A GIS Analysis of Boston Harbor and the Charles River Boston, Massachusetts

1
A GIS Analysis of Boston Harbor and the Charles
RiverBoston, Massachusetts

• Amy Townsend-Small
• GIS in Water Resources
• Fall 2001

The Boston skyline as seen from the Charles River
2
Historical Background

• The Boston Tea Party may have been the first
  recorded incident of the pollution of Boston
  Harbor, but unfortunately it wasnt the last.
• The City of Boston dumped sewage sludge and
  treated sewage into the harbor for over 100
  years.
• In the 1988 presidential election, the Democratic
  candidate, Michael Dukakis, then governor of
  Massachusetts, was criticized for what Republican
  candidate George Bush called the dirtiest harbor
  in the world.

Artists rendition of the Boston Tea Party, 1773
President Bushs comments led to the creation of
several state agencies to clean up Bostons
waterways. Ill be presenting the results of
those clean-up efforts.
3
Monitoring the Pollution of the Waters of Boston
Harbor

• In 1998, sewage discharge was stopped at the Nut
  Island STP and its sewage was pipelined to the
  Deer Island STP, where it was discharged into the
  harbor.
• The Massachusetts Water Resources Authority
  collected the following data before and after the
  transfer
• Nitrogen concentration
• Phosphorus concentration
• Chlorophyll-a concentration
• Dissolved oxygen saturation
• Fecal coliform bacteria counts
• Water clarity

An excess of nutrients like nitrogen and
phosphorus can lead to eutrophication of aquatic
systems, characterized by microalgae blooms and
high dissolved oxygen saturation.
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Dissolved Inorganic Nitrogen in Boston Harbor
Before
After

• Concentrations of DIN decrease after the transfer
  of sewage effluent to the new site

5
Total Nitrogen in Boston Harbor
Before
After

• Concentrations of total nitrogen decrease after
  the transfer of sewage effluent to the new site

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Dissolved Inorganic Phosphorus in Boston Harbor
Before
After

• Concentrations of DIP increase after the transfer
  of sewage effluent to the new site

7
Total Phosphorus in Boston Harbor
Before
After

• Concentrations of total phosphorus increase after
  the transfer of sewage effluent to the new site

8
Chlorophyll-a in Boston Harbor
After
Before

• Standing stocks of chlorophyll-a increased after
  the transfer of sewage effluent to the new site

9
Dissolved Oxygen in Boston Harbor
Before
After

• Dissolved oxygen decreased in saturation after
  the transfer of sewage effluent to the new site

10
Fecal Coliform in Boston Harbor
Before
After

• Fecal coliform counts decreased after the
  transfer of sewage effluent to the new site

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Water Clarity in Boston Harbor
Before
After

• Water clarity improved after the transfer of
  sewage effluent to the new site

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Summary of Water Quality Changes in Boston Harbor

• Phosphorus and chlorophyll-a increased in
  concentration
• Nitrogen, dissolved oxygen, and fecal coliform
  decreased in concentration, and water clarity
  increased.

Whale watchers in Boston Harbor
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Heavy Metal Contamination in the Sediments of
Boston Harbor

• In addition to dumping sewage effluent, Boston
  also disposed of sewage sludge into the harbor
  for over 100 years. In 1991, this practice was
  stopped altogether.
• Sewage sludge is high in heavy metals such as
  iron, copper, and lead.
• How has the concentration of these metals in
  sediments changed since 1991?

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Lead in Boston Harbor Sediments
1991
1998

• Generally, lead concentrations decreased in the
  former sludge dumping site and increased in the
  site closer to shore.

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Copper in Boston Harbor Sediments
1991
1998

• Copper concentrations in the sediments decreased
  in the former sludge dumping site, and copper
  concentrations increased in the site closer to
  shore.

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Iron in Boston Harbor Sediments

• Again, iron concentrations decreased in the
  former sludge dumping site and increased in the
  site closer to shore.

17
Summary of Changes in Metal Content of Harbor
Sediments

• Since the metal content decreased in the former
  sludge dumping site, the cessation of sludge has
  improved harbor conditions. However, there seems
  to be another source of metals to Boston Harbor.

Logan Airport
Charles River
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Pollution of the Charles River

• The Charles River is the largest river that
  discharges to Boston Harbor. It is also an
  important recreational resource for the city.
  However, it is dangerous to swim in because of
  high bacteria levels.
• In 1995, the EPA declared its goal to make the
  Charles swimmable by 2005. Their efforts have
  included picking up trash, the creation of sewage
  treatment plants in towns along the river that
  relied on aging septic systems, and sustainable
  development of communities in the watershed
• How has water quality changed in the Charles
  River?

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Total Phosphorus in the Charles River
1997
2000

• There is a slight increase in total phosphorus
  levels in the Charles River between 1997 and 2000.

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Total Nitrogen in the Charles River
1997
2000

• There was a general decrease in nitrogen in the
  Charles River from 1997 to 2000

21
Chlorophyll-a in the Charles River
1997
2000

• There was a marked decrease in chlorophyll-a
  concentrations from 1997 to 2000

22
Fecal Coliform in the Charles River
1997
2000

• Fecal coliform levels stayed about the same in
  the Charles River from 1997 to 2000

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Summary of Changes in Water Quality of the
Charles River

• There was a slight increase in fecal coliform
  counts and phosphorus in the Charles from 1997 to
  2000.
• There were major improvements in nitrogen and
  chlorophyll-a levels in the Charles from 1997 to
  2000.

A new bridge, part of Bostons Big Dig, crosses
the Charles downtown
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References

• Taylor, D. 2001. Comparison of water quality in
  Boston Harbor before and after inter-island
  transfer. Boston Massachusetts Water Resources
  Authority. Report ENQUAD 2001-09. 104 p.
•  
• Zago, C., Giblin, A.E., and Bergamasco, A. 2001.
  Changes in the metal content of surficial
  sediments of Boston Harbor since the cessation of
  sludge discharge. Marine Environmental Research,
  vol. 51, pp. 389-415.
•  
• Charles River Watershed Authority, www.crwa.org

A dog enjoys a day by the banks of the Charles