U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2009–5063

Prepared in cooperation with the

Massachusetts Department of Environmental Protection—Drinking-Water Program

Hydrogeology and Simulation of Groundwater Flow in 

the Plymouth-Carver-Kingston-Duxbury Aquifer System, 

Southeastern Massachusetts
Cover. Blackmore Pond, Wareham MA. View is to the southeast with the Weweantic River in the background. 

Photograph (copyright) Joseph R. Melanson of www.skypic.com.
Hydrogeology and Simulation of 

Groundwater Flow in the PlymouthCarver-Kingston-Duxbury Aquifer System, 

Southeastern Massachusetts

By John P. Masterson, Carl S. Carlson, and Donald A. Walter

Other contributing authors: Gardner C. Bent and Andrew J. Massey

Prepared in cooperation with the 

Massachusetts Department of Environmental Protection—

Drinking Water Program

Scientific Investigations Report 2009–5063

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: 2009

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Suggested citation:

Masterson, J.P., Carlson, C.S., and Walter, D.A., 2009, Hydrogeology and simulation of groundwater flow in the 

Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts: U.S. Geological Survey Scientific 

Investigations Report 2009–5063, 110 p. 
iii

Contents

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

Introduction ....................................................................................................................................................2

Hydrogeology..................................................................................................................................................2

Geologic Setting....................................................................................................................................4

Hydrologic System................................................................................................................................9

Water Budget ...............................................................................................................................9

Altitude and Configuration of the Water Table .....................................................................10

Effect of Recharge on Water Table ...............................................................................10

Interaction between Groundwater and Surface Water.............................................10

Controls of Hydrogeologic Framework .........................................................................14

Groundwater-Recharge Areas ................................................................................................14

Simulated Response of the Groundwater-Flow System to Changes in Pumping and

Recharge Conditions .....................................................................................................................15

Long-Term Average Conditions ........................................................................................................15

Water Use ...................................................................................................................................15

Change in Water Budget ..........................................................................................................17

Changes in Water Levels..........................................................................................................22

Changes in Streamflows...........................................................................................................26

Effects of Time-Varying Hydrologic Stresses.................................................................................26

Average Monthly Conditions....................................................................................................26

Predevelopment Conditions ...........................................................................................26

Effects of Current and Future Pumping Conditions.....................................................30

Effects of Wastewater Return Flow...............................................................................30

Drought Conditions....................................................................................................................31

Summary and Conclusions.........................................................................................................................36

Acknowledgments.......................................................................................................................................37

References Cited..........................................................................................................................................37

Appendix 1. Development of Groundwater-Flow Model....................................................................41

Appendix 2. Comparison with Previous Model ...................................................................................91

Appendix 3. Water-Level and Streamflow Data by Gardner C. Bent.............................................103

Figures

1. Location of Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern

Massachusetts..............................................................................................................................3

2. Location of continental ice sheets near present-day southeastern Massachusetts

during the late Pleistocene .........................................................................................................4

3. Surficial geology of the Plymouth-Carver-Kingston-Duxbury aquifer system,

southeastern Massachusetts.....................................................................................................6

4. Altitude and configuration of the bedrock surface beneath the Plymouth-CarverKingston-Duxbury aquifer system, southeastern Massachusetts .......................................7

5. Deltaic deposits prograding into a glacial lake, including topset, foreset, and

bottomset deposits .......................................................................................................................8
iv

6. Variability of precipitation and aquifer recharge at the East Wareham,

Massachusetts, weather station from 1931–2006...................................................................9

7. Model-calculated water-table altitude and configuration in the

Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts .....11

8. Variability of precipitation and recharge at East Wareham, Massachusetts, 

and water levels at well PWW–22, Plymouth: (A) total annual precipitation 

and recharge and annual average water levels, and (B) average monthly 

precipitation and recharge for the period 1931–2006 and water levels for the 

period 1961–2006.........................................................................................................................12

9. Variability of precipitation and recharge at East Wareham, Massachusetts, and

water levels at well WFW–51, Wareham: (A) total annual precipitation and

recharge and annual average water levels, and (B) average monthly precipitation

and recharge for the period 1931–2006 and water levels for the period 1961–2006 .......13

10. Changes in monthly streamflow at Jones River, Kingston, Massachusetts, for the

period 1966–2006 compared to average monthly changes in precipitation and

recharge.......................................................................................................................................14

11. Area contributing recharge to a pumping well in a simplified, hypothetical

groundwater-flow system .........................................................................................................15

12. Model-calculated delineations of groundwater-recharge areas to production

wells, ponds, streams, and coastal areas for current (2005) average pumping and

recharge conditions, Plymouth-Carver-Kingston-Duxbury aquifer system,

southeastern Massachusetts...................................................................................................16

13. Pumping rates for the Plymouth-Carver-Kingston-Duxbury aquifer system,

Massachusetts, for 1985 and 2005, and proposed 2030 conditions for 

(A) total combined pumping, (B) public supply, and (C) commercial and 

irrigation withdrawals................................................................................................................18

14. Distribution of wastewater return-flow areas for (A) current (2005) and 

(B) proposed (2030) pumping and recharge conditions .......................................................19

15. Model-calculated delineations of groundwater-recharge areas to production

wells, ponds, streams, and coastal areas for future (2030) average pumping and

recharge conditions, Plymouth-Carver-Kingston-Duxbury aquifer system,

southeastern Massachusetts...................................................................................................21

16. Hypothetical aquifer showing groundwater discharge to a surface-water body

with (A) no pumping, (B) pumping at a rate Q1 high enough for the well to capture

water that would otherwise discharge to the surface-water body, and 

(C) pumping at a higher rate Q2 so that the flow direction is reversed and the 

well pumps water from the surface-water body...................................................................22

17. Model-calculated changes in water levels between (A) predevelopment and

1985, (B) 1985 and 2005, and (C) 2005 and proposed (2030) pumping and recharge

conditions in the Plymouth-Carver-Kingston-Duxbury aquifer system,

southeastern Massachusetts...................................................................................................23

18. Average production-well withdrawals by month for current (2005) pumping

conditions in the Plymouth-Carver-Kingston-Duxbury aquifer system,

southeastern Massachusetts...................................................................................................28

19. Model-calculated monthly changes in water levels relative to long-term average

annual levels at Halfway Pond, Long Pond, and well PWW–414 in Plymouth,

Massachusetts............................................................................................................................28

20. Model-calculated monthly water levels and streamflow at Halfway Pond and the

Halfway Pond surface-water outlet for predevelopment conditions, Plymouth,

Massachusetts............................................................................................................................29
v

21. Model-calculated monthly streamflow in the Eel River with and without

wastewater return-flow recharge for current (2005) conditions, Plymouth,

Massachusetts............................................................................................................................29

22. Model-calculated monthly changes in streamflow at the Halfway Pond

surface-water outlet for predevelopment, current (2005), and proposed (2030)

pumping and recharge conditions...........................................................................................30

23. Model-calculated monthly changes in streamflow in the Eel River for

predevelopment, current (2005), and proposed (2030) pumping and recharge

conditions.....................................................................................................................................31

24. Model-calculated changes in water levels for simulated monthly average and

drought conditions for (A) Halfway Pond, (B) Long Pond, and (C) well PWW–414

for current (2005) pumping conditions ....................................................................................32

25. Model-calculated changes in streamflow at the Halfway Pond surface-water

outlet for simulated monthly average and drought conditions for current (2005)

pumping conditions ....................................................................................................................33

26. Model-calculated changes in water levels from average conditions for simulated

drought conditions in October of Drought YEAR4 with current (2005) pumping and

wastewater return-flow rates ..................................................................................................34

27. Model-calculated streamflows in Harlow Brook in Wareham, Massachusetts, for

monthly average and drought conditions at current (2005) pumping and

wastewater return-flow rates ..................................................................................................35

28. Model-calculated streamflows in the Eel River, Plymouth, Massachusetts, for 

(A) monthly average and drought conditions at current (2005) pumping and

wastewater return-flow rates and (B) drought conditions with and without

wastewater return flow at current (2005) pumping rates ....................................................35

Tables

1. Summary of horizontal hydraulic conductivity values for general 

sediment lithologies, Plymouth-Carver-Kingston-Duxbury aquifer system, 

southeastern Massachusetts.....................................................................................................5

2. Model-calculated hydrologic budget for predevelopment, 1985, 2005, and

proposed 2030 pumping and recharge conditions in the Plymouth-CarverKingston-Duxbury aquifer system, southeastern Massachusetts .....................................17

3. Model-calculated changes in streamflow for predevelopment, 1985, 2005, and

proposed 2030 pumping and recharge conditions................................................................27
vi

List of Acronyms

CV Coefficient of variation

DRN Drain

GHB General head boundary

GIS Geographic information system

MassDEP Massachusetts Department of Environmental Protection

MOVE.1 Maintenance of variance extension, type 1 

OBS Observation process

PES Parameter estimation process

PET Potential evapotranspiration

PCKD Plymouth-Carver-Kingston-Duxbury

RCH Recharge package

RIV River package

SEN Sensitivity process

STR Streamflow-routing package

USGS U.S. Geological Survey

VA Vertical anisotropy

WATBUG Water-budget computer program

WWTF Wastewater-treatment facilities

Conversion Factors, Data, and Abbreviations

Multiply By To obtain

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

square mile (mi2) 2.590 square kilometer (km2) 

foot per day (ft/d) 0.3048 meter per day (m/d)

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

million gallons per day (Mgal/d) 0.04381 cubic meter per second (m3/s)

inch per year (in/yr) 25.4 millimeter per year (mm/yr)

Vertical coordinate information is referenced to the National Geodetic Vertical Datum of 1929 

(NGVD 29). 

Horizontal coordinate information is referenced to the North American Datum of 1927 (NAD 27). 

Altitude, as used in this report, refers to distance above the vertical datum.
Hydrogeology and Simulation of Groundwater Flow in 

the Plymouth-Carver-Kingston-Duxbury Aquifer System, 

Southeastern Massachusetts

By John P. Masterson, Carl S. Carlson, and Donald A. Walter

potentially capture water that would otherwise discharge to 

these surface-water bodies, thereby reducing streamflow and 

pond levels. The areas most affected by proposed increases in 

groundwater withdrawals are in the Towns of Plymouth and 

Wareham where more than half of the proposed increase in 

pumping will occur.

In response to an increase of about 7 Mgal/d of pumping, 

groundwater discharge to streams is reduced by about 

6 cubic feet per second (ft3/s) (about 4 Mgal/d) from a total 

of about 325 ft3/s. Reduction in streamflow is moderated by 

an increase of artificial recharge from wastewater returned to 

the aquifer by onsite domestic septic systems and centralized 

wastewater treatment facilities. It is anticipated that about 

3 Mgal/d of the 7 Mgal/d of increase in pumped water will be 

returned to the aquifer as wastewater by 2030. 

Currently (2005) about 3 percent of groundwater 

discharge to streams is from wastewater return flow to the 

aquifer during average conditions. During drought conditions, 

the component of streamflow augmented by wastewater 

return flow doubles as wastewater recharge remains constant 

and aquifer recharge rates decrease. Wastewater return flow, 

whether as direct groundwater discharge to streams or as an 

additional source of aquifer recharge, increases the height of 

the water table near streams, thereby moderating the effects of 

increased groundwater withdrawals on streamflow.

An analysis of a simulated drought similar to the 1960s 

drought of record indicates that the presence of streams 

moderates the effects on water levels of reduced aquifer 

recharge. The area where water-table altitudes were least 

affected by drought was in the Weweantic River watershed 

in the Town of Carver. Water levels decreased by less than 

2 feet from current average conditions compared to decreases 

of greater than 5 feet in the Town of Plymouth. In the 

Weweantic River watershed the effect of the drought was 

reflected in the 50-percent reduction in streamflow in the 

Weweantic River, rather than a large decrease in water levels. 

The water table in areas where ponds are drained by surfacewater outlets or where large gaining streams are present 

appears to be less affected by droughts than the water table in 

areas where streams are not present or where streams go dry 

under drought conditions. 

Abstract

The glacial sediments that underlie the PlymouthCarver-Kingston-Duxbury area of southeastern Massachusetts 

compose an important aquifer system that is the primary 

source of water for a region undergoing rapid development. 

Population increases and land-use changes in this area has 

led to two primary environmental effects that relate directly 

to groundwater resources: (1) increases in pumping that can 

adversely affect environmentally sensitive groundwater-fed 

surface waters, such as ponds, streams, and wetlands; and 

(2) adverse effects of land use on the quality of water in the 

aquifer. In response to these concerns, the U.S. Geological 

Survey, in cooperation with the Massachusetts Department 

of Environmental Protection, began an investigation in 2005 

to improve the understanding of the hydrogeology in the area 

and to assess the effects of changing pumping and recharge 

conditions on groundwater flow in the Plymouth-CarverKingston-Duxbury aquifer system.

A numerical flow model was developed based on the 

USGS computer program MODFLOW-2000 to assist in the 

analysis of groundwater flow. Model simulations were used to 

determine water budgets, flow directions, and the sources of 

water to pumping wells, ponds, streams, and coastal areas.

Model-calculated water budgets indicate that 

approximately 298 million gallons per day (Mgal/d) of water 

recharges the Plymouth-Carver-Kingston-Duxbury aquifer 

system. Most of this water (about 70 percent) moves through 

the aquifer, discharges to streams, and then reaches the coast 

as surface-water discharge. Of the remaining 30 percent of 

flow, about 25 percent of the water that enters the aquifer as 

recharge discharges directly to coastal areas and 5 percent 

discharges to pumping wells. 

Groundwater withdrawals are anticipated to increase 

from the current (2005) rate of about 14 Mgal/d to about 

21 Mgal/d by 2030. Pumping from large-capacity production 

wells decreases water levels and increases the potential 

for effects on surface-water bodies, which are affected 

by pumping and wastewater disposal locations and rates. 

Pumping wells that are upgradient of surface-water bodies 
2 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Introduction 

The region of southeastern Massachusetts where 

the Towns of Plymouth, Carver, Kingston and Duxbury 

are located is known for its abundant water resources, its 

cranberry agriculture, and its unique ecosystems. Rapid 

population growth in this region, however, has resulted in 

increased competition among agricultural, commercial, 

ecological, and residential demands for water resources. 

Continued population growth has created the potential 

for increased groundwater withdrawals that could deplete 

streamflow and lower surface-water levels in streams, ponds, 

and wetlands and increase the loading of nonpoint-source 

septic contamination. These potential effects may contribute 

to habitat destruction, degradation of water quality, and loss 

of wetlands. 

The unconfined aquifer that underlies this region is 

composed mostly of glacially deposited sediments ranging in 

size from clay to boulders and is the second largest aquifer 

system in Massachusetts (Hansen and Lapham, 1992). It 

ranges in thickness from less than 20 to more than 200 ft, and 

contains more than 500 billion gallons of freshwater (Williams 

and Tasker, 1974). Groundwater discharge from the aquifer 

supports numerous kettle ponds and coastal streams (fig. 

1). The aquifer was designated as a Sole Source Aquifer by 

the U.S. Environmental Protection Agency, recognizing that 

groundwater is a vital source of drinking water for many of the 

communities in the area. 

The population in this region has nearly tripled in the 

past 30 years; as a result, nearly 40 percent of agricultural 

lands in the region have been lost to development (Woods 

Hole Research Center, 2007). Over the next 20 years, the 

overall population of southeastern Massachusetts is projected 

to increase by more than 200,000, making this part of 

southeastern Massachusetts the fastest growing region in the 

State (The Nature Conservancy, 2002). Large increases in 

population and the conversion of open space to residential 

development creates concerns for potential effects on the 

quality and quantity of the region’s water supply. 

Historically, the Plymouth-Carver area has been one 

of the most important centers of cranberry production in the 

United States. Cranberries produced in this region account 

for most of the Massachusetts harvests, and in 2001 were 

about one-third of the Nation’s harvest (New England 

Agricultural Statistics Service, 2002). In recent years, a variety 

of economic factors, including out-of-state competition and 

declining cranberry prices, has led some cranberry growers to 

convert upland portions of their land holdings to residential 

development (Flint, 2002).

The Nature Conservancy has recognized this area as one 

of the most significant ecosystems in the northeastern United 

States. The region contains unique ecosystems such as the 

Plymouth Pinelands, an approximately 30-mi2 area in the 

northeastern portion of the region, a large state forest (Myles 

Standish State Forest), and two State-designated Areas of 

Critical Environmental Concern (Ellisville Harbor and the 

Herring River Watershed) (fig. 1). 

Current and predicted growth in population and 

residential development and the reliance in this area 

on groundwater for water supply created the need for a 

reexamination of the water resources of the PlymouthCarver-Kingston-Duxbury (PCKD) aquifer system. The 

U.S. Geological Survey (USGS), in cooperation with the 

Massachusetts Department of Environmental Protection, 

has conducted previous hydrologic studies of the aquifer 

system, including hydrologic assessments of aquifer yield 

and water quality (Williams and Tasker, 1974; Persky, 1993) 

and a regional modeling study (Hansen and Lapham, 1992). 

Advances in computing capabilities, numerical groundwaterflow models, and geographic information system (GIS) 

tools developed since the previous studies were conducted 

have allowed for the development of a more sophisticated 

groundwater-flow model that builds upon those earlier efforts. 

Water-resources management in the PCKD region offers 

hydrologic challenges beyond those imposed by the competing 

domestic, commercial, agricultural, and environmental 

demands for water. This extensive aquifer system extends 

across the South Coastal, Taunton, and Buzzards Bay 

watershed boundaries, which are typically used by State waterresource managers in planning and protection efforts (fig. 1). 

As a result, comprehensive regional groundwater modeling 

is necessary because the surficial watershed divides in this 

region are not always coincident with groundwater divides 

and may shift in response to changes in recharge and pumping 

conditions.

This report describes the development, calibration, and 

sensitivity analysis of the groundwater-flow model developed 

for this investigation conducted in cooperation with the 

Massachusetts Department of Environmental Protection 

(MassDEP). The numerical model MODFLOW-2000 

(Harbaugh and others, 2000) was used to provide information 

about regional-scale flow in the PCKD aquifer system, 

including changes in groundwater levels, pond levels, and 

streamflows in response to changing pumping and recharge 

conditions. Although detailed analyses of local-scale 

hydrologic conditions were beyond the scope of this regional 

investigation, the flow model may serve as the starting point 

for more detailed, site-specific investigations where local-scale 

models may be developed.

Hydrogeology

The Massachusetts Office of Energy and Environmental 

Affairs subdivided the State into 27 hydrologic-planning 

basins, with many of these planning basins based on drainage 

divides and typically named for the major surface-water 

feature within the basin. The only basins in the State that are 

groundwater systems based on groundwater divides are Cape 

Cod, Martha’s Vineyard, and Nantucket Island. The PCKD 
Hydrogeology 3

Figure 1. Location of Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.

Silver 

Lake

DUXBURY

BAY

KINGSTON

BAY

PLYMOUTH 

 HARBOR

Billington

 Sea

 

Great South 

 Pond

 

Federal 

 Pond

 

South

River Res.

 

College 

 Pond

 Bloody

 Pond

 

Halfway

 Pond

 Savery

 Pond

 

Indian

 Brook

 

Beaver Dam

 Brook

 

 East 

Head

Pond

 

 Glen

Charlie

Pond

 

 White

Island

Pond

 

 Big 

Sandy

Pond

 

 Great

Herring

Pond

 

 Cod 

 

 Cape 

 Canal

 

 Parker Mills

Pond

 

 Agawam

Fresh

Meadow

 Pond

 

Sampson

 Pond

 

South 

 

Wankinco 

 Wareham

 

Meadow 

 

 

River

 

River

 

 

River 

Herring

River

 

Brook

 

 

Weweantic River

 

 Winnetuxet River

 

 

PLYMOUTH 

 BAY

CAPE COD

 BAY

BUZZARDS

 BAY

MASSACHUSETTS BAY

Jones River

South 

Harbor

Green

 River

 River

Eel River

Long Pond

01105870

Rochester

Plympton

Halifax

Marion

Plymouth

South Coastal 

Watershed Taunton 

Watershed

Herring River 

Watershed

Buzzards Bay Watershed

Myles Standish 

State Forest

Pine Hills

Plymouth Pinelands

Ellisville 

Harbor

Carver

Wareham

Middleborough

Hanson

Duxbury

Kingston

Marshfield

Bourne

Sandwich

70°47'30" 70°37'30"

42°00'

41°45'

Base from U.S. Geological Survey and Massachusetts Geographic Information System data sources,

Massachusetts State Plane Coordinate System, Mainland Zone

Inactive model area

Open space

Massachusetts Water 

Resources Commission

watershed boundary

Town boundary

EXPLANATION

Existing well site

Proposed well site

Existing wastewater

treatment facility

Long-term observation well

PWW–22

Proposed wastewater

treatment facility

PWW–22

WFW–51

0 2 MILES

0 2 KILOMETERS

MASSACHUSETTS

73° 71°

43°

41° 0 12.5 25 50 MILES

0 15 30 60 KILOMETERS

Study Area
4 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

aquifer system is the second largest aquifer in Massachusetts; 

however, for planning purposes, it is included in the South 

Coastal, Taunton, and Buzzards Bay drainage basins (fig. 1). 

The groundwater divides within the aquifer do not necessarily 

conform to the surficial divides of the planning-basin 

boundaries and are subject to change with changes in pumping 

and aquifer recharge.

 For the purpose of this investigation the glacial 

sediments that underlie the Towns of Plymouth, Carver, 

Kingston, and Duxbury are grouped together to constitute 

the regional PCKD aquifer system. This aquifer system was 

analyzed under changing hydrologic conditions by use of the 

groundwater-flow model developed for this investigation. 

A detailed discussion of the development and calibration 

of this model is provided in Appendix 1; a comparison 

between the model developed for this investigation and the 

model developed in the mid-1980s in the previous USGS 

investigation of the Plymouth-Carver aquifer (Hansen and 

Lapham, 1992) is presented in Appendix 2.

Geologic Setting

The glacial deposits that constitute the PCKD aquifer 

system consist of sediments that range in size from clay to 

boulders. These sediments were deposited approximately 

15,000 years ago during the late Wisconsinan glacial stage 

of the Pleistocene Epoch (Larson, 1980) as a result of a 

complex series of retreats and readvances of two large sheets 

of ice—the Buzzards Bay and Cape Cod Bay lobes (Mather 

and others, 1942) (fig. 2). The predominant glacial features 

are outwash plains and moraines (fig. 3) in the southern 

Plymouth-Carver area and valley-fill stratified glacial deposits 

bordered by upland till areas in the northern Duxbury area 

(fig. 3). These surficial deposits overlie Paleozoic crystalline 

bedrock that ranges in altitude from about 100 ft above NGVD 

29 in Middleborough to more than 200 ft below NGVD 29 in 

Bourne (fig. 4) (Hansen and Lapham, 1992). 

The primary water-bearing deposits in the PCKD aquifer 

system are the large outwash plain deposits, the Wareham 

and Carver Pitted Plains. These deposits were formed by 

Figure 2. Location of continental ice sheets near present-day southeastern 

Massachusetts during the late Pleistocene.

20 KILOMETERS

0

0

20 MILES

70°30' 70°00'

DIRECTION OF ICE 

MOVEMENT

71°00'

42°00'

41°30'

ATLANTIC OCEAN

Buzzards Bay lobe

Cape Cod Bay lobe

South 

Channel

lobe

NANTUCKET SOUND

BUZZARDS BAY

Martha’s Vineyard

Nantucket

Cape Cod

Plymouth-Carver

-Kingston-Duxbury

Aquifer System

Base from U.S. Geological Survey and Massachusetts Geographic Information System data sources,

Massachusetts State Plane Coordinate System, Mainland Zone
Hydrogeology 5

Table 1. Summary of horizontal hydraulic conductivity values for general sediment lithologies, Plymouth-Carver-Kingston-Duxbury 

aquifer system, southeastern Massachusetts. 

[Hydraulic conductivity values for lithology groups denoted by map ID letters A–K from Williams and Tasker, 1974. Transmissivity values for stratified drift 

groups denoted by map ID letters M–P from Persky, 1993. >, greater than; ft, feet; <, less than; ID, Identification; Map ID letters are shown on figure 1–3]

Surficial 

geology 

code

Hydraulic conductivity (feet per day)

A Well sorted gravel (>150) and fine to coarse sand (40–150) as much as 30 ft thick; locally bouldery. Generally mantles 

stratified silt, sand, gravel, tidal marsh, organic deposits, or till.

B Tidal peat, organic silt, silt (<10) and fine to medium sand (40–100) less than 30 ft thick. Generally mantles silt, sand, 

gravel, and compact silty gravel (till).

C Artificial fill of sand (40–150) and some gravel (150–250) excavated from Cape Cod Canal; riprap and fill in Stony 

Point dike.

D Upper unit of well sorted fine gravel (150–200) and medium to coarse sand (100–150) 15 to 20 ft thick, middle unit of fine 

to coarse sand (40–150) and some pebble gravel (150–200), and lower unit of fine sand (40) and silt and clay (<10) of 

variable thickness. Mantles sand and gravel (40–250) beneath parts of Plymouth kamefield.

E Fine sand (40), overlying silt and clay (<10) generally 10 to about 50 ft thick. In Plymouth, kamefield deposits may lie 

above stratified sand and gravel (40–250); at southern border of Carver outwash, plain deposits lie on compact till or on 

coarse, bouldery ablation deposits.

F Fine to coarse gravel (150–475).

G Medium to coarse sand (100–150).

H Loose, poorly to well sorted, poorly stratified deposits ranging from coarse, bouldery sand and gravel (<250) and silty 

sandy boulder gravel (sandy till) (<100) to fine to coarse sand (40–150) and silt and clay (<10). Wide differences in 

texture and hydraulic conductivity over short vertical and horizontal distances. Thickness as much as 50 ft.

I Loose, unstratified, unsorted sandy silty gravel (sandy till) (<100); poorly stratified and poorly sorted coarse sandy boulder 

gravel containing some well stratified, well sorted sandy gravel (<250).

J Loose, unsorted, unstratified, bouldery silty sandy gravel (sandy till) (<100) less than 30 ft thick that mantles fine to coarse 

sand (40–150) containing some beds of sandy gravel (<250). North of Ellisville Moraine in Manomet, underlying sand 

contains a relatively thin zone of compact till (<10) and rests on basal compact till.

K Compact unsorted silty boulder gravel (till) (<10).

Surficial 

geology 

code

Transmissivity of stratified drift 

(feet squared per day)

M Not examined

N < 1,350

O > 1,350 to 4,000

P > 4,000
6 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Figure 3. Surficial geology of the Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.

70°47'30" 70°37'30"

42°00'

41°45'

Base from U.S. Geological Survey and Massachusetts Geographic

Information System data sources, Massachusetts State Plane Coordinate

System, Mainland Zone 

0 2 MILES

0 2 KILOMETERS

Wareham Pitted 

Plain

Carver Pitted 

Plain

Hog Rock

Moraine

Sandwich

Moraine

Snipituit Moraine

Pine

Hills

Ellisville Moraine

Inactive model area

Surficial geology—Refer

to table 1–2 for description

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

EXPLANATION

Middleborough

Moraine

Surficial geology modified from Williams

and Tasker, 1974; and from Persky, 1993
Hydrogeology 7

Figure 4. Altitude and configuration of the bedrock surface beneath the Plymouth-Carver-Kingston-Duxbury 

aquifer system, southeastern Massachusetts.

Inactive model area

Bedrock-surface contour—

In feet. Interval is variable.

Datum is NGVD 29. 

Dashed where uncertain

Base from U.S. Geological Survey and Massachusetts Geographic

Information System data sources, Massachusetts State Plane Coordinate

System, Mainland Zone

Bedrock-surface data point

Geologic data point

Town boundaries

EXPLANATION

20

70°47'30" 70°37'30"

42°00'

41°45'

Pembroke

Rochester

Plympton

Halifax

Marion

Plymouth

Carver

Wareham

Middleborough

Hanson

Duxbury

Kingston

Marshfield

Bourne

Sandwich

-20

20

-20

20

20

20

40

40

40

40

0

0

0

0

0

-50

60

60

60

60

80

50

50

50

50

50

50

50

50

50

20

100

100

100

0

25

0

0

-50

-50

-50

-50

-50

-50

-100

-100

-100

-100

-100

-100

-150

-150

-150

-200

-200

-25

-25

-25

-25

-50

-50

-50

-100

-50

-50

-20

0 2 MILES

0 2 KILOMETERS

Data modified from Hansen and Lapham, 1992;

and Persky, 1993
8 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

meltwater from the retreating Buzzards Bay and Cape Cod 

Bay lobe ice sheets as deltas deposited sediments into a large 

glacial lake that formed in the wake of the retreating ice sheets 

(Larson, 1980).

The flat surfaces of the outwash plains were altered 

by the numerous kettle holes that were formed as collapse 

structures by the melting of buried blocks of ice stranded by 

the retreating ice lobes. These ice blocks, stranded directly on 

basal till and bedrock, subsequently were buried by prograding 

deltaic sediments. When the buried ice blocks melted, coarse 

sands and gravels collapsed into the resulting depressions. The 

kettle holes that intercept the water table now are occupied by 

the numerous kettle-hole ponds throughout the region. 

The deltaic sediments deposited in this glacial lake 

can be divided into topset, foreset, and bottomset deposits 

or beds (fig. 5). The topset beds consist of glaciofluvial 

outwash of coarse sand and gravel deposited by braided rivers 

flowing from the ice lobes. The underlying foreset beds are 

glaciolacustrine sediments that consist mostly of medium 

to fine sand with some silt that was deposited subaqueously 

in a nearshore lake environment. The bottomset beds are 

glaciolacustrine sediments that consist of fine sand, silt, and 

clay that were deposited in an offshore lake environment. 

The general trends in sediment distribution within deltaic 

deposits are coarsening upward and fining with distance 

from the sediment source. This general trend is illustrated in 

lithologic sections reported by Masterson and others (1997) 

for western Cape Cod. 

Unlike the outwash plain sediments that were deposited 

by meltwater streams flowing from the retreating ice sheets, 

moraine deposits were formed by the collapse of unstable 

ice-block slopes along the margins of the retreating ice sheets. 

This process created debris-flow sediments of gravel, sand, 

silt, and clay. These deposits mark the recessional positions of 

Figure 5. Deltaic deposits prograding into a glacial lake, including topset, foreset, and bottomset deposits.

the retreating ice sheets and therefore have a very hummocky 

topography of hills and depressions and generally are areas of 

greatest topographic relief throughout the study area. Whereas 

outwash sediments generally are well sorted and show some 

stratigraphic continuity, moraine deposits have a more variable 

lithology, given the mechanism by which they were formed. 

Grain size and degree of sorting determine the watertransmitting properties of aquifer sediments. The trends in 

hydraulic conductivity (a measure of the ease in which water 

moves through a porous medium) of outwash sediments 

generally conform to the trends in grain size; the hydraulic 

conductivity of sediments generally decreases with depth and 

with increasing distance from sediment sources, or generally 

southward (Masterson and others, 1997). An exception to this 

general trend can occur in areas where outwash sediments 

were deposited on top of older, coarse-grained moraine 

sediments deposited during previous ice advances, creating 

instances where grain size locally can increase with depth. 

Previous investigations have identified general relations 

between sediment grain size and hydraulic conductivity, as 

determined from aquifer tests in a similar geologic setting 

on Cape Cod (Masterson and others, 1997; Walter and 

Whealan, 2005). 

The preceding discussion on the glacial history and 

geologic setting of the PCKD aquifer system is presented 

to provide a cursory description of the geologic framework 

that served as the foundation for the depositional model of 

the glacial sediments incorporated into the groundwater-flow 

model developed for this investigation. For more detailed 

descriptions and analyses of the glacial history and geologic 

framework of southeastern Massachusetts, readers are referred 

to the following reports: Woodworth and Wigglesworth 

(1934), Mather and others (1942), Williams and Tasker (1974), 

and Larson (1980).

Proglacial lake

Bedrock

Direction of progradation

Topset deposits

Foreset deposits

Fining down

Fining south

Ice

Topset deposits

Bottomset deposits

Lake bottom

Basal till

Foreset deposits

Schematic only, not to scale

EXPLANATION

Depositional units

Ice-contact 

deposits Shoreline

Bottomset deposits
Hydrogeology 9

Figure 6. Variability of precipitation and aquifer recharge at the East Wareham, Massachusetts, 

weather station from 1931–2006.

 Precipitation

 Recharge

1931

1935193919431947195119551959196319671971197519791983198719911995199920032006

ANNUAL PRECIPITATION AND RECHARGE,

IN INCHES

0

10

20

30

40

50

60

70

80

Hydrologic System

The Plymouth-Carver-Kingston-Duxbury aquifer system 

is bounded laterally to the east and south by saline surface 

waters. The northern and western boundaries were selected 

based on the drainage divides to the South River and Green 

Harbor River to the north and to the Winnetuxet River and 

the Weweantic Rivers to the west (fig. 1). It was assumed for 

this investigation that these rivers represent major hydrologic 

divides; because all groundwater flowing toward these rivers 

discharges in them, they represent the lateral extents for 

groundwater flow in the PCKD aquifer system. 

Water Budget

The primary source of freshwater to the PCKD aquifer 

system is precipitation. The national weather station in East 

Wareham, MA, (site 192451) reports an average rainfall rate 

of about 47 in/yr from 1931 to 2006 (National Oceanic and 

Atmospheric Administration, 2007) (fig. 6). The portion of 

precipitation that is not lost to evaporation or the transpiration 

of plants (herein referred to as evapotranspiration) and reaches 

the water table is referred to as aquifer recharge. All of the 

water that flows through the aquifer and discharges to ponds, 

streams, coastal areas, and pumping wells is derived from 

aquifer recharge. Groundwater flows away from regional 

water-table divides towards natural discharge boundaries at 

streams and coastal water bodies; some water flows through 

kettle-hole ponds prior to discharging and some water is 

removed from the system for water supply.

In the PCKD aquifer system the recharge rate for the 

stratified glacial deposits is about 27 in/yr or about 57 percent 

of the total precipitation. Precipitation on surface-water 

bodies such as ponds and wetlands also results in recharge 

to the underlying aquifer. Recharge rates were calculated for 

these surface-water bodies and indicate that ponds receive on 

average about 20 in/yr, whereas wetlands receive only about 

8 in/yr because of the increased rate of evapotranspiration 

from plants in wetlands. Cranberry bogs were assumed to 

be similar to wetlands except in the months of October and 

December, when bogs are flooded for harvesting and frost 

protection and therefore were assumed to be more similar 

to ponds. As a result, cranberry bogs received an additional 

2 in/yr of recharge to account for the months of October 

and December. A detailed discussion of the methods used to 

calculate recharge rates is presented in Appendix 1. 

Given the recharge rates specified for each of the 

aforementioned components, the simulated total flow through 

the aquifer system derived from aquifer recharge is about 

290 Mgal/d. For current conditions (2005), about 8 of the 

13 Mgal/d pumped for public water supply is returned to the 

aquifer as wastewater effluent (as enhanced aquifer recharge) 

through onsite septic systems and centralized wastewater 

treatment facilities. The combination of natural recharge and 

wastewater return flow results in about 298 Mgal/d of water 

moving through the aquifer system for current conditions. 

Most of this water (about 70 percent) moves through the 

aquifer, discharges to streams, and then reaches the coast 

as surface-water discharge. Of the remaining 30 percent of 

flow, about 25 percent of the water that enters the aquifer as 

recharge discharges directly to coastal areas and 5 percent 

discharges to pumping wells. 
10 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Altitude and Configuration of the Water Table

The altitude and configuration of the water table in 

the PCKD aquifer system is affected by factors such as 

changing recharge and pumping conditions, interaction 

between groundwater and surface water, and controls of the 

hydrogeologic framework. In general, groundwater flows from 

the highest point of the water table toward the coast (fig. 7). 

The height of the water table ranges from about 120 ft above 

NGVD 29 in the western part of the study area to near zero at 

the coast.

Effect of Recharge on Water Table 

The height of the water table changes with time as a 

function of precipitation; water levels generally increase 

with increased precipitation and decrease with decreased 

precipitation. Water levels at observation well PWW–22 

in northern Plymouth (shown on fig. 1) were lowest in 

the mid-1960s during the 1960s drought (fig. 6) and were 

generally highest in the mid-1970s and mid-1980s when 

precipitation rates were high (figs. 8, 9). During the early 

1990s, however, precipitation rates were near average, and yet 

water levels at PWW–22 were below normal. This anomaly 

may be related to the timing of precipitation events during 

a given year and (or) the cumulative effects of precipitation 

events that occurred in preceding years. 

A comparison of changes in average monthly water 

levels at long-term observation wells PWW–22 and WFW–51 

(locations shown on fig. 1) shows that water levels are 

generally highest in the spring months and lowest in the 

fall months (figs. 8, 9). The decline in water levels from 

April to July is consistent with the decrease in precipitation 

during that period. From August to November, water levels 

continue to decline while precipitation increases to amounts 

similar to those observed in the spring months. The variation 

in water-level changes as a function of precipitation is the 

result of changes in evapotranspiration rates over time. 

Evapotranspiration rates increase over the summer and 

early fall months; as a consequence, a greater percentage of 

precipitation during these months is lost to evapotranspiration 

compared to the winter and spring months, and thereby the 

amount of recharge to the aquifer in the summer and fall 

is reduced.

 The differing response of water levels at PWW–22 

compared to WFW–51 in the months of November and 

December suggests that there is a lag in the response of the 

water levels at PWW–22 in response to increased recharge 

compared to water levels at WFW–51. The depth to water at 

WFW–51 is about 7 ft compared to about 24 ft at PWW–22, 

and this difference in the depth to water, or thickness of 

the unsaturated zone, could account for the differences in 

the response times of water levels to precipitation at these 

two sites.

Changes in water levels over time also can be affected 

by changes in recharge from preceding months and years. 

In the case of WFW–51, water levels were on average about 

2 ft higher in 1974 compared to 1992, and yet the calculated 

annual recharge rate for 1992 was about 10 in/yr higher than 

in 1972. These results suggest that predicting the potential 

effects of droughts on water levels may require the analysis of 

changes in water levels over a several-year period. 

Interaction between Groundwater and Surface Water

Streams in the study area generally are areas of 

groundwater discharge (gaining streams) and receive water 

from the aquifer over most of their length. Streamflow 

entering the channel as groundwater discharge (base flow) 

generally is the primary component of streamflow; however, 

streamflow may be augmented by surface-water runoff during 

heavy precipitation events. Some stream reaches may lose 

water to the aquifer (losing streams), particularly in areas 

downgradient of pond outflows. Surface runoff, with the 

exception of the extreme western and northern parts of the 

study area, is assumed to be negligible throughout most of the 

aquifer system except during extremely wet periods owing 

to the sandy soils with high infiltration capacity and gently 

sloping topography. 

A plot of monthly changes in streamflow at the Jones 

River in Kingston (fig. 10) shows that streamflow varies 

similarly to groundwater levels and appears to be directly 

related to changes in aquifer recharge rather than precipitation. 

Streamflow may be augmented by overland runoff during 

the winter and spring; however, during the summer and 

early fall months it is apparent that it is recharge rather than 

precipitation rates that control streamflow in this river.

Nearly 70 percent of the total groundwater flow 

simulated in the PCKD aquifer system discharges to streams. 

The four largest rivers—the Weweantic, Jones, Agawam, and 

Wankinco Rivers —account for about 50 percent of the total 

streamflow and, therefore, receive about 35 percent of the 

total groundwater discharge in the aquifer system. Because 

these streams receive such a large amount of groundwater 

discharge, they greatly affect the configuration of the regional 

water table (fig. 7). Groundwater flows perpendicular to 

water-table contours and, by flowing toward both sides of 

these streams creates groundwater divides; groundwater does 

not flow beneath these streams. Depending on the sizes of 

streams and the amount of groundwater that discharges to 

streams, the groundwater divides can define the areal extent of 

the aquifer system. For example, the south-flowing Weweantic 

River separates groundwater flow in the Carver-Wareham area 

from the Middleborough-Rochester area to the west, thereby 

representing the western extent of the PCKD aquifer system.

Water-table contours and groundwater-flow patterns in 

the PCKD aquifer system also are affected by the numerous 

kettle-hole ponds in the region (fig. 1). These ponds are 

surface-water expressions of the water table because, like 

streams, they are hydraulically connected to the groundwaterflow system. Kettle-hole ponds are a unique hydrologic 

feature in this groundwater-flow system because they receive 
Hydrogeology 11

Figure 7. Model-calculated water-table altitude and configuration in the Plymouth-Carver-KingstonDuxbury aquifer system, southeastern Massachusetts.

Silver 

Lake

DUXBURY

BAY

KINGSTON

BAY

PLYMOUTH 

 HARBOR

Billington

 Sea

 

Great South 

 Pond

 

Federal 

 Pond

 

South

River Res.

 

College 

 Pond

 Bloody

 Pond

 

Halfway

 Pond

 

Savery

 Pond

 

Indian

 Brook

 

Beaver Dam

 Brook

 

 East 

Head

Pond

 

 Glen

Charlie

Pond

 

 White

Island

Pond

 

 Big 

Sandy

Pond

 

 Great

Herring

Pond

 

 Cod 

 

 Cape 

 Canal

 

 Parker Mills

Pond

 

 Agawam

Fresh

Meadow

 Pond

 

Sampson

 Pond

 

South 

 

Wankinco 

 

Wareham

 

Meadow 

 

 

River

 

River

 

 

River 

Herring

River

 

Brook

 

 

Weweantic River

 

 

PLYMOUTH 

 BAY

CAPE COD

 BAY

BUZZARDS

 BAY

MASSACHUSETTS BAY

Jones River

South 

Harbor

Green

 River

 River

Eel River

Long Pond

Rochester

Plympton

Halifax

Pembroke

Marion

Plymouth

South Coastal 

Watershed

Taunton 

Watershed

Buzzards Bay Watershed

Carver

Wareham

Middleborough

Hanson

Duxbury

Kingston

Marshfield

Bourne

Sandwich

70°47'30" 70°37'30"

42°00'

41°45'

Inactive model area

EXPLANATION

Streamflow-monitoring site—

Shown in table 3

Model-calculated water-table

contour—Interval is 10 feet.

Datum is NGVD 29

Base from U.S. Geological Survey and Massachusetts Geographic Information System data sources,

Massachusetts State Plane Coordinate System, Mainland Zone

1

10

20

40

60

80

40

100

100

80

120

120

10

50

10

40

60

20

10

60

80

40

50

120

80

0

120

10

20

10

40

60

80

80

100

10

20

10

40

100

100

80

60

100

40

20

60

60

80

20

20

0 2 MILES

0 2 KILOMETERS

3

14

24

19

15

8

13

6

11

4

9 17

12

26

7

18

23

20

2 16

22

5

21

25

1

10

Massachusetts Water 

Resources Commission

watershed boundary
12 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Figure 8. Variability of precipitation and recharge at East Wareham, Massachusetts, and water levels at 

well PWW–22, Plymouth: (A) total annual precipitation and recharge and annual average water levels, and 

(B) average monthly precipitation and recharge for the period 1931–2006 and water levels for the period 

1961–2006. 

 Precipitation

 Recharge

 Mean water level in PWW−22

 Precipitation

 Recharge

 Mean water level in PWW−22

A

B

Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

WATER-LEVEL ALTITUDE, IN FEET ABOVE NGVD 29

AVERAGE MONTHLY PRECIPITATION AND RECHARGE,

IN INCHES

118

119

120

121

122

123

124

0

1

2

3

4

5

19311935193919431947195119551959196319671971197519791983198719911995199920032006

WATER-LEVEL ALTITUDE, IN FEET ABOVE NGVD 29

ANNUAL PRECIPITATION AND RECHARGE,

IN INCHES

0

10

20

30

40

50

60

70

80

116

117

118

119

120

121

122

123

124
Hydrogeology 13

Figure 9. Variability of precipitation and recharge at East Wareham, Massachusetts, and water levels at 

well WFW–51, Wareham: (A) total annual precipitation and recharge and annual average water levels, and 

(B) average monthly precipitation and recharge for the period 1931–2006 and water levels for the period 

1961–2006.

 Precipitation

 Recharge

 Mean water level in WFW−51

 Precipitation

 Recharge

 Mean water level in WFW−51

A

B

Jan. June July Aug. Sept. Oct. Nov. Dec.

1931

1935193919431947195119551959196319671971197519791983198719911995199920032006

Feb. Mar. Apr. May

WATER-LEVEL ALTITUDE, IN FEET ABOVE NGVD 29

WATER-LEVEL ALTITUDE, IN FEET ABOVE NGVD 29

AVERAGE MONTHLY PRECIPITATION AND RECHARGE,

IN INCHES

ANNUAL PRECIPITATION AND RECHARGE,

IN INCHES

10

11

12

13

14

15

16

0

1

2

3

4

5

9 0

17 80

10

11

12

13

14

15

16

10

20

30

40

50

60

70
14 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

groundwater discharge and are a source of groundwater 

recharge. Groundwater-flow paths converge in areas 

upgradient of the ponds, where groundwater discharges 

into the ponds, and diverge in downgradient areas, where 

pond water recharges the aquifer. Some ponds have surfacewater outlets where ponds drain into freshwater streams, 

and therefore changes in pond levels can affect streamflow 

downgradient of the pond. Flow from the outlet at Halfway 

Pond in Plymouth (fig. 1) accounts for about 36 percent of 

the total flow in Agawam River under average conditions 

(Hansen and Lapham, 1992). 

Controls of Hydrogeologic Framework

Water-table patterns and groundwater flow can also 

be affected by the hydrogeologic framework. In the PCKD 

aquifer system, the hydraulic gradient, which is the rate of 

change of the water-table altitude with distance, is much 

steeper in the northern part of the aquifer system than in the 

south. The difference in hydraulic gradient can be attributed 

to the less permeable aquifer material in the Duxbury area 

compared to the more permeable sediments of the Wareham 

pitted plain to the south (fig. 3).

Another cause of the steeper hydraulic gradients in the 

north compared to the south could be the less permeable 

silt and clay deposits in the Plymouth Harbor/KingstonDuxbury Bay area. These fine-grained materials create a 

greater resistance to flow from the aquifer than occurs in the 

more permeable outwash-plain deposits to the south, thereby 

increasing the hydraulic gradient in this area and creating 

the potential for a subsurface seaward displacement of the 

freshwater-flow system (Hansen and Lapham, 1992).

Groundwater-Recharge Areas

All of the water that enters this aquifer system as 

recharge ultimately discharges to pumped wells, streams, and 

coastal areas. Some of this water may flow through kettle-hole 

ponds on its way to these discharge areas. The source of water 

to these discharge points, or receptors, can be determined 

by mapping the area that contributes recharge at the water 

table and that, multiplied by the recharge rate, satisfies the 

total flow to the receptor. The concept of the source of water 

to a hypothetical pumped well is illustrated schematically 

in figure 11. This concept can be applied to any hydrologic 

feature that receives groundwater discharge, such as kettlehole ponds, streams, and coastal areas (Masterson and Walter, 

2000; Walter and others, 2004). The discharge locations of all 

water that enters the aquifer system can be determined once 

the recharge areas to all hydrologic features are calculated by 

the numerical model (fig. 12). 

The sizes of the recharge areas to various hydrologic 

features are proportional to the amount of water that 

discharges to these features when a spatially consistent 

recharge rate has been applied. Mapping recharge areas to 

hydrologic features enables one to visualize the various 

components of the model-calculated water budget reported 

in table 2. For instance, the areas shown on figure 12 that 

delineate the sources of water to the Weweantic River and 

Buzzards Bay illustrate how the streams represent a large 

percentage of the total freshwater flow to the coast compared 

to direct groundwater discharge to coastal waters.

The map of the model-calculated recharge areas also 

indicates the importance of the kettle-hole ponds in the aquifer 

system. Much of the water recharging the aquifer near the top 

of the water-table mound in the Plymouth-Carver area of the 

Wareham pitted plain discharges to kettle-hole ponds prior 

to flowing downgradient and then discharging to streams, 

pumping wells, or directly to coastal waters. Pumping from 

Figure 10. Changes in monthly streamflow at Jones River, Kingston, Massachusetts, for the period 

1966–2006 compared to average monthly changes in precipitation and recharge.

Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

FLOW, IN CUBIC FEET PER SECOND

AVERAGE MONTHLY PRECIPITATION

AND RECHARGE, IN INCHES

0

1

2

3

4

5

Precipitation

Recharge

Measured flow

15

20

25

30

35

40

45

50

55

60 EXPLANATION
Simulated Response of the Groundwater-Flow System to Changes in Pumping and Recharge Conditions 15

production wells captures about 5 percent of the total recharge 

in the aquifer system, and more than half of that is returned 

to the aquifer as wastewater return flow. Understanding the 

source of water to hydrologic features is critical to managing 

and protecting these resources.

Simulated Response of the 

Groundwater-Flow System to Changes 

in Pumping and Recharge Conditions

Withdrawals of groundwater from the aquifer system 

change water levels, flow directions, and the rate of 

groundwater discharge into streams and coastal areas. 

Although most pumped water (about 85 percent) is returned 

to the aquifer at the water table, the effects of pumping and 

redistribution of water on the hydrologic system are greatest 

near pumping wells where there is a local net loss of water. 

Transient changes in natural recharge and pumping rates in 

the PCKD aquifer system cause the effects of pumping to be 

largest during the summer months. Effects of pumping include 

water-level declines, which can dry vernal pools; pondlevel declines, which can affect pond-shore ecosystems; and 

streamflow depletions, which can affect fish habitats.

Long-Term Average Conditions

Model simulations in which pumping and recharge rates 

remain constant are referred to as steady-state simulations. 

Steady-state simulations can be used to evaluate long-term 

average effects of pumping on water levels and streamflows. 

These effects, such as long-term water-level declines 

and streamflow depletions, represent changes in baseline 

hydrologic conditions upon which variations in water levels 

and streamflows would be superimposed in response to 

seasonal and annual changes in recharge. For this analysis, 

four long-term average periods were selected that were 

representative of (1) predevelopment (no pumping) conditions, 

and pumping and recharge conditions for (2) 1985, the period 

simulated in the previous USGS investigation (Hansen 

and Lapham, 1992); (3) 2005, the period representative of 

current conditions; and (4) 2030, the period representative of 

future conditions. 

Water Use

Pumping data were compiled for this analysis for 1985 

and 2005, and projected estimates were compiled for 2030. 

Data for 1985 was obtained from a compilation of pumping 

records for the State of Massachusetts (Bratton, 1991). Data 

for current conditions were obtained by averaging pumping 

data from 2000 through 2005 from the MassDEP Annual 

Statistical Reports provided by each of the water suppliers in 

the study area. Water use for the year 2030 was estimated from 

water-use projections compiled by MassDEP with assistance 

from local communities within the study area (Joseph Cerutti, 

Massachusetts Department of Environmental Protection, 

written commun., 2007). Pumping rates at individual wells 

for current and future pumping scenarios are summarized in 

table 1–4 (Appendix 1). 

Nearly all of the groundwater withdrawals in the 

communities of the PCKD area are pumped for public supply 

(fig. 13A). Production withdrawals increased by about 

25 percent from 1985 to 2005, and are projected to increase 

an additional 40 percent by 2030 (fig. 13A). The Town of 

Plymouth is the largest supplier of drinking water in the study 

area, accounting for about 44 percent of the total pumping for 

current conditions (fig. 13A, B). Future (2030) withdrawals 

in Plymouth are projected to be more than double the amount 

pumped in 1985 because of increased population and the 

conversion of residences currently on private supply to 

public supply.

Commercial and irrigation withdrawals represent only 

a small percentage of the total pumping in the study area. 

For current conditions, the combined pumping from these 

Figure 11. Area contributing recharge to a pumping well 

in a simplified, hypothetical groundwater-flow system.

Well screen

Areal

recharge Area

contributing

recharge Pumping

well

Land

surface

Water table

Saturated

zone

Area

contributing

recharge Pumping

well

Bounding

flow lines

Not to scale

Schematic diagrams, not to scale

A Cross-sectional view

B Map view of saturated zone
16 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Figure 12. Model-calculated delineations of groundwater-recharge areas to production wells, ponds, 

streams, and coastal areas for current (2005) average pumping and recharge conditions, Plymouth-CarverKingston-Duxbury aquifer system, southeastern Massachusetts.

Silver 

Lake

DUXBURY

BAY

KINGSTON

BAY

PLYMOUTH 

 HARBOR

Billington

 Sea

 

Great South 

 Pond

 

Federal 

 Pond

 

South

River Res.

 

College 

 Pond

 Bloody

 Pond

 

Halfway

 Pond

 

Savery

 Pond

 

Indian

 Brook

 

Beaver Dam

 Brook

 

 East 

Head

Pond

 

 Glen

Charlie

Pond

 

 White

Island

Pond

 

 Big 

Sandy

Pond

 

 Great

Herring

Pond

 

 Cod 

 

 Cape 

 Canal

 

 Parker Mills

Pond

 

 Agawam

Fresh

Meadow

 Pond

 

Sampson

 Pond

 

South 

 

Wankinco 

 

Wareham

 

Meadow 

 

 

River

 

River

 

 

River 

Herring

River

 

Brook

 

 

Weweantic River

 

 

PLYMOUTH 

 BAY

CAPE COD

 BAY

BUZZARDS

 BAY

MASSACHUSETTS BAY

Jones River

South 

Harbor

Green

 River

 River

Eel River

Long Pond

70°47'30" 70°37'30"

42°00'

41°45'

Inactive model area

Surface-water bodies

Wells

Ponds

Groundwater source

Surface-water source

Groundwater source 

Surface-water source

Groundwater source 

Surface-water source

Surface-water source

Cape Cod, Duxbury, 

and Plymouth Bays

Cape Cod Canal

Buzzards Bay

Taunton Watershed

Groundwater-recharge area

Model-calculated watertable contour—In feet above

NGVD 29. Contour interval

is 10 feet

EXPLANATION

50

20

40

80

120

60

80

60

40

100

100

120

10 0

60

20

20

80

40

80

80

60

60

40

20

80

40

80

100

100

60

100

60

Rochester

Plympton

Halifax

Pembroke

Kingston

Marion

Plymouth

South Coastal 

Watershed

Taunton 

Watershed

Buzzards Bay Watershed

Carver

Wareham

Middleborough

Hanson

Duxbury

Marshfield

Bourne

Sandwich

Rochester

Plympton

Halifax

Pembroke

Kingston

Marion

Plymouth

South Coastal 

Watershed

Taunton 

Watershed

Buzzards Bay Watershed

Carver

Wareham

Middleborough

Hanson

Duxbury

Marshfield

Bourne

Sandwich

0 2 MILES

0 2 KILOMETERS

Base from U.S. Geological Survey and Massachusetts Geographic Information System data sources,

Massachusetts State Plane Coordinate System, Mainland Zone

Wastewater

treatment facility

Existing well site
Simulated Response of the Groundwater-Flow System to Changes in Pumping and Recharge Conditions 17

Table 2. Model-calculated hydrologic budget for predevelopment, 1985, 2005, and proposed 2030 pumping and recharge conditions in 

the Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts. 

[All units in million gallons per day]

Predevelopment 1985 2005 2030

Inflow

Recharge 289.9 289.9 289.9 289.9

Wastewater 0.0 7.2 7.4 11.2

Total 289.9 297.1 297.3 300.9

Outflow

Stream 216.8 211.1 209.7 206.2

Coast 73.4 74.2 73.4 73.7

Pumping wells 0.0 12.2 14.4 21.3

Total 290.2 297.5 297.5 301.2

Numerical model error 0.3 0.4 0.2 0.3

private-supply sources accounts for less than 10 percent of the 

total withdrawals. The largest change in water supplies not for 

drinking is the withdrawals for golf-course irrigation, which 

increased substantially from 1985 to current (2005) conditions. 

The Town of Plymouth and the community of Pine Hills 

experienced the largest expansion in golf-course irrigation 

from 1985 to 2005. These withdrawals are not anticipated 

to change appreciably from current (2005) to future (2030) 

conditions (fig. 13C). 

Most of the groundwater withdrawn for drinking is 

returned to the aquifer as wastewater return flow. An assumed 

consumptive-loss rate of about 15 percent of total pumping 

results in 85 percent of the total public supply returned to the 

aquifer as increased recharge in residential areas (fig. 14A). 

In Plymouth, Kingston, and Wareham, water also is returned 

to the aquifer as increased recharge at centralized wastewater 

treatment facilities (WWTFs) (fig. 14A). In these cases, 

discharge volumes at WWTFs were compiled from each 

facility; the difference between the volumes discharged at 

the WWTF and the total amount of available wastewater was 

spatially distributed in each water-supply district to model 

cells that contained waterlines without corresponding sewer 

lines. The extent of waterlines without corresponding sewer 

lines in the study area was assumed to be the same for 1985 

as for 2005 (fig. 14A). Projected changes for 2030 included 

(fig. 14B): (1) greater sewer-line extent for Buzzards Bay 

Water District; (2) greater water-line extent for Plymouth 

Water Department; and (3) greater water- and sewer-line 

extents for Wareham Fire District (fig. 14B).

Return flow for water supplies not for drinking was 

also addressed in the model simulations. Several simplifying 

assumptions were made to account for evaporative losses 

on golf courses. It was assumed for the purpose of this 

investigation that 50 percent of the water pumped for 

irrigation was returned to the aquifer as recharge. This 

water was accounted for by a reduction of 50 percent 

in the average irrigation pumping rate. The amount of 

water used for irrigation can vary substantially from year 

to year and is highly dependent upon ambient weather 

conditions. A more detailed accounting of water budgets for 

individual golf courses would require detailed, site-specific 

investigations, which was beyond the scope of this regionalscale investigation.

Change in Water Budget

All water that enters the aquifer system as recharge leaves 

the aquifer as groundwater discharge, and therefore changes in 

groundwater withdrawals at large-capacity pumping wells can 

affect the amount of groundwater discharge to any hydrologic 

feature that receives groundwater discharge. Figure 12 

illustrates for current (2005) conditions the source areas for the 

groundwater discharge to ponds, streams, coastal areas, and 

pumping wells throughout the aquifer system. As groundwater 

withdrawals increase, the areas that contribute water to those 

wells will increase, and that increase in recharge areas will 

come at the expense of downgradient receptors. As pumping 

increases from current (2005) to future (2030) conditions, the 

increase in areas contributing water to wells decreases the 

contributing areas to nearby ponds and streams (figs. 12, 15). 

As areas that contribute recharge to downgradient receptors 

decrease, so does the amount of groundwater flow to these 

receptors, resulting in lower pond levels, reduced streamflow, 

and less freshwater discharge to coastal areas (as shown 

schematically on fig. 16).
18 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Figure 13. Pumping rates for the Plymouth-Carver-Kingston-Duxbury aquifer system, 

Massachusetts, for 1985 and 2005, and proposed 2030 conditions for (A) total combined 

pumping, (B) public supply, and (C) commercial and irrigation withdrawals.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Plymouth

Commercial Irrigation

Carver Plymouth Duxbury Marshfield Pine Hills

1985

2005

2030

0

1

2

3

4

5

6

7

8

9

Plymouth

Wareham

Duxbury

Kingston

Onset

North Sagamore

Buzzards Bay

Marshfield

Carver

Pine Hills

Pembroke

0

5

10

15

20

1985 2005 2030 Commercial

ProductionProductionProduction

Irrigation

Commercial

Irrigation

Commercial

Irrigation

1985

2005

2030

PUMPING, IN MILLION GALLONS PER DAY PUMPING, IN MILLION GALLONS PER DAY PUMPING, IN MILLION GALLONS PER DAY

A

B

C
Simulated Response of the Groundwater-Flow System to Changes in Pumping and Recharge Conditions 19

Figure 14. Distribution of wastewater return-flow areas for (A) current (2005) and (B) proposed (2030) 

pumping and recharge conditions.

Rochester

Plympton

Halifax

Marion

Plymouth

Carver

Wareham

Middleborough

Hanson

Duxbury

Kingston

Marshfield

Bourne

Pembroke Inactive model area

Wastewater treatment facility

Model cells with year-2005

water lines without sewering—

Shading varies by water supplier

EXPLANATION

70°47'30" 70°37'30"

42°00'

41°45'

Base from U.S. Geological Survey and Massachusetts Geographic Information System data sources,

Massachusetts State Plane Coordinate System, Mainland Zone

0 2 MILES

0 2 KILOMETERS

A
20 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Figure 14. Distribution of wastewater return-flow areas for (A) current (2005) and (B) proposed (2030) 

pumping and recharge conditions.—Continued

Rochester

Plympton

Halifax

Marion

Plymouth

Carver

Wareham

Middleborough

Hanson

Duxbury

Kingston

Marshfield

Bourne

Inactive model area

EXPLANATION

70°47'30" 70°37'30"

42°00'

41°45'

Base from U.S. Geological Survey and Massachusetts Geographic Information System data sources,

Massachusetts State Plane Coordinate System, Mainland Zone

Model cells with year-2030

water lines without sewering— Shading varies by water supplier

0 2 MILES

0 2 KILOMETERS

Wastewater treatment facility

B

Pembroke
Simulated Response of the Groundwater-Flow System to Changes in Pumping and Recharge Conditions 21

Figure 15. Model-calculated delineations of groundwater-recharge areas to production wells, ponds, 

streams, and coastal areas for future (2030) average pumping and recharge conditions, Plymouth-CarverKingston-Duxbury aquifer system, southeastern Massachusetts.

Silver 

Lake

DUXBURY

BAY

KINGSTON

BAY

PLYMOUTH 

 HARBOR

Billington

 Sea

 

Great South 

 Pond

 

Federal 

 Pond

 

South

River Res.

 

College 

 Pond

 Bloody

 Pond

 

Halfway

 Pond

 

Savery

 Pond

 

Indian

 Brook

 

Beaver Dam

 Brook

 

 East 

Head

Pond

 

 Glen

Charlie

Pond

 

 White

Island

Pond

 

 Big 

Sandy

Pond

 

 Great

Herring

Pond

 

 Cod 

 

 Cape 

 Canal

 

 Parker Mills

Pond

 

 Agawam

Fresh

Meadow

 Pond

 

Sampson

 Pond

 

South 

 

Wankinco 

 

Wareham

 

Meadow 

 

 

River

 

River

 

 

River 

Herring

River

 

Brook

 

 

Weweantic River

 

 

PLYMOUTH 

 BAY

CAPE COD

 BAY

BUZZARDS

 BAY

MASSACHUSETTS BAY

Jones River

South 

Harbor

Green

 River

 River

Eel River

Long Pond

Inactive model area

Surface-water bodies

Wells

Ponds

Groundwater source

Surface-water source

Groundwater source 

Surface-water source

Groundwater source 

Surface-water source

Surface-water source

Cape Cod, Duxbury, 

and Plymouth Bays

Cape Cod Canal

Buzzards Bay

Taunton Watershed

Groundwater-recharge area

Model-calculated water-table

contour—In feet above NGVD 29.

Contour interval is 10 feet

EXPLANATION

50

70°47'30" 70°37'30"

42°00'

41°45'

Base from U.S. Geological Survey and Massachusetts Geographic Information System data sources,

Massachusetts State Plane Coordinate System, Mainland Zone

20

40

80

120

60

80

60

40

100

100

120

100

60

60

20

20

80

80

40

80

80

60

60

40

20

80

40

100

80

100

100

60

100

60

Rochester

Plympton

Halifax

Pembroke

Kingston

Marion

Plymouth

South Coastal 

Watershed

Taunton 

Watershed

Buzzards Bay Watershed

Carver

Wareham

Middleborough

Hanson

Duxbury

Marshfield

Bourne

Sandwich

Rochester

Plympton

Halifax

Pembroke

Kingston

Marion

Plymouth

South Coastal 

Watershed

Taunton 

Watershed

Buzzards Bay Watershed

Carver

Wareham

Middleborough

Hanson

Duxbury

Marshfield

Bourne

Sandwich

0 2 MILES

0 2 KILOMETERS

Wastewater treatment

facility

Pumping well
22 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Figure 16. Hypothetical aquifer showing groundwater 

discharge to a surface-water body with (A) no pumping, 

(B) pumping at a rate Q1 high enough for the well to capture 

water that would otherwise discharge to the surface-water 

body, and (C) pumping at a higher rate Q2 so that the flow 

direction is reversed and the well pumps water from the surfacewater body. Modified from Alley and others, 1999.

Schematic diagram, not to scale

Unconfined aquifer

Unconfined aquifer

Q1

Q2

Recharge area

Land surface

Water table

C

B

A

Land surface

Land surface

Surface-water

body

Surface-water

body

Surface-water

body

Unconfined aquifer

Water table

Water table

Bedrock

Bedrock

Bedrock

Recharge area

Recharge area

The total water budget for the PCKD aquifer system 

changes as groundwater withdrawals increase from zero 

under predevelopment conditions to the projected rate of 

about 21 Mgal/d for 2030 conditions (table 2). The net effect 

of groundwater withdrawals is reduced because of the return 

of wastewater effluent at centralized wastewater treatment 

facilities and onsite domestic septic systems. Therefore, 

the rate of water loss to the aquifer system as a result of 

either consumptive use or the offshore discharge of treated 

wastewater is about 6, 7, and 11 Mgal/d of water for 1985, 

2005, and 2030, respectively. This loss of water is directly 

correlated to the reductions in streamflow for each of these 

periods in response to increased groundwater withdrawals 

(table 2). The effects of groundwater withdrawals for the 

individual streams in the aquifer system are described below 

in the section “Changes in Streamflows.”

Changes in Water Levels

Changes in model-calculated water levels were mapped 

to illustrate changes from simulated predevelopment to 1985 

(fig. 17A), from 1985 to 2005 (fig. 17B), and from 2005 to 

2030 conditions (fig. 17C). A negative change in water level 

(a decrease in water level—herein referred to as drawdown) 

results from increases in pumping rates at existing wells or 

from the addition of new wells from one period to the next. 

A positive change in water level can result from increases 

in wastewater return flow (that is, increases in aquifer 

recharge) as pumping rates increase from one period to the 

next. The areas where water-level increases were greatest 

were those that received wastewater return flow, either along 

water-distribution lines or at wastewater treatment facilities 

(fig. 14A, B). An additional cause of increases in water levels 

between time periods is the removal of a pumping well or a 

decrease in the pumping rate at a well.

The largest change in water levels occurred between 

predevelopment and 1985 conditions when pumping increased 

the most for the three simulation periods (about 12 Mgal/d). 

The greatest drawdowns occurred in the vicinity of the 

large pumping centers in Plymouth, Kingston, and Duxbury 

(fig. 17A). Drawdowns exceeded 5 ft at the pumping well 

locations, and drawdowns of 1 to 3 ft extended over large 

areas beyond the pumping centers. In response to the increase 

of 12 Mgal/d of pumping from predevelopment to 1985 

conditions, wastewater return flow increased. 

As a result of increased recharge of wastewater effluent 

from onsite septic systems, water levels increased in areas that 

received public water. The areas with the greatest mounding 

from wastewater return flow were in Duxbury away from 

the pumping centers. The model-calculated mounding of 

greater than 3 ft is the result of the simulated low-permeability 

sediments in the area. It should be noted that the model 

simulations do not take into account the local-scale conditions 

of septic-system designs where high-permeability sands and 

gravels are used in leach fields to attenuate the mounding 

effects of wastewater return flow to the aquifer system.

Between 1985 and 2005, groundwater withdrawals 

increased by about 2 Mgal/d (fig. 17B). The largest 

drawdowns occurred in southeastern Plymouth in response 

to increased pumping from additional well fields in the area. 

Water levels increased in 2005 compared to 1985 in northern 

Plymouth, where production pumping was reduced compared 

to 1985 pumping rates. Water levels also increased in 

Kingston and north Plymouth in the vicinity of the centralized 

wastewater treatment facilities, where treated wastewater 

effluent was returned to the aquifer at centralized locations 

rather than through onsite septic systems (fig. 17A).

Pumping rates are projected to increase by about 

7 Mgal/d from current (2005) to future (2030) conditions 

(Joseph Cerutti, Massachusetts Department of Environmental 

Protection, written commun., 2008). The largest changes 

in water levels from this projected increase in groundwater 

withdrawals and accompanying wastewater return flow are 
Simulated Response of the Groundwater-Flow System to Changes in Pumping and Recharge Conditions 23

70°47'30" 70°37'30"

42°00'

41°45'

Inactive model area

Surface water

Stream

Water-level change, in feet

Pumping well and identifier

1985 and 2005

Wastewater treatment

facility

EXPLANATION

Inactive

1985 only

87

85

41

> 3 to 5

> 5

> 1 to 3

> 0.7 to 1

> 0.5 to 0.7

> 0.3 to 0.5

> 0.1 to 0.3

0.1 to < -0.1

-0.1 to < -0.3

-0.3 to < -0.5

-0.5 to < -0.7

-0.7 to < -1

-1 to < -3

-3 to < -5

< -5

Rochester

Plympton

Halifax

Marion

Plymouth

Carver

Wareham

Middleborough

Hanson

Duxbury

Kingston

Marshfield

Bourne

Sandwich

Pembroke

88

86

85

83

59

48

33

21

10

9

4

3

84

81

80

72

66

65

58

57

12

11

60

7

5

73

68

67

56

55

54

53

52

51

13

78

74

38

34

27

26

25

37

23

35

8 6

2

1

87

82

79

77

76

75

69

6463

62

61

50 49

47

46

45

44

43

42

41

39 40

36

32

31

30

29

28

2224

20

19

17 18

16

15

14

71

70

99

0 2 MILES

0 2 KILOMETERS

Base from U.S. Geological Survey and Massachusetts Geographic Information System data sources,

Massachusetts State Plane Coordinate System, Mainland Zone 

A

Figure 17. Model-calculated changes in water levels between (A) predevelopment and 1985, (B) 1985 and 

2005, and (C) 2005 and proposed (2030) pumping and recharge conditions in the Plymouth-Carver-KingstonDuxbury aquifer system, southeastern Massachusetts. Locations of return-flow areas for parts A and B are 

shown on fig. 14A; locations of return-flow areas for part C are shown on fig. 14B.
24 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Figure 17. Model-calculated changes in water levels between (A) predevelopment and 1985, (B) 1985 and 

2005, and (C) 2005 and proposed (2030) pumping and recharge conditions in the Plymouth-Carver-KingstonDuxbury aquifer system, southeastern Massachusetts. Locations of return-flow areas for parts A and B are 

shown on fig. 14A; locations of return-flow areas for part C are shown on fig. 14B.—Continued

Rochester

Plympton

Halifax

Marion

Plymouth

Pine Hills

Carver

Wareham

Middleborough

Hanson

Duxbury

Kingston

Marshfield

Bourne

Sandwich

Pembroke

8 9

7

6

4 5

3

2

1

88

87

86

85

84

83

82

81

80

79

78 77

76

75

74

73

72

69

68

67

66

65

6463

62

61

59

58

57

56

55

54

53

52

51

50 49

48

47

46

45

44

43

42

41

39 40

36 37 38

35 34

33

32

31

30

29

28 27

26

25

24

23

22

20

21

19

17 18

16

15

14

13

12

11

10

71

70

60

99

68 Inactive

70°47'30" 70°37'30"

42°00'

41°45'

Base from U.S. Geological Survey and Massachusetts Geographic Information System data sources,

Massachusetts State Plane Coordinate System, Mainland Zone 

Inactive model area

Surface water

Stream

Water-level change, in feet

Pumping well and identifier

1985 and 2005

Wastewater treatment

facility

EXPLANATION

2005 only

1985 only

87 85

41

> 3 to 5

> 5

> 1 to 3

> 0.7 to 1

> 0.5 to 0.7

> 0.3 to 0.5

> 0.1 to 0.3

0.1 to < -0.1

-0.1 to < -0.3

-0.3 to < -0.5

-0.5 to < -0.7

-0.7 to < -1

-1 to < -3

-3 to < -5

< -5

0 2 MILES

0 2 KILOMETERS

B
Simulated Response of the Groundwater-Flow System to Changes in Pumping and Recharge Conditions 25

99

8 9

7

6

4 5

3

2

1

88

87

86

85

84

83

82

81

80

79

78 77

76

75

74

73

72

69

68

67

66

65

6463

62

61

59

58

57

56

55

54

53

52

51

50 49

48

47

46

45

44

43

42

41

39 40

36 37 38

35 34

33

32

31

30

29

28 27

26

25

24

23

22

20

21

19

17 18

16

15

14

13

12

11

10

71

70

60

Base from U.S. Geological Survey and Massachusetts Geographic Information System data sources,

Massachusetts State Plane Coordinate System, Mainland Zone 

70°47'30" 70°37'30"

42°00'

41°45'

Rochester

Plympton

Halifax

Marion

Plymouth

Carver

Wareham

Middleborough

Hanson

Duxbury

Kingston

Marshfield

Bourne

Sandwich 0 2 MILES

0 2 KILOMETERS

68 Inactive

Inactive model area

Surface water

Stream

Water-level change, in feet

Pumping well and identifier

2005 and 2030

Wastewater treatment

facility

EXPLANATION

2030 only

2005 only 87 10

41

> 3 to 5

> 5

> 1 to 3

> 0.7 to 1

> 0.5 to 0.7

> 0.3 to 0.5

> 0.1 to 0.3

0.1 to < -0.1

-0.1 to < -0.3

-0.3 to < -0.5

-0.5 to < -0.7

-0.7 to < -1

-1 to < -3

-3 to < -5

< -5

C

Figure 17. Model-calculated changes in water levels between (A) predevelopment and 1985, (B) 1985 and 

2005, and (C) 2005 and proposed (2030) pumping and recharge conditions in the Plymouth-Carver-KingstonDuxbury aquifer system, southeastern Massachusetts. Locations of return-flow areas for parts A and B are 

shown on fig. 14A; locations of return-flow areas for part C are shown on fig. 14B.—Continued
26 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

predicted to occur in the Town of Plymouth where nearly half 

of the increase in proposed pumping is anticipated to occur 

(fig. 17C). Other areas of increased drawdowns in Plymouth 

are in the area around the expansion of the Pine Hills 

community and in southern Plymouth in response to increased 

withdrawals in northern Wareham (fig. 17C). 

Changes in Streamflows

Streamflows were depleted in response to simulated 

increases in groundwater withdrawals over time. The 

regional change in total streamflow from predevelopment 

to future conditions is about 11 Mgal/d or 16 ft3/s (table 2). 

This decrease represents only a 5-percent reduction in total 

streamflow over time; however, the local effect of increased 

pumping can be much greater on individual streams. An 

analysis of changes in model-calculated streamflow over 

time for individual streams shows that the greatest decrease 

in streamflow will be in the Jones River in Kingston 

(fig. 1, table 3). The streamflow in the Jones River, decreased 

by about 4 ft3/s from predevelopment to 1985 conditions as 

a result of surface-water withdrawals from Silver Lake for 

the City of Brockton public water supply. Silver Lake is the 

headwater for the Jones River, and the model-calculated 

predevelopment flow from the Silver Lake outlet was about 

8.4 ft3/s (table 3). As simulated withdrawals from the lake 

increased from predevelopment conditions to 1985, the modelcalculated lake level declined about 0.4 ft (fig. 17A), and the 

flow at the lake outlet decreased by about 3 ft3/s, indicating 

that relatively small changes in the lake level can have large 

effects on streamflow at the lake outlet.

Model-calculated streamflow in several streams 

increased from predevelopment to projected 2030 conditions 

(table 3). The increase in flow in streams such as Halls 

Brook in Duxbury (fig. 7) is the result of the redistribution 

of pumped water returned to the aquifer as wastewater return 

flow through onsite septic systems and wastewater treatment 

facilities (fig. 14A, B). The redistribution of wastewater results 

in increases in water levels away from pumping centers, and 

it is the increases in water levels near streams that increase 

groundwater discharge to streams. Streams that showed 

reductions in flow over time also may have benefited from 

wastewater return-flow imports that may have lessened the 

regional effects of pumping over time. 

Effects of Time-Varying Hydrologic Stresses

Steady-state analyses provide estimates of long-term 

average changes to the groundwater-flow system; however, 

in aquifers similar to the PCKD aquifer system, changes 

in recharge over time cause monthly and annual variations 

in water levels and streamflows (figs. 9, 10). The monthly 

pumping demand for public supply in the area shows that 

groundwater withdrawals are not constant over the course of 

a year. Public-supply pumping is on average about 12 Mgal/d 

(fig. 13A), yet it varies from less than 10 Mgal/d in December 

to about 19 Mgal/d in July (fig. 18).

The effects of changing recharge and pumping stresses 

on the hydrologic system are additive, and the total changes in 

water levels and streamflows represent the combined effects 

of both stresses. It is important to determine these effects on 

a time-varying basis rather than just on an average annual 

basis. For instance, in the case of streamflow, it may be more 

important to understand the effects of changing stresses on 

summer low-flow conditions rather than the average change in 

flow (table 3). In the case of vernal pools, understanding the 

effects of changing stresses during the spring months may be 

more relevant than understanding the average annual change 

in the water table. 

Transient numerical models that incorporate timevarying stresses were used to evaluate the effects of changes 

in recharge and pumping on the hydrologic system; the 

development and calibration of these models are documented 

in Appendix 1 of this report. Recharge and pumping stresses 

were simulated for average monthly conditions and for 

drought conditions representative of the 1960s drought. The 

methodology used to calculate average monthly and droughtcondition recharge rates is described in Appendix 1.

Average Monthly Conditions

Average monthly recharge conditions were simulated for 

predevelopment, current (2005), and future (2030) pumping 

stresses to assess the effect of time-varying stresses on the 

groundwater-flow system. Simulations of 5-year periods of 

repeating average monthly pumping and recharge rates were 

conducted to ensure that dynamic equilibrium conditions 

were established so that the initial head and flow conditions 

derived from the steady-state simulation did not influence 

model results. The 5-year periods were also used to assess the 

impact of the drought conditions that occurred from 1963 to 

1967. Results of this analysis are described in the next section 

“Drought Conditions.”

The magnitudes of effects from changing stresses can be 

affected by various factors, including the size and location of 

a surface-water body within the flow system and the proximity 

of a surface-water body to a pumping well. These effects were 

assessed for an observation well (PWW–414), a kettle-hole 

pond (Long Pond), a kettle-hole pond with a stream outlet 

(Halfway Pond), and a stream (Eel River) in Plymouth (fig. 1) 

to illustrate the differences in the response of the water table 

and surface-water bodies to changes in groundwater pumping 

over time. 

Predevelopment Conditions 

A comparison of changes in water levels at PWW–414, 

Long Pond, and Halfway Pond under predevelopment 

conditions illustrates the differences in the responses of the 

water table (PWW–414), a closed kettle-hole pond (Long 

Pond), and a kettle-hole pond with a surface-water outlet 
Simulated Response of the Groundwater-Flow System to Changes in Pumping and Recharge Conditions 27

Table 3. Model-calculated changes in streamflow for predevelopment, 1985, 2005, and proposed 2030 pumping and recharge 

conditions. 

[Streamflows are in cubic feet per second]

River Map ID numbers 

shown on figure 7

Streamflow

Predevelopment 1985 2005 2030

Weweantic River 1 68.14 68.0 66.98 67.33

Agawam River 2 41.07 39.1 38.67 37.15

Jones River 3 37.11 33.39 33.98 31.61

Eel River Mouth 4 25.81 25.95 25.12 25.08

Wankinco River 5 22.61 22.30 22.18 21.75

Town Brook 6 16.73 15.82 15.64 15.21

Halfway Point Outlet 7 15.16 14.93 14.79 14.10

South River 8 14.93 14.91 15.59 15.49

Eel River North 9 14.49 13.36 13.71 13.67

Maple Springs Brook 10 12.58 10.90 10.93 10.79

Billington Sea Outlet 11 12.38 11.63 11.36 10.95

Beaver Brook 12 12.11 12.21 12.17 12.18

Silver Lake Outlet 13 8.40 5.46 5.65 3.33

Halls Brook 14 7.87 8.00 8.30 8.32

Green Harbor River 15 7.26 7.36 7.41 7.18

Red Brook 16 6.17 5.95 5.74 5.63

Eel River South 17 5.51 5.55 5.46 5.40

Herring River Upper 18 5.11 5.15 4.81 4.44

Stone Point Outlet 19 3.78 3.71 3.63 3.64

Holmes Point Brook 20 2.62 2.68 2.66 2.65

Frogfoot Brook 21 2.33 2.30 2.30 2.25

Gibbs Brook 22 1.92 1.89 1.68 1.58

Herring River Lower 23 1.72 1.62 0.94 0.67

West Brook 24 1.54 0.75 0.86 0.64

Harlow Brook 25 1.48 1.25 1.22 1.06

Indian Brook 26 1.35 1.55 1.09 0.67
28 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Figure 18. Average production-well withdrawals by 

month for current (2005) pumping conditions in the 

Plymouth-Carver-Kingston-Duxbury aquifer system, 

southeastern Massachusetts.

0

2

4

6

8

10

12

14

16

18

20

J F M A M J J A S O N D

MONTH

PUMPING,

IN MILLIONS OF GALLONS PER DAY

(Halfway Pond) (fig. 19) to changes in monthly recharge. 

These results illustrate that the water table at PWW–414 

located near Long Pond had a total range in water levels 

of about 2 ft compared to about 1.5 ft at Long Pond. The 

dampened response of water levels in the pond compared 

to those of the aquifer was directly related to the increased 

storage capacity in the pond that reduced the effect of changes 

in monthly recharge.

A comparison between the two kettle-hole ponds, Long 

Pond and Halfway Pond, shows the effect of the surface-water 

outlet on the responses of pond levels to changes in monthly 

recharge. The total range in monthly water levels in Halfway 

Pond was about 0.7 ft, less than half the total range of 1.5 ft in 

Long Pond (fig. 19). The difference in response between the 

two ponds can be attributed to the effect that the surface-water 

outlet at Halfway Pond had on the water levels in the pond. 

Under average annual predevelopment conditions, the average 

flow at the pond outlet was about 15 ft3/s; however, this flow 

rate fluctuated throughout the year from a high of about 

18 ft3/s in March to a low of about 13 ft3/s in August (fig. 

20). Therefore, changes in pond levels in Halfway Pond in 

response to changes in monthly recharge were moderated by 

surface-water flow at the pond outlet.

Streamflow varied in response to monthly changes in 

recharge in a manner similar to water levels and pond levels in 

the aquifer. The Eel River in Plymouth (fig. 1) had a simulated 

average annual flow of about 26 ft3/s under predevelopment 

conditions; however, the total range in streamflow was about 

9 ft3/s with a high of about 31 ft3/s in March and a low of 

about 22 ft3/s in August (fig. 21). As a result, reductions in 

Figure 19. Model-calculated monthly 

changes in water levels relative to longterm average annual levels at Halfway 

Pond, Long Pond, and well PWW–414 in 

Plymouth, Massachusetts.

Halfway Pond

Long Pond

Well PWW414

J M M

YEAR 1 YEAR 2 YEAR 3 YEAR 4 YEAR 5

J S N J M M J S N J M M J S N J M M J S N J M M J S N

WATER-LEVEL CHANGE FROM AVERAGE, IN FEET 

-2

-1

0

1

2
Simulated Response of the Groundwater-Flow System to Changes in Pumping and Recharge Conditions 29

Figure 20. Model-calculated monthly water levels and streamflow at Halfway Pond 

and the Halfway Pond surface-water outlet for predevelopment conditions, Plymouth, 

Massachusetts.

Pond, predevelopment

Surface-water outlet, predevelopment

J M M

YEAR 1 YEAR 2 YEAR 3 YEAR 4 YEAR 5

J S N J M M J S N J M M J S N J M M J S N J M M J S N

MODEL-CALCULATED WATER LEVEL, IN FEET 

61

62

63

64

65

STREAMFLOW, IN CUBIC FEET PER SECOND 

9

10

11

12

13

14

15

16

17

18

19

20

Figure 21. Model-calculated monthly streamflow in the Eel River with and 

without wastewater return-flow recharge for current (2005) conditions, Plymouth, 

Massachusetts.

Average current (2005) pumping with return flow

Average current (2005) pumping without return flow

16

18

20

22

24

26

28

30

32

34

J M M

YEAR 1 YEAR 2 YEAR 3 YEAR 4 YEAR 5

J S N J M M J S N J M M J S N J M M J S N J M M J S N

MODEL-CALCULATED FLOW,

IN CUBIC FEET PER SECOND 
30 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

J M M

YEAR 1 YEAR 2 YEAR 3 YEAR 4 YEAR 5

J S N J M M J S N J M M J S N J M M J S N J M M J S N

MODEL-CALCULATED FLOW,

IN CUBIC FEET PER SECOND 

7

8

9

10

11

12

13

14

15

16

17

18

Predevelopment

Current conditions (2005)

Proposed conditions (2030)

Figure 22. Model-calculated monthly changes in streamflow at the Halfway 

Pond surface-water outlet for predevelopment, current (2005), and proposed (2030) 

pumping and recharge conditions.

streamflow from changes in pumping or recharge would 

have a greater effect as a percentage of total flow during 

the summer and early fall months when streamflow is 

typically lowest.

Effects of Current and Future Pumping Conditions

Current (2005) and future (2030) average monthly 

pumping conditions were simulated to determine the potential 

effects of pumping on the groundwater-flow system. The 

effects of current (2005) and future (2030) pumping were 

superimposed on the monthly fluctuations in water levels and 

streamflow that resulted from monthly changes in recharge. 

These simulations of changes in pumping and recharge 

indicated that the response of Long Pond was similar to the 

response of the water table southeast of the pond at well 

PWW–414, yet the changes in Halfway Pond appeared to 

be moderated by the surface-water outlet. The water levels 

at Long Pond and PWW–414 declined by about 0.5 ft from 

current (2005) to future (2030) pumping conditions, whereas 

the decline at Halfway Pond was only about 0.1 ft for the 

same period. 

Although pumping rates varied with time, the declines 

in water levels in the vicinity of the two ponds appeared to be 

uniform throughout the year. There are no proposed pumping 

wells in the vicinity of Long Pond, so monthly changes in 

pond levels may be moderated by the lag in the response of 

the aquifer to regional changes in pumping so that the impacts 

of monthly changes in pumping are averaged over the year. 

Halfway Pond, however, has a proposed pumping-well site 

(well site 54, fig. 1) nearby that has a range in projected 

pumping from about 0.28 Mgal/d in March to 0.5 Mgal/d in 

August (table 1–4). Despite the nearly twofold increase in 

pumping from March to August, the drawdowns at Halfway 

Pond were about 0.1 ft throughout the year. The decrease in 

flow at the pond outlet, however, was twice as large in August 

compared to March, consistent with the change in pumping 

rates at well site 54 throughout the year (fig. 22).

Effects of Wastewater Return Flow

The effects of wastewater return flow on streamflow 

were assessed for the Eel River under time-varying pumping 

and recharge conditions. The change in streamflow in the 

Eel River from predevelopment to current conditions (2005) 

and from current conditions to future conditions (2030) during 

the low-flow month of August resulted in decreases of about 

0.6 ft3/s for each period (fig. 23). This change in streamflow 

over time was in response to increased pumping and the 

amount of wastewater returned to the aquifer. As pumping 
Simulated Response of the Groundwater-Flow System to Changes in Pumping and Recharge Conditions 31

J M M

YEAR 1 YEAR 2 YEAR 3 YEAR 4 YEAR 5

J S N J M M J S N J M M J S N J M M J S N J M M J S N

MODEL-CALCULATED FLOW,

IN CUBIC FEET PER SECOND 

Current conditions (2005)

Predevelopment

Proposed conditions (2030) 16

18

20

22

24

26

28

30

32

34

rates increased, so did the amount of wastewater returned 

to the aquifer through onsite septic systems and wastewater 

treatment facilities such as the facility west of the Eel River 

(fig. 1). 

An analysis was conducted to determine the effect of 

wastewater returned to the aquifer on the quantity of flow 

in the Eel River for current and future pumping conditions. 

Simulations of current conditions with and without wastewater 

returned to the aquifer indicated that the return of wastewater 

to the aquifer accounted for about 0.7 ft3/s of flow in August, 

similar to the amount of streamflow reduction between 

predevelopment and current conditions. Therefore, if the 

wastewater was not returned to the aquifer, the effects of 

pumping on the Eel River would be doubled. 

These results indicate that wastewater returned to the 

aquifer dampens the effects of pumping on streamflow, and 

the effects are greatest in the summer months when pumping 

and return-flow rates are highest and recharge rates are 

lowest. This benefit may be the result of wastewater return 

flow contributing water directly to the stream or indirectly 

by raising water levels in the surrounding aquifer, thereby 

increasing groundwater discharge to the stream. A particletracking and solute-transport analysis would be required to 

assess the amount and concentration of wastewater effluent 

discharging directly to the stream, an assessment beyond the 

scope of this investigation.

Drought Conditions

The effects of a drought on water levels and streamflows 

were assessed for current and future pumping conditions to 

determine what the impact of a drought similar to the one 

observed in the 1960s (the drought of record) would have on 

water levels and streamflows in the PCKD aquifer system. 

Monthly recharge rates for current and future pumping 

conditions were simulated for a 5-year period representative of 

the 1960s drought (1963–1967) (fig. 6). The changes in water 

levels, pond levels, and flow from the pond surface-water 

outlet for drought-condition recharge rates were compared 

to the 5-year dynamic equilibrium simulations for average 

current conditions to assess the impact of a 1960s drought for 

current conditions. 

Results indicated that the greatest reduction in water 

levels occurred in October of drought YEAR4 (1966 

conditions). Water levels in Long Pond and the nearby aquifer 

at well PWW–414 decreased by about 3.5 ft compared to a 

decrease of about 0.5 ft at Halfway Pond (fig. 24A–C). The 

impact of the drought on the pond level was mitigated by a 

reduction in the amount of flow leaving the pond at the outlet. 

Figure 23. Model-calculated monthly changes in streamflow in the Eel River 

for predevelopment, current (2005), and proposed (2030) pumping and recharge 

conditions.
32 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Well PWW−414 

J M M

YEAR 1 YEAR 2 YEAR 3 YEAR 4 YEAR 5

J S N J M M J S N J M M J S N J M M J S N J M M J S N

58

59

60

61

62

63

64

65

66

67

68

69

Long Pond

J M M

YEAR 1 YEAR 2 YEAR 3 YEAR 4 YEAR 5

J S N J M M J S N J M M J S N J M M J S N J M M J S N

63

64

65

66

67

68

69

70

71

72

73

74

Halfway Pond 5-year dynamic equilibrium

for current (2005) average

conditions

5-year dynamic equilibrium

for current (2005) average

conditions

5-year dynamic equilibrium

for current (2005) average

conditions

1963−1967 drought recharge

conditions with current (2005)

average pumping 

1963−1967 drought recharge

conditions with current (2005)

average pumping 

J M M

YEAR 1 YEAR 2 YEAR 3 YEAR 4 YEAR 5

J S N J M M J S N J M M J S N J M M J S N J M M J S N

MODEL-CALCULATED WATER LEVEL,

IN FEET 

MODEL-CALCULATED WATER LEVEL,

IN FEET 

MODEL-CALCULATED WATER LEVEL,

IN FEET 

61

62

63

64

65 A

B

C

1963−1967 drought recharge

conditions with current (2005)

average pumping 

Figure 24. Model-calculated changes in water levels for simulated monthly 

average and drought conditions for (A) Halfway Pond, (B) Long Pond, 

and (C) well PWW–414 for current (2005) pumping conditions.
Simulated Response of the Groundwater-Flow System to Changes in Pumping and Recharge Conditions 33

Halfway Pond outlet: average conditions

Halfway Pond outlet: drought conditions

J M M

YEAR 1 YEAR 2 YEAR 3 YEAR 4 YEAR 5

J S N J M M J S N J M M J S N J M M J S N J M M J S N

STREAMFLOW, IN CUBIC FEET PER SECOND 

7

8

9

10

11

12

13

14

15

16

17

18

In response to the drought, flow at the surface-water outlet 

decreased by about 4.6 ft3/s or by about 36 percent (fig. 25).

An analysis of drawdowns for October of drought 

YEAR4 showed that areas in the vicinity of streams are 

less prone to large declines in water levels than areas away 

from streams (fig. 26). In the southwestern part of the PCKD 

aquifer system, declines in water-table altitude were less than 

in the southeastern part because of the numerous streams—in 

particular, the Weweantic stream network in Carver (fig. 26)—

draining the south/southwestern part of the aquifer. As was 

the case with the surface-water outlet in Halfway Pond, the 

gaining streams in the aquifer system mitigate the impacts on 

water levels from droughts through reductions in streamflows. 

In the case of the Weweantic River, streamflow decreased by 

about 50 percent compared to average conditions, yet water 

levels in the vicinity of the river decreased by less than 1 ft 

compared to areas to the east, where water-level declines 

exceeded 4 ft. Once a stream goes dry, such as Harlow 

Brook in Wareham (fig. 27), the nearby water table responds 

similarly to areas where no streams are present (fig. 26).

Water-level declines were also moderated in the vicinity 

of the Eel River (fig. 26). Streamflow in the Eel River 

decreased by about 25 percent from average conditions 

in August of drought YEAR4 (fig. 28). A comparison of 

streamflow in August of drought YEAR4 with and without 

wastewater return flow indicated that streamflow is about 1 

ft3/s (or 6 percent) greater when wastewater is returned to the 

aquifer rather than when wastewater is completely removed 

from the groundwater system (fig. 28).

Figure 25. Model-calculated changes in streamflow at the Halfway Pond surfacewater outlet for simulated monthly average and drought conditions for current (2005) 

pumping conditions.
34 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

8 9

7

6

4 5

3

2

1

88

87

86

85

84

83

82

81

80

79

78 77

76

75

74

73

72

69

68

67

66

65

6463

62

61

59

58

57

56

55

54

53

52

51

50 49

48

47

46

45

44

43

42

41

39 40

36 37 38

35 34

33

32

31

30

29

28 27

26

25

24

23

22

21

20

19

17 18

16

15

14

13

12

11

10

71

70

60

Pembroke

Rochester

Plympton

Halifax

Marion

Plymouth

Carver

Wareham

Middleborough

Hanson

Duxbury

Kingston

Marshfield

Bourne

Sandwich

Silver 

Lake

DUXBURY

BAY

KINGSTON

BAY

PLYMOUTH 

 HARBOR

Billington

 Sea

 

Great South 

 Pond

 

Federal 

 Pond

 

South

River Res.

 

College 

 Pond

 Bloody

 Pond

 

Halfway

 Pond

 

Savery

 Pond

 

Indian

 Brook

 

Beaver Dam

 Brook

 

 East 

Head

Pond

 

 Glen

Charlie

Pond

 

 White

Island

Pond

 

 Big 

Sandy

Pond

 

 Great

Herring

Pond

 

 Cod 

 

 Cape 

 Canal

 

 Parker Mills

Pond

 

 Agawam

Fresh

Meadow

 Pond

 

Sampson

 Pond

 

South 

 

Wankinco 

 

Harlow Brook 

 Wareham

 

Meadow 

 

 

River

 

River

 

 

River 

Herring

River

 

Brook

 

 

Weweantic River

 

 

PLYMOUTH 

 BAY

CAPE COD

 BAY

BUZZARDS

 BAY

MASSACHUSETTS BAY

Jones River

South 

Harbor

Green

 River

 River

Eel River

Long Pond

Inactive model area

Surface water

Stream

Water-level change, in feet

Pumping well and identifier

Active (2005)

Wastewater treatment

facility

Base from U.S. Geological Survey and Massachusetts Geographic Information System data sources,

Massachusetts State Plane Coordinate System, Mainland Zone

EXPLANATION

87 Inactive 68

70°47'30" 70°37'30"

42°00'

41°45'

0 to < -1

-1 to < -2

-2 to < -4

-4 to < -6

-6 to < -8

< -8

0 2 MILES

0 2 KILOMETERS

Figure 26. Model-calculated changes in water levels from average conditions for simulated drought conditions 

in October of Drought YEAR4 with current (2005) pumping and wastewater return-flow rates. Locations of returnflow areas are shown in fig. 14A.
Simulated Response of the Groundwater-Flow System to Changes in Pumping and Recharge Conditions 35

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

2.00

Drought conditions

Average conditions

J M M

YEAR 1 YEAR 2 YEAR 3 YEAR 4 YEAR 5

J S N J M M J S N J M M J S N J M M J S N J M M J S N

MODEL-CALCULATED STREAMFLOW,

IN CUBIC FEET PER SECOND 

J M M

YEAR 1 YEAR 2 YEAR 3 YEAR 4 YEAR 5

J S N J M M J S N J M M J S N J M M J S N J M M J S N

Current (2005) average conditions

1963 drought conditions with return flow

Current (2005) average conditions

1963 drought conditions with return flow

J M M

YEAR 1 YEAR 2 YEAR 3 YEAR 4 YEAR 5

J S N J M M J S N J M M J S N J M M J S N J M M J S N

MODEL-CALCULATED STREAMFLOW,

 IN CUBIC FEET PER SECOND 

MODEL-CALCULATED STREAMFLOW,

 IN CUBIC FEET PER SECOND 

A

B

16

18

20

22

24

26

28

30

32

34

16

18

20

22

24

26

28

30

32

34

Figure 27. Model-calculated streamflows in 

Harlow Brook in Wareham, Massachusetts, 

for monthly average and drought conditions at 

current (2005) pumping and wastewater returnflow rates.

Figure 28. Model-calculated streamflows in 

the Eel River, Plymouth, Massachusetts, for 

(A) monthly average and drought conditions at 

current (2005) pumping and wastewater returnflow rates and (B) drought conditions with and 

without wastewater return flow at current (2005) 

pumping rates.
36 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Summary and Conclusions

The Plymouth-Carver-Kingston-Duxbury area is one 

of the fastest growing regions in the State of Massachusetts, 

and development pressures are such that undeveloped and 

agricultural lands continue to be converted to residential 

uses. Because this area includes the second largest solesource aquifer system in the State of Massachusetts, State 

and local officials responsible for managing and protecting 

the water resources of this area are concerned that increased 

groundwater withdrawals may create the potential for 

unacceptable declines in water table and pond altitudes, 

and that groundwater discharge to streams and coastal 

areas will decrease. In response to these concerns, the 

U.S. Geological Survey (USGS) in cooperation with the 

Massachusetts Department of Environmental Protection began 

an investigation in 2005 to improve the understanding of the 

hydrogeology of the Plymouth-Carver-Kingston-Duxbury 

aquifer system and to assess the effects on groundwater flow 

of changing groundwater pumping and recharge conditions. 

Specifically, the objectives of the investigation were to 

(1) determine areas contributing recharge to production wells 

in the region, (2) evaluate the long-term average effects 

of pumping on the hydrologic system, and (3) assess the 

combined effects of time-varying recharge and pumping 

stresses on the hydrologic system, particularly on pond levels 

and streamflows.

A regional numerical flow model was developed as part 

of this investigation to assist in the analysis of the potential 

effects of changing pumping and recharge conditions and to 

demonstrate how the model could serve as a tool for State 

and local managers to assess possible effects of proposed 

water-management strategies in the southeastern region of 

Massachusetts overlying the Plymouth-Carver-KingstonDuxbury aquifer system. The model was used to determine 

water budgets and flow directions throughout the study 

area for predevelopment, 1985, 2005, and proposed 2030 

conditions. Three sets of pumping scenarios were analyzed: 

past (1985) water demands, current (2005) water demands, 

and water demands projected for the year 2030. The model 

was developed to simulate steady-state conditions as well as 

transient conditions with time-varying recharge and pumping 

stresses. Hydrologic changes were evaluated for current 

and future pumping and wastewater return-flow rates under 

average monthly and drought-condition recharge rates similar 

to the 1960s drought of record. 

A comparison also was made between the model 

developed for this study and the model developed by the 

USGS in the late 1980s that simulated the potential effects 

of hypothetical groundwater-development alternatives in 

the Plymouth-Carver aquifer system. The previous model 

has been used extensively during the past 15 years as the 

foundation for subsequent water-supply studies conducted by 

towns within the study area, as well as their environmental 

consultants; therefore, a comparison of model development 

and results is provided in Appendix 2 to assist model users in 

understanding the differences between the two models. 

The primary results of the current investigation are 

listed below.

• Of the approximately 298 Mgal/d of freshwater that 

recharges the aquifer system, about 70 percent of this 

water discharges to streams, and then flows to the coast. 

Of the remaining 30 percent of flow, about 25 percent 

flows through the groundwater-flow system and discharges directly to the coast, and 5 percent discharges to 

pumping wells. 

• Pumping from large-capacity wells increases the potential for adverse effects on surface-water bodies, and 

therefore requires careful planning of future pumping 

and wastewater-disposal locations and rates. Pumping 

wells that are upgradient of surface-water bodies have 

the potential to capture water that would otherwise 

discharge to these surface-water bodies, thereby reducing streamflow and pond levels. Groundwater withdrawals increased by about 14 Mgal/d from predevelopment 

to current (2005) conditions, resulting in a decrease 

in streamflow of about 11 ft3/s (about 7 Mgal/d). The 

projected increase in groundwater withdrawals from 

current to future (2030) conditions of about 7 Mgal/d 

resulted in a decrease of streamflow of about 6 ft3/s 

(about 4 Mgal/d). 

• Much of the groundwater that is withdrawn for public 

supply is returned to the aquifer by onsite domestic septic systems and centralized wastewater treatment facilities. About 50 percent of the groundwater withdrawals 

are returned to the aquifer as wastewater return flow. 

The return of wastewater to the aquifer moderates the 

effects of withdrawals on water levels and streamflows. 

In coastal areas in the Town of Plymouth, wastewater 

return flow increases water levels because the water is 

pumped farther inland and returned to the aquifer in residential areas receiving public supply. Flow in streams 

such as the Eel River can increase by as much as 6 percent as a result of regional increases in the water table as 

wastewater is returned to the aquifer. Drought conditions 

result in large decreases in water levels in areas away 

from streams. Water levels decreased about 1–2 ft in the 

vicinity of most streams in comparison to decreases of 

more than 5 ft in areas farther away from streams. The 

moderating influence of streams on water-level declines 

appears to be related to large decreases in streamflow 

during drought conditions. Areas such as the Weweantic 

River watershed showed the smallest decreases in water 

levels in response to drought conditions because of the 

abundance of streams in the area. Although water-level 

declines were small in the vicinity of the Weweantic River, streamflow in the river decreased by about 

50 percent in response to the drought. 
References Cited 37

Acknowledgments

The authors wish to thank the following individuals for 

their assistance and guidance throughout the investigation: 

Joseph Cerutti, Paul Blain, Jan Drake, and Jim McLaughlin 

of the Massachusetts Department of Environmental 

Protection; Bruce Hansen of the Massachusetts Department 

of Conservation and Recreation; Neal Price of Horsley and 

Witten, Inc.; Peter Newton of S E A Consultants, Inc.; Robert 

Schreiber of Camp Dresser and McKee, Inc.; Brian Wick of 

the Cape Cod Cranberry Growers Association; Blake Martin 

and Brian Thomas of Weston and Sampson Engineers, Inc.; 

Michael Martin of the Wareham Fire District; Paul Anderson 

of the Duxbury Water Department; Matthew Darsch of the 

Kingston Water Department; and Judith Kohn and Tom 

Melehan of A.D. Makepeace, Inc. The authors would also 

like to thank Bruce Campbell and Dennis Risser of the U.S. 

Geological Survey for providing technical reviews of 

this report.

References Cited

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Sustainability of groundwater resources: U.S. Geological 

Survey Circular 1186, 79 p.

Bratton, Lisa, 1991, Public water-supply in Massachusetts, 

1986: U.S. Geological Survey Open-File Report 91–86, 

108 p.

Flint, A., 2002, State’s dual role in preservation poses odd 

conflict of interest, Boston Globe: September 15, 2002.

Hansen, B.P., and Lapham, W.W., 1992, Geohydrology and 

simulated groundwater flow, Plymouth-Carver Aquifer, 

southeastern Massachusetts: U.S. Geological Survey 

Water-Resources Investigations Report 90–4204, 69 p.

Harbaugh, A.W., Banta, E.R., Hill, M.C., and McDonald, 

M.G., 2000, MODFLOW-2000, The U.S. Geological 

Survey modular groundwater model—User guide to 

modularization concepts and the groundwater flow process: 

U.S. Geological Survey Open-File Report 00–92, 121 p.

Larson, G.J., 1980, Nonsynchronous retreat of ice lobes from 

southeastern Massachusetts, in Larson, G.J., and Stone, 

B.D., eds., Late Wisconsinan glaciation of New England: 

Dubuque, Iowa, Kendall/Hall Publishing Co., p. 101–114.

Masterson, J.P., and Walter, D.A., 2000, Delineation 

of groundwater recharge areas, western Cape Cod, 

Massachusetts: U.S. Geological Survey Water-Resources 

Investigations Report 00–4000, 1 pl.

Masterson, J.P., Walter, D.A., and Savoie, Jennifer, 1997, Use 

of particle tracking to improve numerical model calibration 

and to analyze groundwater flow and contaminant 

migration, Massachusetts Military Reservation, western 

Cape Cod, Massachusetts: U.S. Geological Survey WaterSupply Paper 2482, 50 p.

Mather, K.F., Goldthwait, R.P., and Thiesmeyer, L.R., 1942, 

Pleistocene geology of western Cape Cod: Geological 

Society of America Bulletin, v. 53, p. 1127–1174.

New England Agricultural Statistics Service, 2002, U.S. 

cranberry production down 5 per cent, in Cranberries, 

published by NEASS, a field office of the National 

Agricultural Statistics Service, U.S. Department of 

Agriculture, January 28, 2 p.

National Oceanic and Atmospheric Administration, 2007, 

accessed March 21, 2007, at http://www.cdo.ncdc.noaa.gov/

dly/DLY

Persky, J.H., 1993, Yields and water quality of stratifieddrift aquifers in the southeast coastal basin, Cohasset 

to Kingston, Massachusetts: U.S. Geological Survey 

Water-Resources Investigations Report 91–4112, 47 p.

Reilly, T.E., and Pollock, D.W., 1993, Factors affecting areas 

contributing recharge in shallow aquifers: U.S. Geological 

Survey Water-Supply Paper 2412, 21 p. 

The Nature Conservancy, 2002, Conservation across the 

Commonwealth—An update from the Massachusetts 

Chapter of The Nature Conservancy: The Plymouth 

Pinelands—A rich barrens ecosystem, summer 2002, 8 p.

Walter, D.A., Masterson, J.P., and Hess, K.M., 2004, 

Groundwater recharge areas and traveltimes to pumped 

wells, ponds, streams, and coastal water bodies, Cape 

Cod, Massachusetts: U.S. Geological Survey Scientific 

Investigations Map I–2857, 1 sheet.

Walter, D.A., and Whealan, A.T., 2005, Simulated water 

sources and effects of pumping on surface and ground 

water, Sagamore and Monomoy flow lenses, Cape Cod, 

Massachusetts: U.S. Geological Survey Scientific 

Investigations Report 2004–5181, 85 p.

Williams, J.R., and Tasker, G.D., 1974, Water resources of 

the coastal drainage basins of southeastern Massachusetts, 

Plymouth to Weweantic River, Wareham: U.S. Geological 

Survey Hydrologic Investigations Atlas HA–507, 2 sheets, 

scales 1:125,000 and 1:48:000.

Woods Hole Research Center, 2007, Critical mass–land use 

change in southeastern Massachusetts, poster, accessed 

January 12, 2007, at http://www.whrc.org/new_england/

SE_Mass/criticalmass.htm

Woodworth, J.B., and Wigglesworth, Edward, 1934, 

Geography and geology of the region including Cape 

Cod, the Elizabeth Islands, Nantucket, Martha’s Vineyard, 

No Mans Land, and Block Island: Cambridge Mass., 

Harvard College Museum of Comparative Zoology 

Memorandum 52, 322 p.

Heading 1 39

Appendix 1. Development of GroundwaterFlow Model

Figures

1–1. Model extent and distribution of simulated boundary conditions of

groundwater-flow model of Plymouth-Carver-Kingston-Duxbury aquifer system,

southeastern Massachusetts...................................................................................................42

1–2. Altitude and configuration of the bedrock surface beneath the Plymouth-CarverKingston-Duxbury aquifer system, southeastern, Massachusetts ....................................44

1–3. (A) Surficial geology and location of aquifer tests, and (B) hydraulic conductivity

zones for a calibrated groundwater-flow model of the Plymouth-CarverKingston-Duxbury aquifer system, southeastern Massachusetts .....................................49

1–4. Distribution of wastewater return-flow areas for (A) current (2005) and 

(B) proposed (2030) pumping and recharge conditions .......................................................63

1–5. Long-term water levels for wells (A) PWW–22 and (B) WFW–51 from 1961

through 2005 ................................................................................................................................67

1–6. Composite sensitivities for steady-state hydraulic conductivity parameters for the

Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern

Massachusetts............................................................................................................................68

1–7. Observation wells and streamflow sites used for calibration of the

groundwater-flow model of the Plymouth-Carver-Kingston-Duxbury aquifer

system, southeastern Massachusetts ....................................................................................69

Introduction...................................................................................................................................................41

Steady-State Model.....................................................................................................................................41

Model Discretization and Boundaries.............................................................................................41

Spatial Discretization ................................................................................................................41

Hydrologic Boundaries .............................................................................................................41

Hydraulic Properties...........................................................................................................................45

Hydrologic Stresses ...........................................................................................................................52

Recharge..............................................................................................................................................52

Pumping................................................................................................................................................62

Model Calibration................................................................................................................................65

Observation Data .......................................................................................................................65

Sensitivity Analysis....................................................................................................................66

Parameter Estimation................................................................................................................68

Transient Model ...........................................................................................................................................74

Discretization of Time.........................................................................................................................74

Storage Characteristics.....................................................................................................................74

Recharge..............................................................................................................................................77

Pumping................................................................................................................................................77

Comparison of Water Levels and Streamflows .............................................................................80

Limitations of Analysis ................................................................................................................................80

References Cited..........................................................................................................................................85

Appendix 1
40 Hydrogeology and Simulation of Ground-Water Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Tables

1–1. Aquifer-test results reported for the Plymouth-Carver-Kingston-Duxbury aquifer

system, southeastern Massachusetts ....................................................................................46

1–2. Summary of horizontal hydraulic conductivity valuesfor general sediment

lithologies, Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern

Massachusetts............................................................................................................................48

1–3. Simulated hydraulic conductivity and horizontal to vertical anisotropy values 

for the calibrated groundwater-flow model of the Plymouth-Carver-KingstonDuxbury aquifer system, southeastern Massachusetts ......................................................51

1–4a. Groundwater withdrawals for 1985 and 2005, and projected for 2030 

conditions in the Plymouth-Carver-Kingston-Duxbury aquifer system, 

southeastern Massachusetts...................................................................................................53

1–4b. Groundwater withdrawals for average monthly current (2005) conditions in the

Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts .....57

1–5. Wastewater return flow rates from centralized wastewater treatment facilities 

for (A) current (2005) average monthly conditions, and (B) proposed (2030) average

monthly conditions in the Plymouth-Carver-Kingston-Duxbury aquifer system,

southeastern Massachusetts...................................................................................................61

1–6. Comparison between measured and model-calculated water levels for the

confined and unconfined groundwater-flow models of the Plymouth-CarverKingston-Duxbury aquifer system, southeastern Massachusetts .....................................70

1–6. Comparison between measured and model-calculated water levels for the

confined and unconfined groundwater-flow models of the Plymouth-CarverKingston-Duxbury aquifer system, southeastern Massachusetts .....................................72

1–7. Comparison between model-calculated and measured streamflows for the

confined and unconfined groundwater-flow models of the Plymouth-CarverKingston-Duxbury aquifer system, southeastern Massachusetts .....................................76

1–8. Model-predicted changes in water levels and streamflows and 95-percent

condifence intervals on model predictions for 2030 conditions, groundwater flow

model of the Plymouth-Carver-Duxbury-Kingston aquifer system, southeastern

Massachusetts............................................................................................................................83

1–8. Comparison of (A) model-calculated and observed water levels and 

(B) residual (observed minus model-calculated) water levels as a function 

of observed water levels, Plymouth-Carver-Kingston-Duxbury aquifer system, 

southeastern Massachusetts...................................................................................................75

1–9. Estimated monthly recharge to aquifer sediments, ponds, wetlands, and

cranberry bogs in the Plymouth-Carver-Kingston-Duxbury aquifer system,

southeastern Massachusetts...................................................................................................78

1–10. Comparison of model-calculated and observed water levels for simulated drought

recharge conditions for the periods 1963–67 and 1979–83 with current (2005)

pumping conditions for three monitoring sites (A) PWW–22, (B) WFW–51, and (C)

DJW–79 ........................................................................................................................................79

1–11. Comparison of model-calculated and observed average monthly water levels 

for three monitoring sites (A) PWW–22, (B) WFW–51, and (C) DJW–79 in the

Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts .....81

1–12. Comparison of model-calculated and observed average monthly streamflows for

the Jones River in Kingston, Massachusetts.........................................................................82
 Steady-State Model 41

Appendix 1. Development of Groundwater-Flow Model

Introduction

Numerical models provide a means to synthesize 

existing hydrogeologic information into an internally 

consistent mathematical representation of a real system or 

process, and thus are useful tools for testing and improving 

conceptual models or hypotheses of groundwater-flow systems 

(Konikow and Reilly, 1999). A numerical groundwater-flow 

model was developed for the Plymouth-Carver-KingstonDuxbury (PCKD) area of southeastern Massachusetts for the 

purpose of (1) synthesizing the available hydrogeologic data, 

including a conceptual depositional model of the surficial 

glacial sediments of the region; (2) providing estimates of the 

potential effects of changing pumping and recharge conditions 

on surface-water bodies; and (3) delineating the sources of 

water to pumping wells, ponds, streams, and coastal areas for 

current pumping and recharge conditions.

The numerical model developed for simulating 

groundwater flow in the PCKD area of southeastern 

Massachusetts was based on the USGS computer program 

MODFLOW-2000, which numerically solves the threedimensional groundwater-flow equation by finite-difference 

methods (Harbaugh and others, 2000). Two models were 

developed for this aquifer system: a steady-state model that 

represents long-term average hydrologic conditions, and a 

transient model that simulates dynamic changes in hydrologic 

conditions in response to time-varying recharge and pumping 

stresses. The particle-tracking algorithm MODPATH4 

(Pollock, 1994) was used to simulate advective transport in 

the aquifer under steady-state conditions; particle tracking 

was used to delineate sources of water to wells and natural 

receptors. Graphic display of spatial model results was done 

by using a version of the software suite MODTOOLS that was 

modified to work with MODFLOW-2000 (Orzol, 1997).

Steady-State Model

Steady-state models operate on the assumption of 

constant recharge and pumping stresses over time and 

represent long-term average hydrologic conditions in the 

aquifer system. Although water levels and flows in the aquifer 

system change over time in response to changes in recharge, 

advective transport through the aquifer system occurs over 

a time scale that can be on the order of decades. Therefore, 

advective flow patterns are strong indicators of long-term 

average hydrologic conditions in the aquifer (Masterson and 

others, 1997b; Walter and Masterson, 2003). As a result, 

steady-state models can be used to simulate advective 

transport and to estimate areas contributing recharge to wells 

and natural receptors (Masterson and Walter, 2000; Masterson, 

2004; Walter and others, 2004).

Model Discretization and Boundaries

The finite-difference model grid consists of a series of 

orthogonal model cells in which user-specified hydraulic 

parameters, model stresses, and boundary conditions are varied spatially. The conceptualization of how and where water 

enters, moves through, and leaves the aquifer is critical to the 

development of an accurate flow model (Reilly, 2001). Model 

inputs include intrinsic aquifer characteristics for each model 

cell, such as hydraulic conductivity. Boundary conditions are 

applied at some model cells to simulate hydrologic features, 

including streams and coastal estuaries. A detailed discussion 

of grid discretization, boundary conditions, and the use of 

finite-difference equations to simulate groundwater flow is 

presented in McDonald and Harbaugh (1988).

Spatial Discretization

The total active modeled area of the PCKD aquifer 

system is about 290 mi2 (fig. 1–1). The finite-difference 

grid for the numerical model consists of 355 rows and 

270 columns of uniformly spaced model cells that are 400 ft 

on a side. The aquifer was subdivided vertically into 8 layers 

of variable thickness that extend from the water table into 

shallow bedrock.

The glacial stratified deposits were represented by seven 

draping model layers (layers 1–7) from the water table to 

bedrock to allow for the detail necessary to represent the 

vertical changes in the lithology, pumping-well screen zones, 

the depth of kettle ponds, and the thickness of streambed 

sediments. The bottom layer (layer 8) extends from the top 

of the bedrock to 50 ft below the bedrock surface to allow for 

flow in bedrock in areas where unconsolidated deposits are 

thin, such as beneath upland tills.

Hydrologic Boundaries

The hydrologic boundaries, or boundary conditions, in 

the groundwater-flow model are the areas from which, and the 

method by which, all the water entering and leaving the model 

is specified.

The upper boundary of the model is the water table, 

which is a free-surface boundary that receives spatially 

variable recharge from precipitation and wastewater disposal. 

The lower boundary of the model is the low- to mid-grade 

metamorphic bedrock of the Milford-Dedham Zone (Zen and 

others, 1983) that underlies the entire study area. A no-flow 
42 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Silver 

Lake DUXBURY

BAY

KINGSTON

BAY

PLYMOUTH 

 HARBOR

Billington

 Sea

 

Great South 

 Pond

 

Federal 

 Pond

 

South

River Res.

 

College 

 Pond

 

Bloody

 Pond

 Halfway

 Pond

 Savery

 Pond

 

Indian

 Brook

 

Beaver Dam

 Brook

 

 East 

Head

Pond

 

 Glen

Charlie

Pond

 

 White

Island

Pond

 

 Big 

Sandy

Pond

 

 Great

Herring

Pond

 

 Cod 

 

 Cape 

 Canal

 

 Parker Mills

Pond

 

 Agawam

Fresh

Meadow

 Pond

 

Sampson

 Pond

 

South 

 

Wankinco 

 Wareham

 

Meadow 

 

 

River

 

River

 

 

River 

Herring

River

 

Brook

 

 

Weweantic River

 

 

PLYMOUTH 

 BAY

CAPE COD

 BAY

BUZZARDS

 BAY

MASSACHUSETTS BAY

Jones River

Winnetuxet River

South 

Harbor

Green

 River

 River

Eel River

Long Pond

88

86

85

83

59

48

33

20

10

9

4

3

84

81

80

72

66

65

58

57

12

11

60

7

5

73

68

67

56

55

54

53

52

51

13

78

74

38

34

27

26

25

37

23

35

Rochester

Plympton

Halifax

Pembroke

Marion

Plymouth

Carver

Wareham

Middleborough

Hanson

Duxbury

Kingston

Marshfield

Bourne

Sandwich

Existing well site—Codes

listed on table 1–4

Proposed well site—Codes

listed on table 1–4

Proposed wastewater

treatment facility— Codes listed on table 1–5

40

W5

25

70°47'30" 70°37'30"

42°00'

41°45'

Inactive model area

Surface water

EXPLANATION

Model cells 

General head boundary

Drain

Stream

Massachusetts Water 

Resources Commission

watershed boundary

Existing wastewater

treatment facility

W3

8 6

2

1

87

82

79

77

76

75

69

64 63

62

61

50 49

47

46

45

44

43

42

41

39 40

36

32

31

30

29

28

22 24

21

19

17 18

16

15

14

71

70

W1

W3W5

W4

W6

W2

0 2 MILES

0 2 KILOMETERS

Base from U.S. Geological Survey and Massachusetts Geographic Information System data sources,

Massachusetts State Plane Coordinate System, Mainland Zone 

Figure 1–1. Model extent and distribution of simulated boundary conditions of groundwater-flow model of 

Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.
 Steady-State Model 43

boundary condition was set at 50 ft below the bedrock surface 

to allow for simulation of any potential flow in the upper part 

of the bedrock. It was assumed that the upper 50 ft of bedrock 

transmits water into and out of the aquifer system, especially 

beneath the upland areas in Duxbury where thin (less than 

20 ft) till deposits overlie weathered bedrock. The altitude of 

the bedrock surface ranges from about 40 ft above NGVD 29 

to more than 200 ft below NGVD 29 (fig. 1–2).

The lateral boundaries of the model are represented 

as either no-flow or head-dependent flux boundaries. The 

western and northern extents of the modeled area were 

defined by no-flow boundaries, across which it was assumed 

that no flow enters or leaves the aquifer. No-flow boundaries 

were selected to coincide with the surface-water divides that 

separate surface-water flow in the PCKD aquifer system from 

surface-water flow in the Taunton and Lower Buzzards Bay 

Watersheds to the west and in the upper part of the South 

Coastal Watershed to the north (fig. 1–1). The eastern and 

southern extents of the modeled area are defined by coastal 

waters and represented in the model as head-dependent flux 

boundaries (fig. 1–1).

Coastal saltwater boundaries were simulated by the 

General Head Boundary (GHB) Package (McDonald and 

Harbaugh, 1988). Hydraulic heads were specified at these 

boundaries, and discharge fluxes were calculated by the model 

on the basis of the hydraulic gradient between the calculated 

head in the adjacent model cell and the specified-boundary 

head and the conductance at the boundary face. The hydraulic 

heads used for the coastal boundaries were set at 0.6 ft above 

NGVD 29, a level which is consistent with the average longterm water level measured at a tidal gage in Boston Harbor 

(National Oceanic and Atmospheric Administration, 2003).

The simulated discharge at head-dependent boundaries 

is a function of the hydraulic conductance which represents 

resistance to flow across the seabed from fine-grained 

sediments. The hydraulic conductance was calculated for 

each model cell containing a coastal discharge boundary, as 

described in McDonald and Harbaugh (1988), as

C = (K)(W)(L) , (1.1) 

(M)

where

C is the hydraulic conductance of the seabed, in 

square feet per day;

K is the vertical hydraulic conductivity of 

seabed deposits, in feet per day;

W is the width of the seabed within the model 

cell, in feet;

L is the length of the seabed within the model 

cell, in feet; and

M is the thickness of the seabed, in feet.

The simulated vertical hydraulic conductivity of the 

seabed (K) was based on the product of the vertical leakance 

and seabed thickness. A leakance value of 0.02 feet per day 

per foot (ft/d/ft) and a seabed thickness of 10 ft were used to 

determine the vertical hydraulic conductivity (0.2 ft/d) of most 

of the coastal seabed deposits. A leakance of 0.0002 ft/d/ft and 

a seabed thickness of 10 ft were used to determine the vertical 

hydraulic conductivity (0.002 ft/d) for seabed deposits in 

the Duxbury-Kingston Bay area, where it was assumed that 

low-permeability tidal mud was more prevalent than in open 

coastal waters (fig. 1–1). These vertical leakance values are 

consistent with the range of seabed leakance values of 0.0001 

to 0.1 ft/d/ft reported for the nearshore sediments in the 

Kirkwood–Cohansey aquifer system, New Jersey (Nicholson 

and Watt, 1997) and values of 0.01 to 1.0 ft/d/ft reported for 

sandy sediments over most of the Atlantic Coast Plain (Leahy 

and Martin, 1993). The width (W) and length (L) of the coastal 

boundaries within each cell were equal to the width and length 

of the model cell containing these boundaries (400 ft), and the 

thickness (M) was equal to 10 ft.

The streams in the PCKD aquifer system also were 

simulated with head-dependent flux boundaries in model 

layer 1. Many of these streams were simulated by using the 

Streamflow-Routing (STR) Package (Prudic, 1989), which 

allows groundwater discharge (gaining stream reaches) as 

well as infiltration into the aquifer (losing stream reaches). 

Representing streams by using the STR Package allows for the 

simulation of losing conditions downgradient of pond outlets 

or near pumping wells.

The groundwater model simulates only base-flow 

conditions in the streams and as a result will underrepresent 

peak streamflow conditions from overland runoff. Overland 

runoff, however, is assumed to be negligible in most of the 

study area owing to the sandy permeable soils of the stratified 

glacial deposits in the region. Most streams in the aquifer are 

gaining; however, losing conditions can develop downstream 

from pond outlets and near pumping wells. The STR Package 

also accounts for water that is routed through stream networks. 

This routing capability is used in the models to route water 

from pond outlets into receiving streams.

The only stream not represented in the STR Package 

was the Winnetuxet River and its tributaries along the western 

model boundary (fig. 1–1). These streams were simulated with 

the Drain (DRN) Package (McDonald and Harbaugh, 1988) to 

remove water from the aquifer that either discharged to these 

streams within the study area along the western boundary 

or would have discharged farther downstream beyond the 

study area.

Streambed altitudes represented in the model were 

estimated from the digital-elevation data for the study area 

(Peter Steeves, U.S. Geological Survey, written commun., 

2005). The hydraulic conductance (C) of the streambed 

deposits was calculated by the same equation used to 

calculate the conductance of the seabed sediments (eq. 1.1). 
44 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Inactive model area

Bedrock-surface contour—

In feet. Interval is variable.

Datum is NGVD 29. 

Dashed where uncertain

Base from U.S. Geological Survey and Massachusetts Geographic

Information System data sources, Massachusetts State Plane Coordinate

System, Mainland Zone 

Bedrock-surface data point

Geologic data point

Town boundaries

EXPLANATION

20

70°47'30" 70°37'30"

42°00'

41°45'

Plymouth Carver

Rochester

Plympton

Middleborough

Halifax

Pembroke

Duxbury

Kingston

Marshfield

Marion

Wareham

Bourne

-20

20

-20

20

20 20

40

40

40

40

0

0

0

0

0

-50

60

60

60

60

80

50

50

50

50

50

50

50

50

50

20

100

100

100

0

25

0

0

-50

-50

-50

-50

-50

-50

-100

-100

-100

-100

-100

-100

-150

-150

-150

-200

-200

-25

-25

-25

-25

-50

-50

-50

-100

-50

-50

-20

0 2 MILES

0 2 KILOMETERS

Data modified from Hansen and Lapham, 1992;

and Persky, 1993

Figure 1–2. Altitude and configuration of the bedrock surface beneath the Plymouth-Carver-Kingston-Duxbury 

aquifer system, southeastern Massachusetts.
 Steady-State Model 45

For streams, a leakance value of 4.0 ft/d/ft and a streambed 

thickness of 5 ft were used to determine the vertical hydraulic 

conductivity value (K) of 20 ft/d; it was assumed that 

streambed sediments are sandier and have higher conductance 

values than marine sediments. A width (W) of 10 ft and 

a length (L) of 400 ft were assumed for all of the streams 

simulated in the flow model.

Previous analyses of similar hydrogeologic settings, 

such as Cape Cod and coastal Rhode Island (Masterson and 

others, 2007; Masterson, and others, 1997b) showed that large 

changes in estimated hydraulic conductances, and streambed 

altitudes can affect the location and amount of groundwater 

discharge to surface-water bodies. Therefore, local-scale 

analyses of specific surface-water bodies may require more 

detailed hydrologic data collection than was possible for this 

regional analysis.

Ponds in the PCKD aquifer system are similar to the 

kettle ponds on Cape Cod in that they generally are in direct 

hydraulic connection to the aquifer and are regions of the 

aquifer with no effective resistance to flow. As a result, 

groundwater-flow lines converge towards ponds in upgradient 

areas, where water discharges to ponds, and diverge in 

downgradient areas, where ponds recharge the aquifer. In 

the models, ponds are simulated as areas of high hydraulic 

conductivity, 50,000 ft/d, which is about 3 orders of magnitude 

higher than hydraulic conductivity values simulated for the 

surrounding aquifer. This difference in hydraulic conductivity 

causes preferential flow through the pond and simulates the 

observed effects that ponds have on groundwater flow in the 

aquifer system.

Simulated pond geometries were based on bathymetries 

published by the Massachusetts Department of Fisheries and 

Wildlife (1993). Given the model discretization of 400 ft, 

ponds with areas less than about 6 acres (about 2.6 x 105 ft2) 

were not included in the models.

Some ponds, such as Silver Lake, Halfway Pond, and 

Billington Sea also drain into adjacent streams (fig. 1–1). 

In these cases, the pond outlets are simulated as a stream 

boundary with a large streambed conductance resulting 

in no effective resistance to flow; the water entering this 

stream-boundary cell is routed by the STR Package into a 

receiving stream.

Hydraulic Properties

The water-transmitting properties of the aquifer 

sediments, as represented by hydraulic conductivity (K) 

and vertical anisotropy, are functions of lithology and 

differ according to grain size and the degree of sorting of 

the sediments. The relation between lithology and aquifer 

characteristics (hydraulic conductivity and vertical anisotropy) 

was determined through reviews of hydrogeologic information 

from previous investigations (Williams and Tasker, 1974; 

Hansen and Lapham, 1992; Persky, 1993; Masterson and 

others, 1997a) and from a compilation of aquifer tests 

conducted throughout the region as part of water-supply 

investigations by environmental consultants (tables 1–1, 1–2). 

These results show that hydraulic conductivity values 

range widely throughout the region, but nonetheless do 

follow some very general trends that are consistent with 

those observed in previous analyses of aquifer properties 

in the glacial sediments on western Cape Cod (Walter and 

Whealan, 2005; Masterson and others, 1997a; Barlow and 

Hess, 1993). These trends indicate that hydraulic conductivity 

(K) values generally decrease with depth and with increasing 

distances from the original source of the sediments in the large 

outwash plains of the PCKD aquifer system; this spatial trend 

is similar to the trend observed within the Mashpee Pitted 

Plain in western Cape Cod. In the Wareham Pitted Plain, the 

sediment source is denoted by the position of the Hog Rock 

and Ellisville Moraines (fig. 1–3A). These morainal deposits 

represent a period in time in which the retreating ice sheets 

were at a standstill, and water flowing from the melting ice 

deposited deltaic sediments into large glacial lakes, one of 

which created the Wareham Pitted Plain. Because the outwash 

plains were formed as deltas deposited into glacial lakes, the 

coarser grained sediments were deposited in the nearshore 

environment and the finer grained sediments were deposited 

farther from the shore. As a result, the K values in the 

sediments that constitute the outwash plains tend to decrease 

to the south away from the sediment source and with depth, as 

the deltaic deposits extended out into the glacial lake.

Unlike the outwash plains, the moraine and ice-contact 

deposits, such as the Hog Rock, Ellisville, and Middleborough 

Moraines and Pine Hills were deposited directly by melting 

ice rather than by rivers flowing from ice, resulting in deposits 

of sediment that are less sorted and more variable in grain size 

and hydraulic conductivity than the outwash deposits. It was 

assumed for this investigation that the hydraulic conductivity 

values of the morainal deposits were similar to those of fine to 

medium sands.

Vertical anisotropy (VA), which is the ratio of horizontal 

to vertical hydraulic conductivity, generally increases with 

decreasing hydraulic conductivity; general anisotropy values 

for glacial sediments range from 3:1 for coarse sands and 

gravels to 100:1 for clay (Masterson and others, 1997a; 

Masterson and Barlow, 1997). The values of VA and the 

corresponding range in K used in the calibrated model are 

presented in table 1–3. Observations made during trial-anderror model calibrations done as part of this and previous 

investigations indicate that VA ratios generally do not have 

a substantial effect on regional water levels, flows, and 

advective-transport patterns in the aquifer. A more quantitative 

analysis of model sensitivity to different model parameters, 

including VA ratios, is presented in the upcoming section 

“Model Calibration.”

The initial distribution of horizontal hydraulic 

conductivity in the model was based on (1) reported aquifertest values for specific glacial deposits (tables 1–1 and 1–2), 

(2) an understanding of the glacial history of the region, 

and (3) the relation established for grain-size distribution 
46 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts Table 1–1. Aquifer-test results reported for the Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.—Continued [ft2/d, feet squared per day; ft/d, feet per day; --, not available; Site identifier number and surficial geology codes are shown on figure 1–3. Values for hydraulic conductivity calculated from transmissivity and saturated thickness values published in the listed data sources] Site identifier number Surficial geology code Transmissivity (ft2/d) Specific yield (1) Hydraulic conductivity (ft/d) Saturated thickness (feet) Duration of aquifer test Data source

1 G 34,800 0.26 -- -- 5 days D.L. Maher Company (1987)3 M 12,600 0.05 382 33 3 days Woodward and Curran, Inc. (2005)4 G 12,600 0.01 229 55 7 days Haley and Ward, Inc. (1992)5 G 12,600 0.13 126 100 5 days SEA Consultants, Inc. (1991)7 G 26,300 0.04 280 94 5 days SEA Consultants, Inc. (1995)

12

G 23,500 0.02 412 57 5 days SEA Consultants, Inc. (1995)

13

G 19,300 0.04 186 104 7 days SEA Consultants, Inc. (1993)

16

G 7,900 0.13 -- -- 2 days Amory Engineers, P.C. (1998)

17

G 11,100 0.44 -- -- -- Dufresne-Henry, Inc. (1999)

24 I 17,250 0.09 -- -- 5 days Whitman and Howard, Inc. (1993)24 I 9,760 0.2 -- -- 5 days Whitman and Howard, Inc. (1993)24 I 12,670 0.15 -- -- 5 days Whitman and Howard, Inc. (1993)26

M 6,100 0.18 153 40 5 days DeFeo, Wait and Pare, Inc. (1995)

27

M 6,100 0.18 153 40 5 days DeFeo, Wait and Pare, Inc. (1995)

28

M 11,400 -- 219 52 7 days DeFeo, Wait and Pare, Inc. (1995)

29

G 17,500 0.17 438 40 5 days Tighe and Bond, Inc. (2001)

30

G 4,600 -- -- -- 5 days REIS Engineering, Inc. (1986)

32

O 6,400 0.05 183 35 7 days Woodward and Curran, Inc. (1991)

33

G 7,100 -- 142 50 2 days Haley and Ward, Inc. (1997)

34

G 12,100 0.2 86 140 2 hours CDM, Inc. (1988)

36

O 5,500 0.04 100 55 5 days GEI Consultants, Inc. (1990)

37 I 14,700 0.18 123 120 5 days Amory Engineers, P.C. (1992)38

P 6,700 -- 176 38 -- IEP, Inc. (1991)

39

O 8,900 -- 165 54 -- IEP, Inc. (1991)

40

O 3,900 -- 72 54 -- IEP, Inc. (1991)
 Steady-State Model 47

Table 1–1. Aquifer-test results reported for the Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.—Continued[ft2/d, feet squared per day; ft/d, feet per day; --, not available; Site identifier number and surficial geology codes are shown on figure 1–3. Values for hydraulic conductivity calculated from transmissivity and saturated thickness values published in the listed data sources]

Site 

identifier 

number

Surficial 

geology 

code

Transmissivity

 (ft2/d)

Specific

 yield

(1)

Hydraulic 

conductivity 

(ft/d)

Saturated 

thickness 

(feet)

Duration of 

aquifer test Data source

41 P 11,800 -- 231 51 -- IEP, Inc. (1991)42 O 7,500 -- 192 39 -- IEP, Inc. (1991)43 G 9,600 -- 87 110 5 days Horsley and Witten, Inc. (1998)44 G 13,400 0.25 -- -- -- Amory Engineers, P.C. (1998)45 G 13,400 0.25 -- -- -- Amory Engineers, P.C. (1998)46 G 20,400 0.2 122 167 11 days Metcalf and Eddy, Inc. (1972)47 G 6,700 0.25 -- -- -- Amory Engineers, P.C. (1998)48 I 12,000 0.19 -- -- -- Amory Engineers, P.C. (1998)49 G 6,700 0.1 -- -- -- Amory Engineers, P.C. (1998)50 G 6,700 0.03 -- -- -- Amory Engineers, P.C. (1998)51 O 6,500 -- 130 50 -- Whitman and Howard, Inc. (1975)52 G 3,100 -- -- -- 3 days Briggs Engineering and Testing, Inc. (1985a)52 G 10,900 0.01 73 150 -- Briggs Engineering and Testing, Inc. (1985b)53 G 13,400 0.2 223 60 -- Metcalf and Eddy, Inc. (1976)54 G 3,800 0.2 44 86 5 days H.W. Moore Associates, Inc. (1972)55 I 1,100 -- 19 58 4 days H.W. Moore Associates, Inc. (1982)56 F 18,400 0.15 194 95 5 days Metcalf and Eddy, Inc. (1972)57 G 100 -- -- -- -- Briggs Engineering and Testing, Inc. (1987)58 G 15,800 0.02 211 75 -- Metcalf and Eddy, Inc. (1974a)59 G 33,400 -- 272 123 -- Metcalf and Eddy, Inc. (1975a)60 G 28,100 0.2 171 164 5 days Metcalf and Eddy, Inc. (1975b)61 G 26,700 0.1 303 88 7 days Metcalf and Eddy, Inc. (1976)62 I 23,900 0.16 182 131 -- Metcalf and Eddy, Inc. (1974b)63 G 23,200 -- -- -- 2 days OI Geotechnical Engineers, Inc. (1984)64 M 4,810 0.01 120 40 2 days D'Amore Associates, Inc. (2007)
48 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Table 1–2. Summary of horizontal hydraulic conductivity values for general sediment lithologies, Plymouth-Carver-Kingston-Duxbury 

aquifer system, southeastern Massachusetts. 

[Hydraulic conductivity values for lithology groups denoted by map ID letters A–K from Williams and Tasker, 1974. Transmissivity values for stratified drift 

groups denoted by map ID letters M–P from Persky, 1993. >, greater than; ft, feet; <, less than; ID, Identification; Map ID letters are shown on figure 1–3]

Surficial 

geology 

code

Hydraulic conductivity (feet per day)

A Well sorted gravel (>150) and fine to coarse sand (40–150) as much as 30 ft thick; locally bouldery. Generally mantles 

stratified silt, sand, gravel, tidal marsh, organic deposits, or till.

B Tidal peat, organic silt, silt (<10) and fine to medium sand (40–100) less than 30 ft thick. Generally mantles silt, sand, 

gravel, and compact silty gravel (till).

C Artificial fill of sand (40–150) and some gravel (150–250) excavated from Cape Cod Canal; riprap and fill in Stony 

Point dike.

D Upper unit of well sorted fine gravel (150–200) and medium to coarse sand (100–150) 15 to 20 ft thick, middle unit of fine 

to coarse sand (40–150) and some pebble gravel (150–200), and lower unit of fine sand (40) and silt and clay (<10) of 

variable thickness. Mantles sand and gravel (40–250) beneath parts of Plymouth kamefield.

E Fine sand (40), overlying silt and clay (<10) generally 10 to about 50 ft thick. In Plymouth, kamefield deposits may lie 

above stratified sand and gravel (40–250); at southern border of Carver outwash, plain deposits lie on compact till or on 

coarse, bouldery ablation deposits.

F Fine to coarse gravel (150–475).

G Medium to coarse sand (100–150).

H Loose, poorly to well sorted, poorly stratified deposits ranging from coarse, bouldery sand and gravel (<250) and silty 

sandy boulder gravel (sandy till) (<100) to fine to coarse sand (40–150) and silt and clay (<10). Wide differences in 

texture and hydraulic conductivity over short vertical and horizontal distances. Thickness as much as 50 ft.

I Loose, unstratified, unsorted sandy silty gravel (sandy till) (<100); poorly stratified and poorly sorted coarse sandy boulder 

gravel containing some well stratified, well sorted sandy gravel (<250).

J Loose, unsorted, unstratified, bouldery silty sandy gravel (sandy till) (<100) less than 30 ft thick that mantles fine to coarse 

sand (40–150) containing some beds of sandy gravel (<250). North of Ellisville Moraine in Manomet, underlying sand 

contains a relatively thin zone of compact till (<10) and rests on basal compact till.

K Compact unsorted silty boulder gravel (till) (<10).

Surficial 

geology 

code

Transmissivity of stratified drift 

(feet squared per day)

M Not examined

N < 1,350

O > 1,350 to 4,000

P > 4,000
 Steady-State Model 49

Figure 1–3. (A) Surficial geology and location of aquifer tests, and (B) hydraulic conductivity zones for a 

calibrated groundwater-flow model of the Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern 

Massachusetts.

28

27

26

35 36

40

39

38 41

42

32

22

21

50 25

20 19

23

47 56 3

64 58

31

46

44

45

13 61

14

60

62

52

43 53

48

57

49

55

37

17

59

1

16

63

29 30

6 10 7 8 9

11

12 15

54

2 18

51

34

24

5

33

4

Inactive model area

Surficial geology—Refer

to table 1–2 for description

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Aquifer-test well and

identifier—Refer to

table 1–1 for description

EXPLANATION

50

70o 70 37' 30” o 47' 30”

42°00'

41°45'

Base from U.S. Geological Survey and Massachusetts Geographic Information System data sources,

Massachusetts State Plane Coordinate System, Mainland Zone 

0 2 MILES

0 2 KILOMETERS

Wareham Pitted 

Plain

Carver Pitted 

Plain

Hog Rock

Moraine

Sandwich

Moraine

Snipituit Moraine

Pine

Hills

Ellisville Moraine

A

Middleborough

Moraine
50 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

EXPLANATION

Hydraulic conductivity parameter

codes—Refer to table 1–3 for descriptions

Base from U.S. Geological Survey and Massachusetts Geographic Information System data sources, 

Massachusetts State Plane Coordinate System, Mainland Zone. 

1*

2

3*

4

5

6

7

8

9*

10

11

12b

12a

13*

14

15

16

17

18

19*

20

*Indicates parameter codes that represent 

a change in hydraulic conductivity values 

with depth.

70°47'30" 70°37'30"

42°00'

41°45'

0 2 MILES

0 2 KILOMETERS

B

Figure 1–3. (A) Surficial geology and location of aquifer tests and (B) hydraulic conductivity zones for a calibrated 

groundwater-flow model of the Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.—Continued 
 Steady-State Model 51

Table 1–3. Simulated hydraulic conductivity and horizontal to vertical anisotropy values for the calibrated groundwater-flow model of 

the Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts. 

[Map codes shown on figure 1–3B]

Map code

Horizontal hydraulic 

conductivity,

in feet per day

Horizontal to 

vertical anistropy Model layer(s)

1 82 37 to 1 1 to 4

1 30 100 to 1 5 to 8

2 218 4 to 1 1 to 8

3 10 100 to 1 1 to 4

3 30 100 to 1 5 to 8

4 119 13 to 1 1 to 8

5 10 1,000 to 1 1 to 8

6 48 96 to 1 1 to 8

7 64 27 to 1 1 to 8

8 30 100 to 1 1 to 8

9 227 5 to 1 1 to 4

9 34 68 to 1 5 to 8

10 23 144 to 1 1 to 8

11 52 5 to 1 1 to 8

12a 1 100 to 1 1 and 2

12b 7.5 75 to 1 3 to 8

13 50,000 1 to 1 1 to 4

13 150 10 to 1 5 to 8

14 7.5 75 to 1 1 to 8

15 7.5 75 to 1 1 to 8

16 7.5 75 to 1 1 to 8

17 5 100 to 1 1 to 8

18 94 34 to 1 1 to 8

19 1,000 10,000 to 1 1 to 2

19 1 100 to 1 2 to 3 

20 147 11 to 1 1 to 8
52 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

and hydraulic conductivity for stratified glacial deposits on 

Cape Cod (Walter and Whealan, 2005; Masterson and others, 

1997a). This initial distribution of hydraulic conductivity 

values was adjusted to best fit estimates of long-term average 

water levels and streamflows estimated from measured 

values during the parameter-estimation calibration process 

and discussed in the upcoming section “Comparison of 

Water Levels and Streamflows.” The values of hydraulic 

conductivity listed in table 1–3 represent final values for 

the parameter zones displayed on figure 1–3; calibration of 

the model is discussed in the section “Comparison of Water 

Levels and Streamflows.”

For transient simulations, a uniform specific yield value 

of 0.25 consistent with Moench (2001) was used for the 

uppermost active layers, and for the lower, confined layers, 

a uniform specific storage value of 1x10-5 was used based 

on Barlow and Hess (1993). In the cells representing ponds, 

the specific yield and specific storage were set to values of 

1.0 and 1.0 × 10-9, respectively, to account for the high storage 

capacity assumed for the ponds.

For particle-tracking analyses, porosities of 0.3 and 

1.0 were used to represent aquifer sediments and ponds, 

respectively. Porosity affects simulated traveltimes along 

advective transport paths in the aquifer but does not affect 

simulated water levels, flows, or advective transport patterns. 

The porosity value of 0.3 used in the model is consistent with 

previous porosity estimates for stratified glacial deposits in 

southeastern Massachusetts (Garabedian and others, 1991; 

LeBlanc and others, 1991; Masterson and Barlow, 1997) 

and is consistent with published values for glacial sediments 

(Freeze and Cherry, 1979).

Hydrologic Stresses

The hydrologic stresses simulated in the model include 

recharge from precipitation, return flow from domestic waste 

disposal, and pumping for drinking water and for commercial 

and agricultural uses. The recharge estimates are based on 

a water-budget analysis from the East Wareham, MA, and 

Providence, R.I., weather stations and represent long-term 

average conditions. Pumping rates for production, commercial, 

and irrigation supply and the resulting wastewater return-flow 

estimates are based on the average daily pumping rates for 

1985 and 2000–2005 and projected rates for 2030 (Joe Cerutti, 

Massachusetts Department of Environmental Protection, 

written commun., 2007) (tables 1–4, 1–5).

Recharge

The sole source of water to the aquifer is recharge derived 

from areal precipitation. Precipitation at East Wareham, MA, 

has averaged 47 in/yr since 1931 (National Oceanic and 

Atmospheric Administration, 2007). Some precipitation is 

lost to evapotranspiration and overland runoff to streams; the 

remainder recharges the aquifer at the water table or on the 

surfaces of ponds, wetlands, and cranberry bogs. Therefore, 

the simulated recharge to the groundwater system consisted 

of five separate components: (1) areal recharge to the land 

surface, (2) recharge to kettle ponds, (3) recharge to wetlands, 

(4) recharge to cranberry bogs, and (5) return flow from 

wastewater discharge to groundwater.

The average annual recharge rate of 27 in/yr was 

calculated for the aquifer by the climatic water budget 

computer program WATBUG (Wilmott, 1977). WATBUG 

uses the Thornthwaite method (Chow, 1964) to compute 

climatic water budgets on a daily or monthly time scale on 

the basis of daily temperature and precipitation data from the 

East Wareham weather station for 1931 through 2006 and 

an estimate of soil-moisture capacity. Data input required 

for WATBUG include the latitude of the weather station, 

measured daily temperature and precipitation values, and an 

estimate of ambient soil-moisture capacity. Output values 

include actual and potential evapotranspiration rates and the 

change in soil-moisture storage (water available for recharge). 

The soil-moisture capacity, which is the moisture retained 

in the soil after excess moisture is drained through gravity 

drainage, was assumed to be 6 in/yr based on the previous 

work of Carlson and Lyford (2005). Surface-water bodies 

such as ponds, wetlands, and cranberry bogs were determined 

to be areas of net recharge to the aquifer. The simulated 

recharge for ponds was determined by the free-water-surface 

potential-evaporation rate calculated by the Jensen-Haise 

method (Jensen and Haise, 1963). This method uses airtemperature and solar-radiation data to estimate free-watersurface evaporation. Because the East Wareham weather 

station does not collect solar-radiation data, this information 

was obtained from the weather station at T.F. Green Airport, 

Providence, R.I. The estimated free-water-surface potential 

evaporation rate was determined to be 28 in/yr, similar to 

the rate determined by Farnsworth and others (1982) for the 

northeastern United States.

The net recharge rate for ponds for average annual 

conditions was 20 in/yr. This rate was calculated for the period 

1960–2004 at the T.F. Green Airport weather station; during 

this period, the precipitation rate was consistent with the longterm average rate calculated at the East Wareham weather 

station for the period 1931–2006.

In wetlands and cranberry bogs, evapotranspiration is 

assumed to account for a substantial loss of water, which 

can be as large, or larger, than the evaporation loss from 

ponds because of the combined effect of evaporation and 

transpiration in these flooded, vegetated areas. Therefore, 

a uniform recharge rate of 8 in/yr was specified for all the 

wetlands in the study area; this rate is about 40 percent of 

the recharge rate specified for ponds and about 30 percent 

of the rate for the surrounding aquifer. This value was based 

on previous analyses of the New England wetland systems 

(Hemond, 1980; Zarriello and Bent, 2004).

It should be noted, however, that recharge in wetlands 

can vary greatly depending on the extent of open water, 

amount and type of vegetation, location of the wetland in the 
 Steady-State Model 53

Table 1–4a. Groundwater withdrawals for 1985 and 2005 and projected for 2030 conditions in the 

Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.—Continued

[Code is number shown in fig. 1–1. Data source: MassDEP, Massachusetts Department of Environmental Protection. 

All units are in millions of gallons per day]

Mass DEP 

well identifier Code 1985 2005 2030

Production wells

Buzzards Bay Water District

4036001-01G 1 0.19 0.08 0.09

4036001-02G 2 0.18 0.10 0.09

4036001-03G 3 0.00 0.17 0.20

4036001-04G 4 0.00 0.11 0.12

4036001-05G 5 0.00 0.00 0.12

Total 0.37 0.46 0.62

North Sagamore Water District

4036002-01G 6 0.02 0.04 0.06

4036002-02G 7 0.00 0.00 0.00

4036002-03G 8 0.17 0.41 0.28

4036002-04G 9 0.00 0.07 0.28

Total 0.19 0.52 0.62

Carver

4052001-01G 10 0.00 0.08 0.00

4052067-01G 11 0.00 0.03 0.10

4052067-02G 12 0.00 0.03 0.10

4052067-03G 13 0.00 0.00 0.18

Total 0.00 0.14 0.38

Duxbury

4082000-01G 14 0.27 0.12 0.09

4082000-02G 15 0.08 0.16 0.13

4082000-03G 16 0.08 0.00 0.11

4082000-04G 17 0.22 0.14 0.13

4082000-05G 18 0.21 0.27 0.19

4082000-06G 19 0.04 0.00 0.15

4082000-07G 20 0.01 0.28 0.26

4082000-08G 21 0.00 0.08 0.08

4082000-09G 22 0.19 0.25 0.23

4082000-10G 24 0.19 0.13 0.11

4082000-11G 26 0.00 0.00 0.19

4082000-12G 23 0.00 0.00 0.08

4082000-13G 25 0.00 0.00 0.13

Total 1.29 1.43 1.88
54 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Table 1–4a. Groundwater withdrawals for 1985 and 2005 and projected for 2030 conditions in the 

Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.—Continued

[Code is number shown in fig. 1–1. Data source: MassDEP, Massachusetts Department of Environmental Protection. 

All units are in millions of gallons per day]

Mass DEP 

well identifier Code 1985 2005 2030

Production wells—Continued

Kingston

4145000-01G 27 0.00 0.00 0.00

4145000-02G 28 0.16 0.08 0.07

4145000-03G 29 0.29 0.36 0.31

4145000-04G 30 0.12 0.00 0.00

4145000-05G 31 0.17 0.19 0.14

4145000-06G 32 0.32 0.52 0.36

4145000-07G 33 0.00 0.25 0.38

4145000-08G 34 0.00 0.00 0.31

4145000-09G 35 0.00 0.00 0.16

Total 1.06 1.40 1.73

Marshfield

4171000-01G 36 0.32 0.00 0.17

4171000-02G 37 0.00 0.00 0.00

4171000-03G 38 0.00 0.00 0.00

4171000-10G 39 0.10 0.21 0.17

4171000-12G 40 0.01 0.02 0.10

Total 0.43 0.23 0.44

Pembroke

4231000-03G 74 0.00 0.00 0.25

Plymouth Water Company

4239045-01G 57 0.00 0.17 0.25

4239045-02G 58 0.00 0.08 0.25

Total 0.00 0.25 0.50

Plymouth Water Department

4239000-01G 41 0.03 0.00 0.36

4239000-02G 42 0.23 0.26 0.36

4239000-03G 43 0.25 0.40 0.36

4239000-04G 44 0.32 0.42 0.36

4239000-05G 45 0.97 0.70 0.64

4239000-06G 46 0.86 0.49 0.72

4239000-07G 47 0.34 0.51 0.36

4239000-08G 48 0.00 0.33 0.29

4239000-09G 49 0.00 0.82 0.79

4239000-10G 50 0.00 0.87 0.79

4239000-11G 51 0.00 0.25 0.36

4239000-12G 52 0.00 0.00 0.36

4239000-13G 53 0.00 0.00 0.36
 Steady-State Model 55

Table 1–4a. Groundwater withdrawals for 1985 and 2005 and projected for 2030 conditions in the 

Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.—Continued

[Code is number shown in fig. 1–1. Data source: MassDEP, Massachusetts Department of Environmental Protection. 

All units are in millions of gallons per day]

Mass DEP 

well identifier Code 1985 2005 2030

Production wells—Continued

Plymouth Water Department

4239000-14G 54 0.00 0.00 0.36

4239000-15G 55 0.00 0.00 0.36

4239000-16G 56 0.00 0.00 0.36

4239000-1S 99 1.64 0.00 0.00

Total 4.64 5.05 7.19

Pine Hills

4239055-01G 59 0.00 0.13 0.82

Wareham Fire District

4310000-01G 60 0.40 0.20 0.19

4310000-02G 61 0.16 0.32 0.24

4310000-03G 62 0.44 0.27 0.24

4310000-04G 63 0.00 0.29 0.24

4310000-06G 64 0.36 0.15 0.28

4310000-07G 65 0.00 0.40 0.39

4310000-08G 66 0.00 0.01 0.35

4310000-09G 67 0.00 0.00 0.24

4310000-10G 68 0.00 0.00 0.00

Total 1.36 1.64 2.17

Onset Fire District

4310003-01G 69 0.14 0.17 0.16

4310003-02G 70 0.07 0.10 0.09

4310003-03G 71 0.27 0.11 0.10

4310003-04G 72 0.00 0.23 0.22

4310003-05G 73 0.00 0.00 0.21

Total 0.48 0.61 0.78

Commercial wells

Carver

4158000_01N 75 0.09 0.09 0.12

Plymouth

3976000_01N 79 0.25 0.33 0.60

8846000_01N 85 0.07 0.09 0.09

Total 0.32 0.42 0.69
56 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Table 1–4a. Groundwater withdrawals for 1985 and 2005 and projected for 2030 conditions in the 

Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.—Continued

[Code is number shown in fig. 1–1. Data source: MassDEP, Massachusetts Department of Environmental Protection. 

All units are in millions of gallons per day]

Mass DEP 

well identifier Code 1985 2005 2030

Irrigation wells

Duxbury

3974000_01N 76 0.04 0.05 0.05

Marshfield

4024000_01N 77 0.04 0.05 0.01

4024000_02N 78 0.00 0.00 0.04

Total 0.04 0.05 0.05

Plymouth

4034000_01N 80 0.00 0.02 0.02

4034000_02N 81 0.00 0.03 0.03

9386000_01N 82 0.03 0.05 0.05

9101000_01N 83 0.00 0.06 0.06

4887000_01N 84 0.00 0.07 0.07

9058000_01N 85 0.00 0.07 0.06

Wavely Oaks 88 0.00 0.12 0.12

Total 0.03 0.42 0.41

Pine Hills

4908000_01N 86 0.00 0.21 0.22
 Steady-State Model 57

Table 1–4b. Groundwater withdrawals for average monthly current (2005) conditions in the Plymouth-Carver-Kingston-Duxbury aquifer 

system, southeastern Massachusetts.—Continued

[Code is number shown on fig. 1–1. Data source: MassDEP, Massachusetts Department of Environmental Protection. All units are in millions of gallons 

per day]

Well ID Code Jan Feb March April May June July Aug Sept Oct Nov Dec

Production wells

Buzzards Bay Water District

4036001-01G 1 0.06 0.08 0.07 0.07 0.10 0.12 0.11 0.11 0.09 0.07 0.07 0.07

4036001-02G 2 0.09 0.09 0.08 0.09 0.09 0.17 0.20 0.15 0.11 0.10 0.11 0.10

4036001-03G 3 0.13 0.12 0.14 0.16 0.20 0.19 0.29 0.24 0.21 0.15 0.13 0.12

4036001-04G 4 0.09 0.09 0.09 0.09 0.11 0.14 0.19 0.16 0.14 0.09 0.08 0.08

4036001-05G 5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Total 0.37 0.38 0.38 0.41 0.50 0.62 0.79 0.66 0.55 0.41 0.39 0.37

North Sagamore Water District

4036002-01G 6 0.00 0.00 0.04 0.01 0.00 0.01 0.16 0.11 0.04 0.02 0.02 0.01

4036002-02G 7 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

4036002-03G 8 0.29 0.30 0.26 0.28 0.47 0.61 0.68 0.61 0.49 0.39 0.29 0.28

4036002-04G 9 0.09 0.08 0.09 0.21 0.23 0.41 0.42 0.37 0.27 0.11 0.08 0.09

Total 0.38 0.39 0.39 0.50 0.70 1.03 1.26 1.09 0.80 0.52 0.39 0.38

Carver

4052001-01G 10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

4052067-01G 11 0.02 0.03 0.02 0.02 0.02 0.03 0.03 0.03 0.03 0.02 0.02 0.02

4052067-02G 12 0.02 0.03 0.03 0.03 0.04 0.04 0.04 0.04 0.03 0.03 0.02 0.02

4052067-03G 13 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Total 0.04 0.06 0.05 0.05 0.06 0.07 0.07 0.07 0.06 0.05 0.04 0.04

Duxbury

4082000-01G 14 0.09 0.10 0.15 0.16 0.16 0.16 0.18 0.14 0.10 0.06 0.07 0.06

4082000-02G 15 0.13 0.14 0.16 0.18 0.16 0.21 0.22 0.22 0.17 0.15 0.11 0.09

4082000-03G 16 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

4082000-04G 17 0.16 1.05 0.09 0.12 0.17 0.18 0.17 0.16 0.16 0.16 0.14 0.11

4082000-05G 18 0.17 0.25 0.24 0.22 0.33 0.35 0.35 0.34 0.35 0.31 0.22 0.13

4082000-06G 19 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

4082000-07G 20 0.19 0.08 0.11 0.13 0.24 0.33 0.59 0.48 0.19 0.11 0.15 0.18

4082000-08G 21 0.00 0.04 0.01 0.04 0.08 0.13 0.16 0.17 0.12 0.07 0.09 0.07

4082000-09G 22 0.23 0.19 0.16 0.18 0.17 0.31 0.34 0.34 0.38 0.26 0.19 0.25

4082000-10G 24 0.05 0.07 0.11 0.08 0.17 0.23 0.26 0.18 0.16 0.10 0.05 0.10

4082000-11G 26 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

4082000-12G 23 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

4082000-13G 25 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Total 1.02 1.92 1.03 1.11 1.48 1.90 2.27 2.03 1.63 1.22 1.02 0.99
58 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Table 1–4b. Groundwater withdrawals for average monthly current (2005) conditions in the Plymouth-Carver-Kingston-Duxbury aquifer 

system, southeastern Massachusetts.—Continued

[Code is number shown on fig. 1–1. Data source: MassDEP, Massachusetts Department of Environmental Protection. All units are in millions of gallons 

per day]

Well ID Code Jan Feb March April May June July Aug Sept Oct Nov Dec

Production wells—Continued

Kingston

4145000-01G 27 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

4145000-02G 28 0.09 0.05 0.16 0.08 0.07 0.11 0.05 0.02 0.04 0.03 0.09 0.08

4145000-03G 29 0.29 0.24 0.28 0.43 0.41 0.56 0.40 0.33 0.25 0.31 0.31 0.32

4145000-04G 30 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

4145000-05G 31 0.13 0.01 0.14 0.07 0.19 0.23 0.20 0.23 0.14 0.10 0.11 0.19

4145000-06G 32 0.36 0.52 0.37 0.46 0.43 0.47 0.52 0.42 0.54 0.46 0.35 0.31

4145000-07G 33 0.12 0.15 0.11 0.14 0.24 0.34 0.46 0.38 0.27 0.11 0.14 0.10

4145000-08G 34 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

4145000-09G 35 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Total 0.99 0.97 1.06 1.18 1.34 1.71 1.63 1.38 1.24 1.01 1.00 1.00

Marshfield

4171000-01G 36 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

4171000-02G 37 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

4171000-03G 38 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

4171000-10G 39 0.23 0.24 0.20 0.16 0.20 0.23 0.28 0.28 0.20 0.17 0.18 0.20

4171000-12G 40 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.03 0.04 0.04 0.04 0.03

Total 0.23 0.24 0.20 0.16 0.20 0.23 0.29 0.31 0.24 0.21 0.22 0.23

Pembroke

4231000-03G 74 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Plymouth Water Company

4239045-01G 57 0.08 0.09 0.09 0.09 0.21 0.29 0.35 0.28 0.21 0.13 0.08 0.08

4239045-02G 58 0.02 0.01 0.01 0.04 0.07 0.15 0.21 0.16 0.16 0.07 0.04 0.03

Total 0.1 0.1 0.1 0.13 0.28 0.44 0.56 0.44 0.37 0.2 0.12 0.11

Plymouth Water Department

4239000-01G 41 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

4239000-02G 42 0.17 0.18 0.24 0.20 0.28 0.37 0.43 0.32 0.28 0.26 0.19 0.17

4239000-03G 43 0.03 0.33 0.41 0.41 0.49 0.56 0.60 0.43 0.46 0.34 0.22 0.26

4239000-04G 44 0.34 0.33 0.24 0.29 0.39 0.54 0.59 0.60 0.60 0.51 0.34 0.31

4239000-05G 45 0.56 0.58 0.64 0.65 0.66 0.78 0.94 0.86 0.81 0.67 0.65 0.56

4239000-06G 46 0.45 0.46 0.42 0.40 0.44 0.50 0.62 0.60 0.35 0.51 0.46 0.46

4239000-07G 47 0.48 0.51 0.35 0.45 0.58 0.65 0.62 0.59 0.56 0.46 0.46 0.47

4239000-08G 48 0.22 0.20 0.22 0.26 0.42 0.63 0.74 0.49 0.25 0.18 0.19 0.19

4239000-09G 49 0.66 0.69 0.70 0.72 0.99 0.92 1.09 1.05 0.86 0.77 0.71 0.67

4239000-10G 50 0.70 0.73 0.75 0.80 0.93 1.15 1.16 1.06 0.90 0.79 0.77 0.71

4239000-11G 51 0.14 0.13 0.13 0.13 0.16 0.29 0.53 0.60 0.31 0.19 0.24 0.19
 Steady-State Model 59

Table 1–4b. Groundwater withdrawals for average monthly current (2005) conditions in the Plymouth-Carver-Kingston-Duxbury aquifer 

system, southeastern Massachusetts.—Continued

[Code is number shown on fig. 1–1. Data source: MassDEP, Massachusetts Department of Environmental Protection. All units are in millions of gallons 

per day]

Well ID Code Jan Feb March April May June July Aug Sept Oct Nov Dec

Production wells—Continued

Plymouth Water Department

4239000-12G 52 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

4239000-13G 53 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

4239000-14G 54 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

4239000-15G 55 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

4239000-16G 56 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Total 3.75 4.14 4.10 4.31 5.34 6.39 7.32 6.60 5.38 4.68 4.23 3.99

Pine Hills

4239055-01G 59 0.03 0.03 0.03 0.07 0.19 0.17 0.36 0.28 0.20 0.10 0.05 0.05

Wareham Fire District

4310000-01G 60 0.21 0.19 0.28 0.39 0.29 0.30 0.23 0.08 0.10 0.09 0.07 0.12

4310000-02G 61 0.23 0.22 0.09 0.08 0.33 0.34 0.58 0.53 0.30 0.37 0.48 0.29

4310000-03G 62 0.21 0.46 0.38 0.21 0.27 0.28 0.23 0.42 0.41 0.26 0.04 0.13

4310000-04G 63 0.25 0.11 0.22 0.33 0.37 0.47 0.43 0.28 0.28 0.16 0.25 0.30

4310000-06G 64 0.19 0.18 0.21 0.19 0.17 0.29 0.17 0.05 0.07 0.08 0.05 0.13

4310000-07G 65 0.27 0.18 0.13 0.10 0.18 0.30 0.79 0.91 0.68 0.52 0.41 0.30

4310000-08G 66 0.00 0.02 0.00 0.02 0.03 0.11 0.04 0.07 0.30 0.04 0.13 0.13

4310000-09G 67 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

4310000-10G 68 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Total 1.36 1.36 1.31 1.32 1.64 2.09 2.47 2.34 2.14 1.52 1.43 1.40

Onset Fire District

4310003-01G 69 0.10 0.10 0.11 0.08 0.21 0.25 0.30 0.28 0.19 0.14 0.14 0.12

4310003-02G 70 0.08 0.08 0.04 0.05 0.08 0.15 0.20 0.18 0.10 0.08 0.08 0.08

4310003-03G 71 0.10 0.11 0.11 0.11 0.11 0.10 0.15 0.15 0.13 0.09 0.08 0.06

4310003-04G 72 0.22 0.27 0.25 0.22 0.20 0.25 0.30 0.27 0.23 0.19 0.15 0.18

4310003-05G 73 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Total 0.50 0.56 0.51 0.46 0.60 0.75 0.95 0.88 0.65 0.50 0.45 0.44

Commercial wells

Carver

4158000_01N 75 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Plymouth

3976000_01N 79 0.00 0.00 0.00 0.55 0.55 0.55 0.55 0.55 0.55 0.55 0.00 0.00

8846000_01N 85 0.00 0.00 0.00 0.08 0.13 0.23 0.29 0.26 0.19 0.10 0.00 0.00

Total 0.00 0.00 0.00 0.63 0.68 0.78 0.84 0.81 0.74 0.65 0.00 0.00
60 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Table 1–4b. Groundwater withdrawals for average monthly current (2005) conditions in the Plymouth-Carver-Kingston-Duxbury aquifer 

system, southeastern Massachusetts.—Continued

[Code is number shown on fig. 1–1. Data source: MassDEP, Massachusetts Department of Environmental Protection. All units are in millions of gallons 

per day]

Well ID Code Jan Feb March April May June July Aug Sept Oct Nov Dec

Irrigation wells

Duxbury

3974000_01N 76 0.00 0.00 0.00 0.00 0.03 0.08 0.10 0.08 0.00 0.01 0.00 0.00

Marshfield

4024000_01N 77 0.00 0.00 0.00 0.01 0.03 0.07 0.07 0.06 0.05 0.02 0.00 0.00

4024000_02N 78 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Total 0.00 0.00 0.00 0.01 0.03 0.07 0.07 0.06 0.05 0.02 0.00 0.00

Plymouth

4034000_01N 80 0.00 0.00 0.00 0.01 0.02 0.03 0.03 0.02 0.01 0.00 0.00 0.00

4034000_02N 81 0.00 0.00 0.00 0.01 0.04 0.06 0.04 0.04 0.02 0.00 0.00 0.00

9386000_01N 82 0.00 0.00 0.00 0.01 0.02 0.07 0.08 0.06 0.05 0.02 0.00 0.00

9101000_01N 83 0.00 0.00 0.00 0.01 0.04 0.09 0.10 0.10 0.06 0.03 0.00 0.00

4887000_01N 84 0.00 0.00 0.00 0.00 0.05 0.11 0.13 0.10 0.07 0.02 0.00 0.00

9058000_01N 85 0.00 0.00 0.00 0.02 0.03 0.04 0.05 0.06 0.05 0.05 0.02 0.00

Wavely Oaks 88 0.00 0.00 0.01 0.04 0.09 0.15 0.17 0.18 0.11 0.03 0.00 0.00

Total 0.00 0.00 0.01 0.10 0.29 0.55 0.60 0.56 0.36 0.15 0.02 0.00

Pine Hills

4908000_01N 86 0.00 0.00 0.00 0.08 0.13 0.23 0.29 0.26 0.19 0.10 0.00 0.00
 Steady-State Model 61

Table 1–5. Wastewater-return flow rates from centralized wastewater treatment facilities for current (2005) average monthly conditions, and proposed (2030) average monthly conditions in the Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.[Code is number shown on fig. 1–1. F.D., Fire Department; NA, not applicable]

Layer Row Column Code Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec Average

2005

Discharge on land

Plymouth 1 157 157 W1 0.12 0.08 0.11 0.13 0.22 0.19 0.16 0.16 0.11 0.19 0.15 0.19 0.15Pine Hills 1 196 196 W2 0.07 0.08 0.07 0.07 0.09 0.09 0.09 0.09 0.09 0.10 0.10 0.10 0.09Kingston_1 1 110 96 W3 0.18 0.19 0.20 0.20 0.20 0.19 0.19 0.19 0.18 0.21 0.18 0.18 0.19

Offshore discharge

Plymouth NA NA NA NA 1.32 1.37 1.54 1.63 1.69 1.68 1.67 1.65 1.64 1.70 1.62 1.58 1.59Wareham: Buzzards Bay NA NA NA NA 0.00 0.17 0.16 0.18 0.20 0.21 0.19 0.21 0.19 0.13 0.17 0.16 0.16Wareham: Wareham F.D. NA NA NA NA 0.61 0.51 0.65 0.78 0.72 0.56 0.48 0.42 0.28 0.58 0.60 0.70 0.57Wareham: Onset F.D. NA NA NA NA 0.35 0.39 0.36 0.33 0.41 0.52 0.66 0.60 0.45 0.34 0.31 0.30 0.42

2030

Discharge on land

Plymouth 1 157 157 W1 0.15 0.11 0.14 0.17 0.29 0.26 0.21 0.21 0.15 0.25 0.20 0.25 0.20Pine Hills 1 189 192 W4 0.27 0.29 0.26 0.28 0.34 0.32 0.34 0.35 0.32 0.36 0.37 0.37 0.32Kingston_1 1 110 96 W3 0.37 0.37 0.39 0.40 0.41 0.39 0.37 0.37 0.36 0.41 0.36 0.36 0.38Kingston_21 1 110 104 W5 0.37 0.37 0.39 0.40 0.41 0.39 0.37 0.37 0.36 0.41 0.36 0.36 0.38Buzzards Bay1 1 313 199 W6 0.21 0.20 0.22 0.25 0.25 0.24 0.25 0.23 0.16 0.21 0.20 0.22 0.22

Offshore discharge

Plymouth NA NA NA NA 1.47 1.64 1.74 1.80 1.80 1.79 1.76 1.76 1.82 1.73 1.69 1.70 1.72Wareham: Buzzards Bay 0.17 0.16 0.18 0.20 0.21 0.19 0.21 0.19 0.13 0.17 0.16 0.18 0.18Wareham: Wareham F.D. 0.74 0.93 1.12 1.04 0.80 0.69 0.61 0.40 0.84 0.86 1.01 0.82 0.82Wareham: Onset F.D. 0.56 0.51 0.47 0.59 0.74 0.94 0.87 0.64 0.49 0.44 0.43 0.60 0.61

1Not yet in operation.
62 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

flow system, and whether the wetlands have surface-water 

outflows (Phillip Zarriello, U.S. Geological Survey, written 

commun., 2005). The simulated recharge rate for wetlands was 

lower than that determined for the stratified glacial deposits 

because of the additional evapotranspiration from plants in 

these surface-water features.

The simulated recharge rate for cranberry bogs was 

similar to that of wetlands; however, it was assumed that the 

bogs behave more like ponds than wetlands during the month 

of October when the bogs are typically flooded for harvesting, 

resulting in an additional 2 in/yr of recharge. Therefore, the 

simulated recharge rate for cranberry bogs was 10 in/yr as 

compared to the 8 in/yr specified for wetlands.

An additional source of recharge to the aquifer system is 

the portion of water pumped for public supply that is returned 

to the aquifer through domestic septic systems and centralized 

wastewater treatment facilities. Most of the groundwater 

withdrawn for public supply is returned to the aquifer as 

wastewater return flow. An assumed consumptive-loss rate of 

about 15 percent of total pumping results in 85 percent of the 

total public supply being returned to the aquifer as enhanced 

recharge (by means of the RCH Package) in residential areas 

(figs. 1–4A, B). In the Towns of Plymouth, Kingston, and 

Wareham, treated wastewater also is returned to the aquifer 

as enhanced recharge at centralized wastewater treatment 

facilities (WWTFs) or discharged directly to coastal waters 

(figs. 1–4A, B). In the instances where wastewater is returned 

to the aquifer, discharge volumes at WWTFs were compiled 

from each facility; the difference between the volumes 

discharged to the aquifer or coastal waters at the WWTF 

and the total amount of available wastewater generated from 

public supply was spatially distributed in each water-supply 

district to model cells that contained waterlines without 

corresponding sewer lines to simulate wastewater return flow 

through on-site domestic septic systems (figs. 1–4A, B).

The amount of wastewater returned to the aquifer is 

related to the amount of municipal pumping. Because the 

change in municipal pumping between 1985 and 2005 was 

small, the simulated wastewater return flows for those two 

periods were similar. As a result, the extents of waterlines 

without corresponding sewer lines in the study area were 

assumed to be the same for 1985 as for 2005 (fig. 1–4A).

The largest change in pumping and therefore wastewater 

return flow occurred between current (2005) and future 

(2030) conditions. As a result of the increased water use, the 

simulated extent of waterlines without corresponding sewer 

lines was expanded for 2030 conditions (fig. 1–4B). Projected 

changes for 2030 included (1) a greater sewer-line extent for 

Buzzards Bay Water District, (2) greater waterline extent for 

the Plymouth Water Department, and (3) greater waterline and 

sewer-line extents for the Wareham Fire District (fig. 14B).

Return flows for water supplies not for drinking were 

also addressed in the model simulations. Several simplifying 

assumptions were made to account for evaporative losses 

on golf courses. It was assumed for the purpose of this 

investigation that 50 percent of the water pumped for 

irrigation was returned to the aquifer as recharge. This 

water was accounted for by a reduction of 50 percent in the 

simulated irrigation pumping rate. A more detailed accounting 

of water budgets for individual golf courses would require 

detailed site-specific investigations, which were beyond the 

scope of this regional-scale investigation.

Cranberry operations encompass about 10,000 acres 

(16 mi2), or about 6 percent of the total active model area, 

in the study area. The current annual average water use for 

the bog operations is about 80 Mgal/d (James McLaughlin, 

Massachusetts Department of Environmental Protection, 

written commun., 2006). However, unlike water pumped 

for public supply, most of this water originates from the 

localized manipulation of flow in surface-water bodies such 

as the diversion and impoundment of streamflow, rather than 

from the pumping and exporting of water for use away from 

the pumping source. Groundwater is typically pumped for 

cranberry irrigation adjacent to the bog areas, where the wells 

capture water that otherwise would have discharged naturally 

to the bogs. Therefore, it was assumed for the purpose of 

this regional analysis that the water use related to cranberrybog operations was accounted for in the simulated recharge 

rate described previously. The determination of site-specific 

cranberry-bog-irrigation effects on individual surface-water 

bodies would require detailed local-scale analyses of the 

water-use operations for individual bogs, and thus would be 

beyond the scope of this investigation.

The primary water use in the PCKD aquifer system is 

municipal supply with wastewater returned to the aquifer 

through on-site septic systems (Joseph Cerutti, Massachusetts 

Department of Environmental Protection, oral commun., 

2008). For the purpose of this investigation, it was assumed 

that the water pumped from and returned to the same part of 

the aquifer system resulted in no effect on the flow system, 

and therefore pumping from domestic wells and recharge from 

septic wastewater were not explicitly simulated in the model. 

For water pumped for commercial activities such as sand 

and gravel mining operations, it was assumed that nearly all 

of the water pumped was returned nearby to the aquifer, and 

therefore was not simulated in the model.

Pumping

Pumping wells, which are represented by a specifiedflux boundary condition, were simulated by the Well 

(WEL) Package (McDonald and Harbaugh, 1988). Three 

pumping scenarios were simulated in the steady-state 

models: (1) pumping conditions approximating groundwater 

withdrawals for the years 1980–85; (2) pumping conditions 

approximating current groundwater withdrawals for the 

years 2000–05; and (3) a set of future pumping conditions 

approximating groundwater withdrawals in the year 2030.
 Steady-State Model 63

Plymouth Carver

Rochester

Plympton

Middleborough

Halifax

Pembroke

Duxbury

Kingston

Marshfield

Marion

Wareham

Bourne

Inactive model area

Wastewater treatment

facility

Model cells with year 2005

water lines without sewering—

Color denotes water supplier

EXPLANATION

70°47'30" 70°37'30"

42°00'

41°45'

Base from U.S. Geological Survey and Massachusetts Geographic Information System data sources,

Massachusetts State Plane Coordinate System, Mainland Zone

0 2 MILES

0 2 KILOMETERS

A

Figure 1–4. Distribution of wastewater return-flow areas for (A) current (2005) and (B) proposed (2030) 

pumping and recharge conditions.
64 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Plymouth Carver

Rochester

Plympton

Middleborough

Halifax

Pembroke

Duxbury

Kingston

Marshfield

Marion

Wareham

Bourne

70°47'30" 70°37'30"

42°00'

41°45'

Base from U.S. Geological Survey and Massachusetts Geographic Information System data sources,

Massachusetts State Plane Coordinate System, Mainland Zone

Inactive model area

EXPLANATION

Model cells with year 2030

water lines without sewering—

Color denotes water supplier

Wastewater treatment

facility

0 2 MILES

0 2 KILOMETERS

B

Figure 1–4. Distribution of wastewater return-flow areas for (A) current (2005) and (B) proposed (2030) 

pumping and recharge conditions.—Continued
 Steady-State Model 65

Model Calibration

Model calibration is the process by which modifications 

are made to the initial model-input parameters for the purpose 

of making the model output more closely match observed 

water levels and streamflows (Reilly and Harbaugh, 2004). 

Historically, the calibration process consisted of a trial-anderror approach of adjusting model input parameters, such as 

hydraulic conductivity and recharge, to match field data of 

water levels and streamflows; this method was often timeconsuming, subjective, and inconclusive. Formal methods 

have been developed to estimate parameter values given a 

mathematical model of system processes and a set of relevant 

observations. These methods are referred to as inverse 

modeling or parameter estimation (Hill and Tiedeman, 2007).

MODFLOW-2000 and its suite of supporting programs 

allowed for the incorporation of parameter estimation into 

the modeling analysis. Specifically, the Observation (OBS), 

Sensitivity (SEN), and Parameter Estimation (PES) Processes 

(Hill and others, 2000) were used to incorporate observed 

hydraulic data into the model and to use these observations 

to evaluate model sensitivities and to estimate optimal 

parameter values.

For the purpose of this investigation, parameter 

estimation was used only as a means to refine estimates of 

hydraulic conductivity values of the stratified glacial deposits 

of the PCKD aquifer system. Parameter estimation techniques 

work best for linear models; therefore, a linear model of the 

PCKD aquifer system was created using a fixed transmissivity 

approach. This approach is equivalent to simulating a confined 

aquifer. The layer most affected by this approach is the 

uppermost layer because the model-calculated transmissivity 

is dependent upon the thickness of the layer and the specified 

hydraulic conductivity.

 In the case of the uppermost layer, the layer thickness 

is dependent on the water-table altitude; as the water table 

fluctuates, the transmissivity calculated by the model changes. 

For steady-state simulations in which the recharge rate is 

constant and changes in water-table altitude associated with 

pumping are small relative to the total saturated thickness, 

the fixed transmissivity approach provides a reasonable 

approximation of the unconfined aquifer; however, for 

transient conditions in which changes in recharge and 

pumping result in large changes in water-table altitude 

relative to the total saturated thickness, the transmissivity, and 

therefore model-calculated results, can differ compared to a 

simulation of unconfined conditions.

In this analysis, a water-table altitude was determined 

based on a preliminary model simulation to provide a 

reasonable estimate of the water table that was then specified 

as the top of model layer one. Once the parameter estimation 

analysis was completed, the final estimates of hydraulic 

conductivity were used in simulations of transient, unconfined 

conditions. A comparison of heads and flows between the 

linear (confined) and nonlinear (unconfined) models was 

made to illustrate that the results of model calibration did not 

change between models. Additional information on the theory, 

methodology, and approaches to inverse nonlinear parameter 

estimation methods can be found in Hill (1998) and Hill 

and Tiedeman (2007). A practical application of this method 

in a similar hydrogeologic setting on western Cape Cod is 

presented in Walter and LeBlanc (2008).

The stratified glacial deposits of the PCKD aquifer 

system were partitioned into 26 hydraulic conductivity zones 

based on the surficial geology of the area (fig. 1–3, table 1–3) 

and on an understanding of the geologic processes that 

formed these deposits. Hydraulic conductivity values were 

initially assigned based on the general relation between grain 

size and hydraulic conductivity established for the study 

area (tables 1–1, 1–2) and for similar deposits on Cape Cod 

(Masterson and others, 1997a; Walter and Whealan, 2005). 

Variability in the reported aquifer tests for the glacial deposits 

reflects the heterogeneity of these deposits spatially and 

with depth. Because numerical models synthesize existing 

hydrogeologic information into an internally consistent 

mathematical representation of a real system, the numerical 

representation is a much simpler, generalized representation 

of the real system. Hydraulic properties are represented in the 

model as parameter values assigned to multiple cells within a 

region of the model. By representing the aquifer properties of 

stratified glacial deposits by one or several values, the actual 

hydraulic properties are averaged. In instances where deposits 

are very heterogeneous, such as moraine and ice-contact 

deposits, average properties used to simulate these deposits 

can differ greatly from measured values.

Unlike in trial-and-error model calibration where all 

active model cells are assigned specified values of horizontal 

and vertical hydraulic conductivity (K), in a parameterized 

model these properties are represented as a parameter value 

assigned to specified zones of the aquifer. Although several 

contiguous cells within the domain of a trial-and-error model 

can share a common value of hydraulic conductivity, input is 

required for each individual model cell in that region of the 

model. Conversely, the parameter-estimation method allows 

for a single value to be assigned to multiple cells within a 

region of the model. Not only is the input data more efficiently 

managed, but also the parameters can vary during the 

estimation of optimal parameter values. By using parameters 

to define input properties, zones of the aquifer (representing 

the distribution of lithologic units) are defined, and each zone 

is assigned a common parameter value.

Observation Data

The Observation (OBS) Process was used to incorporate 

observations of heads and flows into the analysis of model 

calibration and uncertainty. This package allows the user to 

specify the values and locations of observations of hydrologic 

conditions within the model domain as well as estimates 

of uncertainty associated with the observations. Sources of 

observation uncertainty, which are additive, could include 

measurement and survey error. For observations representing 
66 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

estimates of steady-state hydrologic conditions, an additional 

component of uncertainty relates to how well the estimates 

represent actual long-term hydrologic conditions. Uncertainty 

is represented as a measure of spread, such as a variance, 

standard deviation, or coefficient of variation.

The analysis of model calibration and uncertainty used 

measurements of water levels and streamflows. Water levels 

were collected from a number of sources. Ideally, water-level 

and streamflow measurements used for model calibration 

were made over a relatively short period (within several days) 

and represent long-term average conditions. Most of the data 

used for the model calibration were collected as part of the 

previous USGS study of the Plymouth-Carver aquifer (Hansen 

and Lapham, 1992). Water-level and pond-level data were 

collected in 1984 at a time when water levels in the long-range 

observation wells PWW–22 and WFW–51 were representative 

of long-term average conditions (figs. 1–5A, B). Pond-level 

data also were supplemented by pond levels reported on 

USGS 1:24,000 topographic maps for the study area; the 

topographic-map data generally appeared to be consistent 

with pond levels measured in 1984 and provided additional 

calibration points.

The previous modeling investigation did not extend 

north of the Jones River (fig. 1–1), and therefore water-level 

measurements were not made in this area. Water-level data 

from wells in previous studies in the Town of Duxbury were 

used in the model calibration, but were given a lower weight 

than those collected as part of the Plymouth-Carver study 

because these wells were not measured during the period of 

the Plymouth-Carver study and because of the unverifiable 

accuracy of the measurements (GEI Consultants Inc., 1990; 

IEP, Inc., 1986; and Whitman and Howard, Inc., 1984).

Streamflows were measured as part of the previous 

investigation at 17 sites in the Plymouth-Carver aquifer in 

June 1986. Also, long-term monitoring data were available 

for the Jones River (station 1105876) for 1966–2005, for 

the Eel River (station 01105876) for 1969–71, and for the 

Weweantic River (station 01105895) for 1964–71. All 

observations of streamflow were included in the analysis of 

model calibration and uncertainty.

The OBS Process allows for the assignment of differing 

weights to the calibration data to account for differing degrees 

of confidence in the accuracy of the data. Streamflows can 

respond quickly to precipitation events and generally are more 

variable over time than are water levels. The use of single 

partial-record streamflow observations may not be reliable 

measures of long-term flows, whereas data from long-term 

monitoring sites likely are more reasonable measures of longterm average flow conditions. As a result, the observations 

from the 3 long-term streamflow-monitoring sites were 

given a greater weight than were observations from the 

17 partial-record sites.

Weights specified as coefficients of variation (CV) for the 

long-term records at the Jones River and north branch of the 

Eel River were assigned values of 0.1, which indicates a high 

degree of confidence in the observations. The partial-record 

sites were assigned coefficients of variation (CV) of 0.2, 

representing a lower degree of confidence in the observations 

from the partial-record sites; a CV of 0.5 was used for the 

Weweantic River because cranberry-bog operations along the 

river resulted in extensive streamflow manipulation and a high 

degree of uncertainty in measured flows.

The use of a CV causes the observation weight to be a 

function of the magnitude of the observation, so that a weight 

of 0.1 indicates that a flow observation is considered to be 

within 10 percent of long-term average values, whereas a CV 

of 0.5 would indicate that the flow measurement is assumed to 

be only within 50 percent of long-term average values.

For the observation wells, the weighting was specified 

as a standard deviation, and a uniform weight was used for all 

water-level observations from the previous Plymouth-Carver 

investigation (Hansen and Lapham, 1992). The weight was 

specified as a standard deviation of 1.0 ft; this value represents 

a high degree of confidence in the water-level observations. 

For wells in the Duxbury area that were not measured as 

part of the previous investigation, weights of 2 and 3 ft 

were assigned to these measurements because they were not 

necessarily collected during a period in which water levels 

were representative of long-term average conditions, and the 

accuracy of these measurements cannot be verified. It should 

be noted that changing the weights of observations would 

affect the parameter solution; however, an analysis of the 

effects of different observation weights on model calibration 

and uncertainty was not included in this investigation.

Sensitivity Analysis

The Sensitivity (SEN) Process in MODFLOW-2000 

was used to calculate the sensitivities of heads and flows to 

each hydraulic conductivity parameter (Hill, 1998). The SEN 

Process produces observation sensitivities of model-calculated 

heads and flows at each observation site specified with 

respect to each parameter. The SEN Process also produces a 

composite scaled sensitivity that is a measure of the overall 

sensitivity of each parameter to all observations in the 

calibration set. The composite sensitivity of a given parameter 

is the square root of the mean squared sum of sensitivities for 

individual observations. The SEN Process yields quantitative 

data that are useful as a diagnostic tool as well as the 

sensitivities necessary to estimate optimal parameter values.

The SEN Process can be used as a diagnostic tool for 

a variety of analyses, including (1) identifying regions of 

the aquifer where additional observations would improve 

calibration, (2) identifying influential observations, or 

(3) evaluating the importance of different parameters for 

calibration at individual observation sites. Prior to the 

implementation of parameter estimation, the SEN Process 

can be used to (1) determine what parameters can adequately 

be estimated from available observations, and (2) identify 

observations that may not warrant inclusion in the parameterestimation process (Hill and others, 2000).
 Steady-State Model 67

8

9

10

11

12

13

14

15

16

17

18

1961 1965 1970 1975 1980 1985 1990 1995 2000 2005

December 1984

YEAR

WATER-LEVEL ALTITUDE, IN FEET ABOVE NGVD 29

A

B

115

116

117

118

119

120

121

122

123

124

125

126

1961 1965 1970 1975 1980 1985 1990 1995 2000 2005

W

December 1984 A

TER-LEVEL ALTIT

UDE, IN FEET

YEAR

Figure 1–5. Long-term water levels for wells (A) PWW–22 and (B) WFW–51 from 1961 through 2005. 

Median water level shown as solid line.
68 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Composite scaled sensitivities were determined for 

heads and flows at observation sites in the calibration set 

to the hydraulic conductivity parameters in the model. The 

results show that simulated heads and flows generally are 

insensitive to vertical hydraulic conductivity parameters 

and are most sensitive to horizontal hydraulic conductivity 

parameters in the upper portions of the outwash, moraine, 

and ice-contact deposits. The results show which hydraulic 

conductivity zones have the greatest effects on simulated 

heads and flows at the observation sites. Prior to implementing 

the Parameter Estimation (PES) Process, this information can 

be used to decide what parameters likely can be estimated and 

therefore should be included in the estimation. The hydraulic 

conductivity zones considered for parameter estimation are 

shown in figure 1–3B.

Parameter Estimation

The PES Process in MODFLOW-2000 uses a modified 

Gauss-Newton optimization method—an iterative form of 

linear regression—to perform a nonlinear regression and 

estimate the optimal parameter values that best fit observed 

data (for example, minimizing the objective function) (Hill, 

1998). This is an iterative method in which parameters are 

repeatedly updated and adjusted until a convergence criterion 

is met, indicating that the nonlinear regression has been 

completed and the objection function has been minimized.

Initially, all hydraulic conductivity parameters, with the 

exception of vertical hydraulic conductivities, were included 

in the parameter-estimation regression; vertical hydraulic 

conductivities were not included because the low composite 

scaled sensitivities indicated that observation data were 

insufficient to estimate these parameters. The final parameters 

chosen for the analysis were based on relative sensitivities and 

the stability of the regression analysis. The final 11 parameters 

chosen for the regression analysis represented the major 

water-bearing zones in the PCKD aquifer system (fig. 1–6). A 

method known as “Prior Information” was used to constrain 

the parameters representing the outwash deposits in order 

to maintain the general fining-with-depth grain-size trend 

observed in many of the lithologic logs in the study area.

Starting parameter values were based on previous 

estimates of hydraulic conductivity values for glacial 

deposits in similar hydrogeologic settings. The GaussNewton procedure adjusts parameters to minimize the 

objective function, and the resulting parameter values 

represent a statistical best fit to the observation data. Final 

parameter values for hydraulic conductivity produced from 

the regression analysis are shown in table 1–3. These values 

for outwash, moraine, and ice-contact deposits generally fall 

within reasonable ranges reported in previous studies for these 

deposits. Hydraulic conductivity values for moraine and icecontact deposits are typically lower than those reported from 

aquifer tests for these materials because of the bias in reported 

data for water supply, so that only values from locations 

where aquifer tests were conducted after preliminary drilling 

exploration indicated the potential for high yield based on an 

assessment of the lithology. Given the highly variable grainsize distribution associated with sediment deposited directly 

by ice, conductivity values required to represent the average 

properties of these materials were lower than those reported in 

aquifer tests.

A comparison was made of the degree of fit between 

simulated and measured water levels and flows (locations 

shown on fig. 1–7) between the linear model used for 

parameter estimation and the unconfined model used for 

the modeling analysis to assess differences between the 

two models and to determine if the unconfined model 

was reasonably calibrated and suitable for predictions of 

hydrologic conditions. A comparison of the match between 

model-calculated water levels and observed water levels for 

both models indicates that both models reasonably match the 

observed water-level data (table 1–6).

The comparison between model-calculated and observed 

water levels included a determination of the mean of the 

residuals (the differences between measured and modelcalculated water levels) and the absolute mean of the residuals. 

Ideally, the residuals will be randomly distributed and close 

to zero, indicating no bias in the results, and the mean of the 

absolute residuals will be less than 5 percent of the total range 

in head for the water-level measurements used for model 

calibration (Anderson and Woessner, 1992). The absolute 

mean of the residuals for the linear and the unconfined models 

were 2.35 ft and 2.24 ft, respectively. These values correspond 

to about 2 percent of the total (125-ft) range in water levels 

for the PCKD aquifer system and indicate that the modelcalculated water levels were in reasonable agreement with the 

observed data.

Figure 1–6. Composite sensitivities for steady-state hydraulic 

conductivity parameters for the Plymouth-Carver-KingstonDuxbury aquifer system, southeastern Massachusetts. Model 

input parameter codes are shown on figure 1–2. Zone 9L is the 

lower portion of 9, the Wareham Pitted Plain.

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

9 1 7 4 10 18 9 L 20 2 6 11

HYDRAULIC CONDUCTIVITY PARAMETER ZONES

COMPOSITE SENSITIVITY, DIMENSIONLESS
 Steady-State Model 69

Figure 1–7. Observation wells and streamflow sites used for calibration of the groundwater-flow model of the 

Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.

70°47'30" 70°37'30"

42°00'

41°45'

Inactive model area

EXPLANATION

Pond-calibration point

Well-calibration point

Stream-calibration point—

Stream identifiers listed in

table 1–7

0 2 MILES

0 2 KILOMETERS

Jones River

Town Brook

Eel River

Beaver Brook

Red Brook

Agawam River

Wankinco River

Indian Brook

15

16

10 3

4 5

2

11

6

9

8

7

12

14

1 18 19

14

13

South River

Reservoir

Silver Lake

Pine Lake

Indian Creek Pond

Smelt Pond

Muddy Pond

Muddy

Pond

Johns Pond

Vaughn Pond

Little Muddy Pond

Triangle Pond

Billington Sea

Cooks Pond Briggs Reservoir

Fresh Pond

Bartlett Pond

Island Pond

Gallows Pond

Long Pond

Bloody Pond

Hodges Pond

Little Herring Pond

Great Herring Pond

Island

Pond

Horse Pond

Goat Pasture Pond

Savery Pond

Halfway Pond

Fawn Pond

Little Duck Pond

Little Rocky Pond

Big Sandy Pond

Glen

Charlie

Pond

Spectacle Pond

White

Island

Pond

Little Long Pond

Lilly Pond

Shallow

Pond

Beaver Pond

Tihonet Pond

Fearing Pond

East Head Pond

Golden Field Pond

Sampson

Pond

Pond near Huckleberry

Unnamed-2

Indian Pond

Unnamed Pond

Big West

Pond

Micajah

Pond

S. Triangle Pond

Great South Pond

Curlew Pond

Widgeon Pond

Island Pond

Hoyts Pond

Crooked Pond

College Pond

Wright Reservoir

Rocky Pond

20

D4W-79

W&H-35

GEI-P2

GEI-P1 GEI-P5

PEW-217

KGW-92

CDW-119

CDW-120

CDW-121

PWW-517

PWW-22

PWW-505

PWW-502

PWW-503

PWW-261

PWW-215

PWW-504

PWW-506 PWW-242

PWW-501

PWW-241

PWW-285

PWW-313

PWW-243 PWW-245

PWW-244

PWW-240

PWW-414

PWW-518

PWW-253

PWW-251

PWW-519

PWW-368 BHW-293

PWW-418

PWW-319

PWW-513

WFW-297

WFW-51

WFW-295 WFW-245

PWW-238

PWW-236

PWW-430

PWW-431

PWW-415

PWW-511

PWW-510

PWW-512

PWW-369

CDW-85

CDW-86

CDW-122 CDW-125 CDW-201

CDW-99

CDW-123

PWW-237

PWW-509

PWW-379

PWW-305

PWW-507

PWW-416

PWW-315

PWW-306

PWW-516

PWW-413

Base from U.S. Geological Survey and Massachusetts Geographic Information System data sources,

Massachusetts State Plane Coordinate System, Mainland Zone
70 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Table 1–6. Comparison between measured and model-calculated water levels for the confined and unconfined groundwater-flow 

models of the Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.—Continued

[Sites are shown on fig.1–7. NGVD 29, National Geodetic Vertical Datum of 1929. All units are feet]

Site

identifier

Measured 

water-level 

altitudes, 

in feet above 

NGVD 29

Modelcalculated

(linear 

model)

Modelcalculated

(unconfined 

model)

Linear 

minus 

observed

Unconfined

model 

minus 

observed

Residual 

(difference between 

linear minus observed 

and unconfined 

minus observed)

Observation well

BHW-293 25.22 28.78 27.93 -3.56 -2.71 -0.85

CDW-85 62.84 57.82 57.94 5.02 4.90 0.12

CDW-86 64.80 60.98 61.09 3.82 3.71 0.12

CDW-99 98.92 99.81 100.07 -0.89 -1.15 0.26

CDW-119 114.70 114.74 114.42 -0.04 0.28 -0.32

CDW-120 92.60 98.63 98.77 -6.03 -6.17 0.14

CDW-121 103.23 103.09 103.12 0.14 0.11 0.03

CDW-122 76.10 77.37 77.46 -1.27 -1.36 0.09

CDW-123 83.97 85.47 85.19 -1.50 -1.22 -0.28

CDW-125 79.66 84.38 84.85 -4.72 -5.19 0.46

CDW-201 78.14 77.24 77.38 0.90 0.76 0.14

D4W-79 47.00 51.40 51.80 -4.40 -4.80 0.40

PWW-22 120.98 120.00 119.13 0.98 1.85 -0.88

PWW-215 81.90 84.12 83.69 -2.22 -1.79 -0.43

PWW-236 55.71 55.98 56.29 -0.27 -0.58 0.31

PWW-237 51.09 48.45 48.58 2.64 2.51 0.12

PWW-238 55.51 52.08 52.24 3.43 3.27 0.17

PWW-240 71.78 69.31 68.77 2.47 3.01 -0.54

PWW-241 67.73 62.53 62.00 5.20 5.73 -0.53

PWW-242 72.59 69.97 69.58 2.62 3.01 -0.39

PWW-243 79.20 81.35 80.93 -2.15 -1.73 -0.42

PWW-244 87.20 81.06 80.65 6.14 6.55 -0.40

PWW-245 57.79 56.06 55.24 1.73 2.55 -0.82

PWW-251 43.60 44.59 44.68 -0.99 -1.08 0.09

PWW-253 46.59 47.95 48.07 -1.36 -1.48 0.12

PWW-261 74.05 74.98 73.15 -0.93 0.90 -1.83

PWW-285 36.60 48.71 48.62 -12.11 -12.02 -0.09

PWW-305 102.07 100.84 100.55 1.23 1.52 -0.29

PWW-306 101.66 100.07 99.82 1.59 1.84 -0.25

PWW-313 38.59 48.37 48.40 -9.78 -9.81 0.03

PWW-315 102.71 102.98 102.80 -0.27 -0.09 -0.18

PWW-319 21.04 23.59 23.88 -2.55 -2.84 0.29

PWW-368 28.98 31.37 31.08 -2.39 -2.10 -0.29

PWW-369 56.02 56.20 56.39 -0.18 -0.37 0.20

PWW-379 82.05 84.89 84.53 -2.84 -2.48 -0.36
 Steady-State Model 71

Table 1–6. Comparison between measured and model-calculated water levels for the confined and unconfined groundwater-flow 

models of the Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.—Continued

[Sites are shown on fig.1–7. NGVD 29, National Geodetic Vertical Datum of 1929. All units are feet]

Site

identifier

Measured 

water-level 

altitudes, 

in feet above 

NGVD 29

Modelcalculated

(linear 

model)

Modelcalculated

(unconfined 

model)

Linear 

minus 

observed

Unconfined

model 

minus 

observed

Residual 

(difference between 

linear minus observed 

and unconfined 

minus observed)

Observation well—Continued

PWW-413 123.73 126.37 126.10 -2.64 -2.37 -0.27

PWW-414 64.07 65.95 65.56 -1.88 -1.49 -0.39

PWW-415 91.34 87.87 88.04 3.47 3.30 0.18

PWW-416 108.18 108.83 108.20 -0.65 -0.02 -0.63

PWW-418 22.16 25.83 26.06 -3.67 -3.90 0.23

PWW-430 61.56 61.80 62.15 -0.24 -0.59 0.35

PWW-431 75.15 75.53 75.75 -0.38 -0.60 0.21

PWW-501 5.88 4.81 5.14 1.07 0.74 0.33

PWW-502 81.63 87.46 86.40 -5.83 -4.77 -1.05

PWW-503 77.41 84.34 81.36 -6.93 -3.95 -2.98

PWW-504 99.03 98.21 97.84 0.82 1.19 -0.37

PWW-505 118.30 115.86 115.56 2.44 2.74 -0.30

PWW-506 98.88 99.02 98.66 -0.14 0.22 -0.36

PWW-507 112.95 112.44 111.67 0.51 1.28 -0.77

PWW-509 70.45 70.55 70.18 -0.10 0.27 -0.37

PWW-510 95.00 91.05 90.70 3.95 4.30 -0.35

PWW-511 101.01 95.23 95.34 5.78 5.67 0.12

PWW-512 69.78 64.21 65.09 5.57 4.69 0.88

PWW-513 47.75 47.91 48.32 -0.16 -0.57 0.41

PWW-516 77.03 79.96 79.52 -2.93 -2.49 -0.44

PWW-517 123.73 123.70 123.66 0.03 0.07 -0.04

PWW-518 52.39 53.98 53.76 -1.59 -1.37 -0.21

PWW-519 46.61 42.87 42.77 3.74 3.84 -0.10

WFW-245 46.21 39.84 39.92 6.37 6.29 0.08

WFW-295 45.81 43.59 43.25 2.22 2.56 -0.33

WFW-297 39.49 37.88 38.31 1.61 1.18 0.43

PEW-217 101.00 91.73 92.09 9.27 8.91 0.36

KGW-92 59.00 58.12 57.97 0.88 1.03 -0.15

W&H-35 35.47 35.58 35.38 -0.11 0.09 -0.20

GEI-P-1 27.03 31.41 32.31 -4.38 -5.28 0.91

GEI-P-2 28.40 26.53 27.06 1.87 1.34 0.53

GEI-P-5 25.85 24.32 25.16 1.53 0.69 0.84
72 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Table 1–6. Comparison between measured and model-calculated water levels for the confined and unconfined groundwater-flow 

models of the Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.—Continued

[NGVD 29, National Geodetic Vertical Datum of 1929. All units are in feet]

Site

identifier

Measured 

water-level 

altitudes, 

in feet above 

NGVD 29

Modelcalculated

(linear 

model)

Modelcalculated

(unconfined 

model)

Linear 

minus observed

Unconfined

model 

minus 

observed

Residual 

(difference between 

linear minus observed 

and unconfined 

minus observed)

Pond

Bartlett_Pond 6.53 6.24 7.42 0.29 -0.89 1.18

Fresh_Pond 14.24 14.06 20.22 0.18 -5.98 6.15

Beaver_Dam_Pond 20.66 27.55 22.07 -6.89 -1.41 -5.48

Shallow_Pond 31.19 32.96 32.94 -1.77 -1.75 -0.02

Little_Muddy_Pond 108.70 111.57 110.25 -2.87 -1.55 -1.32

Briggs_Reservoir 87.41 85.61 86.33 1.80 1.08 0.72

Cooks_Pond 87.08 85.42 85.51 1.66 1.57 0.09

Lilly_Pond 11.09 19.03 19.16 -7.94 -8.07 0.13

Micajah_Pond 108.20 109.33 109.57 -1.13 -1.37 0.24

Island_Pond 88.79 90.94 90.19 -2.15 -1.40 -0.75

Unnamed_Pond-1 122.44 119.72 119.96 2.72 2.48 0.23

Crooked_Pond 95.78 98.06 97.67 -2.28 -1.89 -0.39

Savery_Pond 26.08 28.11 28.20 -2.03 -2.12 0.09

Widgeon_Pond 108.17 111.17 110.44 -3.00 -2.27 -0.73

Curlew_Pond 108.00 112.30 111.32 -4.30 -3.32 -0.98

Rocky_Pond 107.52 109.90 108.49 -2.38 -0.97 -1.41

College_Pond 99.00 100.49 100.59 -1.49 -1.59 0.11

Hodges_Pond 33.52 35.11 35.20 -1.59 -1.68 0.09

Vaughn_Pond 101.81 101.03 101.50 0.78 0.31 0.47

Little_Duck_Pond 47.07 47.72 47.84 -0.65 -0.77 0.12

Little_Rocky_Pond 46.87 43.47 43.63 3.40 3.24 0.16

Unnamed_Pond-2 57.00 55.32 56.69 1.68 0.31 1.37

Horse_Pond 40.64 36.23 35.70 4.41 4.94 -0.53

Golden_Field_Pond 74.04 67.75 68.61 6.29 5.43 0.86

Goat_Pasture_Pond 20.76 22.62 21.56 -1.86 -0.80 -1.07

Pond_near_Huckleberry 72.91 70.13 69.22 2.78 3.69 -0.91

Great_Herring_Pond1 34.00 34.06 33.33 -0.06 0.67 -0.73

Big_Sandy_Pond1 48.00 47.53 47.95 0.47 0.05 0.42

Island_Pond1 39.00 38.91 38.74 0.09 0.26 -0.18

White_Island_Pond1 48.00 47.47 48.20 0.53 -0.20 0.73

Little_Herring_Pond1 36.00 37.00 37.28 -1.00 -1.28 0.28
 Steady-State Model 73

Table 1–6. Comparison between measured and model-calculated water levels for the confined and unconfined groundwater-flow 

models of the Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.—Continued

[NGVD 29, National Geodetic Vertical Datum of 1929. All units are in feet]

Site

identifier

Measured 

water-level 

altitudes, 

in feet above 

NGVD 29

Modelcalculated

(linear 

model)

Modelcalculated

(unconfined 

model)

Linear 

minus observed

Unconfined

model 

minus 

observed

Residual 

(difference between 

linear minus observed 

and unconfined 

minus observed)

Pond—Continued

Fawn_Pond1 59.00 58.98 59.00 0.02 0.00 0.01

Fearing_Pond1 83.00 76.68 76.93 6.32 6.07 0.26

Glen_Charlie_Pond1 35.00 33.32 33.59 1.68 1.41 0.27

East_Head_Pond1 89.00 89.20 89.22 -0.20 -0.22 0.03

Halfway_Pond1 63.00 62.58 62.89 0.42 0.11 0.31

Long_Pond1 68.00 70.19 69.78 -2.19 -1.78 -0.41

Gallows_Pond1 69.00 70.33 70.09 -1.33 -1.09 -0.24

Little_Long_Pond1 70.00 70.97 70.66 -0.97 -0.66 -0.31

Bloody_Pond1 58.00 60.17 59.81 -2.17 -1.81 -0.37

Sampson_Pond1 76.00 76.36 76.65 -0.36 -0.65 0.28

Island_Pond1 51.00 53.78 52.81 -2.78 -1.81 -0.97

Great_South_Pond1 100.00 98.80 98.42 1.20 1.58 -0.38

Big_West_Pond1 117.00 116.65 116.30 0.35 0.70 -0.35

Hoyts_Pond1 96.00 98.29 98.32 -2.29 -2.32 0.03

South_Triangle_Pond1 90.00 91.95 91.27 -1.95 -1.27 -0.68

Billington Sea 81.00 82.56 82.75 -1.56 -1.75 0.19

Triangle_Pond1 105.00 107.00 105.14 -2.00 -0.14 -1.86

Smelt_Pond1 107.00 105.46 103.65 1.54 3.35 -1.81

Muddy_Pond1 125.00 124.53 124.38 0.47 0.62 -0.15

Indian_Pond1 123.00 122.89 123.05 0.11 -0.05 0.16

Muddy_Pond1 95.00 94.60 94.62 0.40 0.38 0.02

Johns_Pond1 111.00 105.82 107.16 5.18 3.84 1.34

Tihonet_Pond1 35.00 36.82 36.90 -1.82 -1.90 0.07

Spectacle_Pond1 15.00 16.21 16.25 -1.21 -1.25 0.05

Silver_Lake1 47.00 46.63 47.47 0.37 -0.47 0.84

Indian_Creek_Pond1 36.00 33.26 33.26 2.74 2.74 0.00

Wright_Reservoir1 25.00 24.72 25.37 0.28 -0.37 0.65

South_River_Reservoir1 51.00 51.09 51.12 -0.09 -0.12 0.03

Pine_Lake1 75.00 70.69 71.22 4.31 3.78 0.53

1 Pond levels obtained from U.S. Geological Survey 1:24,000 topographic maps.
74 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

The means of the residuals (observed minus simulated) 

for the linear and unconfined models were -0.12 and -0.05 ft, 

respectively, indicating that both model residuals have a 

near-random distribution around zero. A comparison of 

model-calculated and observed water levels and of the 

residual water levels as a function of observed water levels 

for the unconfined-model simulation illustrates that the model 

provides a reasonable match to observed water levels and 

that the residuals in this simulation are generally unbiased 

throughout the range of observed water levels in the aquifer 

system (figs. 1–8A, B).

A comparison of model-calculated and measured 

streamflows for both models indicates that the modelcalculated streamflows are in good agreement with long-term 

average base-flow conditions at the USGS stream-gaging 

station on the Jones River (station 01105870) in Kingston and 

are in good agreement with streamflows measured at partialrecord sites in June 1986 when water levels were at long-term 

average conditions (table 1–7).

Transient Model

Whereas steady-state models represent hydrologic 

conditions under constant hydraulic stresses, transient models 

incorporate time-varying stresses and can be used to evaluate 

the effects of temporal changes in recharge and pumping 

on the hydrologic system. Transient models use the same 

model inputs to represent aquifer characteristics—including 

hydraulic-conductivity and aquifer geometries—as do 

steady-state models, but require additional information. These 

additional input parameters include confined and unconfined 

storage properties of the aquifer sediments, changing recharge 

and pumping inputs over the time scale of interest, and, in 

some cases, temporal adjustments to simulated hydrologic 

boundaries.

Discretization of Time

Hydrologic stresses were simulated for monthly 

conditions for several periods. These periods included 

predevelopment; 1985, the period simulated in the previous 

USGS investigation of the Plymouth-Carver area (Hansen and 

Lapham, 1992); 2005, representative of current conditions; 

and 2030, representative of future conditions. In transient 

models, time is subdivided, or discretized, into stress periods 

and time steps. Stress periods refer to periods of time in which 

specified model stresses, such as pumping and recharge, are 

constant; changing stresses over periods of time are simulated 

by using sequential stress periods with changing stresses from 

one stress period to the next. Stress periods are further divided 

into time steps, which are units of time for which water levels 

and flows are calculated.

In the transient models representing average monthly 

variations in hydrologic stresses, conditions over an average 

year were simulated by dividing the annual hydrologic cycle 

into 12 monthly stress periods representing average pumping 

and recharge during each month. Each stress period consisted 

of 14 time steps to increase model stability.

A total of 61 stress periods were simulated for each 

simulation period. The first stress period in each simulation 

was specified as steady state followed by 5 years of monthly 

stress periods (or 60 stress periods). The water levels 

produced in the initial steady-state stress period were used 

as initial conditions for each transient simulation. The 

5 years of monthly stress periods were simulated to ensure 

that enough time had elapsed in the simulation to achieve 

a state of dynamic equilibrium, defined as a condition in 

which simulated water levels and flows do not change year 

to year for a given stress period and time step. The final year 

of simulated time (12 stress periods) was used to represent 

hydrologic conditions over an average year.

Storage Characteristics

The storage characteristics of the aquifer, which quantify 

the volume of water the aquifer releases for a given decline in 

head, consists of two components, specific yield and specific 

storage. Specific yield, which is a function of sediment 

porosity and moisture-retention characteristics, is unconfined 

storage and represents gravity-driven dewatering of the aquifer 

at a declining water table. Specific yields cannot exceed 

sediment porosity, which is about 0.39 in stratified glacial 

deposits in southeastern New England (Garabedian and others, 

1991). Specific storage is a function of the compressibility of 

the aquifer and, to a much lesser extent, of water; a measure of 

confined storage, specific storage represents a release of water 

because of compression of the aquifer. In unconfined aquifers, 

such as the PCKD system, specific yield typically is orders 

of magnitude larger than specific storage and is the most 

important storage property.

Specific yields for glacial sediments from southeastern 

New England typically range from 0.2 to 0.3, whereas specific 

storage typically is less than 0.00001 ft-1; most numerical 

models of the region use specific yields between 0.24 and 0.30 

(Barlow and Dickerman, 2001; Moench, 2001; Masterson and 

Barlow, 1997; Masterson and others, 1998). A specific yield 

of 0.26 and a specific storage of 1.0 x 10-5 ft-1 were used in the 

numerical models to simulate storage in the aquifer sediments; 

these values are consistent with storage values of 0.26 and 

1.3 x 10-5 ft-1 reported by Moench (2001) for Cape Cod and are 

within the range of reasonable values.

Ponds have porosities of 1 and therefore have a high 

unconfined storage and low confined storage; confined 

storage in ponds is controlled only by the compressibility of 

water, which is small. The specific yield and specific storage 

of simulated ponds were specified as 1.0 and 1.0 x 10-9 ft-1, 

respectively. Flooded wetlands and cranberry bogs were 

assumed to behave similarly to ponds in the upper layer and 

therefore were assigned a specific yield value of 1.0.
 Transient Model 75

0

10

20

30

40

50

60

70

80

90

100

110

120

130

0 10 20 30 40 50 60 70 80 90 100 110 120 130

M

ODEL-CALCULA

TED W

A

TER LEVELS, IN FEET

OBSERVED WATER LEVELS, IN FEET

Line of perfect agreement

-15

-10

-5

0

5

10

15

0 10 20 30 40 50 60 70 80 90 100 110 120 130

OBSERVED WATER LEVELS, IN FEET

Line of perfect agreement

RESIDU

AL, IN FEET

A

B

Figure 1–8. Comparison of (A) model-calculated and observed water levels and (B) residual (observed 

minus model-calculated) water levels as a function of observed water levels, Plymouth-Carver-KingstonDuxbury aquifer system, southeastern Massachusetts.
76 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Table 1–7. Comparison between model-calculated and measured streamflows for the confined and unconfined groundwater-flow 

models of the Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.

[Map code shown on figure 1–7. All units are in cubic feet per second.]

Stream-site name Map 

code

Measured 

streamflows, 

in cubic feet 

per second

Modelcalculated 

(linear 

model)

Modelcalculated 

(unconfined 

model)

Linear 

model minus 

measured 

streamflow

Unconfined 

model minus 

measured 

streamflow

Residual

(difference)

Agawam River 1 33.4 39.0 39.1 5.6 5.7 -0.1

Beaver Dam Brook 2 11.8 14.3 12.2 2.5 0.4 2.1

Eel River: Mouth 3 23.2 24.6 25.0 1.4 1.8 -0.4

Eel River: North Branch 4 14.9 13.8 13.4 -1.1 -1.5 0.4

Eel River: South Branch 5 7.9 5.5 5.6 -2.4 -2.3 -0.1

Halfway Pond: Outlet 6 12.0 15.6 14.9 3.6 2.9 0.7

Herring River: A 7 6.2 2.9 0 -3.3 -6.2 2.9

Herring River: B 8 7.2 6.3 1.6 -0.9 -5.6 4.7

Herring River: C 9 10.0 1.2 5.2 -8.8 -4.8 -4.0

Holmes Brook 10 1.1 2.0 2.7 0.9 1.6 -0.7

Indian Brook 11 1.2 0.7 1.5 -0.5 0.3 -0.8

Red Brook 12 6.1 5.3 5.8 -0.8 -0.3 -0.5

Savery: Cranberry Bog 13 0.4 1.2 0.7 0.8 0.3 0.5

Savery Pond: Outlet 14 0.4 0.7 0.6 0.3 0.2 0.1

Stone Pond: Outlet 15 1.4 3.5 3.7 2.1 2.3 -0.2

Town Brook 16 15.0 16.0 15.8 1.0 0.8 0.2

Union Pond: Outlet 17 0.5 0.0 0.0 -0.5 -0.5 -0.0

Wankinco River 18 18.6 21.5 22.3 2.9 3.7 -0.9

Weweantic River 19 70.0 59.2 68.0 -10.8 -2.0 -8.8

Jones River 20 31.9 29.8 33.4 -2.1 1.5 -3.6
 Transient Model 77

Recharge

The record of precipitation measured over a period of 

47 years (1960–2006) at the East Wareham, MA, weather 

station was used to estimate monthly and annual average 

recharge rates for the region. Measured precipitation at East 

Wareham has varied from a high of 74 in/yr in 1972 to a low 

of 28 in/yr in 1965. Annual and monthly average recharge 

rates were estimated by applying the methods described 

previously in the steady-state-model discussion.

Recharge onto stratified glacial deposits, ponds, wetlands, 

and cranberry bogs varied monthly. Average estimated 

monthly recharge rates onto stratified glacial deposits varied 

from 0.1 in. in July to 4.3 in. in March (fig. 1–9). Recharge, as 

a percentage of precipitation, ranged from about 80 percent in 

March to about 5 percent in July.

Although ponds, wetlands, and cranberry bogs are areas 

of net recharge under steady-state conditions, they become net 

sinks when surface evaporation and plant transpiration exceed 

precipitation. Potential evapotranspiration (PET) rates were 

estimated from long-term atmospheric data for the Providence, 

R.I., area by using the Jensen-Haise Equation (Jensen and 

Haise, 1963), which is based on measurements of temperature 

and integrated solar radiation. Monthly recharge rates onto 

pond surfaces were determined by taking the differences 

between measured precipitation and average monthly PET 

estimates. The estimated recharge rates onto pond surfaces 

ranged from a net loss in July of 2.8 in. to a net gain in 

December of 4.4 in. (fig. 1–9). There were a total of 25.7 in. of 

recharge onto pond surfaces from September through May and 

a total water loss of 5.7 in. from June through August, yielding 

a net annual recharge of 20.0 in.

Wetlands are areas of net recharge during the winter 

months and areas of net water loss during the growing season, 

resulting in net recharge of about 8 in/yr (Hemond, 1980). 

Wetland recharge rates range from a net loss of about 8 in. 

in July when wetland plant growth is highest to a net gain of 

about 4.6 in. in December (fig. 1–9). There were a total of 

21.7 in. of recharge onto wetlands from November to May 

and a total water loss of 13.7 in. from June through October, 

yielding a net annual recharge of 8.0 in.

Cranberry bogs had monthly recharge rates similar to 

wetlands except for the month of October, when the bogs are 

typically flooded for harvesting. During the month of October, 

it was assumed the recharge rate for cranberry bogs was 2 in. 

(similar to ponds), rather than the net loss of 0.1 in. assumed 

for wetlands for October. The total recharge for cranberry bogs 

was 10 in/yr.

Recharge rates were also determined for the 5-year 

periods that represent the droughts of the mid–1960s and 

early 1980s. These drought conditions were then simulated 

with current (2005) and future (2030) pumping conditions to 

determine the potential effects of these drought conditions on 

the aquifer system for current and future pumping conditions. 

A comparison of the changes in measured water levels relative 

to long-term average conditions at monitoring wells PWW–22, 

WFW–51, and DJW–79 for the drought conditions of the 

mid–1960s and early 1980s was used to determine how well 

the model matched observed field data for these drought 

conditions. Although current (2005) pumping rates were 

used in the simulation rather than the actual pumping rates 

of the mid–1960s and early 1980s, this comparison indicated 

that the simulated changes in recharge appeared to provide a 

reasonable representation of the drought conditions (fig. 1–10).

Although there are uncertainties in the recharge 

estimates, the method does incorporate major elements 

of the precipitation record for the study area, including 

major droughts in the mid-1960s and early 1980s and is a 

good approximation of general recharge values and trends. 

Therefore, the analysis does effectively illustrate concepts 

related to the effects of transient recharge on hydrologic 

conditions in the aquifer. The results of the transient-modeling 

analysis are intended to illustrate the general effects of 

time-varying recharge and pumping on the water levels and 

streamflows and how these effects may vary within different 

areas of the aquifer. The simulation results for a particular 

year should not be considered accurate estimates of hydrologic 

conditions for that specific year.

Pumping

Pumping increases because the demand for water for 

both public supply and irrigation increases during the summer 

months. Transient simulations incorporate temporal changes 

in pumping and simulate the effects of these changing stresses 

on the hydrologic system. Pumping records and demand 

projections used to estimate average steady-state pumping 

rates were used to estimate average monthly pumping rates for 

current (2005) and future (2030) conditions (table 1–4a–c). 

Monthly pumping data were compiled from MassDEP Annual 

Statistics Reports for each of the water suppliers in the study 

area. Pumping rates for MassDEP Registered and Permitted 

irrigation and commercial water uses were provided by the 

MassDEP (Joseph Cerutti, Massachusetts Department of 

Environmental Protection, written commun., 2007). The 

pumping rates for current conditions were determined from the 

average pumping rates for the 2000–05 period (table 1–4a).

Future (2030) monthly pumping rates were estimated 

for existing wells from the ratios of average current (2005) 

pumping for each month to total annual pumping. For new 

wells, future monthly pumping rates were estimated from the 

ratios of townwide pumping for each month to total annual 

pumping planned for the town (Joseph Cerutti, Massachusetts 

Department of Environmental Protection, written commun., 

2007) (table 1–4c).

Wastewater return flow was estimated for each month 

on the basis of the total monthly pumping rates for each 

town. Wastewater was returned to the aquifer as enhanced 

recharge within residential areas (fig. 1–4A, B). In towns with 

wastewater disposal facilities, the fraction of total generated 

wastewater that is currently discharged at the facilities and 
78 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Figure 1–9. Estimated monthly recharge to aquifer sediments, ponds, wetlands, and cranberry bogs in the 

Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.

-10

-8

-6

-4

-2

0

2

4

6

JAN FEB MAR APR MAY JUNE JULY AUG SEPT OCT NOV DEC

MONTH

RECHARGE, IN INCHES

 Aquifer recharge

 Pond recharge

 Wetland recharge

 Cranberry-bog recharge
 Transient Model 79

Figure 1–10. Comparison of model-calculated and observed water 

levels for simulated drought recharge conditions for the periods 1963–67 

and 1979–83 with current (2005) pumping conditions for three monitoring 

sites (A) PWW–22, (B) WFW–51, and (C) D4W–79.

J M M

YEAR 1 YEAR 2 YEAR 3 YEAR 4 YEAR 5

J S N J M M J S N J M M J S N J M M J S N J M M J S N

CHANGE IN WATER-LEVEL ALTITUDE FROM AVERAGE,  IN FEET -5

-4

-3

-2

-1

0

1

2

3

J M M

YEAR 1 YEAR 2 YEAR 3 YEAR 4 YEAR 5

J S N J M M J S N J M M J S N J M M J S N J M M J S N

CHANGE IN WATER-LEVEL ALTITUDE FROM AVERAGE,  IN FEET -5

-4

-3

-2

-1

0

1

2

3

J M M

YEAR 1 YEAR 2 YEAR 3 YEAR 4 YEAR 5

J S N J M M J S N J M M J S N J M M J S N J M M J S N

CHANGE IN WATER-LEVEL ALTITUDE FROM AVERAGE,  IN FEET -5

-4

-3

-2

-1

0

1

2

3

Measured: 1979−83 

Model-calculated: 1963−67

Model-calculated: 1979−83

Measured: 1963−67

A

B

C

Measured: 1979−83 

Model-calculated: 1963−67

Model-calculated: 1979−83

Measured: 1963−67

Measured: 1979−83 

Model-calculated: 1979−83
80 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

the estimated monthly pumping were used to determine the 

monthly estimated discharge at the plants; the remaining 

wastewater was discharged as septic-system return flow in 

residential areas. The same approach was used to estimate 

monthly wastewater return flow for future pumping.

Comparison of Water Levels and Streamflows

Simulated changes in monthly water levels and 

streamflows were compared to average monthly measurements 

in long-term monitoring wells and at streamflow sites to assess 

the capacity of the model to predict the effects of changing 

stresses on the hydrologic system. A comparison was made 

of the model-calculated average monthly water levels to the 

average monthly measured water levels for the three long-term 

observation wells that had been measured monthly since 1960 

(fig. 1–11).

Water levels were plotted as a departure from the average 

values for the period of record to compare the monthly 

fluctuations in water levels between measured and modelcalculated values. Because the model-calculated values plot 

between the average highest and average lowest monthly 

measured values, they generally are in good agreement 

with the average monthly measured values, indicating that 

the model provides a reasonable representation of monthly 

changes in water levels in this analysis.

The data indicate that minimum and maximum water 

levels vary among the three wells and may be a function of 

depth to water (for example, thickness of the unsaturated zone) 

and geologic setting (fig. 1–11). The simulated water levels 

at the three sites have minimum water levels in October and 

maximum water levels in April. There is no variation in waterlevel responses among the three sites because it is assumed in 

the model that aquifer recharge occurs instantaneously at the 

water table, and therefore the model does not account for any 

lag in the response of water levels to hydrologic conditions in 

the unsaturated zone.

A comparison of model-calculated flows for current 

(2005) average monthly conditions for the Jones River was 

made to long-term measured monthly flows from a USGS 

station operating continuously since August 1966 in Kingston 

(station number 01105870). This comparison shows that 

the model provides a reasonable estimate of streamflow 

(fig. 1–12). The simulated hydrograph has the same apparent 

shape as the measured one; however, it does not capture 

high-flow conditions in the spring because of overland runoff, 

and does not capture summer low-flow conditions which 

may result from an overestimate of storage properties or 

summer recharge.

Limitations of Analysis

The use of numerical models to simulate groundwaterflow systems such as the PCKD aquifer system has inherent 

limitations; however, choice of model code and proper 

design and calibration of the flow models can minimize 

these limitations. Assumptions made regarding modelboundary conditions can affect model results, and therefore 

an understanding of these assumptions and their potential 

influence on model results should be considered.

In the case of this aquifer system, the western and 

northern boundaries of the active modeled area were defined 

by no-flow boundaries where it was assumed that no flow 

enters or leaves the aquifer. These no-flow boundaries 

were selected to coincide with the surface-water-drainage 

divides that separate surface-water flow in the PCKD aquifer 

system from surface-water flow in the Taunton and Lower 

Buzzards Bay Watersheds to the west and in the upper 

part of the South Coastal Watershed to the north (fig. 1–1). 

Because these no-flow boundaries were based on surfacewater-drainage divides, they may not necessarily coincide 

with groundwater divides, which in these areas may shift in 

response to changes in pumping and recharge conditions. 

Therefore, an analysis of model results, such as recharge-area 

delineations and changes in water levels and streamflows in 

areas adjacent to these boundaries should take into account 

the potential for model-boundary effects on these results. 

An additional limitation regarding model-boundary effects 

in this aquifer system is the position and movement of the 

boundary between freshwater and saltwater along the eastern 

and southern boundaries. In this analysis MODFLOW-2000 

was used to simulate freshwater flow only. It was assumed 

for this analysis that, given the pumping rates and locations 

of the existing and proposed wells relative to the coastline, 

changes in groundwater withdrawals will have no effect on the 

position and movement of the boundary between freshwater 

and saltwater, often referred to as the freshwater-saltwater 

interface. In the event that additional wells are developed in 

the future along the coast, model codes such as SEAWAT-2000 

(Langevin and others, 2003) would be required to account for 

potential changes to the freshwater-saltwater interface.

Differences between simulated and actual hydrologic 

conditions arise from a number of sources and are collectively 

known as model error. One component of model error relates 

to model discretization. Models represent a hydrologic 

system as a series of discrete spatial units, throughout each 

of which intrinsic properties and stresses are uniform. The 

use of a discretized model to represent a hydrologic system 

introduces some limitations, especially if model discretization 

is much larger than the hydrologic features being simulated; 

these limitations are minimized by designing models with the 

appropriate discretization for the hydrologic system.

Transient models are further discretized into a series 

of discrete units of time, during each of which hydrologic 

stresses are constant. The use of discretized time introduces 

additional sources of model inaccuracy, which can be 

minimized by choosing appropriate temporal discretization to 

address the time scale of interest. Model errors also can arise 

from the numerical solution; these errors are minimized by 
 Limitations of Analysis 81

Figure 1–11. Comparison of model-calculated and 

observed average monthly water levels for three 

monitoring sites (A) D4W-79, (B) WFW–51, and (C) PWW-22 

in the Plymouth-Carver-Kingston-Duxbury aquifer system, 

southeastern Massachusetts. CHANGE IN WATER-LEVEL ALTITUDE FROM AVERAGE, IN FEET CHANGE IN WATER-LEVEL ALTITUDE FROM AVERAGE, IN FEET

D4W−79

Lowest

Average

Highest

Water-level change

EXPLANATION

Steady-state

WFW−51

-5

-4

-3

-2

-1

0

1

2

3

4

5

-5

-4

-3

-2

-1

0

1

2

3

4

5

CHANGE IN WATER-LEVEL ALTITUDE

FROM AVERAGE, IN FEET

June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May

PWW−22

-5

-4

-3

-2

-1

0

1

2

3

4

5

A

B

C
82 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

STREAMFLOW, IN CUBIC FEET PER SECOND

AVERAGE MONTHLY PRECIPITATION

AND RECHARGE, IN INCHES

0

1

2

3

4

5

 Precipitation

 Recharge

 Measured flow

 Simulated flow, 2005

15

20

25

30

35

40

45

50

55

60

Figure 1–12. Comparison of model-calculated and observed average monthly streamflows for the Jones River 

in Kingston, Massachusetts.

ensuring that the model solution reaches a reasonable state of 

mass balance.

An additional component of model error arises from 

how well model-input values represent the actual hydrologic 

system. The degree of model error is difficult to quantify; 

however, the capacity of a model simulation to provide a 

reasonable representation of the hydrologic system can be 

evaluated by comparing simulated hydrologic conditions 

with those observed in the field. Comparisons of simulated 

and observed hydrologic conditions provide insight into 

the ability of the model to reproduce existing field data, 

but do not provide a means to quantify the error or model 

uncertainty associated with model predictions of future 

hydrologic conditions such as the 2030 conditions simulated 

in this investigation.

Recent modeling tools have been developed to assess 

model uncertainty by determining confidence intervals on 

model predictions. An uncertainty analysis was conducted 

as part of this investigation by using the YCINT program 

in MODFLOW-2000 to calculate linear confidence and 

prediction intervals on predicted changes in pond levels 

and streamflows used as part of the model-calibration 

process to predict future hydrologic conditions in 2030. A 

95-percent confidence interval is reported for each of the 

calibration points. This interval indicates that there is a 

95-percent probability that the actual value will be within the 

indicated range.

The model was calibrated to 1985 hydrologic conditions 

and then used to predict the effects of future pumping 

and recharge conditions on water levels and streamflows. 

Table 1–8 illustrates what the predicted changes in these 

model-calculated water levels and streamflows would be in 

response to changing stresses from current (2005) to future 

(2030) conditions. The predicted values for 2030 conditions 

are reported with the 95-percent confidence interval to provide 

an estimate of the uncertainty of the model predictions on the 

basis of the available data used for model calibration.
 Limitations of Analysis 83

Table 1–8. Model-predicted changes in water levels and streamflows and 95-percent confidence intervals on model 

predictions for 2030 conditions in the Plymouth-Carver-Duxbury-Kingston aquifer system, southeastern Massachusetts.—

Continued

[CI, confidence interval. Pond-level altitudes are in feet above National Geodetic Vertical Datum 1929. Streamflows are in cubic feet per second]

Identification Current 

(2005) Predicted (2030) Standard deviation

Lower 

95-percent 

CI

Upper 

95-percent 

CI

Pond

Bartlett Pond 7.42 7.42 0.02 7.38 7.46

Fresh Pond 14.10 14.07 0.02 14.03 14.12

Beaver Dam Pond 21.40 21.39 0.15 21.09 21.68

Shallow Pond 33.00 32.65 0.21 32.23 33.06

Little Muddy Pond 111.00 111.48 1.52 108.47 114.49

Briggs Reservoir 85.80 85.60 0.27 85.08 86.13

Cooks Pond 86.10 85.33 2.28 80.83 89.83

Lilly Pond 18.00 18.25 0.81 16.65 19.84

Micajah Pond 109.00 108.40 1.54 105.36 111.44

Island Pond 90.50 90.03 0.83 88.40 91.67

Crooked Pond 97.90 97.35 1.28 94.82 99.87

Savery Pond 28.10 28.12 0.02 28.08 28.16

Widgeon Pond 110.00 110.32 1.21 107.93 112.70

Curlew Pond 111.00 111.20 1.08 109.06 113.33

Rocky Pond 108.00 108.31 0.91 106.50 110.12

College Pond 100.00 99.88 1.59 96.73 103.04

Hodges Pond 35.20 35.03 0.18 34.67 35.39

Vaughn Pond 101.00 101.93 0.46 101.02 102.84

Little Duck Pond 48.10 48.03 0.52 47.00 49.06

Little Rock Pond 43.90 43.93 0.59 42.76 45.10

Horse Pond 36.20 36.11 1.11 33.91 38.30

Golden Field Pond 67.90 67.76 0.31 67.15 68.38

Goat Pasture Pond 23.30 23.25 1.08 21.11 25.39

Great Herring Pond 34.30 34.23 0.23 33.77 34.69

Big Sandy Pond 48.00 48.03 0.44 47.16 48.90

Island Island Pond 39.20 39.11 0.35 38.42 39.79

White Island Pond 48.10 48.10 0.07 47.97 48.24

Little Herring Pond 37.20 37.20 0.04 37.11 37.28

Fawn Pond 59.00 59.00 0.02 58.96 59.04

Fearing Pond 77.10 76.91 0.95 75.03 78.79

Glen Charlie Pond 33.50 33.43 0.00 33.43 33.43

East Head Pond 89.20 89.21 0.08 89.06 89.36

Halfway Pond 62.80 62.76 0.06 62.64 62.87

Long Pond 70.20 69.61 0.84 67.95 71.27

Gallows Pond 70.30 69.85 0.73 68.40 71.29

Little Long Pond 70.90 70.35 0.79 68.79 71.91

Bloody Pond 60.00 59.32 0.85 57.63 61.01

Sampson Pond 76.40 76.42 0.10 76.23 76.60

Island Pond 52.40 50.97 1.69 47.62 54.32

Great South Pond 98.90 98.86 1.17 96.55 101.17
84 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Table 1–8. Model-predicted changes in water levels and streamflows and 95-percent confidence intervals on model 

predictions for 2030 conditions in the Plymouth-Carver-Duxbury-Kingston aquifer system, southeastern Massachusetts.—

Continued

[CI, confidence interval. Pond-level altitudes are in feet above National Geodetic Vertical Datum 1929. Streamflows are in cubic feet per second]

Identification Current 

(2005) Predicted (2030) Standard deviation

Lower 

95-percent 

CI

Upper 

95-percent 

CI

Pond

Big West Pond 116.00 116.02 1.71 112.63 119.40

Hoyts Pond 98.10 97.85 0.98 95.90 99.80

South Triangle Pond 92.10 91.91 1.23 89.48 94.34

Billington Sea 82.80 82.79 0.15 82.48 83.09

Triangle Pond 107.00 107.29 1.59 104.13 110.44

Smelt Pond 106.00 105.45 2.05 101.40 109.51

Muddy Pond 124.00 122.51 3.62 115.34 129.68

Indian Pond 123.00 122.39 1.71 119.01 125.77

Muddy Pond 94.60 94.61 0.03 94.56 94.67

Johns Pond 106.00 106.35 0.84 104.69 108.02

Tihonet Pond 36.80 36.83 0.07 36.70 36.97

Spectacle Pond 16.10 16.09 0.01 16.08 16.11

Silver Lake 47.50 47.12 0.01 47.10 47.15

Indian Creek Pond 32.00 32.08 3.88 24.41 39.75

Wright Reservoir 25.70 24.90 0.71 23.49 26.30

South River Reservoir 51.10 51.12 0.00 51.12 51.12

Pine Lake 71.10 71.49 0.27 70.96 72.01

Stream

Agawam River 39.35 37.90 0.30 37.32 38.49

Beaver Brook 12.38 12.38 0.11 12.16 12.61

Eel River: Mouth 4.05 4.10 0.05 4.01 4.20

Eel River: North Branch 16.44 16.38 0.84 14.71 18.04

Eel River: South Branch 5.47 5.40 0.28 4.85 5.96

Halfway Pond Outlet 15.05 14.32 0.45 13.43 15.22

Herring River: B 6.75 6.35 1.86 2.68 10.02

Herring River: C 7.69 7.30 0.32 6.67 7.93

Holmes Brook 2.00 2.00 0.02 1.96 2.05

Indian Brook 0.80 0.50 0.76 -1.01 2.00

Red Brook 5.94 5.82 0.79 4.27 7.38

Savery Pond: Cranberry Bog Outlet 1.19 1.19 0.12 0.94 1.44

Savery Pond Outlet 0.27 0.29 0.31 -0.32 0.90

Stone Pond Outlet 3.61 3.66 0.18 3.30 4.01

Town Brook 16.20 15.93 1.08 13.78 18.07

Union Pond Outlet 0.75 0.74 0.03 0.68 0.81

Wankinco River 22.34 21.98 1.22 19.56 24.40

Weweantic River 66.20 66.71 2.12 62.51 70.91

Jones River 34.03 31.76 0.29 31.19 32.32
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Heading 1 89

Appendix 2. Comparison With Previous Model

Figures

2–1. Extents of new and previous groundwater-flow models, water levels calculated 

by the previous model, and the distribution of model boundary conditions in the

previous model for the Plymouth-Carver-Kingston-Duxbury aquifer system,

southeastern Massachusetts...................................................................................................92

Introduction...................................................................................................................................................91

Model Extent and Grid Discretization.......................................................................................................91

Representation of Surface-Water Boundaries.......................................................................................91

Model Stresses ............................................................................................................................................93

Hydraulic Properties....................................................................................................................................93

Comparison of Model-Calculated Water Levels and Streamflows .....................................................93

References Cited..........................................................................................................................................99

Tables

2–1. Comparison of hydrologic budgets between the previous and new models of the

Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts .....94

2–2. Comparison of model-calculated and observed water levels between the new

and previous models of the Plymouth-Carver-Kingston-Duxbury aquifer system,

southeastern Massachusetts...................................................................................................95

2–3. Comparison of model-calculated and measured streamflows between the new

and previous models of the Plymouth-Carver-Kingston-Duxbury aquifer system,

southeastern Massachusetts...................................................................................................98

Appendix 2
90 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts
 Representation of Surface-Water Boundaries 91

Appendix 2. Comparison with Previous Model

the tidal portions of the Agawam and Wareham Rivers only 

(fig. 2–1).

The vertical extents of both models are from the water 

table to bedrock. The glacial stratified deposits in the previous 

model were subdivided into four layers, whereas in the new 

model these deposits were subdivided into seven layers as 

described previously in the section “Spatial Discretization” 

in Appendix 1. The new model also includes an additional 

layer that extends from the bedrock surface to 50 ft below 

the bedrock surface to account for the potential hydraulic 

connection between bedrock and the overlying glacial 

stratified deposits in the northern part of the study area where 

these deposits are relatively thin.

Representation of SurfaceWater Boundaries

Surface-water boundaries can be represented by a number 

of methods to account for inflows and outflows of water in the 

aquifer system. Streams were simulated in the previous model 

by the MODFLOW River (RIV) package and by specified 

or constant-head boundaries. The RIV package allows for 

groundwater to discharge to or from model cells that simulate 

rivers to account for gaining and losing portions of rivers. A 

limitation of the RIV package, however, is that streamflow 

is not routed between model cells to accumulate gains or 

losses of streamflow. Also, if the model-calculated water level 

in the aquifer drops below the simulated river bottom in a 

model cell, a condition is created in which the river becomes 

an infinite source of water to the aquifer or to a nearby well; 

this condition is unrealistic for streams with low streamflow. 

The Streamflow Routing (STR) package was used in the new 

model to correct for this limitation so that streamflow can be 

routed between adjoining model cells; therefore, if the water 

level in the aquifer drops below the streambed, the river can 

only contribute the water that has accrued from upstream 

reaches and cannot become an infinite source of water as is the 

case with the RIV package.

In the previous model the coastal waters of Cape Cod 

Bay, Cape Cod Canal, Buttermilk Bay and the Jones River 

were represented as a specified or constant-head boundary 

condition (fig. 2–1). This boundary condition is used for 

large surface-water bodies because it is assumed that flow to 

or from these water bodies will not affect water levels. The 

amount of water flowing between the surface-water body and 

the aquifer in the model depends on the groundwater heads 

in the model cells that surround the specified-head boundary. 

In the new model, the coastal areas were represented by the 

General Head Boundary (GHB) package. The GHB package 

creates a head-dependent boundary condition that allows for 

Introduction

The groundwater-flow model documented in this report 

was based on a model previously developed by the USGS in 

the mid–1980s (Hansen and Lapham, 1992) in cooperation 

with the Massachusetts Department of Conservation and 

Recreation (formerly known as the Massachusetts Department 

of Environmental Management) and the Town of Plymouth. 

The earlier study was conducted as part of the Massachusetts 

Chapter 800 legislation, which provided funding for 

quantitative assessments of groundwater resources and the 

effects of the use of groundwater on contiguous surface water 

in the State.

The model developed for the earlier study was designed 

to simulate the potential effects of hypothetical groundwater 

development alternatives in the Plymouth-Carver aquifer 

system. The model has been used extensively as the 

foundation for subsequent water-supply studies conducted 

by the towns within the study area and their environmental 

consultants. The purpose of Appendix 2 is to compare the 

previous model and the model developed as part of the current 

investigation to assist model users in understanding the 

differences between the two models.

Model Extent and Grid Discretization

The previous model of the Plymouth-Carver aquifer 

system consists of 85 rows and 115 columns of uniformly 

spaced model cells that were 1,000 ft on a side and that 

covered an active model area of about 208 mi2. The active 

modeled area was bounded to the north by the Jones River, to 

the east by Cape Cod Bay, to the south by the Cape Cod Canal 

and tidal portions of Agawam and Wareham Rivers, and to 

the west by the watershed boundary of the Weweantic River 

(fig. 2–1).

The model developed as part of the current investigation 

consists of 355 rows and 270 columns of uniformly spaced 

model cells that are 400 ft on a side; the model grid covers 

an active model area of about 290 mi2. The active area of 

this model includes the previous model and extends farther 

north than the previous model to the Town of Marshfield to 

include the entire Jones River and Kingston Bay watersheds. 

In the case of the Jones River, it was not possible to assess the 

match between measured and model-calculated streamflows 

in the previous model because only the southern portion of the 

watershed was represented in the previous model. The new 

model also extends farther west to include the tributaries of the 

Winnetuxet River. Unlike the previous model, the new model 

extends south to include the entire coastal area rather than to 
92 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Figure 2–1. Extents of new and previous groundwater-flow models, water levels calculated by the previous 

model, and the distribution of model boundary conditions in the previous model for the Plymouth-CarverKingston-Duxbury aquifer system, southeastern Massachusetts.

Rochester

Plympton

Halifax

Pembroke

Kingston

Plymouth Carver

Wareham

Rochester

Plympton

Halifax

Hanson

Pembroke

Duxbury

Kingston

Marshfield

Bourne

Marion

Inactive model area

Surface water

EXPLANATION

Model cells 

Water-table contour

calculated by the previous

model—In feet. Interval is

10 feet. Datum is NGVD 29

Extent of new model

Constant head boundary

Stream

10

70°47'30" 70°37'30"

42°00'

41°45'

Silver 

Lake

DUXBURY

BAY

KINGSTON

BAY

PLYMOUTH 

 HARBOR

Billington

 Sea

 

Great South 

 Pond

 

Federal 

 Pond

 

South

River Res.

 

College 

 Pond

 Bloody

 Pond

 

Halfway

 Pond

 

Savery

 Pond

 

Indian

 Brook

 

Beaver Dam

 Brook

 

 East 

Head

Pond

 

 Glen

Charlie

Pond

 

 White

Island

Pond

 

 Big 

Sandy

Pond

 

 Great

Herring

Pond

 

 Cod 

 

 Cape 

 Canal

 

 Parker Mills

Pond

 

 Agawam

Fresh

Meadow

 Pond

 

Sampson

 Pond

 

South 

 

Wankinco 

 

Meadow 

 

 

River

 

River

 

 

River 

Herring

Agawam-Wareham

 River

 

Brook

 

 

Weweantic River

 

 

PLYMOUTH 

 BAY

CAPE COD

 BAY

BUZZARDS

 BAY

MASSACHUSETTS BAY

Jones River

South 

Harbor

Green

 River

 River

Eel River

Long Pond

 Parker Mills

Pond

 

Wareham

 River

 

Middleborough

Sandwich

10

30 10 10

20

100

110

110

120

130

120

90

80

70 70 60

50 40

30

30

40

20

10

60

90

50

60

70

90 80 110 100

0 2 MILES

0 2 KILOMETERS

Base from U.S. Geological Survey and Massachusetts Geographic Information System data sources,

Massachusetts State Plane Coordinate System, Mainland Zone
 Comparison of Model-Calculated Water Levels and Streamflows 93

the simulation of the resistance to flow from changes in 

seabed properties. In areas such as Duxbury and Kingston 

Bay where fine-grained deposits are prevalent, the vertical 

conductance of the seabed can be adjusted downward from 

the conductance values assumed for other areas along 

the coast.

In addition to the difference in the method used to 

represent surface-water bodies between the models, the 

new model included many smaller surface-water features 

that were not included in the previous model because of the 

increased model discretization (such as smaller cell size). A 

finer model discretization also allowed for a more realistic 

representation of the geometry of streams and other 

surface-water bodies and for the simulation of smaller 

water bodies that were not included in the previous model 

with the coarser grid spacing. In the previous model, ponds 

less than 23 acres in size were represented by one model 

cell; in the new model, a pond of 23 acres in size was 

represented by 6 model cells, allowing for a more realistic 

representation of the pond geometry in the flow model.

Model Stresses

The model stresses simulated in both models were 

pumping and recharge. For the purpose of comparing the 

two models, the pumping rates were consistent between 

the models and represented 1985 steady-state pumping 

conditions. The aquifer recharge rates between the two 

models differed primarily with respect to the methods 

used to represent surface-water bodies. In both models 

it was assumed that the aquifer recharge rate for average 

conditions was about 27 in/yr; however, in the previous 

model, surface-water bodies such as cranberry bogs were 

assumed to be areas of negative recharge (-17 in/yr), 

and ponds and wetlands were assumed to be areas of 

no net recharge. In the new model, the recharge rates in 

surface-water bodies varied from 8 to 20 in/yr as described 

earlier in Appendix 1. The difference in recharge rates for 

surface-water bodies resulted in an additional 40 ft3/s of 

water in the new model over the same area simulated in the 

previous model. The additional 40 ft3/s is about 13 percent 

more water in the new model compared to the previous 

model (table 2–1).

Hydraulic Properties

The hydraulic property required for model input 

for steady-state simulations was hydraulic conductivity. 

The previous model used a generalized representation 

of the glacial stratified deposits that was based on an 

assumed overall fining of grain size, and therefore, a 

decrease in hydraulic conductivity with depth. The new 

model incorporated more detail in the stratified glacial 

deposits on the basis of the surficial geology described in 

the “Hydraulic Properties” section of Appendix 1. The new 

model differentiated between two types of glacial stratified 

deposits; morainal and outwash deposits had differing values 

of hydraulic conductivity (fig. 1–2) based on grain size and 

depositional history.

A comparison of several of the major stratified glacial 

deposits in the Plymouth-Carver area indicated that in the 

previous model, higher hydraulic conductivity values were 

assigned to these deposits than in the new model. For example, 

the simulated hydraulic conductivity for Wareham Pitted Plain 

in the new model varied from 227 ft/d in the upper four layers 

to 34 ft/d in the lower three layers. Moraine and ice contact 

deposits such as Ellisville Harbor Moraine and Pine Hills were 

assigned hydraulic conductivity values of 64 and 119 ft/d, 

respectively, for the entire saturated thickness. In the previous 

model, the hydraulic conductivity values for all stratified 

glacial deposits decreased from 250 ft/d in layer 1 to 150 ft/d 

in layer 2 to 50 ft/d in layers 3 and 4.

Hydraulic conductivity values were initially assigned in 

the new model based on the general relation between grain 

size and hydraulic conductivity established for similar deposits 

on Cape Cod (Masterson and others, 1997a) and on available 

aquifer-test data for the study area (tables 1–1, 1–2). These 

values were assigned to hydraulic conductivity zones based on 

the surficial geology and an understanding of the depositional 

history of the glacial sediments in southeastern Massachusetts. 

Values of hydraulic conductivity were adjusted as part of 

the parameter estimation process during model calibration 

described in the “Model Calibration” section of Appendix 1.

Comparison of Model-Calculated 

Water Levels and Streamflows

The differences in the distribution of hydraulic 

conductivity values between the models are the result of 

adjustments to this hydraulic property to adequately match 

water levels and streamflows during the model calibration 

process. A comparison of the match of model-calculated and 

measured water levels between the previous model and the 

new model is presented in table 2–2. A comparison between 

the two models indicates that the absolute means of the 

residuals for the previous and the new models were 3.94 ft 

and 2.24 ft, respectively. These values correspond to less 

than 4 percent of the total (118 ft) range in water levels for 

the Plymouth-Carver aquifer, indicating that both models 

provide a reasonable match to the water-level data. The means 

of the residuals for the previous and the new models were 

-0.34 ft and 0.16 ft, respectively, indicating that both model 

residuals are randomly distributed around zero and generally 

are unbiased.

A comparison of model-calculated streamflows between 

the previous and new models is presented in table 2–3. The 

model-calculated streamflows for the new model are generally 
94 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Table 2–1. Comparison of hydrologic budgets between the previous and new models of the Plymouth-Carver-Kingston-Duxbury 

aquifer system, southeastern Massachusetts. 

Budget 

component

Rate of flow (cubic feet per second)

Previous model New model Difference between models

Inflow

Recharge

310 351 -41

Cape Cod Canal streams

1 0 1

Total 311 351 -40

Outflow

Streamflow

Winnetuxet River, western boundary 2 9 -7

Jones River, northern boundary 25 27 -2

Duxbury and Kingston streams 9 22 -13

Cape Cod Bay streams 37 41 -4

Cape Cod Canal streams 0 7 -7

Buzzards Bay streams 116 142 -26

Subtotal 189 248 -59

Coastal discharge

Cape Cod Bay 60 48 12

Cape Cod Canal 18 15 3

Buzzards Bay 12 25 -13

Duxbury and Kingston Bays 21 4 17

Subtotal 111 92 19

Pumping

11 11 0

TOTAL 311 351 -40
 Comparison of Model-Calculated Water Levels and Streamflows 95

Table 2–2. Comparison of model-calculated and observed water levels between the new and previous models of the 

Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.—Continued

[Water-level altitudes in feet above National Geodetic Vertical Datum of 1929]

Site 

identifier

X coordinate 

(state plane,

in feet)

Y coordinate 

(state plane,

in feet)

Observed

Simulated

(new 

model)

Simulated

(previous 

model)

Residual

(observed 

minus new 

model)

Residual

(observed 

minus old 

model)

BHW-293 850,488 283,995 25.22 27.93 19.41 -2.71 5.81

CDW-85 811,953 296,670 62.84 57.94 59.70 4.90 3.14

CDW-86 812,771 298,296 64.80 61.09 63.47 3.71 1.33

CDW-99 816,504 312,199 98.92 100.07 102.74 -1.15 -3.82

CDW-119 799,711 337,455 114.70 114.42 115.63 0.28 -0.93

CDW-120 801,522 329,170 92.60 98.77 99.09 -6.17 -6.49

CDW-121 803,357 326,858 103.23 103.12 102.02 0.11 1.21

CDW-122 799,451 306,175 76.10 77.46 78.80 -1.36 -2.70

CDW-123 819,662 306,357 83.97 85.19 88.28 -1.22 -4.31

CDW-125 815,785 306,497 79.66 84.85 89.00 -5.19 -9.34

CDW-201 798,021 305,150 78.14 77.38 76.44 0.76 1.70

PWW-22 809,644 334,304 120.98 119.13 118.76 1.85 2.22

PWW-215 828,144 336,807 81.90 83.69 84.26 -1.79 -2.36

PWW-236 816,810 295,601 55.71 56.29 59.11 -0.58 -3.40

PWW-237 815,387 293,867 51.09 48.58 52.26 2.51 -1.17

PWW-238 819,859 293,504 55.51 52.24 53.16 3.27 2.35

PWW-240 847,322 325,059 71.78 68.77 63.26 3.01 8.52

PWW-241 844,782 329,182 67.73 62.00 63.83 5.73 3.90

PWW-242 843,423 328,965 72.59 69.58 68.30 3.01 4.29

PWW-243 842,016 326,116 79.20 80.93 77.83 -1.73 1.37

PWW-244 842,794 323,999 87.20 80.65 78.55 6.55 8.65

PWW-245 850,194 325,292 57.79 55.24 52.63 2.55 5.16

PWW-251 848,942 300,883 43.60 44.68 49.03 -1.08 -5.43

PWW-253 848,309 303,508 46.59 48.07 53.84 -1.48 -7.25

PWW-261 829,311 341,171 74.05 73.15 70.69 0.90 3.36

PWW-285 853,898 325,534 36.60 48.62 39.72 -12.02 -3.12

PWW-305 823,566 333,320 102.07 100.55 99.35 1.52 2.72

PWW-306 823,945 333,223 101.66 99.82 98.78 1.84 2.88

PWW-313 853,973 325,535 38.59 48.40 39.43 -9.81 -0.84

PWW-315 827,043 325,661 102.71 102.80 103.55 -0.09 -0.84

PWW-319 858,175 301,389 21.04 23.88 19.22 -2.84 1.82

PWW-368 844,703 286,363 28.98 31.08 30.01 -2.10 -1.03

PWW-369 816,201 295,899 56.02 56.39 59.12 -0.37 -3.10

PWW-379 840,230 323,263 82.05 84.53 85.41 -2.48 -3.36

PWW-413 809,019 344,927 123.73 126.10 118.68 -2.37 5.05

PWW-414 847,017 311,086 64.07 65.56 68.00 -1.49 -3.93

PWW-415 824,116 307,615 91.34 88.04 94.89 3.30 -3.55

PWW-416 822,378 323,085 108.18 108.20 111.54 -0.02 -3.36

PWW-418 857,644 301,484 22.16 26.06 21.92 -3.90 0.24
96 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Table 2–2. Comparison of model-calculated and observed water levels between the new and previous models of the 

Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.—Continued

[Water-level altitudes in feet above National Geodetic Vertical Datum of 1929]

Site 

identifier

X coordinate 

(state plane,

in feet)

Y coordinate 

(state plane,

in feet)

Observed

Simulated

(new 

model)

Simulated

(previous 

model)

Residual

(observed 

minus new 

model)

Residual

(observed 

minus old 

model)

PWW-430 816,028 298,225 61.56 62.15 65.17 -0.59 -3.61

PWW-431 820,460 302,012 75.15 75.75 79.83 -0.60 -4.68

PWW-502 822,019 344,845 81.63 86.40 81.43 -4.77 0.20

PWW-503 825,595 342,349 77.41 81.36 76.88 -3.95 0.53

PWW-504 824,225 335,553 99.03 97.84 91.59 1.19 7.44

PWW-505 816,421 337,200 118.30 115.56 110.21 2.74 8.09

PWW-506 827,686 329,514 98.88 98.66 98.11 0.22 0.77

PWW-507 819,172 326,193 112.95 111.67 112.70 1.28 0.25

PWW-509 842,719 316,709 70.45 70.18 78.49 0.27 -8.04

PWW-510 828,774 311,203 95.00 90.70 99.04 4.30 -4.04

PWW-511 823,921 312,168 101.01 95.34 104.29 5.67 -3.28

PWW-512 824,959 298,816 69.78 65.09 68.25 4.69 1.53

PWW-513 844,422 298,709 47.75 48.32 52.49 -0.57 -4.74

PWW-516 830,277 335,208 77.03 79.52 81.93 -2.49 -4.90

PWW-517 805,873 341,659 123.73 123.66 122.04 0.07 1.69

PWW-518 850,158 307,577 52.39 53.76 56.18 -1.37 -3.79

PWW-519 844,877 291,426 46.61 42.77 42.50 3.84 4.11

WFW-245 814,278 290,921 46.21 39.92 45.07 6.29 1.14

WFW-295 818,825 290,660 45.81 43.25 43.58 2.56 2.23

WFW-297 820,959 289,364 39.49 38.31 37.78 1.18 1.71

Bartlett Pond 856,438 339,547 6.53 7.42 3.59 -0.89 2.94

Fresh Pond 856,765 330,851 14.24 20.22 14.54 -5.98 -0.30

Beaver Dam Pond 852,936 328,592 20.66 22.07 32.99 -1.41 -12.33

Shallow Pond 857,556 325,537 31.19 32.94 26.25 -1.75 4.94

Little Muddy Pond 814,754 346,252 108.70 110.25 101.02 -1.55 7.68

Briggs Reservoir 821,964 339,357 87.41 86.33 90.88 1.08 -3.47

Cooks Pond 826,916 337,288 87.08 85.51 85.44 1.57 1.64

Lilly Pond 861,766 319,198 11.09 19.16 10.86 -8.07 0.23

Micajah Pond 818,165 336,420 108.20 109.57 106.77 -1.37 1.43

Island Pond 833,866 329,291 88.79 90.19 88.62 -1.40 0.17

Unnamed Pond-1 799,010 343,144 122.44 119.96 119.70 2.48 2.74

Crooked Pond 832,298 324,520 95.78 97.67 98.18 -1.89 -2.40

Savery Pond 858,422 310,026 26.08 28.20 26.77 -2.12 -0.69

Widgeon Pond 821,064 325,725 108.17 110.44 111.56 -2.27 -3.39

Curlew Pond 818,405 325,509 108.00 111.32 112.80 -3.32 -4.80

Rocky Pond 819,085 323,654 107.52 108.49 112.17 -0.97 -4.65

College Pond 827,629 317,269 99.00 100.59 106.65 -1.59 -7.65

Hodges Pond 854,492 302,442 33.52 35.20 35.82 -1.68 -2.30

Vaughn Pond 796,038 325,392 101.81 101.50 103.15 0.31 -1.34
 Comparison of Model-Calculated Water Levels and Streamflows 97

Table 2–2. Comparison of model-calculated and observed water levels between the new and previous models of the 

Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.—Continued

[Water-level altitudes in feet above National Geodetic Vertical Datum of 1929]

Site 

identifier

X coordinate 

(state plane,

in feet)

Y coordinate 

(state plane,

in feet)

Observed

Simulated

(new 

model)

Simulated

(previous 

model)

Residual

(observed 

minus new 

model)

Residual

(observed 

minus old 

model)

Little Duck Pond 846,655 298,928 47.07 47.84 50.98 -0.77 -3.91

Little Rocky Pond 842,952 291,669 46.87 43.63 43.37 3.24 3.50

Unnamed Pond-2 827,708 297,054 57.00 56.69 60.09 0.31 -3.09

Horse Pond 846,960 286,880 40.64 35.70 30.51 4.94 10.13

Golden Field Pond 810,636 300,187 74.04 68.61 74.55 5.43 -0.51

Goat Pasture Pond 845,763 283,117 20.76 21.56 19.16 -0.80 1.60

Pond near Huckleberry 800,301 304,066 72.91 69.22 73.13 3.69 -0.22

Great Herring Pond 854,974 293,233 34.00 33.33 26.67 0.67 7.33

Big Sandy Pond 844,084 297,083 48.00 47.95 51.07 0.05 -3.07

Island Pond 851,576 297,013 39.00 38.74 38.79 0.26 0.21

White Island Pond 840,339 296,459 48.00 48.20 49.01 -0.20 -1.01

Little Herring Pond 852,136 301,759 36.00 37.28 41.38 -1.28 -5.38

Fawn Pond 835,080 302,346 59.00 59.00 62.66 0.00 -3.66

Fearing Pond 827,149 303,826 83.00 76.93 82.56 6.07 0.44

Glen Charlie Pond 832,923 289,340 35.00 33.59 35.00 1.41 0.00

East Head Pond 821,717 308,254 89.00 89.22 95.21 -0.22 -6.21

Halfway Pond 841,088 311,724 63.00 62.89 75.91 0.11 -12.91

Long Pond 843,859 314,278 68.00 69.78 75.88 -1.78 -7.88

Gallows Pond 841,137 315,675 69.00 70.09 78.94 -1.09 -9.94

Little Long Pond 841,329 317,940 70.00 70.66 81.51 -0.66 -11.51

Bloody Pond 849,858 310,351 58.00 59.81 61.38 -1.81 -3.38

Sampson Pond 803,501 310,713 76.00 76.65 81.90 -0.65 -5.90

Island Pond 851,945 323,820 51.00 52.81 49.77 -1.81 1.23

Great South Pond 825,817 330,973 100.00 98.42 98.81 1.58 1.19

Big West Pond 814,759 335,692 117.00 116.30 113.92 0.70 3.08

Hoyts Pond 831,093 325,869 96.00 98.32 97.88 -2.32 -1.88

South Triangle Pond 827,633 334,496 90.00 91.27 91.14 -1.27 -1.14

Billington Sea 820,707 341,446 81.00 82.75 89.39 -1.75 -8.39

Triangle Pond 816,600 347,352 105.00 105.14 92.54 -0.14 12.46

Smelt Pond 810,957 353,577 107.00 103.65 90.73 3.35 16.27

Muddy Pond 806,749 349,513 125.00 124.38 112.71 0.62 12.29

Indian Pond 800,605 351,021 123.00 123.05 109.04 -0.05 13.96

Johns Pond 794,440 331,122 111.00 107.16 111.19 3.84 -0.19

Tihonet Pond 813,296 288,547 35.00 36.90 32.82 -1.90 2.18

Spectacle Pond 827,781 281,438 15.00 16.25 16.01 -1.25 -1.01
98 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Table 2–3. Comparison of model-calculated and measured streamflows between the new and previous models of the 

Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts. 

Stream Previous model

(in cubic feet per second)

New model

(in cubic feet per second)

Observed flow 

(in cubic feet per second)

Town Brook 10.5 15.8 15

Eel River 21.3 25.0 23.2

Beaver Dam Brook 14.8 12.2 12.3

Indian Brook 0 1.5 1.2

Savory Pond Creek 0 0.6 10.33

Great Herring River 2-0.9 0 26.4

Red Brook 5.9 5.8 6.1

Agawam River 30.8 39.1 33.5

Halfway Pond outlet 1.7 14.9 12

Wankinco River 18.7 22.3 18.6

Weweantic River 53 68.0 370

1

 Measurement period: September 1, 2003 to August 31, 2004.

2

 Net loss of 0.9 cubic feet per second from 7.3 cubic feet per second between Great Herring Pond outlet and Cape Cod Canal.

3

 Measurement period: December 12, 1969 to September 30, 1971.
 References Cited 99

higher than those calculated for the previous model for the 

major streams in the modeled area; however, both models 

reasonably represent the measured streamflows used for model 

calibration in both studies (table 2–3).

The hydrologic budget of the modeled areas differs 

between the two models in that the new model required 

13 percent more recharge than the previous model to 

match the same water-level and streamflow measurements 

(table 2–1). This additional 13 percent (40 ft3/s) of recharge 

in the new model is reflected in the streamflow and direct 

groundwater-discharge components of the hydrologic budget. 

The amount of discharge to streams in the new model is about 

59 ft3/s more than that calculated in the previous one; however, 

the direct groundwater-discharge component of the water 

budget in the previous model is 19 ft3/s more than the new 

model. At the regional scale, the difference in streamflow as a 

percentage of total flow between the two models is only about 

10 percent—about 71 percent of the total flow in the aquifer in 

the new model compared to 61 percent in the previous model.

A comparison of flow to individual discharge areas 

shows where the greatest differences between the models 

occur (table 2–1). In the Buzzards Bay area there is about 

29 ft3/s more streamflow in the new model as compared to 

the previous model. This difference in streamflow between 

the two models is small as a percentage of total flow to the 

Buzzards Bay area. In the old model, streamflow represented 

90 percent of the total discharge to Buzzards Bay compared 

to 86 percent in the new model. In the Duxbury and Kingston 

Bay area there is about 18 ft3/s more streamflow in the new 

model compared to the previous model. Given that there is 

much less total flow to Duxbury and Kingston Bay compared 

to Buzzards Bay, the percentage of the streamflow component 

of the total flow to these bays increases from about 40 percent 

in the previous model to about 90 percent in the new model as 

a result of this increase in streamflow.

The more detailed model discretization and the resulting 

representation of smaller streams and tributaries not simulated 

in the previous model creates a redistribution of flow in 

terms of direct groundwater discharge to coastal areas 

compared with groundwater discharge to coastal areas through 

streamflow. The improved representation of streams in the 

new model results in higher rates of simulated streamflow in 

the new model that otherwise would have exited the aquifer 

as streamflow closer to the coast or as direct groundwater 

discharge to coastal areas.

The increase in simulated stream density in the new 

model affects model calibration because of the effect of 

additional groundwater-discharge sinks (streams) distributed 

throughout the modeled area. Proportionally more water that 

enters the aquifer as recharge in the new model discharges as 

streamflow rather than as direct groundwater discharge to the 

coast. The effect of this redistribution of flow is that higher 

recharge rates and lower hydraulic conductivity values are 

required in the new model to match the same data used in 

the previous model. As a result, model-predicted drawdowns 

and the delineation of the sources of water to ponds, streams, 

coastal waters, and pumping wells differ between the models.

References Cited

Hansen, B.P., and Lapham, W.W., 1992, Geohydrology and 

simulated groundwater flow, Plymouth-Carver aquifer, 

southeastern Massachusetts: U.S. Geological Survey WaterResources Investigations Report 90–4204, 69 p.

Masterson, J.P., Stone, B.D., Walter, D.A., and Savoie, 

Jennifer, 1997, Hydrogeologic framework of western Cape 

Cod, Massachusetts: U.S. Geological Survey Hydrologic 

Investigations Atlas 741, 1 pl.
100 Hydrogeology and Simulation of Ground-Water Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts
Heading 1 101

Appendix 3. Water-Level and Streamflow Data

By Gardner C. Bent and Andrew J. Massey 

Introduction.................................................................................................................................................103

Water-Level Data.......................................................................................................................................103

Streamflow Data ........................................................................................................................................103

References Cited........................................................................................................................................110

Figures

3–1. Locations of observation wells and streamflow-gaging sites for data-collection

effort from May 2006 through June 2007, Plymouth-Carver-Kingston-Duxbury

aquifer system, southeastern Massachusetts ....................................................................104

Tables

3–1. Water levels measured from May 2006 through June 2007 in the PlymouthCarver-Kingston-Duxbury aquifer system, southeastern Massachusetts......................105

3–2. Streamflow-gaging stations for which streamflow records were correlated in 

and near the Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern

Massachusetts, during the study period from June 2006 to June 2007 ..........................107

3–3. Estimated monthly mean streamflows measured in and near the PlymouthCarver aquifer system, southeastern Massachusetts, from June 2006 to June 2007...108

3–4. Estimated mean and annual mean monthly streamflows measured in and 

near the Plymouth-Carver aquifer system, southeastern Massachusetts, for 

long-term conditions during water months 1967–2007.......................................................109

Appendix 3
102 Hydrogeology and Simulation of Ground-Water Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts
 Streamflow Data 103

on a monthly basis at the eight partial-record stations. All 

streamflow measurements and calculations of streamflow at 

the three continuous streamflow-gaging stations followed 

USGS procedure outlined by Rantz and others (1982).

Monthly mean streamflows for June 2006 through June 

2007 for the three continuous streamflow-gaging stations 

are shown in table 3–3. Monthly mean streamflows were 

estimated for the Eel River at Route 3A near Plymouth 

(01105876) from June through September 2006. Monthly 

mean streamflows were estimated for the eight partial-record 

stations for June 2006 through June 2007. The long-term 

(generally water years 1967–2006) monthly mean and annual 

mean streamflow were also estimated for all stations except 

Jones River at Kingston (01105870), which was operated 

continuously during this period (table 3–4).

Mean monthly streamflows for the period June 2006 

through June 2007 and long-term mean monthly and annual 

streamflows were estimated by correlating streamflow 

measurements at partial-record stations plus historical 

measurements to concurrent daily mean streamflow at five 

nearby continuous streamflow-gaging stations with long-term 

(more than 10 years) records. One station, the Jones River at 

Kingston (01105870), is in the study area, and the other four 

stations are within about 25 miles of the study area in similar 

hydrogeologic settings. Old Swamp River (01105600) is about 

15 miles northwest, Indian Head River (01105730) is about 

5 miles north, Quashnet River (011058756) is about 15 miles 

south, and Wading River (01109000) is about 20 miles west of 

the Plymouth-Carver-Kingston-Duxbury aquifer area. These 

four stations have 18 to 41 years of streamflow record.

A scatterplot of log-transformed streamflow for each 

partial-record station against same-day log-transformed daily 

mean discharges at each of the five long-term continuous 

stations was made to determine the nature and quality of the 

relation between the stations. If the scatterplots indicated a 

log-linear relation, the maintenance of variance extension, 

type 1 (MOVE.1) technique (Hirsch, 1982), was used to 

provide an equation that related streamflow at the partialrecord station to that at the long-term stations. The long-term 

station with the highest correlation coefficient, the Jones River 

at Kingston (table 3–2), was used as the station to estimate 

streamflows at the partial-record stations. If the correlation 

coefficient at Jones River was not the highest, but was similar 

to the highest correlation coefficient, the Jones River station 

was used as the predictor station because it was in the study 

area and was closest in proximity to the partial-record stations. 

For three partial-record stations (Eel River at Russell Mills 

Road—01105876, Red Brook near Buzzards Bay—01105886, 

and Agawam River at East Wareham—01105890) (fig. 3–1), 

Jones River was used as the predictor even though correlation 

coefficients for other stations were higher, because the 

Appendix 3. Water-Level and Streamflow Data

Introduction

Hydrologic data were collected for this investigation 

that began in 2005 to expand on the data collected during the 

previous (1980s) investigation (Hansen and Lapham, 1992) 

and to provide data for the calibration of the groundwater-flow 

model developed as part of the current investigation. Waterlevel and streamflow data were collected monthly from May 

2006 through June 2007. The data collected as part of this 

investigation were not used in the calibration of the steadystate model because of the project schedule and the need for 

a calibrated model prior to July 2007. The collected data set, 

however, was used to assess how accurately the output from 

the calibrated model portrayed monthly changes in aquifer 

recharge and pumping for current conditions.

Water-Level Data

A water-level network consisting of 49 wells was 

established to measure monthly changes in water levels 

throughout the study area (fig. 3–1). The monitoring-well 

network consisted of 42 wells from the network measured 

in June 1986 as part of the previous U.S. Geological Survey 

(USGS) study and 7 additional wells drilled after 1986. The 

initial site list of 66 wells measured as part of the previous 

network was reduced to 42 wells after the field reconnaissance 

visits of March and April 2006 revealed that 24 wells were 

destroyed, not located, or deemed to be inaccessible after 20 

years of development and land-use changes in the study area. 

After locating the selected wells, the hydraulic connection of 

each well to the aquifer was verified by slug testing prior to 

field measurements. Monthly measurements were then made 

over a 10-day period at the end of each month from May 2006 

through June 2007. Throughout the well-monitoring period, 

588 measurements were recorded (table 3–1). All waterlevel measurements are stored in the USGS National Water 

Information System (NWIS) database.

Streamflow Data

Streamflow data were collected at three continuous 

streamflow-gaging stations and at eight partial-record stations 

from June 2006 through June 2007 in the Plymouth-Carver 

aquifer area (table 3–2). The continuous streamflow-gaging 

station at the Eel River at State Route 3A near Plymouth, 

MA, (station 01105876) (fig. 3–1) was not operational until 

late September 2006. Streamflow measurements were made 
104 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

Figure 3–1. Locations of observation wells and streamflow-gaging sites for data-collection effort from May 

2006 through June 2007, Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.

Rochester

Plympton

Halifax

Pembroke

Kingston

Marion

Plymouth Carver

Wareham

Rochester

Plympton

Halifax

Hanson

Pembroke

Duxbury

Kingston

Marshfield

Bourne

Marion

D4W 79

PWW 22

PWW 531

1105874

PWW 484

PWW 416

PWW 475

PWW 540

PWW 443

PWW 469

PWW 466

PWW 464

PWW 294

1105877 PWW 467-468

PWW 457-458

PWW 461

 -462

1105876

11058756

PWW 477

PWW 497 PWW 483

PWW 494

PWW 489

PWW 735

PWW 734

PWW 733

PWW 736

PWW 498 PWW 500

PWW 536

PWW 485

CDW 127

WFW 498

 

WFW 499

 WFW 500

 

1105895

1105892 1105890 1105886

110588389

11058839

WFW 51

CDW 125

CDW 140

CDW 120

CDW 122

CDW 123

PWW 415

PWW 215

PWW 261

PWW 490

 -492

PWW 487

 -488

PWW 480

 -481

PWW 533

 -534

Inactive model area

Well and identifier

Streamflow-measurement

point and identifier

Long-term monitoring

Measured for this study

EXPLANATION

70°47'30" 70°37'30"

42°00'

41°45'

1105874

PWW 540

D4W 79

0 2 MILES

0 2 KILOMETERS

Base from U.S. Geological Survey and Massachusetts Geographic Information System data sources,

Massachusetts State Plane Coordinate System, Mainland Zone

Middleborough
 Streamflow Data 105

Table 3–1. Water levels measured from May 2006 through June 2007 in the Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.—Continued[Water-level altitudes in feet above National Geodetic Vertical Datum of 1929; --, not measured]

Well name

Water levels measured from May 2006 through June 2007 

(ft)

May-06 Jun-06 Jul-06 Aug-06 Sep-06 Oct-06 Nov-06 Dec-06 Jan-07 Feb-07 Mar-07 Apr-07 May-07 Jun-07

Observation wells measured in this study

MA-CDW 120 92.90 93.53 92.61 92.72 91.70 91.64 92.52 92.06 92.59 93.01 93.41 93.59 92.38 91.89MA-CDW 122 74.64 75.22 74.74 74.12 73.84 73.51 73.99 73.87 74.25 74.20 74.83 75.52 75.50 74.58MA-CDW 123 84.92 84.91 84.50 84.25 84.12 83.89 83.81 83.55 84.33 83.82 84.13 84.66 84.39 83.84MA-CDW 125 80.00 80.28 79.60 79.15 79.02 79.71 79.13 79.71 80.20 80.37 80.09 80.14 79.53 78.94MA-CDW 127 74.51 75.27 74.62 73.78 73.01 72.33 72.46 72.46 72.75 72.90 73.78 74.82 74.89 74.15MA-CDW 140 85.11 85.41 84.87 84.67 84.74 85.02 84.99 84.62 86.65 85.05 85.33 85.42 84.94 84.68MA-PWW 215 82.98 83.99 83.87 83.22 82.64 82.09 82.06 82.06 82.07 81.91 82.31 82.93 83.28 82.87MA-PWW 261 75.13 76.48 76.19 75.41 74.76 73.94 74.09 74.01 74.03 73.66 74.03 74.72 75.21 74.78MA-PWW 294 39.69 41.18 40.18 38.87 38.02 36.58 37.12 36.79 36.89 36.77 37.81 39.07 39.58 38.65MA-PWW 415 91.20 92.07 91.91 91.53 91.10 90.38 90.19 89.98 89.76 89.52 89.74 90.75 91.53 91.33MA-PWW 416 108.30 109.18 109.71 109.36 108.90 108.22 107.58 107.31 107.21 107.04 107.15 107.64 108.56 108.74MA-PWW 443 10.13 11.15 11.26 10.83 10.35 9.74 9.28 8.96 8.75 8.54 8.66 9.23 9.90 10.10MA-PWW 457 54.56 54.78 55.14 55.48 55.89 56.09 55.95 55.61 55.45 54.81 54.36 54.14 53.84 53.89MA-PWW 458 51.38 51.78 52.25 52.56 52.69 52.46 52.19 51.85 51.75 51.21 50.93 50.92 51.02 51.35MA-PWW 461 71.88 73.01 72.74 71.92 71.57 71.15 71.01 70.33 70.59 70.13 70.68 71.23 71.55 70.54MA-PWW 462 71.69 73.00 72.57 71.64 71.19 70.73 70.58 70.34 70.23 69.99 70.50 71.16 71.33 70.69MA-PWW 464 61.53 62.44 61.92 61.13 60.65 59.98 60.23 59.75 59.75 59.43 60.10 60.96 61.07 60.67MA-PWW 466 47.42 48.42 48.73 48.23 47.70 46.94 46.33 45.94 45.66 45.24 45.29 45.87 46.66 46.93MA-PWW 467 42.84 43.93 43.67 43.15 42.62 41.88 41.60 41.20 41.04 40.81 41.24 42.10 42.66 42.49MA-PWW 468 41.84 42.75 42.47 42.02 41.52 40.84 40.69 40.18 40.07 39.79 40.27 41.12 41.63 41.41MA-PWW 469 16.60 17.85 17.35 16.55 15.93 15.28 15.30 15.13 15.14 15.13 15.72 16.45 16.97 16.57MA-PWW 475 62.72 63.93 63.62 62.87 62.21 61.44 61.36 61.12 61.00 60.61 61.23 62.20 62.61 62.16MA-PWW 477 96.99 97.78 97.42 96.93 96.66 96.19 96.43 96.10 96.05 95.80 96.30 96.78 96.90 96.70MA-PWW 480 87.24 88.30 88.74 88.33 87.86 87.13 86.44 86.09 85.79 85.56 85.77 86.22 87.03 87.17MA-PWW 481 87.11 88.18 88.62 88.21 87.69 86.99 86.32 85.98 85.67 85.44 85.67 86.13 86.92 87.05MA-PWW 483 89.20 90.14 90.68 90.43 90.00 89.29 88.51 88.18 87.91 87.69 87.77 88.27 89.12 89.35MA-PWW 484 106.85 107.84 107.62 107.04 106.54 105.95 105.95 105.67 105.70 105.51 105.97 106.82 107.16 106.81MA-PWW 485 39.18 40.45 40.45 39.84 39.18 38.29 38.09 37.96 37.82 37.67 38.03 38.75 39.34 39.07MA-PWW 487 105.07 105.77 105.27 104.70 104.28 103.66 104.17 104.05 104.01 103.81 104.33 105.32 104.99 104.65MA-PWW 488 105.49 106.09 105.61 105.00 104.59 104.00 104.58 104.37 104.42 104.16 104.75 105.76 105.38 105.03
106 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts Table 3–1. Water levels measured from May 2006 through June 2007 in the Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts.—Continued [Water-level altitudes in feet above National Geodetic Vertical Datum of 1929; --, not measured] Well name Water levels measured from May 2006 through June 2007 (ft) May-06 Jun-06 Jul-06 Aug-06 Sep-06 Oct-06 Nov-06 Dec-06 Jan-07 Feb-07 Mar-07 Apr-07 May-07 Jun-07 MA-PWW 489 98.66 99.72 99.15 98.63 98.32 97.72 97.89 98.59 97.52 97.14 97.66 98.56 98.73 98.32 MA-PWW 490 114.39 114.42 113.49 112.81 112.50 112.86 114.12 113.80 114.63 114.11 114.59 115.04 113.72 113.03 MA-PWW 491 112.38 112.73 111.94 111.52 111.21 111.43 112.22 112.19 112.58 112.29 112.52 112.88 112.06 111.52 MA-PWW 492 113.50 113.80 113.00 112.48 112.24 112.93 113.41 113.56 114.24 113.75 113.63 113.99 113.19 112.59 MA-PWW 497 108.22 109.35 109.64 109.27 108.76 108.08 107.36 107.19 107.01 106.79 106.86 107.62 108.33 108.53 MA-PWW 498 58.45 59.12 59.30 58.84 58.46 58.08 57.84 57.61 57.57 57.58 57.65 57.97 58.52 58.47 MA-PWW 500 42.63 43.56 43.55 43.08 42.62 42.04 41.76 41.54 41.35 41.17 41.39 41.82 42.31 42.17 MA-PWW 531 104.57 105.52 105.55 104.96 104.39 103.91 103.52 103.66 103.71 103.53 103.76 104.34 104.99 104.70 MA-PWW 533 72.79 73.48 73.18 72.78 72.49 72.10 72.24 71.93 71.87 71.71 72.05 72.64 72.63 72.40 MA-PWW 534 73.81 74.49 74.19 73.81 73.52 73.14 73.26 72.95 72.88 72.73 73.08 73.64 73.65 73.44 MA-PWW 536 46.40 47.63 47.10 46.42 46.09 45.16 45.70 45.20 45.23 44.88 45.48 46.20 46.31 45.76 MA-PWW 540 19.46 21.49 22.27 21.92 21.42 20.71 20.00 19.44 19.24 18.91 19.00 19.48 20.33 21.10 MA-PWW 733 -- -- -- 52.07 51.94 51.74 51.78 51.55 52.11 51.71 51.94 52.35 52.18 51.87 MA-PWW 734 -- -- 51.10 50.80 50.55 50.38 50.88 50.62 50.71 50.50 50.94 51.50 51.35 50.95 MA-PWW 735 -- -- -- 45.51 45.42 45.27 45.70 45.46 45.58 45.73 46.17 46.43 46.22 45.75 MA-PWW 736 -- -- 52.71 52.50 52.37 52.21 52.23 52.00 52.50 52.13 52.32 52.76 52.63 52.30 MA-WFW 498 -- -- 32.78 32.41 32.10 31.89 31.99 31.84 32.58 32.75 32.24 32.55 32.56 32.22 MA-WFW 499 -- -- 42.70 42.05 41.44 41.00 40.95 40.69 40.77 41.03 41.14 42.16 42.81 42.39 MA-WFW 500 -- -- 41.37 41.03 40.72 40.42 40.32 40.08 40.19 40.21 40.12 40.57 41.14 40.85 Long-term monitoring wells D4W79 47.47 48.06 46.96 46.53 46.32 46.51 47.96 47.13 47.36 46.98 47.83 48.20 47.73 46.58 WFW51 14.60 16.24 14.37 13.05 12.36 11.91 12.92 12.87 13.59 12.92 14.40 15.57 15.05 13.74 PWW22 123.04 124.78 125.10 123.37 122.25 121.49 121.70 121.60 121.55 121.30 121.78 122.90 123.17 122.73 PWW494 102.88 103.95 103.80 103.37 102.92 102.45 102.27 101.90 101.81 101.45 101.87 102.64 102.80 102.64
 Streamflow Data 107

Table 3–2. Streamflow-gaging stations for which streamflow records were correlated in and near the Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts, during the study period from June 2006 to June 2007.[USGS station number: Locations are shown in figure 3–1. USGS, U.S. Geological Survey; CG, continuous gage; DG, discontinued gage; PR, partial-record station; mi2, square miles; MA, Massachusetts; --, not applicable]

USGS 

station 

number

Station name 

and location

Station 

type

Latitude 

(decimal 

degree)

Longitude 

(decimal 

degree)

Drainage 

area

(mi2)

Period of record

Period of 

record used in 

analysis

Number of 

measurements

Number of 

measurements from 

June 2006 to 

June 2007

Number of 

measurements used 

in MOVE1 

analysis

Correlation 

coefficient 

with record 

from Old 

Swamp 

River at 

South Weymouth, MA 

(01105600)

Correlation 

coefficient 

with record 

from Indian 

Head River 

near Hanover, MA 

(01105730)

Correlation 

coefficient 

with record 

from Jones 

River at 

Kingston, MA 

(01105870)

Correlation 

coefficient 

with record 

from Quashnet River 

at Waquoit 

Village, MA 

(011058756)

Correlation 

coefficient 

with record from 

Wading 

River near 

Norton, MA 

(01109000)

01105600 Old Swamp River near 

South Weymouth, MA

CG 42.1903779 -70.9447679 4.50 1966–present 1966–2006 -- -- -- -- -- -- -- --

01105730 Indian Head River at 

Hanover, MA

CG 42.1006571 -70.8225415 30.3 1966–present 1966–2006 -- -- -- -- -- -- -- --

01105870 Jones River at 

Kingston, MA

CG 41.9909362 -70.7336491 15.7 1966–present 1966–2006 -- -- -- -- -- -- -- --

01105874 Town Brook at 

Plymouth, MA

PR 41.9562145 -70.6617019 9.04 1969–71, 1986, 

and 2006–07

1969–71, 1986, 

and 2006–07

19 10 19 0.9 0.93 0.96 0.95 0.91

011058756 Eel River at Russell Mills 

Road near Plymouth, MA

CG 41.9176039 -70.6264226 5.71 2006–present 2006–07 -- -- -- 0.57 0.69 0.68 0.86 0.64

101105876 Eel River at Route 3A near 

Plymouth, MA

CG 41.9417704 -70.6225338 14.7 1969–71, 1986, 

2006–present

1969–71, 1986, 

2006–07

-- -- -- 0.73 0.70 0.72 -- 0.69

01105877 Beaver Dam Brook at 

Manomet, MA

PR 41.8728825 -70.5622533 4.78 2006–07 2006–07 15 15 14 0.93 0.92 0.92 0.85 0.85

011058756 Quashnet River at 

Waquoit Village, MA

CG 41.5923318 -70.5078058 2.58 1988–present 1988–2006 -- -- -- -- -- -- -- --

011058756 Herring River, Great 

Herring Pond Outlet, at Bournedale, MA

PR 41.7862166 -70.5644746 6.86 1986, 1992–94, 

and 2006–07

1986, 1992–94, 

and 2006–07

24 12 24 0.42 0.60 0.77 0.81 0.61

2011058839 Herring River at Bournedale, MA PR 41.7726056 -70.5622521 7.74 1986, 1988, and 2006–07 1986, 1988, and 2006–07 12 10 10 0.88 0.92 0.93 0.56 0.8901105886 Red Brook near 

Buzzards Bay, MA

PR 41.7634381 -70.6325321 9.84 1969–71, 1986, 

and 2006–07

1969–71, 1986, 

and 2006–07

21 12 21 0.55 0.63 0.83 0.89 0.63

01105890 Agawam River at 

East Wareham, MA

PR 41.7612154 -70.6772558 17.1 1969–71, 1986, 

and 2006–07

1969–71, 1986, 

and 2006–07

19 12 19 0.89 0.85 0.81 0.46 0.82

01105892 Wankinco River at 

Wareham, MA

PR 41.7662148 -70.7217018 20.5 1969–71, 1986, 

and 2006–07

1969–71, 1986, 

and 2006–07

17 10 17 0.65 0.70 0.87 0.73 0.7

301105895 Weweantic River at 

South Wareham, MA

DG 41.7701033 -70.7544806 56.1 1969–71, 1986, 

1991, and 2006–07

1969–71, 1986, 

1991, and 2006–07

671 9 658 0.89 0.9 0.88 -- 0.93

01109000 Wading River near 

Norton, MA

CG 41.9476002 -71.1767155 43.3 1925–present 1925–2006 -- -- -- -- -- -- -- --

1 Station 01105876: one miscellaneous discharge measurement was made in 1986.2 Station 011058839: on two different days, two measurements were made, and the average of the two measurements was used to represent the discharge for that day.3 Station 01105895: two miscellaneous discharge measurements were made in 1986 and 1991.
108 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts Table 3–3. Estimated monthly mean streamflows measured in and near the Plymouth-Carver aquifer system, southeastern Massachusetts, from June 2006 to June 2007. [USGS station number: Locations are shown in figure 3–1. USGS, U.S. Geological Survey; mi2, square miles; MA, Massachusetts; --, not applicable] USGS station number Station name and location Drainage area (mi2

)

Mean

June 

2006

July 

2006

August 

2006

September 

2006

October 

2006

November 

2006

December 

2006

January 

2007

February 

2007

March 

2007

April 

2007

May 

2007

June 

2007

01105600 Old Swamp River near 

South Weymouth, MA

4.50 36 6.0 2.9 2.0 5.8 15.0 6.1 7.5 7.3 18 27 8.2 3.4

01105730 Indian Head River at 

Hanover, MA

30.3 244 70 25 20 32 108 67 66 34 134 191 68 28

01105870 Jones River at Kingston, 

MA

15.7 122 51 26 19 18 48 32 30 18 70 108 58 8.4

01105874 Town Brook at Plymouth, 

MA

9.04 35.5 25.9 20.4 18.2 17.8 25.3 22.0 21.3 17.7 29.1 34.0 27.3 13.6

011058756 Eel River at Russell Mills 

Road near Plymouth, MA

5.71 24 20 18 18 17 18 16 16 14 17 22 23 18

01105876 Eel River at Route 3A near 

Plymouth, MA

14.7 41.5 33.4 28.3 26.2 30 35 30 31 28 35 43 35 29

01105877 Beaver Dam Brook at 

Manomet, MA

4.78 23.9 14.6 10.0 8.4 8.1 14.1 11.3 10.8 8.1 17.5 22.3 15.8 5.3

011058756 Quashnet River at 

Waquoit Village, MA

2.58 32.5 29.5 24.6 21.1 20.2 21.5 19.5 19.6 17.0 21.4 26.4 26.3 21.8

0110588389 Herring River, Great Herring Pond Outlet, at 

Bournedale, MA

6.86 19.9 17.4 13.6 11.0 10.4 11.3 9.9 10.0 8.2 11.2 15.0 14.9 11.5

011058839 Herring River at 

Bournedale, MA

7.74 19.6 13.4 10.1 8.9 8.6 13.1 11.1 10.7 8.6 15.4 18.6 14.3 6.2

01105886 Red Brook near 

Buzzards Bay, MA

9.84 17.1 11.2 8.1 7.0 6.7 10.8 9.0 8.6 6.7 13.0 16.1 12.0 4.7

01105890 Agawam River at East 

Wareham, MA

17.1 88.2 60.1 45 39.2 38 58.5 49.2 47.5 37.9 69.1 83.6 64 27.4

01105892 Wankinco River at 

Wareham, MA

20.5 77.2 43.0 27.6 22.4 21.4 41.3 32 30 21 53 71 47 13

01105895 Weweantic River at 

South Wareham, MA

56.1 230 99 44 45 87 169 123 123 88 178 206 128 91

01109000 Wading River near Norton, 

MA

43.3 274 65 16 17 52 162 95 95 54 178 227 102 56
 Streamflow Data 109

Table 3–4. Estimated mean monthly and annual mean streamflows measured in and near the Plymouth-Carver aquifer system, southeastern Massachusetts, for long-term conditions during water months 1967–2007.[USGS station number: Locations are shown in figure 3–1. USGS, U.S. Geological Survey; mi2, square miles; MA, Massachusetts; --, not applicable]

USGS 

station 

number

Station name 

and location

Drainage 

area 

(mi2)

Long-term mean

June July August Septem- ber October Novem- ber Decem- ber January February March April May Annual

01105600 Old Swamp River near 

South Weymouth, MA

4.50 7.8 2.9 3.3 3.3 5.8 9.6 12.7 12.2 12.8 17.2 13.8 10.2 9.3

01105730 Indian Head River at 

Hanover, MA

30.3 51.5 23.5 24.2 22.6 39.6 63.1 85.0 84.4 90.7 119.6 101.4 70.2 64.5

01105870 Jones River at Kingston, 

MA

15.7 30.2 18.5 17.8 17.5 20.7 30.6 36.2 38.9 45.7 59.1 54.9 42.2 34.3

01105874 Town Brook at 

Plymouth, MA

9.04 21.5 18.0 17.8 17.7 18.8 21.6 23.0 23.6 25.0 27.4 26.7 24.3 22.5

011058756 Eel River at Russell Mills 

Road near Plymouth, MA

5.71 17.9 16.3 16.2 16.1 16.7 18 18.6 18.8 19.4 20.4 20.1 19.1 18.4

01105876 Eel River at Route 3A 

near Plymouth, MA

14.7 29.4 26 25.8 25.6 26.8 29.5 30.7 31.3 32.6 34.7 34.1 31.9 30.3

01105877 Beaver Dam Brook at 

Manomet, MA

4.78 10.9 8.3 8.1 8.0 8.8 11.0 12.1 12.6 13.8 15.9 15.3 13.2 11.7

011058756 Quashnet River at 

Waquoit Village, MA

2.58 18.9 16.1 15.2 14.7 13.5 14.5 13.8 14.0 14.9 17.1 20.3 20.0 16.1

0110588389 Herring River, Great 

Herring Pond Outlet, at Bournedale, MA

6.86 9.5 7.6 7.0 6.7 6.0 6.6 6.2 6.3 6.8 8.2 10.5 10.2 7.6

011058839 Herring River at 

Bournedale, MA

7.74 10.8 8.7 8.6 8.5 9.2 10.8 11.6 12.0 12.9 14.4 13.9 12.4 11.4

01105886 Red Brook near 

Buzzards Bay, MA

9.84 8.7 6.8 6.7 6.7 7.2 8.7 9.5 9.8 10.6 12.0 11.6 10.2 9.2

01105890 Agawam River at 

East Wareham, MA

17.1 47.9 38.7 38 37.7 40.6 48.2 51.9 53.6 57.5 64.3 62.3 55.5 50.7

01105892 Wankinco River at 

Wareham, MA

20.5 30.4 21.9 21.4 21.1 23.6 30.7 34.4 36.1 40.2 47.7 45.4 38.1 33.1

01105895 Weweantic River at 

South Wareham, MA

56.1 91.4 56.5 51.8 50.3 65.2 94.2 120.9 127.7 131.6 162.9 152.6 114.6 106.3

01109000 Wading River near 

Norton, MA

43.3 57.1 25.3 21.7 20.7 32.2 60.1 91.9 100.9 106.2 152.6 136.5 83.9 73.9
110 Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Massachusetts

estimated streamflows seemed unreasonable. The streamflows 

at the long-term stations for the selected monthly mean and 

annual mean streamflows were then substituted into the 

equation to obtain the corresponding monthly mean and 

annual mean streamflows at the partial-record stations. The 

estimated monthly mean streamflows for June 2006 through 

June 2007 are presented in table 3–3 and the mean monthly 

and annual mean streamflows for water years 1967–2006 are 

presented in table 3–4.

Although surface-water and groundwater drainage 

divides do not always coincide in the Plymouth-CarverKingston-Duxbury aquifer system, monthly and annual 

mean streamflows on a per square mile basis (based on their 

surface-water drainage area) are in close agreement for most 

of the stations. Streamflows per square mile for Eel River at 

Russell Mills Road (011058756) and Agawam River at East 

Wareham (01105890) are higher than at the other sites, and 

at Herring River at Great Herring Pond Outlet (0110588389) 

and Red Brook near Buzzards Bay (01105886) are lower than 

at the other sites. These differences in streamflow per square 

mile may be a result of differences in the surface-water and 

groundwater drainage divides.

References Cited

Hansen, B.P., and Lapham, W.W., 1992, Geohydrology and 

simulated groundwater flow, Plymouth-Carver Aquifer, 

southeastern Massachusetts: U.S. Geological Survey WaterResources Investigations Report 90-4204, 69 p.

Hirsch, R.M., 1982, A comparison of four streamflow record 

extension techniques: Water Resources Research, v. 18, 

no. 4, p. 1081–1088.

Rantz, S.E., and others, 1982, Measurement and computation 

of streamflow, v. 1, measurement of stage and discharge: 

U.S. Geological Survey Water-Supply Paper 2175, 284 p.
Prepared by the Pembroke Publishing Service Center.

For more information concerning the research in this report, contact:

Director 

USGS Massachusetts-Rhode Island 

Water Science Center

10 Bearfoot Road

Northborough, MA 01532

or visit our Web site at:

http://ma.water.usgs.gov
Masterson and others—Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Southeastern Massachusett—Scientific Investigations Report 2009–5063