Transcript Sediment Cleanup Options

Sediment Cleanup Options
Choosing Among Options
• Regulatory framework for descisions (Materials
courtesy of Portland Office, ACOE)
•CDF Example: Ross Island (Materials courtesy of
Stuart Albright, Hart Crowser)
• Wyckoff/Eagle Harbor (Puget Sound)
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W. Fish, Portland State University
Copyright, 1996 © Dale Carnegie & Associates, Inc.
Quantities of Dredged
Sediments
250 million cubic yards from
25,000 miles of navigation channels
75 million cubic yards from permits
325 million cubic yards each year
How Much Dredged Material?
> 5½ feet deep over
Washington, D.C.
> 1½ feet deep
over Chicago
Authorization
Rivers and Harbors Act of 1899,
Section 10
Clean Water Act
Section 404
Marine Protection, Research, and
Sanctuaries Act
Section 103
Regulatory Authorities
 U.S. National Marine Fisheries Service
 U.S. Fish and Wildlife Service
 U.S. Environmental Protection Agency
 State Fish and Game Agencies
 State Water Quality Certifying Agencies
 State Coastal Zone Management Agencies
 Other Federal and State Agencies
Federal Standard
The disposal alternative or alternatives
identified by the Corps which represents the
least costly alternative consistent with sound
engineering practices and meeting the
environmental standards established by the
404(b)(1) evaluation process or ocean
dumping criteria.
Framework for Environmental
Acceptability of Dredged Material
Disposal Alternatives
Evaluation of Dredging Project Requirements
Identification of Alternatives
Initial Screening of Alternatives
Detailed Assessment of Alternatives
Alternative Selection
Technical Framework
Summary
Reflects real-world conditions
Reflects aquatic, intertidal, and upland
environments
Indicates biological availability of
contaminants
Predicts potential environmental impacts
Provides appropriate level of protection
Is consistent with CWA, MPRSA, and NEPA
TIER I
• Existing
Data
TIER II
• Physical/Chem. data
• Screening Tests
•Predictive models
TIER III
• Toxicity Tests
• Bioaccumulation Tests
TIER IV
• Chronic Sublethal Tests
• Steady-State Bioaccumulation Tests
• Risk Assessment
https://www.nwp.usace.army.mil/ec/h/hr/
Basic Dredge Types
Hydraulic
Pipeline
Hopper
Mechanical
Clamshell
Other / Combinations
Factors in Selection of
Dredging Equipment
Physical characteristics of sediments
Quantities to be dredged
Dredging depth
Distance to disposal area
Physical environment of and between
areas
Contamination level of sediments
Method of disposal
Dredged Material Disposal
Alternatives
Open Water Placement
Ocean ~ Estuarine ~ Lakes ~ Rivers
Confined Disposal Facilities (CDFs)
Diked containment
Beneficial Use Applications
Beneficial Use (BU)
Applications
BU is alternative of first choice
Needs and Opportunities
Material Suitability
Logistical Constraints
Regulatory Requirements Vary
CWA / MPRSA
Other
Confined Disposal
Facilities
Site characterization / selection
Engineering design
Operational considerations
Contaminant pathways and controls
Long-term management
Monitoring
Confined Disposal Alternatives
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Engineering Issues
Reduce Contaminant Pathways
Disposal pathways
Physical disturbance
Seepage
Optimize Capacity
Physical Disturbance
 Erosion and Scour
 Slope Stability
Nature of underlying materials
Stability of existing and future slopes
 Excavation and Removal
 Intended End Use of Site
 Consolidation and Settlement
 Cap Properties
Seepage
Excess Pore Water
Long Term Seepage
Other Considerations
Dredged disposal volume
Area of land desired
Habitat mitigation requirements
Cost comparisons
Ross Island
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Typical Cross Section
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Disposal Methods
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Potential Contaminant
Migration Pathways Disposal Processes
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Potential Contaminant
Migration Pathways - Groundwater
Transport (Present and Future)
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Potential Contaminant
Migration Pathways Physical Disturbance
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Groundwater Movement
through Cells
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Potential Groundwater
Transport from Containment
Cells
Upward groundwater flow.
Predicted discharge concentrations
below risk-based criteria.
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Potential Physical
Disturbance of Containment
Cells
Natural erosion (floods).
Human influence (mining).
Geotechnical stability.
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Slope Instability
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Potential Physical
Disturbance of Cells
Minimal erosion potential due to dike.
Mining controls would avoid impacts.
Slopes are receiving fills.
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Wyckoff/Eagle Harbor
Bainbridge Island, in Central Puget Sound
3,780-acres
Inactive 40-acre wood treating facility
owned by Wyckoff
Adjacent 500-acre Eagle Harbor
Other upland sources of contamination
(Shipyard)
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W. Fish, Portland State University
Wyckoff/Eagle Harbor
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W. Fish, Portland State University
Site History
Shipyard operated from 1903 to 1959 on
the northwest shore of Eagle Harbor,
resulting in releases of metals and organic
contaminants.
1905 to 1988, wood treating operations
were conducted on the southeast shore
involving pressure treatment with
creosote and pentachlorophenol
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W. Fish, Portland State University
Historical Sources
Preservative chemicals were stored in
tanks on the property.
Contamination of soil and ground water at
wood treatment facility led to seepage
into adjacent sediments.
Wastewater discharged into Eagle Harbor
for many years; storing treated pilings
and timber in the water continued until
the late 1940's.
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W. Fish, Portland State University
Contaminants of Concern
Shipyard: Levels toxic to marine life
polyaromatic hydrocarbons (PAHs) and
other organics
heavy metals such as mercury, copper,
lead, and zinc
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Contaminants of Concern
Wyckoff facility, soil and groundwater are
contaminated with:
Creosote
Accompanying PAHs
pentachlorophenol (PCP)
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Discovery
1984: NOAA investigations of the Harbor
revealed that sediment, fish, and shellfish
from Eagle Harbor contained elevated
levels of PAHs
EPA required Wyckoff to conduct
environmental investigation activities
under RCRA, and the state required
immediate action to control stormwater
runoff and seepage of contaminants
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W. Fish, Portland State University
CERCLA Operable Units
1991, EPA defined three operable units at
the Wyckoff/Eagle Harbor site:
Wyckoff (OU1)
East Harbor (OU2)
West Harbor (OU3)
Wyckoff Facility groundwater (OU4, 1994)
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W. Fish, Portland State University
East Harbor Capping (OU2)
Sept 1993-March 1994, EPA and the
Corps of Engineers covered contaminated
sediments in the East Harbor
Cap of clean sediment at water depths of
17 m and 13 m, respectively.
Sediment was dredged from the
Snohomish River as part of an annual
project for ship navigation
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W. Fish, Portland State University
Capping Methods
Split Hull: Fast but uneven.
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W. Fish, Portland State University
Capping Methods
Hydraulic washoff:
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West Harbor CDF (OU3)
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W. Fish, Portland State University