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Chesapeake Bay


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Title: Chesapeake Bay

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
  • 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
  • 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 (30-35 ppt) at
    the Chesapeake's mouth.

Chesapeake Bay watershed sub-basins
Quick Facts Environment and Economy
  • Value of the Bay estimated to be above a
  • 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. 
  • The Chesapeake is a commercial and recreational
    resource for the more than 16 million people who
    live in its basin.
  • Produces 500 million pounds of seafood per year.
  • Bay has two of the five major North Atlantic
    ports in the United States (Baltimore and Hampton
  • 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. 
  • The Chesapeake was the first in the nation to be
    targeted for restoration as an integrated
    watershed and ecosystem.

Chesapeake Bay HistoryBay formation and early
  • 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
  • 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.
  • 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.
  • 1750 Colonial population reaches 380,000
  • 20-30 of forests are stripped for settlements.
  • 1775 Colonial population reaches 700,000
  • 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
  • First invasive species start being transported to
    the bay area.

1775 1820 period
  • 1800 Population reaches 1,000,000 persons.
  • 1813 Oyster raking begins in the Bay.
  • 1817 Baltimore Gas Lighting Company, nations
    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
  • 1880 Oyster breeding stocks severely
  • Industrialization, urban growth, transportation
    improvements radically transformed Chesapeake Bay
  • Farmers cleared 40-50 of the land for planting
  • Untreated sewage from cities ? water pollution.

Oyster Tongers
Urbanization 1880-1930
  • 1880s Skipjack boats first produced.
  • 1890 60 of watershed forests are cleared.
  • 1900 Population reaches 3 million.
  • less than 30 of the watersheds original
    forest remains
  • 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 its ability to save
    valuable oyster beds.
  • 1920 Population exceeds 4.5 million.
  • Pollution is intensified.
  • Wetlands are drained to create more farmlands and
    to destroy breeding grounds for mosquitoes.
  • Poultry farms starting becoming more prevalent.

Chesapeake Metropolis 1930-2000
  • 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.

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Impervious surface map for 2000 for the
Chesapeake Bay watershed. Source Woods Hole
Research Center.
Chesapeake Bay ProgramPartnership
  • 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.
  • 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.
  • 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.
  • 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.
  • 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

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Chesapeake Bay Agreement
  • The Agreement serves as the framework for the
    multi-jurisdictional Chesapeake Bay Program.
  • 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.
  • 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).
  • 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.
  • 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.
  • 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

Chesapeake Bay CommissionLegislative Arm
  • The Chesapeake Bay Commission was created in 1980
    (MD and VA only) to coordinate Bay-related 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.
  • 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.
  • 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.
  • 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.
  • 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 FoundationSave the Bay

  • 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.
  • 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.
  • 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.
  • Focus areas - reduce pollution
  • - protect natural resources
  • - restore habitat and replenish fish stocks
  • - educate, inspire and engage constituents to
    take action for the Bay.
  • 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
  • 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
  • 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
  • Major fish and shellfish populations have
    suffered serious declines (shad, blue crabs,
    menhaden and oysters).
  • 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
  • Stripped bass have rebounded, but half the
    population is affected by disease.
  • 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
  • Natural filters (oyster reefs and grass beds)
    have severely diminished.
  • On land natural filters (forests and wetlands)
    have also decreased in acreage.

Nitrogen sourcesUrban has the weakest
significance level.Land-to-water
deliverySoil permeability was the only
significant factor (weakly significant).Q Why
such low significance?A Lack of data for
statistical detail.Instream lossAll 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.
No development
Most developed
Export distribution varies with land cover
0.10 kg NO3--N/ha/yr
5.28 kg NO3--N/ha/yr
4.37 kg NO3--N/ha/yr
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
    grassesmost commonly large-lot single family
    housing units, parks, golf courses, and
    vegetation planted in developed settings (NLCD

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Export timing across a stream network
Duration curves and climate variation
  • Duration curves show variation between wet and
    dry years
  • Variation is greater in less disturbed catchments
  • Most urban catchment displays very minimal

0.08 kg NO3--N/ha/yr
0.03 kg NO3--N/ha/yr
0.21 kg NO3--N/ha/yr
7.69 kg NO3--N/ha/yr
9.02 kg NO3--N/ha/yr
1.83 kg NO3--N/ha/yr
1.42 kg NO3--N/ha/yr
7.29 kg NO3--N/ha/yr
7.45 kg NO3--N/ha/yr
Impact of climate variation on discharge-concentra
tion relationship
  • Concentration-discharge relationship exhibits
    interannual shifts
  • Shifts are not explained by difference in flow
    duration alone
  • Ecological processes also part of the equation