U.S. Geological Survey Page 1

U.S. Department of the Interior

May 2003

FS 042-03

Testing Ground-Water-Management Alternatives in the 

Upper Charles River Basin, Eastern Massachusetts

Ground water pumped from 

municipal wells supplies 

most of the drinking water 

used in the Upper Charles 

River Basin. This area, along 

the Interstate 495 corridor 

in eastern Massachusetts, 

has undergone rapid land 

development and population 

growth in recent years. The 

increased water demand 

associated with this growth 

has created concerns about 

the effects of current and 

future withdrawals on 

streamflow and pond levels 

in the basin. To aid waterresource planning in the 

basin, a computer model of 

the hydrologic system was 

developed to test the effects 

of current and hypothetical 

ground-water withdrawals 

and other water-management 

practices. The model is 

applied by using optimization 

methods that can help 

balance water-supply and 

environmental needs. 

Figure 1. Surficial geology and locations of water withdrawals and wastewater 

discharges in the Upper Charles River Basin, Eastern Massachusetts

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EXPLANATION

AQUIFER THICKNESS

TOWN BOUNDARY

BASIN BOUNDARY

0 70 140 FEET

0

0 1 2

1 2 MILES

3 KILOMETERS

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TILL AND BEDROCK

SAND AND GRAVEL

WATER WITHDRAWAL

WASTEWATER DISCHARGE

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Echo

Lake Lake

Winthrop

Milford

Pond

Louisa

Lake

Populatic

Pond

Kingsbury

Pond

Box

Pond

Lake

Pearl

City Mills

Pond

Spring

Pond

Bush

Pond

Lake

Archer

Beaver Brook

Charles River

Charles River

Hopping B

S

rook

tall Brook

Charles River

M iscoe Brook

Bogastow

Broo k

Dirty Mead ow Brook

Dopping Broo k

Jar Brook

Chicken Brook

Cress B rook

Ea gle Brook

Miller Brook

Shepards Brook

Charles R vi er

Mill River

Mine Brook

Dix Brook

Godfrey Br ook

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I-495

Great Black Swamp

Great Black Swamp
Page 2 

INTRODUCTION

Ground water withdrawn from 

sand and gravel aquifers provides 

nearly all of the drinking water for

a population of about 100,000 in 

eight towns in the Upper Charles 

River Basin (UCRB), which is in 

Eastern Massachusetts along the 

Interstate 495 corridor (fig. 1). More 

than 30 municipal wells withdraw 

about 10 million gallons per day 

(Mgal/d) of water from the sand 

and gravel aquifers (fig. 1). These 

aquifers are high-yielding, but thin 

and discontinuous; they occur along 

the Charles River and its major 

tributaries and are surrounded by less 

permeable uplands of bedrock and 

glacial till. Because ground water 

in the aquifers and surface water in 

streams, ponds, and wetlands are 

closely connected (fig. 2), withdrawals from ground-water wells reduce 

flow in nearby streams (called 

“streamflow depletion”), either by 

capturing water that naturally would 

discharge to the stream or by drawing stream water into the aquifer. 

When streamflows are reduced, there 

may not be enough water to support 

populations of aquatic life such as 

fish. Water levels in ponds and wetlands also may be lowered by water 

withdrawals. 

Population increases of as much 

as 30 percent in the past decade in 

some towns resulted in increased 

water withdrawals and wastewater 

discharges, which are likely to affect 

streams and ponds. Water supply 

and wastewater disposal are managed locally by towns, but their 

effects on the hydrologic system 

are regional, because the streams, 

ponds, and aquifers cross municipal 

boundaries (fig. 1). To provide tools 

to evaluate these effects and watermanagement alternatives, the U.S. 

Geological Survey, in cooperation 

with the Massachusetts Departments 

of Environmental Management and 

Environmental Protection and the 

Charles River Watershed Association, developed a computer-based 

numerical model of the hydrologic 

system in the basin. The hydrologic 

model was used to simulate water 

withdrawals and discharges that 

occurred during the recent past, to 

assess the effects on water resources 

of several hypothetical scenarios of 

increased withdrawals and altered 

recharge, and to test the usefulness 

for balancing water-supply and 

environmental needs of linking the 

hydrologic model with optimization 

techniques—known as simulationoptimization.

Till and Bedrock Uplands Sand and Gravel Aquifers

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Sand and Gravel Aquifers

Till

Bedrock

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Water table

Schematic diagram, not to scale

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Figure 2. Schematic diagram showing water inflows to and outflows from the hydrologic system in the Upper Charles 

River Basin. Most withdrawals for municipal supply are from the sand-and-gravel aquifers.
Page 3

UPPER CHARLES HYDROLOGIC MODEL

The hydrologic model developed for the UCRB 

simulates ground-water levels, ground-water flow 

directions and velocities, and interactions between 

ground water and surface-water bodies such as streams. 

The model accounts for all inflows and outflows of 

water to the aquifers and their associated streams in the 

basin, including aquifer recharge from precipitation, 

discharge from septic systems, withdrawals from 

municipal wells or directly from streams, and 

wastewater discharges to streams (fig. 2). One 

component that is not simulated is direct runoff carried 

by streams during storm events—streamflow in the 

model is simulated as the component that comes from 

discharging ground water (the “base flow” component 

of streamflow), augmented by discharges or depleted 

by withdrawals. Direct runoff typically is a small 

component (about 20 percent) of streamflow in the 

Upper Charles River and its major tributaries. 

The hydrologic model developed for the UCRB 

simulates average annual and monthly conditions for 

1989-98 (“existing conditions”). It shows that the 

hydrologic system is dominated by one major inflow, 

recharge (90 percent), and one major outflow, stream 

base flow out of the basin (90 percent) (fig. 3). Water 

withdrawals and wastewater discharges to streams 

are small, but important, components, each averaging 

annually about 7 percent of the total flow of water 

through the simulated hydrologic system.

APPLICATION OF THE MODEL TO TEST 

INCREASED WITHDRAWALS

The effects of increased water withdrawals from 

streams and ground-water wells that might result from 

future development were tested in two ways with the 

hydrologic model: 

• Pumping rates at existing sources were increased to 

levels currently permitted by the Massachusetts Water 

Management Act (WMA) (test 1). 

• Pumping rates were increased at existing and 

proposed sources to levels that included increases in 

WMA permits that were requested at the time of the 

study (test 2). 

 Figure 3. Major components of the annual water budget for the 

Upper Charles River Basin, as represented by the hydrologic 

model. The hydrologic system is dominated by one major inflow, 

recharge from precipitation, and one major outflow, stream base 

flow out of the basin.

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Figure 4. Average annual withdrawal rates and current 

and proposed rates permitted by the Massachusetts Water 

Management Act for existing conditions and for two tests of 

increased withdrawals in the Upper Charles River Basin. (CC, 

country club; NEA, Northeast Energy Association).

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Figure 5. Model-calculated average September base flow along Mine and Miscoe 

Brooks for existing conditions and for two tests of increased withdrawals in the Upper 

Charles River Basin. (Ground-water withdrawals along the river are indicated as

FR-01P, FR-03G, FR-06G, FR-01G, FR-02G, MGCC-01G, and FR-07G. Identifiers 

ending in “P” indicate proposed ground-water withdrawals.) 

Figure 6. Model-calculated average September base flow along the Charles River for 

existing conditions and for two tests of increased withdrawals in the Upper Charles 

River Basin. (Ground- (G) and surface- (S) water withdrawals along the river are indicated as MF-01S, MF-01G, MF-02G, MF-03G, MF-04G, MF-05G, BL-12G, MD-01G, 

MD-03G, FR-08G, and FR-02P; wastewater discharges are indicated as MTF, Milford 

Treatment Facility, and CRPCD, Charles River Pollution Control District Facility in 

Medway. Identifiers ending in “P” indicate proposed ground-water withdrawals.)

The hypothetical withdrawals are 

compared with existing withdrawals 

on an annual average basis in

figure 4; withdrawals were 

increased in the model at each 

source with monthly variations 

(greater withdrawals in summer 

months) that mimic the existing 

seasonal patterns in the basin. 

Overall, total withdrawal rates in 

the basin in the two tests (14.2 to 

15.4 Mgal/d) were 42 to 54 percent 

greater than existing withdrawal 

rates. Wastewater discharges at 

treatment facilities and through 

septic systems also were increased, 

in accordance with existing waterdisposal practices.

Increased withdrawals led to 

additional streamflow depletion 

relative to that simulated for 

existing conditions in both tests. 

The flow reductions were generally 

greatest in late summer and early 

fall, when streamflow was low and 

increased withdrawals were large 

compared to other months of the 

year. Effects varied in magnitude 

among tributaries to the Charles 

River. In the Mine Brook tributary 

in Franklin, increased withdrawals 

reduced stream base flow by about 

12 percent relative to existing flows 

along Mine Brook in September 

(fig. 5). The effects of the two tests 

were similar along most of the 

Mine Brook tributary, but differed 

in its headwaters along Miscoe 

Brook, where flow downstream of a 

proposed well (FR-01P, fig. 5) was 

reduced by as much as 50 percent 

in test 2. In general, the effects of 

increased withdrawals were largest 

where supply wells were located 

in headwater areas or near small 

streams, such as Miscoe Brook, 

Stall Brook, Bellingham

(late-summer flow reductions of 

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have implications for water quality 

in the Charles River. Stream base 

flow in September was about 90 

and 27 percent treated wastewater 

downstream of the Milford and 

Medway treatment facilities in 

these increased-withdrawal tests, as 

compared with 80 and 18 percent 

wastewater, respectively, under 

existing conditions.

APPLICATION OF THE 

MODEL TO TEST ALTERED 

RECHARGE FROM

SEWERING AND WATER 

CONSERVATION

The effects of altered recharge 

associated with human influence 

were simulated in the Mine Brook 

tributary subbasin in Franklin, MA, 

in two ways:

• The effects of sewering in a 

typical aquifer area were tested 

by adding an areal recharge equal 

to the amount of water estimated 

as removed from the subbasin by 

sewers (test 3).

• The effects of a water-conservation practice, the capture and 

recharge of runoff from rooftops, 

were tested by adding an areal recharge representing the amount of 

rainwater that could be collected 

from residential rooftops (test 4). 

Results of these tests (fig.7) 

indicated that the effects of 

sewering on stream base flow can be 

substantial, equivalent to an increase 

in base flow in September of about 

12 percent along the length of Mine 

Brook relative to existing conditions. 

In contrast, the increase in base 

flow from recharge of residential 

rooftop runoff was small, up to 

about 3 percent relative to existing 

conditions (fig. 7). 

Figure 7. Model-calculated average September base flow along Mine and Miscoe 

Brooks for existing conditions and for two tests of altered recharge in the Upper Charles 

River Basin. (Ground-water withdrawals along the river are indicated as FR-01P, FR03G, FR-01G, FR-02G, FR-06G, MGCC-01G, and FR-07G. Identifiers ending in “P” 

indicate proposed ground-water withdrawals.)

and flowed at least partly to streams 

far from the withdrawal site. Second, 

water withdrawn from a well near a 

stream reduced streamflow almost 

immediately, but most of the septicsystem discharge did not reach the 

depleted stream until months later. 

In the Charles River, flow 

depletions from increased 

withdrawals were balanced by flow 

augmentations from wastewater 

discharge from two treatment 

facilities in Milford and Medway 

(stream-miles 4 and 21; fig. 6). 

Simulated base flow in the Charles 

River, where it exits the modeled 

area, increased in September in the 

two tests, because the wastewater 

discharges from high summer 

withdrawals were delivered 

immediately to the river in summer 

months, but the flow depletion in 

the river and its tributaries from the 

high summer pumping rates took 

longer to occur. These changes also 

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more than 60 percent), and Miller 

Brook, Franklin (late summer flow 

reductions of more than 80 percent) 

(fig. 1). 

Stream base flow was reduced 

in tributary streams from increased 

withdrawals whether the withdrawn 

water was returned to the aquifer 

after use through septic systems or 

removed from the tributary subbasin through sewers. The effects 

were greater and more widespread, 

however, when sewers removed the 

water from the subbasin. In sewered 

areas such as the Mine Brook subbasin, where wastewater was delivered to a downstream treatment 

facility, reductions in flow generally 

equalled the increased withdrawals along the length of the stream. 

In unsewered subbasins, reductions 

in stream base flow were a fraction 

of upstream withdrawals for two 

reasons. First, septic-system discharge occurred over a wide area, 
Page 6 

Figure 8. Aquifer area in the Upper Charles River Basin where simulation-optimization methods were applied. (Municipal 

wells without identifiers were not included in the example optimization problem.)

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NF-01G

C3

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Mill Riv

er

FR-08G

FR-02P

NF-01G

FR-04G

NF-01P

FR-05G

C1

C2 C3

C4

C6

C5

Kingsbury

Pond

Populatic

Pond

MEDWAY

FRANKLIN

NORFOLK
Page 7

of streams to pumping at wells 

distributed throughout the hydrologic 

system. 

CONCLUSIONS

A hydrologic model and 

simulation-optimization 

techniques can effectively test 

scenarios of increased water 

withdrawals, altered recharge, 

and other changes in inflows 

and outflows to the hydrologic 

system in the Upper Charles 

River Basin. Effects on stream 

base flow are demonstrated that 

provide insight on the connections 

between ground water, surface 

water, recharge, withdrawals, 

and discharges in a developing 

area. This information and results 

of similar tests can inform and 

guide water-management actions 

by towns, State regulators, and 

others involved in water-resource 

management in the basin. 

stream base flow at six constraint 

locations (fig. 8) had to equal or 

exceed simulated base flow under 

existing conditions during summer 

months. 

Results suggested that additional 

water could be withdrawn in this area 

without decreasing streamflows during 

the summer months. Under existing 

conditions, summer pumping rates 

from all wells averaged 1.55 Mgal/d. 

By altering pumping schedules and 

using new wells, summer pumping 

rates increased by 26 percent to 1.95 

Mgal/d (fig. 9). These gains were 

obtained without decreasing stream 

base flow during summer months at 

constraint locations by pumping less 

in summer from wells close to streams 

(FR-05G), distributing pumping to 

new wells (FR-02P and NF-01P), 

and pumping more in summer from 

wells distant from streams (FR-04G 

and NF-01G). Thus, the solution, as 

determined by simulation-optimization 

modeling, takes advantage of 

differences in the response times 

SIMULATIONOPTIMIZATION OF

WATER WITHDRAWALS

In simulation-optimization 

modeling, a numerical hydrologic 

model is used with optimization 

techniques to find the “best” way to 

meet a water-resource goal defined 

as some quantity to be maximized or 

minimized. Limitations (constraints) 

are set on the allowed response 

of the hydrologic system. Use of 

these techniques was tested in the 

UCRB by constructing several 

hypothetical management problems 

for a small part of the basin near the 

confluence of the Charles and Mill 

Rivers (fig. 8). One management 

problem quantified how much more 

water could be withdrawn from the 

aquifer in this area while maintaining 

streamflow during the high-demand 

months of June, July, and August. 

Constraints were set on the increased 

withdrawals, by specifying that 

Figure 9. Monthly pumping rates for existing conditions and for an example optimization problem where withdrawals at existing (G) 

and proposed (P) wells are increased but streamflow is maintained during summer months (June through August). 

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Page 8

More information on the Upper Charles River Basin 

hydrologic model and simulation results can be 

obtained in:

DeSimone, L.A., Walter, D.A., Eggleston, J.R., and 

Nimiroski, M.T., 2002, Simulation of groundwater flow and evaluation of water-management 

alternatives in the Upper Charles River Basin, 

Eastern Massachusetts: U.S. Geological Survey 

Water-Resources Investigations Report 02-4234, 

94 p. 

By Leslie A. DeSimone

For further information about water resource 

activities in Massachusetts contact the USGS at:

U.S. Geological Survey

Massachusetts-Rhode Island District Office

10 Bearfoot Road

Northborough, MA, 01532

telephone: 508-490-5000

fax: 508-590-5068

http://ma.water.usgs.gov

For more information about the U.S. Geological 

Survey, go to:

http://www.usgs.gov. 

Charles River, Medway, Massachusetts (courtesy of John R. Eggleston)