12/1999 73.65 881.66

R-4D INTERCEPTION 955.31 10/7/1999 74.55 880.76

R-4D INTERCEPTION 955.31 11/16/1999 80.35 874.96

R-4D INTERCEPTION 955.31 11/24/1999 78.09 877.22

R-4D INTERCEPTION 955.31 1/4/2000 81.29 874.02

R-4D INTERCEPTION 955.31 5/19/2000 80.19 875.12

R-4D INTERCEPTION 955.31 7/10/2000 80.34 874.97

R-4D INTERCEPTION 955.31 1/8/2001 67.98 887.33

R-4D INTERCEPTION 955.31 4/6/2001 68.76 886.55

R-4D INTERCEPTION 955.31 7/9/2001 74.81 880.50

R-4D INTERCEPTION 955.31 1/4/2002 75.43 879.88

R-4D INTERCEPTION 955.31 1/31/2002 67.19 888.12

Elevations relative to project datumNotes: (-) Water Level above Measuring Point

(1) Depth below measuring point (>) Water Level Below Bottom of Casing

Date Depth to Water (feet) (1)

Water Elevation (feet)

Station ID

R-4D INTERCEPTION 955.31 4/19/2002 73.51 881.80

R-4D INTERCEPTION 955.31 7/11/2002 52.79 902.52

R-4D INTERCEPTION 955.31 1/14/2003 78.55 876.76

R-4D INTERCEPTION 955.31 7/7/2003 76.89 878.42

R-4D INTERCEPTION 955.31 1/12/2004 73.95 881.36

R-4D INTERCEPTION 955.31 4/28/2004 78.64 876.67

R-4D INTERCEPTION 955.31 4/29/2004 55.82 899.49

R-4D INTERCEPTION 955.31 5/5/2004 54.05 901.26

R-4D INTERCEPTION 955.31 5/12/2004 52.76 902.55

R-4D INTERCEPTION 955.31 5/19/2004 51.46 903.85

R-4D INTERCEPTION 955.31 5/26/2004 50.66 904.65

R-4D INTERCEPTION 955.31 6/9/2004 49.23 906.08

R-4D INTERCEPTION 955.31 6/23/2004 48.22 907.09

R-4D INTERCEPTION 955.31 7/16/2004 47.11 908.20

R-4D INTERCEPTION 955.31 1/7/2005 67.03 888.28

R-4D INTERCEPTION 955.31 5/26/2005 69.97 885.34

R-4D INTERCEPTION 955.31 7/18/2005 72.55 882.76

R-4D INTERCEPTION 955.31 10/4/2005 78.91 876.40

R-4D INTERCEPTION 955.31 1/13/2006 77.19 878.12

R-4D INTERCEPTION 955.31 6/28/2006 56.36 898.95

R-4D INTERCEPTION 955.31 9/25/2006 80.60 874.71

R-4D INTERCEPTION 955.31 1/8/2007 77.73 877.58

R-5S INTERCEPTION 942.75 7/16/1994 19.64 923.11

R-5S INTERCEPTION 942.75 1/15/1998 21.71 921.04

R-5S INTERCEPTION 942.75 7/7/1998 17.39 925.36

R-5S INTERCEPTION 942.75 7/16/1998 20.78 921.97

R-5S INTERCEPTION 942.75 7/23/1998 21.60 921.15

R-5S INTERCEPTION 942.75 7/30/1998 22.70 920.05

R-5S INTERCEPTION 942.75 8/6/1998 23.32 919.43

R-5S INTERCEPTION 942.75 8/10/1998 23.73 919.02

R-5S INTERCEPTION 942.75 8/17/1998 22.57 920.18

R-5S INTERCEPTION 942.75 8/24/1998 22.28 920.47

R-5S INTERCEPTION 942.75 8/31/1998 22.37 920.38

R-5S INTERCEPTION 942.75 9/15/1998 24.82 917.93

R-5S INTERCEPTION 942.75 12/11/1998 24.32 918.43

R-5S INTERCEPTION 942.75 1/8/1999 23.89 918.86

R-5S INTERCEPTION 942.75 5/19/1999 27.24 915.51

R-5S INTERCEPTION 942.75 7/12/1999 22.28 920.47

R-5S INTERCEPTION 942.75 10/7/1999 --

R-5S INTERCEPTION 942.75 1/4/2000 26.04 916.71

R-5S INTERCEPTION 942.75 5/19/2000 22.81 919.94

R-5S INTERCEPTION 942.75 7/10/2000 22.03 920.72

R-5S INTERCEPTION 942.75 1/8/2001 26.04 916.71

R-5S INTERCEPTION 942.75 4/6/2001 25.50 917.25>

R-5S INTERCEPTION 942.75 7/9/2001 25.11 917.64

R-5S INTERCEPTION 942.75 1/4/2002 --

R-5S INTERCEPTION 942.75 1/31/2002 25.13 917.62

R-5S INTERCEPTION 942.75 4/19/2002 NA

R-5S INTERCEPTION 942.75 7/11/2002 18.71 924.04

R-5S INTERCEPTION 942.75 1/14/2003 24.28 918.47

R-5S INTERCEPTION 942.75 7/7/2003 25.20 917.55

R-5S INTERCEPTION 942.75 1/12/2004 26.88 915.87

R-5S INTERCEPTION 942.75 4/29/2004 24.22 918.53

R-5S INTERCEPTION 942.75 5/5/2004 22.84 919.91

R-5S INTERCEPTION 942.75 5/12/2004 22.10 920.65

R-5S INTERCEPTION 942.75 5/19/2004 21.51 921.24

R-5S INTERCEPTION 942.75 5/26/2004 21.03 921.72

R-5S INTERCEPTION 942.75 6/9/2004 20.20 922.55

R-5S INTERCEPTION 942.75 6/23/2004 19.64 923.11

R-5S INTERCEPTION 942.75 7/16/2004 19.64 923.11

R-5S INTERCEPTION 942.75 1/7/2005 26.44 916.31

R-5S INTERCEPTION 942.75 5/26/2005 23.13 919.62

R-5S INTERCEPTION 942.75 7/15/2005 21.87 920.88

Elevations relative to project datumNotes: (-) Water Level above Measuring Point

(1) Depth below measuring point (>) Water Level Below Bottom of Casing

Date Depth to Water (feet) (1)

Water Elevation (feet)

Station ID

R-5S INTERCEPTION 942.75 10/4/2005 24.34 918.41

R-5S INTERCEPTION 942.75 1/13/2006 22.12 920.63

R-5S INTERCEPTION 942.75 6/28/2006 20.82 921.93

R-5S INTERCEPTION 942.75 9/25/2006 25.60 917.15

R-5S INTERCEPTION 942.75 1/8/2007 22.74 920.01

R-6D INTERCEPTION 942.70 1/15/1998 26.09 916.61

R-6D INTERCEPTION 942.70 7/7/1998 25.33 917.37

R-6D INTERCEPTION 942.70 7/16/1998 40.16 902.54

R-6D INTERCEPTION 942.70 7/23/1998 28.90 913.80

R-6D INTERCEPTION 942.70 7/30/1998 42.34 900.36

R-6D INTERCEPTION 942.70 8/6/1998 42.97 899.73

R-6D INTERCEPTION 942.70 8/10/1998 43.45 899.25

R-6D INTERCEPTION 942.70 8/17/1998 44.30 898.40

R-6D INTERCEPTION 942.70 8/24/1998 44.89 897.81

R-6D INTERCEPTION 942.70 8/31/1998 45.55 897.15

R-6D INTERCEPTION 942.70 9/15/1998 46.76 895.94

R-6D INTERCEPTION 942.70 12/11/1998 45.54 897.16

R-6D INTERCEPTION 942.70 1/8/1999 47.26 895.44

R-6D INTERCEPTION 942.70 5/19/1999 50.59 892.11

R-6D INTERCEPTION 942.70 7/12/1999 50.79 891.91

R-6D INTERCEPTION 942.70 10/7/1999 50.57 892.13

R-6D INTERCEPTION 942.70 11/16/1999 52.09 890.61

R-6D INTERCEPTION 942.70 11/24/1999 51.29 891.41

R-6D INTERCEPTION 942.70 1/4/2000 51.94 890.76

R-6D INTERCEPTION 942.70 5/19/2000 51.52 891.18

R-6D INTERCEPTION 942.70 7/10/2000 49.95 892.75

R-6D INTERCEPTION 942.70 1/8/2001 47.56 895.14

R-6D INTERCEPTION 942.70 4/6/2001 51.24 891.46

R-6D INTERCEPTION 942.70 7/9/2001 53.15 889.55

R-6D INTERCEPTION 942.70 1/4/2002 54.55 888.15

R-6D INTERCEPTION 942.70 1/31/2002 50.43 892.27

R-6D INTERCEPTION 942.70 4/19/2002 54.04 888.66

R-6D INTERCEPTION 942.70 7/11/2002 46.20 896.50

R-6D INTERCEPTION 942.70 1/14/2003 55.68 887.02

R-6D INTERCEPTION 942.70 7/7/2003 56.24 886.46

R-6D INTERCEPTION 942.70 1/12/2004 58.66 884.04

R-6D INTERCEPTION 942.70 4/28/2004 59.54 883.16

R-6D INTERCEPTION 942.70 4/29/2004 44.00 898.70

R-6D INTERCEPTION 942.70 5/5/2004 41.84 900.86

R-6D INTERCEPTION 942.70 5/12/2004 40.35 902.35

R-6D INTERCEPTION 942.70 5/19/2004 38.99 903.71

R-6D INTERCEPTION 942.70 5/26/2004 38.14 904.56

R-6D INTERCEPTION 942.70 6/9/2004 36.67 906.03

R-6D INTERCEPTION 942.70 6/23/2004 35.61 907.09

R-6D INTERCEPTION 942.70 7/16/2004 34.49 908.21

R-6D INTERCEPTION 942.70 1/7/2005 50.72 891.98

R-6D INTERCEPTION 942.70 5/26/2005 54.05 888.65

R-6D INTERCEPTION 942.70 7/18/2005 56.85 885.85

R-6D INTERCEPTION 942.70 10/4/2005 60.12 882.58

R-6D INTERCEPTION 942.70 1/13/2006 58.44 884.26

R-6D INTERCEPTION 942.70 6/28/2006 44.53 898.17

R-6D INTERCEPTION 942.70 9/25/2006 60.85 881.85

R-6D INTERCEPTION 942.70 1/8/2007 57.16 885.54

R-7S INTERCEPTION 934.06 1/15/1998 13.03 921.03

R-7S INTERCEPTION 934.06 7/7/1998 8.72 925.34

R-7S INTERCEPTION 934.06 7/16/1998 12.80 921.26

R-7S INTERCEPTION 934.06 7/23/1998 13.48 920.58

R-7S INTERCEPTION 934.06 7/30/1998 14.81 919.25

R-7S INTERCEPTION 934.06 8/6/1998 15.51 918.55

R-7S INTERCEPTION 934.06 8/10/1998 16.12 917.94

R-7S INTERCEPTION 934.06 8/17/1998 17.33 916.73

R-7S INTERCEPTION 934.06 8/24/1998 13.67 920.39

R-7S INTERCEPTION 934.06 8/31/1998 13.84 920.22

Elevations relative to project datumNotes: (-) Water Level above Measuring Point

(1) Depth below measuring point (>) Water Level Below Bottom of Casing

Date Depth to Water (feet) (1)

Water Elevation (feet)

Station ID

R-7S INTERCEPTION 934.06 9/15/1998 16.17 917.89

R-7S INTERCEPTION 934.06 12/11/1998 15.35 918.71

R-7S INTERCEPTION 934.06…