Boston Harbor water quality update, 1995 to 2017

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Boston Harbor Water Quality Update
1995 - 2017 
Massachusetts Water Resources Authority 
Environmental Quality Department 
Report 2018-06

Citation: Taylor, DI. 2018. Boston Harbor Water Quality Update, 1995-2017 . Boston:
Massachusetts Water Resources Authority Report 2018-06. 16 p.

i 
BOSTON HARBOR WATER QUALITY 
UPDATE, 1995 - 2017 
Prepared by: 
David I Taylor 
MASSACHUSETTS WATER RESOURCES AUTHORITY 
Environmental Quality Water and Wastewater Department 
100 First Avenue, Charlestown Navy Yard, 
Boston, MA 02129 
September 2018 
Report No: 2018-06 
Acknowledgements: Laura Ducott, Kelly Coughlin, Eric Sanderson, Chris Goodwin, Doug Hersh,
Caitlin Chafee, Bryan Burton, Tim Heckmann, Elmire Hilaire, Renee Angelo, Julia Wallace

ii 
TABLE OF CONTENTS 
EXECUTIVE SUMMARY ……………………………………………………………… 1 
1. INTRODUCTION …………………………………………………………………. 2 
2. SAMPLING PROGRAM …………………………………………………………... 2 
3. RESULTS … 
NITROGEN AND PHOSPHORUS CONCENTRATIONS…………………… 4 
NUTRIENT CONCENTRATION
RATIOS………………………………………………………………………... 6 
PHYTOPLANKTON BIOMASS ……………………………………………… 7 
SUSPENDED SOLIDS, PARTICULATE ORGANIC MATTER…………….. 8 
TRANSPARENCY…………………………………………………………….. 10 
BOTTOM-WATER DISSOLVED OXYGEN…………………………………. 11 
PATHOGEN INDICATOR COUNTS…………………………………………. 14 
WATER TEMPERATURES AND SALINITY…………………………….….. 15 
RIVER DISCHARGES TO THE HARBOR…………………………………… 15 
4. CONCLUSIONS …………………………………………………………………… 16 
5. REFERENCES ………………….…………………………………………….. 16

1 
EXECUTIVE SUMMARY 
The Massachusetts Water Resources Authority has monitored water quality in Boston Harbor since the
early to mid-1990’s in support of its wastewater engineering projects, that have included among others,
the Boston Harbor Project, the CSO Control Plan, TRAC pretreatment program, and programs to decrease
infiltration into the sewer system. This report documents water quality in Boston Harbor during 2017,
and compares it with water quality since 1994 to 2016. The aspects of water quality addressed in the
report are relevant to public use of the harbor (microbial pathogen counts, water column transparency)
and to the health of the harbor ecosystem (nutrients concentrations, amounts of algae, particulate organic
matter in the water, transparency dissolved oxygen concentrations). In the late 1980’s, the harbor
ecosystem was severely degraded, and in many regions unsafe for human recreation use. 
During 2017, many of the water quality changes that have followed the implementation of the wastewater
projects continued. Water column total N and P concentrations were both lower than during years the
harbor received wastewater discharges from Deer Island and Nut Island WWTF’s or from DI WWTF
alone. The proportion of the total N contributed by DIN remained lower, and the proportion of the DIN
contributed by NO3+2 higher than during the wastewater discharges. Primary production, as in most post-
diversion summers, was N relative to Si and P limited. 
2017 summer phytoplankton biomass, as in all except one year since outfall diversion (2002 being the
exception), was lower than during summers the harbor received the wastewater discharges. Annual
biomass during 2017 was, however, the second highest since the discharges to the harbor were
discontinued. Increases in biomass since ca. 2012-2013 have occurred in the Inner Harbor and the
Dorchester Bay regions of the harbor, [perhaps caused by lower than average river inflows, and increased
hydraulic residence times in these regions. 
Total suspended solids (TSS) and particulate organic C concentrations too have been elevated since
approximately 2012 or 2013. Consistent with this, the transparency of the water column too has been
relatively low in recent years. Resuspension of inorganic bottom sediments or erosion of the shoreline in
the east – southeastern portion of the harbor, perhaps caused by wind direction or intensity changes, have
been responsible for the increases since 2012-2013. Bottom-water DO concentrations, which have shown
a progressive increase since the mid-1990’s, were the second highest since monitoring was started, and
easily met the State Standard. Enterococcus counts averaged harbor-wide were low, and too easily met
the State Standard. 
Monitoring by the MWRA has provided valuable information on the changes, which in many cases have
been improvements, the harbor has undergone since the early 1990’s. The wastewater infrastructure
improvements undertaken by the MWRA and others, in combination with differences in river discharge
and long-term temperature increases, have likely contributed to these changes.

2 
1. INTRODUCTION 
During the past 20 years, and in support of its
wastewater engineering projects, MWRA has
monitored water quality in Boston Harbor ( Fig.
1 ). The engineering projects have included,
among others, the Boston Harbor Project (BHP),
the combined sewer overflow (CSO) Control
Plan (MWRA 2015), the TRAC pretreatment
program, and programs to decrease infiltration
into the sewer system. The BHP was
implemented from 1991 through 2000, and the
CSO Control Plan from 1996 to 2015. The
TRAC pretreatment and the Infiltration and
Inflow programs are ongoing. 
This report addresses trends in three aspects of
water quality pertinent to the health of the
Boston Harbor ecosystem and to public using
the harbor, specifically: 
• system over-enrichment or
eutrophication (measured as amounts of
algae, nutrient concentrations and
bottom-water dissolved oxygen), 
• water transparency (measured as total
suspended solids and irradiance or light
attenuation coefficients), and 
• microbial pathogen indicator counts
(measured as counts of the enteric
bacterium, Enterococcus ). 
• In this report, which is an update of
Taylor (2016), we document Boston
Harbor’s water quality in 2017, and
compare it with water quality since the
monitoring started (1994 for certain
variables and 1995 for others). The
report takes a big-picture approach,
focusing on annual and seasonal water
quality, averaged for the Harbor as a
whole, and for the two main regions of
the Harbor, the Inner Harbor (IH) and
Outer Harbor (OH). 
Fig. 1. View into Boston Harbor from
Massachusetts Bay, with Deer Island WWTF
on the right, and Boston to the rear. 
2. SAMPLING PROGRAM 
Water quality was measured at 9 locations in the
harbor as part of MWRA’s Boston Harbor Water
Quality Monitoring (BHWQM) project ( Fig. 1 ).
Three locations were sampled in the IH (137,
138 and 24), the other six locations were located
in or at the mouth of the OH (106, 124, 139,
1409, 141 and 142). Station coordinates are
shown in Table 1. Sampling was conducted at
least once per every two weeks. Sampling and
analytical procedures are described in Rex and
Taylor (2000). All harbor-wide averages are
volume-weighted by region (described in Taylor
et al. 2011). Horizontal bars at the top of each
graph show the 17 years since the discharges to
the harbor were diverted offshore in Sept. 2000.

3 
Fig. 2. Boston Harbor showing the nine
water column sampling locations, and the
Inner Harbor (IH) and Outer Harbor (OH)
regions. 
Table 1. Boston Harbor sampling locations 
Station
Id 
Marine or
freshwater 3 Description Coordinates Monitoring
years 1 
024 Marine; Inner harbor mouth 42 20.66, 71 2.74 1993 – 2017 
106 Marine; Outer harbor, NE of Long Island 42 19.95, 70 57.54 1993 – 2017 
124 Marine; Hingham Bay, Crow Point flats 42 16.36, 70 53.86 1993 – 2017 
137 Marine; Mystic River mouth 42 23.21, 71 3.77 1993 – 2017 
138 Marine; 
l d b b 
Central inner harbor 42 21.56, 71 2.74 1993 – 2017 
139 Marine; Quincy Bay, SW of Hangman Island 42 17.20, 70 58.10 1993 – 2017 
140 Marine; 
l d b b 
Neponset River mouth/S. Dorchester Bay 42 18.35 71 2.43 1993 – 2017 
141 Marine; Outer harbor, NE of Peddocks Island 42 18.30, 70 55.85 1993 – 2017 
142 Marine; 
l d b b 
Outer harbor, President Roads, south
channel 
42 20.35, 70 55.89 1993 – 2017

4 
3. RESULTS 
Nitrogen (N) and phosphorus (P)
concentrations 
During 2017, as in all other years since the
wastewater discharges to the harbor were
diverted offshore (2000), harbor total nitrogen
(N) and total phosphorus (P) concentrations
were lower than during the years the harbor
received the wastewater discharges ( Fig. 4 and
5 ). 2017 total N and P concentrations were the
highest since the discharges to the harbor were
discontinued, but neither nutrient has shown an
uptrend since 2000. 
During 2017, as in other post-diversion years,
dissolved inorganic N (DIN) contributed a
smaller proportion the harbor’s total N ( Fig. 6 ).
(DIN contributed most of the wastewater N that
used to be discharged to the harbor). As in other
post-diversion years, 2017 nitrate + nitrite:
ammonium (or NO3+2: NH4) concentration ratios
were greater than during years the harbor
received the wastewater discharges. 
Not only have the amounts of N in the harbor
water column been lowered, but the composition
of this smaller N pool too has been changed. All
nine locations have seen decreased total N and
ammonium concentration since 1996 ( Fig. 7 ).
From the Mystic River arm of the IH (Stn. 137)
south to the Hingham Bay region of the Outer
Harbor (Stn. 124), the N and ammonium
declines brought about by the Boston Harbor
Project have been sustained into 2017. 
Fig. 3. Technical staff taking water samples
and measurements of water quality in Boston
Harbor.

5 
0
10
20
30
40
50
2017
2015
2013
2011
2009
2007
2003
2005
2001
1999
1997
Monthy harbor-wide average
conc. (micromol/L) 
DIN
NON-DIN 
1995
N CONCENTRATION
Post-diversion 
Fig. 4. Time series plot of monthly harbor-wide average total N concentrations partitioned into the
dissolved inorganic N (DIN) and non-DIN fractions, 1995-2017. 
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016 0
10
20
30
40 
TOTAL NITROGEN 
Annual average TN
(  mol l -1 )
NON-DIN
DIN
Post-diversion
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016 0.0
0.5
1.0
1.5
2.0
2.5 
Post-diversion
TOTAL P 
Annual average conc.
(  mol l -1 )
Non-DIP
DIP 
Fig. 5. Annual average total N (top) and total
P concentrations (bottom). 
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016 10
20
30
40
50
% 
DIN as % TOTAL N 
Post - diversion 
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016
0
1
2
3
4
5
6
Post-diversion 
ANNUAL MOLAR
N0 3+2 : NH 4 RATIO 
NO 3+2 : NH 4 
Fig. 6. Annual DIN expressed as percent total
N (top), and NO3+2: NH4 molar ratios
(bottom).

6 
Fig. 7. Annual total N concentrations partitioned into the non-ammonium and ammonium
fractions at the nine sampling locations, 1995-2015. 
Nutrient concentration ratios 
The implementation of the Boston Harbor
Project also altered the DIN: DIP concentration
ratios in the harbor (Fig. 8). DIN in the harbor
tends to be drawn down relative to DIP during
summers (when algae production is greatest and
river inflows lowest), and during all except one
of the summers since the discharges to the
harbor were discontinued (2008 being the
exception), DIN: DIP concentrations have been
lower than during years the harbor received the
discharges ( Fig. 9 left ).

7 
Based on its summer DIN: DIP and DIN: DISi
ratios relative to Redfield (N:P = 16:1 and N:Si
= 1.07, blue dashed lines), during years the
harbor received the wastewater discharges, its
summer primary production was Si relative to N
and P limited ( Fig. 9 right ). The diversion of the
discharges to the harbor caused the primary
nutrient liming production to shift from Si to N . 
0
5
10
15
20
25
30
35 
2017
2015
2013
2011
2009
2007
2003
2005
2001
1999
1997
Monthy harbor-wide DIN:DIP
(molar)
1995
DIN:DIP
Post-diversion 
Redfield
Ratio =
16:1 
Fig. 8. Annual total N concentrations partitioned into the non-ammonium and ammonium
fractions at the nine sampling locations, 1995-2015. 
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016
0
5
10
15
20
Post-diversion 
DIN:DIP (molar) 
MOLAR DIN:DIP
(summer) 
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016
0.0
0.5
1.0
1.5
2.0
2.5
Post-diversion 
Summer dissolved inorganic
N:Si molar ratio 
DIN:DISi
(summer) 
Redfield Ratio
(N:Si = 1.07:1) 
Fig. 9. Summer DIN: DIP and DIN: DISi concentration ratios, 1995-2017. Summer = J, J, A and S

8 
Phytoplankton (floating microalgae)
biomass 
During most years since the discharges to the
harbor were discontinued, and especially during
summers, harbor phytoplankton biomass has
been lower than during the discharges ( Fig. 10,
11 ). Biomass during 2017 was in the upper
range for years since the final wastewater
diversion. During years since the diversion
biomass variability year to year has been greater
than for instance, nutrients. Elevated biomass
during this post-diversion period was observed
in 2002-2003, and then again in from 2012 or
2013 through 2017. 
0
4
8
12
16
2017
2015
2013
2011
2009
2007
2003
2005
2001
1999
1997
Monthy harbor-wide average
conc. (microgram/L) CH 
1995
CHLOROPHYLL A
Post-diversion 
Fig. 10. Time series plot of monthly average phytoplankton biomass (measured as chlorophyll-a),
1995-2017. 1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016
0
2
4
6
8
Post-diversion 
Annual average chl-a conc. ( μ g L -1 ) 
PHYTOPLANKTON BIOMASS
(annual) 
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016
0
2
4
6
8
10
Post-diversion 
Mean chl-a conc. ( μ g L -1 ) 
PHYTOPLANKTON BIOMASS
(summer) 
Fig. 11. Annual and summer (J,J,A,S) average phytoplankton biomass, 1995-2017

9 
The summer biomass increases since 2012 have
been observed at all nine locations, but
especially at the three Inner Harbor stations
(137, 138 and 24) and the single Dorchester Bay
station (140) in the Outer Harbor ( Fig. 12 ). 
Fig. 12. Summer chl-a concentrations at the nine sampling locations, 1995-2017.

10 
Suspended solids and particulate
organic matter 
Harbor total suspended solids (TSS) in 2017,
unlike for nutrients, were greater than during
years the harbor received the wastewater
discharges ( Fig. 13 ). 2017 particulate organic C
(POC) concentrations were the highest since the
discharges to the harbor were discontinued, but
fell within the range seen during the discharges.
Although both TSS and POC have increased
during the 17 years since the discharges were
diverted offshore, the percent POC content of
the TSS has shown a progressive decrease,
suggesting increased inorganic particle (silts or
clays) concentrations have been largely
responsible for the increases. 
Unlike for chl-a, where the increases during
recent years have been greatest in the Inner
Harbor and Dorchester Bay, the TSS increases
have been focused in Dorchester Bay (140) and
the southeast portions of the Outer Harbor (139
and 141) ( Fig. 14 ). 
Transparency 
2017 water column transparency, measured as
rates of light attenuation through the water
column, was the poorest since 1996 ( Fig. 13 )
Note the greater the attenuation coefficients (k),
the poorer the transparency. The slightly poorer
transparency from 2012 to 2017 corresponds the
elevated chl-a, TSS and POC concentrations
observed during the same five years. 
From 1996 through 2017, the potential 1%
incident light penetration depth, which is the
depth above which photosynthesis exceeds
respiration, has averaged 7.3 m ( Fig. 15 ). This
is time the mid-tide water depth, suggesting
algae production during the 22-year period has
not been limited by light availability. 
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016 0
2
4
6
8
10 
TSS PARTITIONED INTO POC AND
NON-POC 
Annual average TSS
(mg l -1 )
NON-POC
POC
Post-diversion 
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016
0
20
40
60
Post-diversion 
Annual POC conc. ( μ mol l -1 ) 
POC 
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016 0
5
10
15
20
25 
POC as % TSS 
Annual mean POC as
% TSS
Post-diversion 
Fig. 13. TSS, POC and POC as % TSS (by
weight), 1996-2017.

11 
Fig. 14. Spatial patterns of TSS concentrations, 1995-2017. 
Bottom-water dissolved oxygen (DO) 
Bottom-water DO concentrations in the harbor
each year are typically lowest during late
summers. During 2017, as in every summer
except 2009 since the discharges to the harbor
were discontinued, harbor-wide average bottom-
water DO concentrations were greater than
during 1994 to 1999, when the harbor received
the discharges ( Fig. 16 ). Years in which
summer DO concentrations were greater than
during the discharges are indicated by circles in
the Figure. The DO increase between 2000 and
2001, coincided with the final wastewater
diversion offshore in 2000. 
Minimum survey harbor-wide average bottom-
water DO increased from 5.9 mg l -1 slightly
below the State Standard of 6.0 mg l -1 in 1994 to
7.5 mg l -1 in 2017 ( Fig. 17 ). Both the Inner
Harbor and Outer Harbor regions showed the
DO increases. values in 2017 were the third
highest since 1994 ( Fig. 17 right ).

12 
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016 0.2
0.4
0.6
0.8 Post-diversion
LIGHT ATTENUATION 
Annual average k
(m -1 ) 
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016 -10
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1
water surface
1%
Mean depth of 1% and 20% incident
irradiance penetration (m)
sediment surface
Post-diversion 
LIGHT PENETRATION 
Fig. 15. Vertical light attenuation coefficients, a measure of transparency (left), and potential 1%
incident irradiance penetration depths (right). 
6
8
10
12
14
2017
2015
2013
2011
2009
2007
2003
2005
2001
1999
1997
Monthly harbor-wide average
DO conc. (milligram/L)
1995
BOTTOM-WATER DO
Post-diversion
State std 
Denote summers when minimum monthly values were greater
than during all six of the final summers the harbor received the
wastewater discharges 
Fig. 16. Time-series monthly harbor-wide average bottom-water DO concentrations. 
As can be seen from Figure 18 , bottom-
water DO concentrations have been
increased at all nine locations, with the
increases in the Inner Harbor occurring from
lower initial values than in the Outer Harbor.

13 
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016
4
5
6
7
8
9
10 
Post-diversion
Minimum survey average bottom-water
DO conc. ( MG L -1 ) 
Bottom-water DO 
State
std. 
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016 4
6
8
10 
IH 
Minimum bottom-water DO
conc. (mg l -1 ) 
MINIMUM BOTTOM-WATER DO 
Post - diversion 
OH 
State
std 
Fig. 17. Lowest survey-average bottom-water DO concentrations observed each year for the
harbor as a whole (left) and for the Inner and Outer Harbor regions (right), 1994-2017. 
Fig. 18. Minimum monthly-average bottom-water DO concentrations, 1994-20170. Shaded areas
show years the values failed to meet State Standard.

14 
Pathogen indicator counts 
Harbor-wide geometric mean counts of the
pathogen indicator bacterium, Enterococcus ,
in 2017 were in the order of one third of
what they were in the early to mid-1990s
( Fig. 19 ). At all nine locations, 2017 counts
were also lower than they were during the
early to mid-1990s ( Fig. 20 ). During all
years, for the harbor as a whole and for all
nine locations, geomean Enterococcus 
counts have been < 33 cfu 100 ml -1 , the
State swimming standard. 
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016 0
4
8
12
16
20 
Post-diversion 
GEOMETRIC MEAN ENTEROCCUS
COUNTS (MPN 100 ML -1 ) 
ENTEROCOCCUS 
Fig. 19. Annual average Enterococcus counts. 
Fig. 20. Annual geomean Enterococcus counts, 1994-2017.

15 
Water temperature and salinities 
Harbor-wide average water temperatures during
2017 were the third highest since 1994, and
above the long-term average ( Fig. 21 ). Average
salinities approximated the long-term average
(30.6 psu). Water temperatures in the Inner
Harbor (Stations 137, 138 and 24) have shown
no trend since 1993, but in the outermost Outer
Harbor (stations 106, 142, 139 and 141), and
both in the near-surface and near-bottom-waters)
have increased (Fig. 22). 
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016
6
7
8
9
10
11
12
13
Post-diversion 
ANNUAL MEAN TEMPERATURE
( o C) 
WATER TEMPERATURE 
Long-term mean 
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016
28
29
30
31
32
Post-diversion 
ANNUAL MEAN SALINITY
(PSU) 
SALINITY 
Fig. 21. Average harbor water temperatures
and salinities, 1994-2017. Dashed lines show
long term averages for the period 1995
through 2017. 
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016
2018 13
14
15
16
17
18
19
20
21
22
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016
2018 13
14
15
16
17
18
19
20
21
22 OUTER HARBOR 
Near surface
Near bottom 
INNER HARBOR 
Mid-summer average water temperature ( o C)
Near-surface
Near-bottom 
Fig. 22. Near-surface and near-bottom, mid-
summer (J, A, S) average water temperatures
in the Inner Harbor and outermost Outer
Harbor regions, 1994-2017. 
River discharges to the harbor 
Annual river discharges, which vary widely, and
from between 1.4 x10 6 m 3 d -1 to 3.2 x10 6 m 3 d -1
year to year, has shown no trend since 1990
( Fig. 23 ). Discharges during five of the last six
years of this study, were well below the long-
term average of 2.2 x10 6 m 3 d -1 . Discharges
during previous years have fallen to levels seen
in 2012-2013 to 2017, but not for the extended
period seen at the end of this study.

16 
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
2016
2014
Long-term
average
1990 - 2017
(2.2 x10 6 m 3 d -1 )
2012
2010
2008
2006
2004
2002
2000
1998
1996
ANNUAL AVERAGE RIVER FLOWS
(x10 6 M 3 D -1 )
1994 
RIVER DISCHARGE 
Post-diversion 
Fig. 23. Annual average river flows (Charles,
Mystic, Neponset, Weymouth-Weir) to
Boston Harbor (data from USGS). 
4. CONCLUSIONS 
Many of the harbor water quality improvements
that followed the implementation of the BHP
and CSO Control Plan continued into 2017.
Total N, total P, POC as %TSS, and 
Enterococcus counts during 2017 were among
the lowest since the study started. Mid-summer
bottom-water DO concentrations during 2017
were the third highest since 1994. 
For a number of variables, including
phytoplankton biomass, TSS, POC and light
attenuation coefficients, values have increased
from 2012 or 2013 into 2017. These increases
were perhaps related to the low river inflows the
harbor received during all except one of these
final six years. 
5. REFERENCES 
MWRA 2015. Combined Sewer Overflow
Control Plan: Annual Progress Report 2014.
Massachusetts Water Resources Authority,
Boston. 
Rex A., Taylor D.I., 2000. Combined
Work/Quality Assurance Project Plan
(CW/QAPP) for Water Quality Monitoring and
Combined Sewer Overflow Receiving Water
Monitoring in Boston Harbor and Its Tributary
Rivers. Boston: Massachusetts Water Resources
Authority. Report 2000-ms-67. 48 p. 
Taylor DI. 2016. Boston Harbor Water Quality
1994-2015. Boston: Massachusetts Water
Resources Authority. Report 2016-08. 14 p. 
Taylor, D.I., Oviatt, C.A., Borkman, D.G., 2011.
Non-linear responses of a coastal aquatic
ecosystem to large decreases in nutrient and
organic loadings. Estuaries Coasts 34, 745-757.

33 
Massachusetts Water Resources Authority 
Charlestown Navy Yard 
100 First Avenue 
Boston, MA 02129 
(617) 242-6000 
www.mwra.com