U.S. Department of the Interior

U.S. Geological Survey

Data Series 588

TOXIC SUBSTANCES HYDROLOGY PROGRAM

Prepared in cooperation with the 

AIR FORCE CENTER FOR ENGINEERING AND THE ENVIRONMENT

Water-Quality Data from Shallow Pond-Bottom Groundwater 

in the Fishermans Cove Area of Ashumet Pond, Cape Cod, 

Massachusetts, 2001–2010
Cover Photographs. (1) Groundwater samples being collected in Fishermans Cove, 

Ashumet Pond, Massachusetts (view looking west) (2) pond-bottom piezometers being 

installed from a barge using a vibratory ATV-mounted drilling rig; (3) excavators digging out 

pond-bottom materials to a depth of 3 feet, and a mixing bucket (red apparatus on the right) 

mixing iron filings into the pond-bottom sediment; and (4) U.S. Geological Survey scientists 

installing samplers below the bottom of Ashumet Pond to monitor the effectiveness of the 

geochemical barrier. 

12

34
Toxic Substances Hydrology Program

Water-Quality Data from Shallow PondBottom Groundwater in the Fishermans 

Cove Area of Ashumet Pond, Cape Cod, 

Massachusetts, 2001–2010

By Timothy D. McCobb and Denis R. LeBlanc

Prepared in cooperation with the Air Force Center for Engineering and 

the Environment

Data Series Report 588

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2011

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Government.

Although this report is in the public domain, permission must be secured from the individual copyright owners to 

reproduce any copyrighted materials contained within this report.

Suggested citation:

McCobb, T.D., and LeBlanc, D.R., 2011, Water-quality data from shallow pond-bottom groundwater in the Fishermans 

Cove area of Ashumet Pond, Cape Cod, Massachusetts, 2001–2010: U.S. Geological Survey Data Series 588, 13 p., at 

http://pubs.usgs.gov/ds/588.
iii

Contents

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................1

Water-Quality Data for Samples Collected from Temporary Drive Points ...........................................4

Water-Quality Data for Samples Collected from Permanent Instrumentation near the 

Permeable Reactive Barrier...........................................................................................................4

Summary........................................................................................................................................................11

Acknowledgments.......................................................................................................................................11

References Cited..........................................................................................................................................12

Figures

1. Map showing location of the Massachusetts Military Reservation, extent of the 

treated-wastewater plume, and altitude of the water table, western Cape Cod, 

Massachusetts..............................................................................................................................2

2. Map showing areal distribution of maximum phosphate concentrations in 

groundwater upgradient of Ashumet Pond, Cape Cod, Massachusetts, 

May–August 2007 .........................................................................................................................3

3. Map showing locations of temporary drive points installed in August–September 

2001 to delineate the discharge area of treated-wastewater-plume constituents, 

Ashumet Pond, Cape Cod, Massachusetts ..............................................................................5

4. Map showing locations of temporary drive points installed in June 2003 to 

delineate the discharge area of treated-wastewater-plume constituents, Ashumet 

Pond, Cape Cod, Massachusetts ...............................................................................................6

5. Map showing locations of temporary drive points installed in June–July 2004 to 

delineate the discharge area of treated-wastewater-plume constituents prior to 

the installation of a pond-bottom permeable reactive barrier, Ashumet Pond, 

Cape Cod, Massachusetts ..........................................................................................................7

6. Map showing locations of temporary drive points installed in August 2006 at 0.5, 

1.5, and 3.0 feet below the pond bottom in the area of the permeable reactive 

barrier, Ashumet Pond, Cape Cod, Massachusetts ................................................................8

7. Map showing locations of temporary drive points installed in August 2009 at 0.5, 

1.5, and 3.0 feet below the pond bottom in the area of the permeable reactive 

barrier, Ashumet Pond, Cape Cod, Massachusetts ................................................................9

8. Map showing locations of vertical multilevel samplers, multilevel diffusion 

chambers, horizontal multiport samplers, pond-bottom piezometers, and seepage 

meters in and near the permeable reactive barrier at Ashumet Pond, Cape 

Cod, Massachusetts...................................................................................................................10
iv

Tables

1. Summary of data reported by date, sampling method, extent of sampling area, and 

analyses performed. [Click here]

2. Physical properties of sampling locations and chemical analyses of groundwater 

samples collected from temporary drive points driven below the pond bottom, 

Ashumet Pond, Cape Cod, Massachusetts, August 22–September 13, 2001. [Click here]

3. Physical properties of sampling locations and chemical analyses of groundwater 

samples collected from temporary drive points driven below the pond bottom, 

Ashumet Pond, Cape Cod, Massachusetts, June 9–26, 2003. [Click here]

4. Physical properties of sampling locations and chemical analyses of groundwater 

samples collected from temporary drive points below the pond bottom, Ashumet 

Pond, Cape Cod, Massachusetts, June 29–July 2, 2004. [Click here]

5. Physical properties of sampling locations and chemical analyses of groundwater 

samples collected from temporary drive points below the pond bottom, Ashumet 

Pond, Cape Cod, Massachusetts, August 2–28, 2006. [Click here]

6. Physical properties of sampling locations and chemical analyses of groundwater 

samples collected from temporary drive points below the pond bottom, Ashumet 

Pond, Cape Cod, Massachusetts, August 3–12, 2009. [Click here]

7. Physical properties of sampling locations and chemical analyses of groundwater 

samples collected from vertical multilevel samplers in and near a pond-bottom 

permeable reactive barrier, Ashumet Pond, Cape Cod, Massachusetts, July 

2004–July 2010. [Click here]

8. Physical properties of sampling locations and chemical analyses of groundwater 

samples collected from multilevel diffusion chambers in and near a pond-bottom 

permeable reactive barrier, Ashumet Pond, Cape Cod, Massachusetts, October 

2004–August 2010. [Click here]

9. Physical properties of sampling locations and chemical analyses of groundwater 

samples collected from horizontal multiport samplers at a pond-bottom permeable 

reactive barrier, Ashumet Pond, Cape Cod, Massachusetts, October 

2004–July 2010. [Click here]

10. Physical properties of sampling locations and chemical analyses of groundwater 

samples collected from pond-bottom piezometers near pond-bottom 

permeable reactive barrier, Ashumet Pond, Cape Cod, Massachusetts, August 

2004–July 2010. [Click here]

11. Physical properties of sampling locations, water flux, and chemical analyses of 

samples collected from seepage meters in and near a pond-bottom permeable 

reactive barrier, Ashumet Pond, Cape Cod, Massachusetts, November 2004–

July 2010. [Click here]
v

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

acre 4,047 square meter (m2

)

square foot (ft2

) 0.09290 square meter (m2)

square inch (in2

) 6.452 square centimeter (cm2)

Volume

cubic foot (ft3

) 0.02832 cubic meter (m3) 

Flow rate

cubic foot per second (ft3

/s) 0.02832 cubic meter per second (m3/s)

inch per hour (in/h) 0 .0254 meter per hour (m/h)

Mass

ounce, avoirdupois (oz) 28.35 gram (g) 

Vertical coordinate information is referenced to North American Vertical Datum of 1988 

(NAVD 88).). 

Horizontal coordinate information is referenced to North American Datum of 1983 (NAD 83).

Altitude, as used in this report, refers to distance above the vertical datum.

Conversion Factors, Data, and Abbreviations
This page has been left blank intentionally.
the Environment (AFCEE), has studied the distribution and 

transport of phosphate in the plume, including the discharge 

of phosphate to the Fishermans Cove area of the pond (fig. 2) 

(Walter and others, 1996; McCobb and others, 2003; Parkhurst 

and others, 2003; McCobb and others, 2009a; McCobb and 

others, 2009b). These studies at the MMR indicated that 

phosphate transport in the groundwater is greatly retarded 

because phosphate sorbs strongly to the aquifer sediments. 

Phosphate concentrations in the groundwater will remain 

above background levels for many decades as uncontaminated 

groundwater flushes the aquifer (disposal ended in 1995), 

and phosphate is desorbed from the sediments (Parkhurst and 

others, 2003). These investigations have been prompted by 

the need to better understand the distribution and transport of 

phosphate in the glacial sand and gravel aquifer so that the 

potential effects of continued phosphate input on the ecology 

of Ashumet Pond can be evaluated (Air Force Center for 

Environmental Excellence (AFCEE) 2002a; AFCEE 2002b). 

This report documents all of the water-quality data 

collected by the USGS between 2001 and 2010 in the area 

of Fishermans Cove, Ashumet Pond, Falmouth, MA. In 

1999, McCobb and others (2003) mapped the distribution 

of phosphate and other treated-wastewater constituents 

discharging to Ashumet Pond by using drive-point sampling. 

This Data Series report documents the sampling results from 

two subsequent drive-point surveys in 2001 and 2003 that 

covered the same area as the 1999 study. In addition, in 2004, 

a drive-point-sampling round that focused on the area of 

greatest phosphate concentrations north of Fishermans Cove 

was conducted. A zero-valent-iron permeable reactive barrier 

(PRB) was mixed into the bottom sediment of Ashumet Pond 

in August 2004 by AFCEE to reduce phosphate concentrations 

in groundwater discharging to the pond (AFCEE, 2004; 

McCobb and others, 2009a). The 2004 drive-point survey was 

the last mapping of the discharge area of the phosphate plume 

prior to the installation of the PRB. In 2006 and 2009, the 

performance of the PRB was evaluated by using drive-point 

sampling at multiple depths in and adjacent to the PRB. These 

datasets and accompanying index maps are also included in 

this report.

Water-Quality Data from Shallow Pond-Bottom 

Groundwater in the Fishermans Cove Area of Ashumet 

Pond, Cape Cod, Massachusetts, 2001–2010

By Timothy D. McCobb and Denis R. LeBlanc

Abstract

The U.S. Geological Survey (USGS) collected waterquality data between 2001 and 2010 in the Fishermans Cove 

area of Ashumet Pond, Falmouth, Massachusetts, where the 

eastern portion of a treated-wastewater plume, created by 

more than 60 years of overland disposal, discharges to the 

pond. Temporary drive points were installed, and shallow 

pond-bottom groundwater was sampled, at 167 locations in 

2001, 150 locations in 2003, and 120 locations in 2004 to 

delineate the distribution of wastewater-related constituents. 

In 2004, the Air Force Center for Engineering and the 

Environment (AFCEE) installed a pond-bottom permeable 

reactive barrier (PRB) to intercept phosphate in the plume 

at its discharge point to the pond. The USGS monitored the 

performance of the PRB by collecting samples from temporary 

drive points at multiple depth intervals in 2006 (200 samples 

at 76 locations) and 2009 (150 samples at 90 locations). 

During the first 5 years after installation of the PRB, water 

samples were collected periodically from five types of 

pore-water samplers that had been permanently installed 

in and near the PRB during the barrier’s emplacement. The 

distribution of wastewater-related constituents in the pondbottom groundwater and changes in the geochemistry of the 

pond-bottom groundwater after installation of the PRB have 

been documented in several published reports that are listed in 

the references.

Introduction

A plume of groundwater contaminated by treated 

wastewater was created by more than 60 years of disposal 

to infiltration beds at a former wastewater-treatment facility 

at the Massachusetts Military Reservation (MMR) (fig. 1) 

(LeBlanc, 1984; Savoie and LeBlanc, 1998). The eastern 

side of this plume discharges to Ashumet Pond, a kettlehole pond about 1,600 ft downgradient of the disposal beds. 

Since the early 1990s, the U.S. Geological Survey (USGS), 

in cooperation with the Air Force Center for Engineering and 
2 Water-Quality Data from Shallow Pond-Bottom Groundwater, Ashumet Pond, Cape Cod, Massachusetts, 2001–2010

Figure 1. Location of the Massachusetts Military Reservation, extent of the treated-wastewater plume, 

and altitude of the water table, western Cape Cod, Massachusetts.

EXPLANATION

Extent of treated-wastewater

plume (Savoie and LeBlanc, 1998)

Extent of study area—Detailed in figure 2

Water-table contour—Shows altitude of 

water table. Contour interval is 10 feet. Datum

is NGVD 29 (From Savoie, 1995)

BUZZARDS BAY

CAPE COD

BAY

VINEYARD SOUND

NANTUCKET SOUND

Ashumet

Pond

State plane coordinate system datum is NAD83 in meters

Base from U.S. Geological Survey digital data

Universal Transverse Mercator projection

Zone 19, 1:24,000, 1991

CAPE COD CANAL

60

50

40

30

20

10

10

ATLANTIC

OCEAN

Massachusetts

Military

Reservation

CAPE

COD

100,000 200,000

950,000

270,000 70°37’30" 280,000 70°27’30"

41°42’30"

41°32’30"

835,000

815,000

5 MILES 

5 KILOMETERS 

0

0

1

2

2 3 4

1 3 4

42°30’

50 KILOMETERS

50 MILES 

73°00’ 72°00’

71°00’

70°00’

41°30'

MASSACHUSETTS

0

0
Introduction 3

Figure 2. Areal distribution of maximum phosphate concentrations in groundwater upgradient of Ashumet Pond, Cape Cod, 

Massachusetts, May–August 2007. The extent of each drive-point-sampling event by date and the area of the permeable reactive 

barrier (PRB) are delineated.

0.1

0.5

1.0

1.5

2.0

3.0

2.0 1.5

1.5

0 200 400 600 FEET

0 50 100 150 METERS

Area of permeable 

reactive barrier

Areal extent of maximum concentration 

of phosphate in groundwater, 

May–August 2007—In milligrams per

liter as P. Contour is dashed where 

inferred. Interval is varied

Monitoring-well cluster site

Multilevel-sampler site 

greater than 3.0

greater than 2.0 to 3.0

greater than 1.5 to 2.0

greater than 1.0 to 1.5

greater than 0.5 to 1.0

0.1 to 0.5 

EXPLANATION

820,800

821,600

279,400 280,000

41°38'15"

41°38'

70°32'45" 70°32'15"

Ashumet Pond

Extent of 2004 

drive-point

sampling 

Extent of 2006 and 2009 

drive-point sampling 

Extent of 2001 and 2003

 drive-point sampling 

DECOMMISSIONED 

INFILTRATION BEDS

Fishermans Cove

Source of phosphate data: Douglas B. Kent, U.S. Geological Survey, National Research Program, Menlo Park, CA 

State plane coordinate system datum is NAD83 in meters

Base from U.S. Geological Survey digital data

Universal Transverse Mercator projection

Zone 19, 1:24,000, 1991
4 Water-Quality Data from Shallow Pond-Bottom Groundwater, Ashumet Pond, Cape Cod, Massachusetts, 2001–2010

As part of the PRB-performance monitoring, multiple 

types of permanent pond-bottom instrumentation were 

designed, developed, and installed in and near the PRB. 

McCobb and others (2009a) describe these devices in detail 

and provide results from the first 24 months following 

installation of the PRB. Data collected by using these 

instruments between July 2004 and August 2010 also are 

tabulated in this report. The data presented in this document 

are summarized in table 1 by date, sampling method, extent of 

sampling area, and sample analyses performed. 

Water-Quality Data for Samples 

Collected from Temporary Drive Points

The methods used to obtain the data presented in this 

report, including the sample-collection and chemical-analysis 

methods for both the temporary drive points and permanently 

placed PRB instrumentation, have been previously described 

in detail in reports by McCobb and others (2003; 2009a; 

2009b) and are summarized by date in table 1.

Between 2001 and 2009, samples were collected from 

603 locations in the Fishermans Cove area of Ashumet 

Pond from well points (Macho Model, K-V Associates, Inc., 

Mashpee, MA) and small-diameter microwells (PushPoint 

Sampler, MHE Products, East Tawas, MI) driven temporarily 

into the pond bottom. Although the objectives of these 

sampling events differed, the sampling procedures and 

methodology described by McCobb and others (2003) were 

followed closely. In general, after being placed over a targeted 

location, the sampling device was advanced into the pondbottom sediment to a targeted depth. A peristaltic pump 

was used to collect water samples through a sampling tube 

connected to the device. Selected water-quality parameters, 

including specific conductance, pH, and concentrations of 

dissolved oxygen and orthophosphate, were determined in 

the field. Samples were generally collected for subsequent 

laboratory analysis of selected inorganic solutes, including 

phosphate, nitrate, and ammonium. 

Temporary drive-point sampling covering the complete 

area of Fishermans Cove was used in August–September 2001 

and June 2003 to delineate the discharge area of the treatedwastewater plume; these efforts covered the same area as the 

1999 sampling round reported in McCobb and others (2003). 

In 2001, 167 locations were sampled for field parameters, 

inorganic solutes (including phosphate), and nitrogen species 

(including nitrate, nitrite, and ammonia) (fig. 3 and table 2). 

In 2003, 150 locations were sampled for the same set of 

parameters and constituents (fig. 4 and table 3).

In 2004, drive-point sampling at 120 locations in an area 

where previous (2003) phosphate detections were greater 

than 1 mg/L as P yielded a similar discharge footprint as 

that observed in 1999 (McCobb and others, 2003; McCobb 

and others, 2009b) (fig. 5 and table 4). Samples from these 

drive points provided a background dataset that represented 

conditions prior to the installation of the PRB. A map 

showing the 2004 distribution of phosphate concentrations in 

groundwater below the pond bottom is available in McCobb 

and others (2009b). 

In August 2006 and August 2009, drive points were used 

to delineate the distributions of treated-wastewater indicators 

(including phosphate) at multiple depths in the area of the 

PRB to evaluate the performance of the remedial system 

(figs. 6 and 7). In 2006, 200 drive points were installed at 

76 locations and pumped to collect water samples for analysis 

of field parameters and species of phosphate and nitrogen. 

The drive-point sampling-site characteristics and results from 

the chemical analyses are tabulated in table 5. A graphical 

display of these data in McCobb and others (2009b) shows 

each parameter and constituent, mapped by depth, below the 

pond bottom. In August 2009, 150 drive points were installed 

at 90 locations and pumped to collect water samples for 

analysis of the same parameters and species. The drive-point 

characteristics and results from the chemical analyses are 

tabulated in table 6.

Water-Quality Data for Samples 

Collected from Permanent 

Instrumentation near the Permeable 

Reactive Barrier

Prior to and during installation of the pond-bottom 

permeable reactive barrier (PRB), which was intended to 

intercept the phosphate plume at its discharge point to the 

pond, the USGS installed five types of groundwater-sampling 

devices in the PRB area to evaluate changes in geochemistry 

over time. Placement of the PRB was based on the area 

indicated by prior temporary drive-point sampling where 

phosphate detections were greater than 1 mg/L as P. Thirty 

tons of zero-valent iron (Fe0

) was mixed into excavated pondbottom sediment and placed back onto the pond bottom to 

a thickness of about 2 ft. AFCEE (2004) describes the PRB 

design and installation in detail. 

The sampling devices installed to monitor the 

performance of the PRB over time are distributed horizontally 

and vertically throughout and adjacent to the PRB area (fig. 8). 

Details about the design, construction, and placement of these 

devices, as well as a presentation of the results from the first 

two years of data collection, are given in McCobb and others 

(2009a) and only briefly presented here. The devices include 

vertical multilevel samplers (VMLS), multilevel diffusion 

chambers (MLDC), horizontal multiport samplers (HMPS), 

pond-bottom piezometers, and seepage meters. Tables 7–11 

present sampling-site characteristics and chemical analysis by 

sampling device type for 2004–10.

VMLS are miniwells consisting of five 1/8-in.-diameter 

polyurethane tubes that are fitted with fiberglass screens and 

extend to different vertical positions below the pond bottom, 
Water-Quality Data for Samples Collected from Permanent Instrumentation near the Permeable Reactive Barrier 5

Figure 3. Locations of temporary drive points installed in August–September 2001 to delineate the discharge area of treatedwastewater-plume constituents, Ashumet Pond, Cape Cod, Massachusetts.

Base from Office of Geographic and Environmental Information (MassGIS), orthophoto 1:5000, 2003

Massachusetts state plane coordinate system datum is NAD 83 in meters

Ashumet Pond

TOWN OF FALMOUTH

TOWN OF MASHPEE

70°32'25" 70°32'20"

41°38'05"

41°38'

Transect line and line number—Transects

are numbered north (N) and south (S) of Line 000

Temporary pond-bottom 

drive-point sampler

EXPLANATION

279,920 280,100

820,840

821,020

Line 800N

Line 750N

Line 700N

Line 650N

Line 600N

Line 550N

Line 500N

Line 450N

Line 400N

Line 300N Line 350N

Line 250N

Line 200N

Line 150N

Line 100N

Line 50N

Line 000

Line 100S

Line 200S

Line 300S

0 100 200 FEET

0 30 60 METERS

August 2001 

shoreline position

Line 300S
6 Water-Quality Data from Shallow Pond-Bottom Groundwater, Ashumet Pond, Cape Cod, Massachusetts, 2001–2010

Figure 4. Locations of temporary drive points installed in June 2003 to delineate the discharge area of treated-wastewaterplume constituents, Ashumet Pond, Cape Cod, Massachusetts.

Base from Office of Geographic and Environmental Information (MassGIS), orthophoto 1:5000, 2003. 

Massachusetts state plane coordinate system datum is NAD 83 in meters

Ashumet Pond

TOWN OF FALMOUTH

TOWN OF MASHPEE

Transect line and line number—Transects are 

numbered north (N) and south (S) of Line 000

Temporary pond-bottom 

drive-point sampler

EXPLANATION

70°32'25" 70°32'20"

41°38'05"

41°38'

279,920 280,100

820,840

821,020

June 2003 

shoreline position

Line 750N

Line 700N

Line 650N

Line 600N

Line 550N

Line 500N

Line 450N

Line 400N

Line 350N

Line 250N

Line 175N

Line 100N

Line 000

Line 100S

Line 200S

0 100 200 FEET

0 30 60 METERS

Line 200S
Water-Quality Data for Samples Collected from Permanent Instrumentation near the Permeable Reactive Barrier 7

Figure 5. Locations of temporary drive points installed in June–July 2004 to delineate the discharge area of treatedwastewater-plume constituents prior to the installation of a pond-bottom permeable reactive barrier, Ashumet Pond, Cape 

Cod, Massachusetts.

70°32'22" 70°32'20"

41°38'08"

41°38'06"

Base from Office of Geographic and Environmental Information (MassGIS), orthophoto 1:5000, 2003 

Massachusetts state plane coordinate system datum is NAD 83 in meters

Ashumet Pond

TOWN OF MASHPEE

TOWN OF FALMOUTH

Transect line and line number

Temporary pond-bottom 

drive-point sampler

EXPLANATION

Line 01

821,020

820,960

280,020 280,060 280,100

Line 02

Line 03

Line 04

Line 05

Line 06

Line 07

Line 08

Line 09

Line 10

Line 11

Line 12

Line 13

Line 14

Line 15

June 2004 

shoreline position

Line 01

0 40 80 FEET

0 10 20 METERS
8 Water-Quality Data from Shallow Pond-Bottom Groundwater, Ashumet Pond, Cape Cod, Massachusetts, 2001–2010

Figure 6. Locations of temporary drive points installed in August 2006 at 0.5, 1.5, and 3.0 feet below the pond bottom in the area of the 

permeable reactive barrier, Ashumet Pond, Cape Cod, Massachusetts. The unlabeled nearshore sampling points represent locations of 

temporary drive-point samplers that collected groundwater at the 0.5-foot depth. The sampling points are listed at the end of table 5 by 

line number and distance from shore.

TOWN OF MASHPEE

TOWN OF FALMOUTH

Base from Office of Geographic and Environmental Information (MassGIS), orthophoto 1:5000, 2003

Massachusetts state plane coordinate system datum is NAD 83 in meters

Ashumet Pond

Line 04

Line 05

Line 06

Line 07

Line 08

Line 09

Line 10

Line 11

Line 12

Line 13

Line 14

Line 15

70°32'24" 70°32'20"

41°38'08"

41°38'04"

Areal extent of permeable reactive barrier

Temporary pond-bottom drive-point sampler—Label A03 is 

abbreviated version of MA–FSW 669–A03 

EXPLANATION

820,910

279,980

821,060

280,070

A01 A03

A05

A02

A04

A06

A07

A08

A09

A10

A11

A12

A13

A14

A15

A16

A17

A18A19

A20

A21

A22 A23

A24

A25

A26

A27A28A29A30

A31

A32

A33

A34 A35

A36

A37

A38 A39

A40

A41

A42 A43A44 A45

A46

A47A48A49

A50

A51 A52 A53

A54 A55A56

A57A58 A59

A60

A61A62

A63

A64

A65 A66

A67 A68

A69

A70

A71 A72

A73

A74

A75

A76

A03

July 2006 

shoreline position

0 160 FEET

0 20 40 METERS

80
Water-Quality Data for Samples Collected from Permanent Instrumentation near the Permeable Reactive Barrier 9

Figure 7. Locations of temporary drive points installed in August 2009 at 0.5, 1.5, and 3.0 feet below the pond bottom in the area of 

the permeable reactive barrier, Ashumet Pond, Cape Cod, Massachusetts.

TOWN OF MASHPEE

TOWN OF FALMOUTH

Base from Office of Geographic and Environmental Information (MassGIS), orthophoto 1:5000, 2003

Massachusetts state plane coordinate system datum is NAD 83 in meters

Ashumet Pond

70°32'24" 70°32'20"

41°38'08"

41°38'04"

Areal extent of permeable reactive barrier

Temporary pond-bottom drive-point sampler—Label A03 is 

abbreviated version of MA–FSW 710–A03 

EXPLANATION

A16

A21

A27

A51

A63

A75

A86

A33

A03

820,910

279,980

821,060

280,070

A01

A03

A05

A02

A04

A06

A07

A08

A09

A10

A11

A12

A13

A14

A15

A16

A17

A18

A19

A20

A21

A22

A23

A24

A25

A26

A27

A28

A29

A30

A31

A32

A34

A35

A36

A37

A38

A39

A40 A41

A42A43

A44

A45

A46A47

A48 A49

A50

A51

A52

A53 A54 A55

A56

A57

A58

A59

A60 A61

A62

A63

A64 A65

A66 A67

A68

A69

A70 A71 A72 A73

A74

A75 A76 A77 A78 A79 A80

A81A82 A83 A84 A85

A86 A87A88 A89 A90

A33

August 2009 

shoreline position

0 160 FEET

0 20 40 METERS

80
10 Water-Quality Data from Shallow Pond-Bottom Groundwater, Ashumet Pond, Cape Cod, Massachusetts, 2001–2010

Figure 8. Locations of vertical multilevel samplers, multilevel diffusion chambers, horizontal multiport samplers, 

pond-bottom piezometers, and seepage meters in and near the permeable reactive barrier at Ashumet Pond, 

Cape Cod, Massachusetts.

Ashumet Pond

TOWN OF MASHPEE

TOWN OF FALMOUTH

EXPLANATION 

821,020

820,960

280,020 280,100

July 2009 shoreline position

June 2004 shoreline position

F633-P01

F635–P01

F636–P01

DC2

DC3

DC4

DC5

DC6

DC7

DC8

F639–P01

SM1

DC1

F640–P01 F641–P01

F642–P01

F643–P01

F644–P01

F645–P01

F646–P01

F647–P01

F648–P01

F636–P01

F645–P01

DC5

SM1

SM2

SM3

SM4

70°32'22" 70°32'20"

41°38'08"

41°38'06"

Base from Office of Geographic and Environmental Information (MassGIS), orthophoto 1:5000, 2003 

Massachusetts state plane coordinate system datum is NAD 83 in meters 

F709

F708

F709

Areal extent of permeable reactive barrier

Horizontal multiport sampler—Identifier 

abbreviated from MA–FSW 709–M01 

Vertical multilevel sampler—Identifier 

abbreviated from MA–FSW 645–P01 

Multilevel diffusion chambers

Pond-bottom piezometer—Identifier 

abbreviated from MA–FSW 636–P01

Seepage meter—Paired seepage meters are 5 feet apart

 

Modified from McCobb and others (2009a)

0 40 80 FEET

0 10 20 METERS

280,060
Acknowledgments 11

with the deepest sampling port installed slightly below the 

PRB layer (fig. 8). Data from samples collected from the 

VMLS between July 2004 and July 2010 are reported in 

table 7. 

MLDC consist of a 4-ft-long, square, hollow polyvinyl 

chloride (PVC) post with 13 holes drilled vertically along one 

face (fig. 8). Each hole is covered with a fiberglass screen to 

limit the entry of outside materials into the interior of the post. 

During a sampling event, a rack holding 13 diffusion samplers, 

which are 60-mL polyethylene bottles filled with deionized 

water and covered with a 10-μm nylon mesh, is set in the 

external chamber for a 2-week equilibration period. At the end 

of the 2-week period, the specific conductance and phosphate 

concentration were determined for the water in each sample 

bottle. In addition, the color of the nylon mesh was noted as 

an indicator of the presence of the the iron-containing PRB. 

MLDCs were sampled on nine occasions between October 

2004 and August 2010 (table 1). Data from samples collected 

since the PRB was installed are reported in table 8.

HMPS are horizontal multiport wells that are positioned 

under the pond bottom perpendicular to the shoreline (fig. 8). 

Two samplers were emplaced in tandem, one in the untreated 

sediment just below the barrier (3.0 ft below the pond bottom) 

and one just below the sediment/water interface in the barrier 

(0.5 ft below the pond bottom). Each HMPS consists of 

a 1.25-in.-diameter PVC pipe containing 15 color-coded, 

0.25-in.-diameter polyethylene tubes. The tubes exit the PVC 

pipe at different distances from shore and are screened with 

nylon material (McCobb and others, 2009a). HMPS were 

sampled on eight occasions between October 2004 and July 

2010 (table 1). Data from samples collected from the HMPS 

since the installation of the PRB are reported in table 9. 

Twelve pond-bottom piezometers were installed in 

August 2004, prior to the installation of the PRB, to monitor 

the phosphate plume before its discharge to Ashumet Pond 

(fig. 8). Each piezometer consists of a 3⁄4-in.-diameter steel 

pipe with a mill-slotted 1-ft-long steel well screen. The wells 

were installed in three clusters (MA-FSW 633-P01, MA-FSW 

635-P01, and MA-FSW 636-P01), with each cluster consisting 

of four piezometers extending to 10, 30, 60, and 100 ft 

below the pond bottom. The piezometers were installed by a 

vibratory-drilling rig mounted on an all-terrain vehicle placed 

on a barge. On eight occasions between July 2004 and August 

2010, the piezometers were sampled with the assistance 

of divers for field parameters and laboratory analyses of 

selected inorganic solutes (including phosphate), nitrate, and 

ammonium. Results of the field and laboratory analyses from 

the pond-bottom piezometers are reported in table 10.

Four pairs of permanent Lee-type seepage meters (Lee, 

1977) were installed in and adjacent to the PRB during 

the barrier’s installation (fig. 8). Each meter consists of a 

55-gal polyethylene drum cut to a length of 2.5 ft and fitted 

with a removable lid. An outlet hole drilled into the removable 

lid allows for the outflow or inflow to be measured. The 

meter design and sampling procedure are described in detail in 

McCobb and others (2009a). Multiple discharge measurements 

at each seepage meter were made on seven occasions. The 

water discharging through each meter was analyzed in the 

field to determine the specific conductance and phosphate 

concentration. The results of each sampling round are reported 

in table 11.

Summary

From 2001 to 2010, the U.S. Geological Survey, in 

cooperation with the Air Force Center for Engineering and the 

Environment, collected groundwater samples and measured 

pond-bottom discharge in the area of a treated-wastewater 

plume, which originates from wastewater-disposal beds at 

the Massachusetts Military Reservation and discharges to the 

Fishermans Cove area of Ashumet Pond, Falmouth, Cape Cod, 

Massachusetts. Analyses of groundwater samples provided 

data on the distribution, transport, and fate of phosphate, a 

constituent of the treated-wastewater plume. This Data Series 

report complements published reports about the discharge of 

the phosphate plume to the pond and the performance of a 

pond-bottom permeable reactive barrier. The data presented 

include (1) physical properties for the devices installed 

at each sampling location, including position, depth, and 

altitude information; (2) field parameters, including specific 

conductance, pH, and field-measured concentrations of 

dissolved oxygen and phosphate, and (3) laboratory results, 

including concentrations of selected inorganic solutes 

(including phosphate) and nitrogen species.

Acknowledgments

The authors thank Jeffrey Barbaro, Gillian Fairchild, 

Joshua Koch, Andrew Massey, Jennifer Savoie, and 

Jason Sorenson of the USGS and USGS interns (National 

Association of Geoscience Teachers) Amanda Cains, Megan 

Chaisson, Jessica Cochrane, Nick Geboy, Sara Henry, 

Jonathan King, Cody Munday, Luke Parsons, Jennifer Riker, 

Laura Strumness, and Derek Wagner, who helped to install 

instrumentation and collect water samples. The diving 

support from Sandy Baldwin, Dann Blackwood, Michael 

Casso, Richard Rendigs, and Charles Worley of the USGS 

Woods Hole Coastal and Marine Science Center is greatly 

appreciated. The authors are also grateful for the watersample analyses provided by the laboratories of Douglas Kent 

(USGS–Menlo Park, CA) and Richard Smith (USGS–Boulder, 

CO). The support and cooperation of Jon Davis (AFCEE), 

and Spence Smith and Jonathan Blount (CH2M Hill), is also 

greatly appreciated. 
12 Water-Quality Data from Shallow Pond-Bottom Groundwater, Ashumet Pond, Cape Cod, Massachusetts, 2001–2010

References Cited

Air Force Center for Environmental Excellence (AFCEE), 

2002a, Final Ashumet Pond trophic health technical 

memorandum, v. I, text, tables, and figures: Jacobs 

Engineering Group, Inc., AFC–J23–35S18402–M17–0012, 

July 2002, variously paged.

_____, 2002b, Final Ashumet Pond trophic health technical 

memorandum, v. II, appendixes A–H: Jacobs Engineering 

Group, Inc., AFC–J23–35S18402–M17–0012, July 2002, 

variously paged.

Air Force Center for Environmental Excellence (AFCEE), 

2004, Ashumet Pond geochemical barrier for phosphorus 

removal—Design, testing, and installation workplan, 

Massachusetts Military Reservation, Installation Restoration 

Program: CH2MHill, Inc., 176585–SPEIM–ASHPO–

WRKPLN–002, August 2004, variously paged.

Antweiler, R.C., Patton, C.J., and Taylor, H.E., 1993, 

Automated, colorimetric methods for determination of 

nitrate plus nitrite, nitrite, ammonium and orthophosphate 

ions in natural water samples: U.S. Geological Survey 

Open-File Report 93–638, 40 p.

Fishman, M.J., ed., 1993, Methods of analysis by the U.S. 

Geological Survey National Water Quality Laboratory—

Determination of inorganic and organic constituents in 

water and fluvial sediments: U.S. Geological Survey OpenFile Report 93–125, 217 p.

 LeBlanc, D.R., 1984, Sewage plume in a sand and gravel 

aquifer, Cape Cod, Massachusetts: U.S. Geological Survey 

Water-Supply Paper 2218, 28 p.

Lee, D.R., 1977, A device for measuring seepage flux in lakes 

and estuaries: Limnology and Oceanography, v. 22, no. 1, 

p. 140–147.

McCobb, T.D., LeBlanc, D.R., Walter, D.A., Hess, K.M., 

Kent, D.B., and Smith, R.L., 2003, Phosphorus in a groundwater contaminant plume discharging to Ashumet Pond, 

Cape Cod, Massachusetts, 1999: U.S. Geological Survey 

Water-Resources Investigations Report 02–4306, 69 p.

McCobb, T.D., LeBlanc, D.R., and Massey, A.J., 2009a, 

Monitoring the removal of phosphate from ground water 

discharging through a pond-bottom permeable reactive 

barrier: Ground Water Monitoring & Remediation, v. 29, 

no. 2, p. 43–55.

McCobb, T.D., LeBlanc, D.R., Parsons, L.A., and Blount, 

J.G., 2009b, Distribution of treated-wastewater constituents 

in pore water at a pond-bottom permeable reactive barrier, 

Cape Cod, Massachusetts: U.S. Geological Survey 

Scientific Investigations Map 3078, 1 pl.

Parkhurst, D.L., Stollenwerk, K.G., and Colman, J.A., 2003, 

Reactive-transport simulation of phosphorus in the sewage 

plume at the Massachusetts Military Reservation, Cape 

Cod, Massachusetts: U.S. Geological Survey WaterResources Investigations Report 03–4017, 33 p.

Patton, C.J., and Kryskalla, J.R., 2003, Methods of analysis 

by the U.S. Geological Survey National Water Quality 

Laboratory—Evaluation of alkaline persulfate digestion 

as an alternative to Kjeldahl digestion for determination 

of total dissolved nitrogen and phosphorus in water: U.S. 

Geological Survey Water-Resources Investigations Report 

03–4174, 33 p.

Savoie, Jennifer, 1995, Altitude and configuration of the water 

table, western Cape Cod aquifer, Massachusetts, March 

1993: U.S. Geological Survey Open-File Report 94–462, 

1 pl.

Savoie, Jennifer, and LeBlanc, D.R., eds., 1998, Waterquality data and methods of analysis for samples collected 

near a plume of sewage-contaminated ground water, 

Ashumet Valley, Cape Cod, Massachusetts, 1993–94: U.S. 

Geological Survey Water-Resources Investigations Report 

97–4269, 208 p.

Savoie, J.G., Kent, D.B., Smith, R.L., LeBlanc, D.R., and 

Hubble, D.W., 2004, Changes in ground-water quality near 

two granular-iron permeable reactive barriers in a sand and 

gravel aquifer, Cape Cod, Massachusetts, 1997–2000: U.S. 

Geological Survey Water-Resources Investigations Report 

03–4309, 77 p.

Smith, R.L., Buckwalter, S.P., Repert, D.A., and Miller, 

D.N., 2005, Small-scale, hydrogen-oxidizing-denitrifying 

bioreactor for treatment of nitrate-contaminated drinking 

water: Water Research, v. 39, p. 2014–2023.

 Walter, D.A., Rea, B.A., Stollenwerk, K.G., and Savoie, 

Jennifer, 1996, Geochemical and hydrologic controls 

on phosphorus transport in a sewage-contaminated 

sand and gravel aquifer near Ashumet Pond, Cape Cod, 

Massachusetts: U.S. Geological Survey Water-Supply 

Paper 2463, 89 p.
Tables 13

Tables 

Click on link to view tables

1. Summary of data reported by date, sampling method, extent of sampling area, and analyses performed. [Click here]

2. Physical properties of sampling locations and chemical analyses of groundwater samples collected from temporary 

drive points driven below the pond bottom, Ashumet Pond, Cape Cod, Massachusetts, August 22–September 13, 2001. 

[Click here]

3. Physical properties of sampling locations and chemical analyses of groundwater samples collected from temporary 

drive points driven below the pond bottom, Ashumet Pond, Cape Cod, Massachusetts, June 9–26, 2003. [Click here]

4. Physical properties of sampling locations and chemical analyses of groundwater samples collected from temporary 

drive points below the pond bottom, Ashumet Pond, Cape Cod, Massachusetts, June 29–July 2, 2004. [Click here]

5. Physical properties of sampling locations and chemical analyses of groundwater samples collected from temporary 

drive points below the pond bottom, Ashumet Pond, Cape Cod, Massachusetts, August 2–28, 2006. [Click here]

6. Physical properties of sampling locations and chemical analyses of groundwater samples collected from temporary 

drive points below the pond bottom, Ashumet Pond, Cape Cod, Massachusetts, August 3–12, 2009. [Click here]

7. Physical properties of sampling locations and chemical analyses of groundwater samples collected from vertical 

multilevel samplers in and near a pond-bottom permeable reactive barrier, Ashumet Pond, Cape Cod, Massachusetts, 

July 2004–July 2010. [Click here]

8. Physical properties of sampling locations and chemical analyses of groundwater samples collected from multilevel 

diffusion chambers in and near a pond-bottom permeable reactive barrier, Ashumet Pond, Cape Cod, Massachusetts, 

October 2004–August 2010. [Click here]

9. Physical properties of sampling locations and chemical analyses of groundwater samples collected from horizontal 

multiport samplers at a pond-bottom permeable reactive barrier, Ashumet Pond, Cape Cod, Massachusetts, 

October 2004–July 2010. [Click here]

10. Physical properties of sampling locations and chemical analyses of groundwater samples collected from pond-bottom 

piezometers near pond-bottom permeable reactive barrier, Ashumet Pond, Cape Cod, Massachusetts, August 2004–July 

2010. [Click here]

11. Physical properties of sampling locations, water flux, and chemical analyses of samples collected from seepage 

meters in and near a pond-bottom permeable reactive barrier, Ashumet Pond, Cape Cod, Massachusetts, 

November 2004–July 2010. [Click here]
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For more information concerning this report, contact:

Director

U.S. Geological Survey

Massachusetts-Rhode Island Water Science Center

10 Bearfoot Road, 

Northborough, MA 01532

dc_ma@usgs.gov

or visit our Web site at

http://ma.water.usgs.gov
McCobb and LeBlanc—Water-Quality Data from Shallow Pond-Bottom Groundwater, Cape Cod, Massachusetts, 2001–2010—Data Series 588