Chesapeake
Bay
The word Chesepiooc is a Native
American word commonly believed to
mean “Great Shellfish Bay”
or “Great Water”.
Quick Facts: Geography
• Drains all or parts of six states, Delaware, Maryland, New York,
Pennsylvania, Virginia, and West Virginia, and all of the District of
Columbia.
• Largest estuary in the United States:
– Watershed area 64,000 mi2
– Bay area is 4,000 mi2 (so huge watershed to bay area ratio)
– Bay is approximately 200 miles long.
– Width varies from 3.4 miles to 35 miles near the mouth of the
Potomac River.
– Very shallow - average depth is 21 feet.
– Bay and its tidal tributaries have around 11,684 miles of
shoreline (more than the entire West Coast).
• Largest rivers flowing into the bay, from north to south, are:
Susquehanna River, Patapsco River, Choptank River, Patuxent
River, Potomac River, Rappahannock River, York River, and James
River.
States drained
by the
Chesapeake
Bay
watershed
Quick Facts: Water
• The Chesapeake holds more than 18 trillion gallons of water.
• Receives about half of its water volume from the Atlantic Ocean, the
rest drains into the Bay from the watershed.
• Eight to 90 percent of the freshwater entering the Bay comes from
the northern and western sides. The remaining 10 to 20 percent is
contributed by the Eastern Shore.
• Fifty major tributaries pour water into the Chesapeake every day.
• The Susquehanna River provides about 50% of the freshwater
coming into the Bay.
• Salinity ranges from freshwater (0-0.5 parts per thousand or ppt)
near the Susquehanna River to water of nearly oceanic salinity (3035 ppt) at the Chesapeake's mouth.
Chesapeake
Bay
watershed
&
sub-basins
Quick Facts: Environment and Economy
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Value of the Bay estimated to be above a trillion!
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The Bay supports more than 3,600 species of plants, fish and animals,
including 348 species of finfish, 173 species of shellfish and over 2,700
plant species. It is home to 29 species of waterfowl and is a major resting
ground along the Atlantic Migratory Bird Flyway.
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The Chesapeake is a commercial and recreational resource for the more
than 16 million people who live in its basin.
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Produces 500 million pounds of seafood per year.
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Bay has two of the five major North Atlantic ports in the United States
(Baltimore and Hampton Roads).
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Everyone in the watershed lives just a few minutes from one of the more
than 100,000 streams and rivers that drain into the Bay.
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The Chesapeake was the first in the nation to be targeted for restoration as
an integrated watershed and ecosystem.
Chesapeake Bay History
Bay formation and early inhabitants
• 9000 B.C. – Sea level rise from melting glaciers fills the
lower Susquehanna valley and begins forming the
Chesapeake Bay (at the end of the last Ice Age).
• Native tribes arrive in the Bay region.
• 2000 B.C. – The Bay assumes its current shape.
• 1000 B.C. – Native American agriculture begins. Crops
include corn, squash, beans and tobacco.
European contact and
colonization 1500-1775
•
1500s – Spanish and French explorers reach the Bay.
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1607 – The first permanent New World English settlement is established in
Jamestown, Virginia. John Smith, a member of its governing council, begins his
exploration of the Bay.
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1650s – The Colonists establish booming businesses in ship masts and timber.
Quickly develop agriculture economies, able to sustain their new colonies. Clear land
for agriculture and use, tobacco becomes main export item.
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1750 – Colonial population reaches 380,000 persons.
20-30% of forests are stripped for settlements.
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1775 – Colonial population reaches 700,000 persons.
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Most scholars agree that the first centuries of contact between Indians, Europeans
and Africans resulted in the greatest environmental change in the region since the
last Ice Age.
Trees cut for planting, lumber, and charcoal production  erosion  sedimentation.
Water impoundments behind mill dams  breeding ground for mosquitoes 
diseases (malaria, yellow fever).
First invasive species start being transported to the bay area.
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1775 – 1820 period
• 1800 – Population reaches 1,000,000 persons.
• 1813 – Oyster raking begins in the Bay.
• 1817 – Baltimore Gas Lighting Company, nation’s first
gas company.
• Expanding cities and harbors, major infrastructure
(roads, dams, bridges), first commercial steamboats on
the bay  more sedimentation, sewer and animal waste,
air pollution from burning coal.
1820 – 1880 period
• 1832 - 1835 – First imported fertilizers are used  improved
plantation agriculture.
• 1850 – Population exceeds 1.8 million.
• Oyster industry becomes big business.
• Oyster war between traditional oystermen (tongs) and those who
use dredging techniques  led to 1868 Oyster Navy (worked to
enforce anti-dredging laws).
• 1880 – Oyster breeding stocks severely threatened.
• Industrialization, urban growth, transportation improvements
radically transformed Chesapeake Bay landscape.
• Farmers cleared 40-50% of the land for planting fields.
• Untreated sewage from cities  water pollution.
Oyster Tongers
Skipjack
Urbanization 1880-1930
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1880s – Skipjack boats first produced.
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1890 – 60% of watershed forests are cleared.
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1900 – Population reaches 3 million.
less than 30% of the watershed’s original forest remains
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1914 – City of Baltimore is the last major American city to install sewer lines,
but one of the first to adopt a waste treatment system. System is installed
based on it’s ability to save valuable oyster beds.
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1920 – Population exceeds 4.5 million.
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Pollution is intensified.
Wetlands are drained to create more farmlands and to destroy breeding
grounds for mosquitoes.
Poultry farms starting becoming more prevalent.
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Chesapeake Metropolis 1930-2000
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1930 – Population of region reaches 5 million.
1940 – Population nears 5.5 million.
1945 – Widespread use of chemical fertilizers begins. Human population explodes,
and the suburb is born.
1967 – Chesapeake Bay Foundation is created (private environmental organization).
1970s – Commercial catches of striped bass dropped from 15 to 2 million pounds per
year. Major anoxic zones discovered.
1972 – Clean Water Act is passed.
1973 – Senator Charles Matthias of Maryland begins supporting studies to assess
the anthropogenic impacts on the Bay.
1980 – Chesapeake Bay Commission, a tri-state legislative body, is created.
1983 – Chesapeake Bay Program is established after Agreement is signed.
1984 – Chesapeake Bay water quality monitoring program is initiated by the CBP.
1986 – Bay program initiates its first nutrient management efforts.
1987 – Chesapeake Bay agreement is signed.
1990 – Population reaches 10.5 million.
2000 – Population reaches 12 million.
Chesapeake 2000 Agreement is signed.
Only 1.2 million of the original 3.5 million acres of wetland remain.
Impervious surface
map for 2000 for
the Chesapeake
Bay watershed.
Source: Woods Hole Research Center.
Chesapeake Bay Program
“Partnership”
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In the late 1970s and early 1980s, Congress funded scientific and estuarine research
of the Bay, and the findings pinpointed three areas that required immediate attention:
nutrient over-enrichment, dwindling underwater Bay grasses and toxic pollution.
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The Chesapeake Bay Program was established with the signing of The 1983
Chesapeake Bay Agreement, to restore and protect the Bay. It is a unique regional
partnership that directs and conducts the restoration of the Chesapeake Bay.
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CBP partners include the states of Maryland, Pennsylvania, Virginia; the District of
Columbia; the Chesapeake Bay Commission, a tri-state legislative body; the
Environmental Protection Agency, representing the federal government; and
participating citizen advisory groups, academia and non-profit organizations.
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Program Structure: designed to encourage collaboration. Members from partner
organizations participate in a series of committees that drive and implement the Bay
Program's efforts.
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Three main types of committees:
– committees that govern the Bay Program and guide policy changes
– advisory committees that provide external perspectives on current issues and
events
– subcommittees that work internally to coordinate restoration activities
Chesapeake Bay Agreement
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The Agreement serves as the framework for the multi-jurisdictional Chesapeake Bay
Program.
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The 1983 Chesapeake Bay Agreement, was signed by MD, PA, VA, DC, EPA, CBC,
after research In the late 1970s and early 1980s pinpointed significant environmental
and ecological degradation. The agreement marked the formation of the
Chesapeake Bay Program whose goal is to restore and protect the Bay.
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The 1987 Chesapeake Bay Agreement established the Bay Program's goal to
reduce the amount of controllable nutrients-primarily nitrogen and phosphorous-that
enter the Bay by 40% by 2000 (based on 1985 measurements).
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In 1992, the Bay Program partners agreed to continue the 40 percent reduction goal
beyond 2000 and to attack nutrients at their source, upstream, in the Bay's
tributaries. To help meet this goal, Pennsylvania, Maryland, Virginia and the District of
Columbia developed tributary strategies: river-specific cleanup plans for reducing
the nutrients and sediment that flow into the Chesapeake Bay.
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Chesapeake 2000, a Bay agreement intended to guide restoration activities
throughout the Bay watershed through 2010 sets goals to remove all nutrient and
sediment impairments within the Bay by 2010.
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In addition to identifying key measures necessary to restore the Bay, Chesapeake
2000 provided the opportunity for Delaware, New York and West Virginia to become
more involved in the Bay Program partnership. These headwater states now work
with the Bay Program to reduce nutrients and sediment flowing into rivers from their
jurisdictions (but not signatories of the 2000 Agreement).
Chesapeake Bay Commission
“Legislative Arm”
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The Chesapeake Bay Commission was created in 1980 (MD and VA only) to coordinate Bayrelated policy across state lines and to develop shared solutions. The catalyst for its creation was
the Environmental Protection Agency's (EPA) landmark seven-year study (1976-1983) on the
decline of the Chesapeake Bay. PA became a member in 1985.
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As a signatory, the Commission serves as the legislative arm of the Chesapeake Bay Program
and is fully involved in all Bay Program policy and implementation decisions.
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Mission: The Chesapeake Bay Commission is a tri-state legislative commission which
represents and advises the General Assemblies of Virginia, Maryland and Pennsylvania in
cooperatively managing the Chesapeake Bay.
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Charged with:
- identifying concerns requiring inter jurisdictional coordination and cooperation;
- collecting, analyzing, and disseminating information pertaining to the region and its resources for the
respective legislative bodies;
- recommending legislative and administrative actions necessary to encourage effective and
cooperative management of the Bay;
- representing the common interests of the member states as they are affected by the activities of the
federal government;
- providing an arbitration forum to serve as an advisory mediator for conflicts among the states.
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Organization:
comprised of 21 members
- 15 legislators (5 per state)
- 3 Governor cabinet members (1 per state)
- 3 citizen representatives (1 per state)
Chesapeake Bay Foundation
“Save the Bay”
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Founded in 1967, the Chesapeake Bay Foundation (CBF) is the largest privately
funded, non-profit organization dedicated solely to protecting and restoring the
Chesapeake Bay.
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Fights for strong and effective laws and regulations. CBF also works cooperatively
with government, business, and citizens in partnerships to protect and restore the
Bay.
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Mission: mission is to restore and sustain the Bay's ecosystem by substantially
improving the water quality and productivity of the watershed and to maintain a high
quality of life for the people of the Chesapeake Bay region.
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Focus areas: - reduce pollution
- protect natural resources
- restore habitat and replenish fish stocks
- educate, inspire and engage constituents to take action for the Bay.
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CBF measures the health of the Bay in its annual “State of the Bay” Report by
evaluating 12 key health indicators: wetlands, forested buffers, underwater grasses,
resource lands, toxics, water clarity, phosphorus and nitrogen, dissolved oxygen,
crabs, rockfish, oysters and shad.
State of the Bay
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Agriculture accounts for 1/4 of land
Bay ranks in the top 10% in the US
in terms of manure related nitrogen
runoff, leaching and loadings from
confined livestock and poultry
operations.
Some areas in S.E. Pennsylvania
and S. Virginia are in the upper 10 %
of watersheds in use of commercial
nitrogen fertilizer.
Developed land is 9% of watershed
area
Population growth is over 1 million
per 10 years.
While population has increased by
8% in past decade impervious cover
has increased by 41% and vehicle
miles traveled rose 26%.
Forest only covers 58 % of the
basin (forest is destroyed at a rate of
100 acres/day).
Nutrients and
sedimentation
are the 2 major
issues in the
Bay today.
Source: Chesapeake Bay
Watershed Model
Source: Chesapeake Bay Watershed
Model
Varying dissolved
oxygen levels and
overall fish catch in
the Chesapeake
Bay through July,
2003.
Source: Virginia Institute of Marine
Science.
During peak summer
months, the Chesapeake
hypoxic zone has grown to
encompass a volume of 11
billion m3.
As much as 40% of the Bay
in some years has either too
little oxygen to support fish
and shellfish or not at all.
Environmental and economic effects
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Major fish and shellfish populations have suffered serious declines (shad,
blue crabs, menhaden and oysters).
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Virginia crab harvests:
– 1984 over 50 million pounds
– 2003 just over 21 million pounds
Virginia oyster harvests:
– 1984 over 4 million pounds
– 2003 just over 77,000 pounds
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Stripped bass have rebounded, but half the population is affected by
disease.
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Underwater grass beds cover only 1/3 of the area they did a few decades
ago. Modest improvements in 1980s, but total acreage has remained
stagnant since.
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Natural filters (oyster reefs and grass beds) have severely diminished.
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On land natural filters (forests and wetlands) have also decreased in
acreage.
Nitrogen sources:
Urban has the weakest
significance level.
Land-to-water
delivery:
Soil permeability was
the only significant
factor (weakly
significant).
Q: Why such low
significance?
A: Lack of data for
statistical detail.
Instream loss:
All are significant.
Smaller streams have
the highest parameter
because there is higher
decay in smaller
streams.
Nutrient generation
is particularly high in
areas of south-central
Pennsylvania, central
Maryland and
Virginia, and eastern
shore of Maryland
and Delaware.
(Incremental yields).
Delivered yields are
much lower than
incremental yields for
many reaches particularly
those that are far from the
Bay, because as travel
times increase there is a
greater potential for
instream loss.
High potential for delivery exists in
areas close to the Bay that have short
travel times so little potential for
instream loss.
Also, watershed units associated with
large reaches which have lower
estimated loss rates so less instream
loss.
Point sources are most
important in major
urban areas where large
sewage treatment
plants discharge into
stream reaches.
Agricultural sources are more widely
dispersed.
Mean annual TN, NO3 export
12.00
10.00
Export (kg N/ha)
8.00
TN
NO3
6.00
4.00
2.00
0.00
Pond
Baisman's
Villanova
Carroll Park
Gwynnbrook
Glyndon
Dead Run
site
No development
Most developed
Export distribution varies with land cover
1
0.10 kg NO3-N/ha/yr
0.75
% NO 3 - load
5.28 kg NO3-N/ha/yr
0.5
4.37 kg NO3-N/ha/yr
0.25
Pond Branch
(forested
reference)
Baismans
Run
(suburban)
Dead Run
(urban)
0
0.01
0.1
1
q (mm/d)
10
100
Results: Export distribution and development
• Area of watershed in
open development is
most significant land
cover variable
– Increasing area in open
development leads to
greater proportion of NO3,
TN export occurring at high
flows
• Open development
– “mostly vegetation in the
form of lawn
grasses…most commonly
large-lot single family
housing units, parks, golf
courses, and vegetation
planted in developed
settings” (NLCD 2002)
Export timing across a stream network
Duration curves and climate variation
Pond Branch (forested reference)
•Duration curves show variation
between wet and dry years
1
0.08 kg NO3-N/ha/yr
% NO 3 - load
0.75
NO3--
0.03 kg
N/ha/yr
•Variation is greater in less
disturbed catchments
2004
2003
2002
0.5
0.25
•Most urban catchment displays
very minimal variation
0.21 kg NO3-N/ha/yr
0
0.01
0.1
1
10
100
q (mm/d)
Baismans Run (Suburban)
Dead Run (urban)
1
9.02 kg NO3-N/ha/yr
0.75
NO3--
1.42 kg
N/ha/yr
0.5
2004
2003
2002
7.29 kg NO3-N/ha/yr
7.69 kg NO3-N/ha/yr
0.75
% NO 3 - load
% NO 3 - load
1
1.83 kg NO3-N/ha/yr
2004
2003
2002
0.5
0.25
0.25
7.45 kg NO3-N/ha/yr
0
0
0.01
0.1
1
q (mm/d)
10
100
0.01
0.1
1
q (mm/d)
10
100
Impact of climate variation on dischargeconcentration relationship
Pond Branch (forested reference)
[NO 3 - ] (mg/L)
0.30
0.20
2002
2003
2004
0.10
0.1
1
10
•Shifts are not explained by
difference in flow duration alone
•Ecological processes also part of
the equation
0.00
0.01
•Concentration-discharge
relationship exhibits interannual
shifts
100
q (mm/d)
Dead Run (urban)
Baismans Run (suburban)
3.00
2.00
2004
2003
2002
1.00
0.1
2.00
2002
2003
2004
1.00
0.00
0.00
0.01
[NO 3 - ] (mg/L)
[NO 3 - ] (mg/L)
3.00
1
q (mm/d)
10
100
0.01
0.1
1
q (mm/d)
10
100