The Environmental Sensitivity of Rhode Island

1
The Environmental Sensitivity of Rhode Islands
Coastal Salt Ponds
by
Edward Callender, Ph.D.
Vice-President and Chair, EnvironmentalCommittee,
Salt Ponds Coalition
Retired, Senior Research Hydrologist, United
States Geological Survey
Page 1 E. Callender CRMC Salt Ponds SAMP
Hearing April 11, 2006
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Introduction

• R.I. Division Statewide Planning notes that
  suburban and rural growth is 20 (1985-2010).
• Salt Ponds Region SAMP recognizes that water
  quality, land-use, habitat, and geology all
  impact the health of the salt ponds.
• The 1999 SAMP facilitates the implementation of
  R.Is Coastal Nonpoint Pollution Control Program
  (CNPCP) with the concern of addressing growing
  population density.
• Salt Ponds prime habitat for fishing and many
  recreational activities.

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Residential Development

• As of 2004, 35 of land area in Salt Ponds SAMP
  Region is occupied by residential housing
  development.
• The 1999 Salt Ponds SAMP stipulates regulations
  that should reduce extent of development and
  pollutant sources in watersheds.
• However, environmental data (see below) show that
  the cumulative impact of nonpoint sources of
  bacteria and nitrogen continue to result in
  closed shellfish beds and eutrophic conditions in
  several of South Countys salt ponds.

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Evidence of Cumulative Impacts of Development

• Eutrophication (more algae, less dissolved
  oxygen).
• Permanent Closure of Shellfish Beds.
• Groundwater Underlying Populated Areas has
  Nitrogen Concentrations 10-50 times Background
  levels (0.2 mg/l).
• Sedimentation from Nonpoint Sources and
  Breachways have Covered Shellfish Habitat.
• Between 1960 and 1992, Ninigret Pond has Lost 30
  of its Eelgrass.

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Water Quality Concerns

• Bacteria and Nitrogen are major factors that
  impair water quality of R.I.s Salt Ponds.
• Septic Systems primary human source of fecal
  coliform bacteria in Salt Ponds.largest source
  is wildlife in watershed and pond
• Septic Systems contribute major quantity of
  nitrogen to groundwater that infiltrates the
  ponds.surface runoff and atmos.precip. other
  major inputs to ponds
• ExampleNinigret Pond-15 bacteria and 60
  nitrogen come from septic systems.fertilized
  lawns add 14 nitrogen
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Nitrate, Total Nitrogen, and Fecal Coliform
Bacteria Concentrations versus Time in Ninigret
Pond
Data from Lee and Ernst (1997) Salt Ponds
Coalition and URI Watershed Watch, 2005
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Bacteria Levels in Ninigret Pond

• Fluctuated between 6 MPN/100 ml in 1988 to 40
  MPN/100 ml in 1992 to 2000.
• Thereafter, levels have declined slightly with
  only one year below shellfish standard of 15
  MPN/100 ml.
• Graphic shows that Ninigret Pond has exceeded
  shellfish standard 13 out of 18 years.

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Nitrate Concentrations in Ninigret Pond

• Have declined from 200-100 to 60 ugrams/liter for
  the period 1985 to 1995.
• Thereafter, concentrations have increased from a
  low of 35 ugrams/liter in 2000 to 120
  ugrams/liter in 2005.
• Most concentrations several times the value for
  seawater (40 ugrams/liter) that enters Pond via
  breachway.
• Studies at URIs Marine Ecosystem Research Lab
  have shown that small increases in nitrate above
  seawater concentrations can cause adverse
  water-quality effects, including eelgrass health.

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Total Dissolved Nitrogen Concentrations in
Ninigret Pond

• TDN mimic distribution of nitrate concentrations.
• Increasing from conc. of 310 ugrams/liter in 2001
  to 800 ugrams/liter in 2005.
• Ninigret Pond is evolving from a relatively
  healthy mesotrophic state to an unhealthy
  eutrophic state.
• Mass. Estuary Project (MAEP) found that 400
  ugrams/liter TDN represents threshold between
  suitable and impaired waters.
• Ninigret Pond TDN data suggest water quality is
  becoming impaired.

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Eutrophication

• Process whereby excessive nutrient loading
  (nitrogen inputs to salt ponds) results in
  massive growth of algae and subsequent depletion
  of dissolved oxygen resulting from plant decay.
• Chlorophyll and Dissolved Oxygen data for
  Ninigret Pond (2001-2005) show that stressed
  dissolved oxygen concentration (2-4 mgrams/liter)
  follow summer periods of algae blooms where
  chlorophyll levels average 13 ugrams/liter.
• MAEP guidelines for aquatic environmental health
  indicate Ninigret Pond on the edge between
  moderate and impaired water quality.
• Rhode Island DEMs eutrophication index for
  Ninigret Pond (57) indicates that the Ponds
  water quality is fair.
• Symptoms of coastal eutrophication are loss of
  eelgrass habitat, increased disease in
  fish-crabs-lobsters, toxic phytoplankton blooms,
  and loss of aesthetic quality and recreational
  use.

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Nitrogen Inputs to Ninigret Pond

• 72 of Dissolved Inorganic Nitrogen (DIN) Inputs
  are from Groundwater (GW).
• Under Current Zoning (1 residence/2 acres), 65
  of GW DIN comes from Septic Systems.
• Under Proposed Zoning (2.5 residences/1 acre),
  80 of GW DIN would come from Septic Systems.
• With regard to Nitrate Concentrations
  (mgrams/liter) in GW recharge
• Background 0.2
• Watershed 1.6 Data from URIs Coop. Extension
  MANAGE model
• Current Zoning 2.2
• Proposed Zoning 10.8 (5 times current zoning)
  such Nitrate Increases will put Ninigret Pond
  Over the Edge

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How Does Ground Water Recharge Move?
Toward the Ponds!
Small arrows indicate approximate direction of
ground-water flow
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Green Hill Pond Water Quality Data, 2000-2005
Note Eutrophic Algae Levels and Stressed
Dissolved Oxygen Levels
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Eastern Ninigret Pond Water Quality Data,
2000-2005
Note Some Eutrophic Algae Levels and Stressed
Dissolved Oxygen Levels
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Western Ninigret Pond Water Quality Data,
2000-2005
The Water Quality of Ninigret Pond is Dedgading!
It is beginning to look like Green Hill Pond!
Do we want this to happen??
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Charlestown Housing Data versus Ninigret Pond
Nitrate Concentrations
(Note the strong statistical relationship between
Nitrate in the Pond and Housing Units in
Charlestown)
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Summary

• The Salt Ponds SAMP is intend-ed to regulate
  residential growth in order to improve the water
  quality of the Ponds.
• Over the past decade there have been some
  improvements in the water quality of a few of the
  Salt Ponds but many still remain impaired. Note
  the deteriorated condition of Green Hill Pond and
  the deteriorating condition of Ninigret Pond.
• From the above observations, it is obvious that
  the Salt Ponds SAMP should not be weakened by
  changing the housing density regulation.

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Acknowledgements and Sources of Information
1984 Salt Pond Region SAMP 1999 Salt Pond Region
SAMP RI DEM Nitrogen Load Reductions, 2006 URI
Nonpoint Education for Municipal Officials,
2005 Horsley Witten Group, Watershed Assessment
Report, 2005 Salt Ponds Coalition Water Quality
Databases, 1997 and 2005 URI Watershed Watch,
2006 Town of Charlestown Tax Assessor and Town
Planner
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Callender Environmental Resume   Edward (Ted)
Callender 2 Schumann Road Westerly, RI
02891 401-322-8877 ecallender_at_cox.net     MS
Degree in Geology (1963) Ph.D. Degree in Geology
with minors in Chemistry and Limnology(1966)   196
6-1970 Research Geochemist, Great Lakes Research
Division, University of Michigan 1970-1975
Assistant Professor of Chemical Oceanography,
Department of Atmospheric and Oceanic Sciences,
University of Michigan 1975-2004 Research
Hydrologist (Geochemistry), Water Resources
Division, United States Geological
Survey 2005-Present Vice-President and Chairman,
Environmental Committee, Salt Ponds
Coalition   Research Includes ?Geochemistry of
Great Lakes Sediments especially those
containing FerroManganese
Nodules ?Intersitial Water Geochemistry of
Pacific Ocean Sediments underlying FerroManganese
Nodule Deposits ?Trace-Metal Geochemistry
of GeoPressured Fluids in the U.S.Gulf
Coast ?Nitrogen, Phosphorous, and Silica
Geochemistry of the Potomac River Estuary ?Iron,
Manganese, Phosphorus, and Silica Geochemistry of
Lake Baikal, Siberia, Russia ?PaleoLimnological
Distributions of Trace Metals as Indicators of
U.S. Air and Water- Quality Trends during
the 20th Century
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