alternative sediment remediation authorities to cercla ... · alternative sediment remediation...
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Alternative Sediment
Remediation Authorities to
CERCLA: Elizabeth River
Demonstration
Robert Engler ([email protected]) Moffatt &
Nichol), Vicksburg,
Mississippi, (USA)
Eric Smith ([email protected]), Baltimore,
Maryland, (USA)
Alternative Sediment Remediation Permitting
Authorities •Full and Continuing Coordination with Federal, State, Local permitting and
Review Agencies and the Elizabeth River Project at the Outset of Project.
•Full Commercial Navigation Requirements Must Be Maintained.
•Pre-operational Assessment
oClean Water Act – CWA (USACE Guidance/Review
oVA DEQ, DCR, VIMS, DGIF, MRC Guidance/Review
•Dredging
oUSACE, Section 10, Rivers and Harbors Act (R&HA),
Clean Water Act 404(b)1 Guidance, Manuals
oVA DEQ CWA, Water Quality Certification
oVA DCR Oversight
oVIMS Review
• Dredge Material Rehandling/Treatment/Disposal
oVA Authorized Land Fill Rules; Land Farming/Solidification and
stabilization
oTSCA – VA Rules
• Capping/Wetlands Restoration, Oyster Habitat
oUSACE, Section 10 R&HA, CWA 404(b)1 Guidance, Manuals
oVA DEQ, CWA – Water Quality Certification
oVA – DCR, DGIF, MRC Oversight
oVIMS Review
• Source Control/Air Quality
oVA Regulations
• USEPA Guidance and Oversight as Appropriate Under CWA
• Threatened and Endangered Species Coordination – VA DNR,
USNMFS, USF&WS
• Essential Fish Habitat – VA DNR, USWMFS, USF&WS
Remediation Methods
Natural Recovery
Removal of Sediments (Dredging)
Isolation and Containment of Sediments
(Capping)
Combination of Above
Dredged Material Management
1. Mechanical Dredging
2. Transport to Weanack Plantation (or other site)
3. Landfarming
4. Dewatering/Stabilization to Landfill (e.g. Charles City
County)
5. Placement at Other Approved Upland Site
Cap Engineering Development
Chemical Isolation Modeling
Follow US EPA Design Guidance
Isolation of Contaminants to ERM or Less
100-Year Plus Design Life
Cap Stability Assessment
Tidal and Storm Currents
Ship Induced Currents
Propwash
Cap Requirements
Mixed Bioturbation Mixed Bioturbation
LayerLayer
Sediment –
Water Interface
Clean Sediments
Contaminated Sediments
Isolation Cap
Protection Cap
Cap thicknesses for erosion protection and chemical isolation
Focus for health
benchmarks
Isolation Cap Modeling
Used two models (both in EPA guidance)
RECOVERY (v 4.3) model for design
Lampert & Reible model (LRM) for confirmation and additional tests
RECOVERY
USACE developed and validated model, 20 years of use with continual updating
Numerical, time-varying, mass balance
LRM
Analytical, steady-state, mass balance
Cap Isolation
Conclusion/Recommendation
12 inch sand cap is protective given the
expected low groundwater upwelling rates
The 12 inch protective cap on top of isolation
adds extra protection
Cap Stability Assessment
Tidal and Storm Currents
Hydrodynamic Model of Tides and Storm Surge
Ship-Induced Currents
Numerical Model of Passing Ship
Propwash
Analytical Calculation of Prop Scour from Tugs
Hydrodynamic Model Domain
MIKE FM Model
Increased Resolution in Project Area
25-YEAR HURRICANE VALIDATED
Passing Vessel Model
Model DELPASS developed by Pinkster Marine
Hydrodynamics
Panel model based on 3-d potential flow
Panels represent river bathymetry and vessel
Output 3 time-dependent velocity components
on grid points of the river bottom
Grid points match MIKE3 model resolution
Tug Propeller Wash
Propeller Wash for Max and Typical Tugs
5100 HP Z-drive Twin Screw
1700 HP Twin Open Screw
22.22
max),(
x
r
x eurxu Velocity with axial distance (x)
and radial distance (y)
Alternative 1 Dredge + Cap
Dredge 2’
Cap 2’
2’ Sand Cap / Wetlands
Dredge 2’ w/
Armored Cap
Dredge to El -39’
w/ Armored Cap
Armored Cap
Dredge 2’
Cap 2’
2’ Sand Cap
Armored Cap
Dredge to
El -42’
Dredge Volume 172,460 cy
Alternative 2 Optimal Dredge + Cap
Cap 2’
2’ Sand Cap / Wetlands
Armored Cap
Dredge to El -39’
w/ Armored Cap
Armored Cap
Dredge 2’
Cap 2’
2’ Sand Cap
/ Wetlands
Armored Cap
Dredge to
El -42’
Dredge Volume 79,500 cy
Alternative 4 No Dredging + Cap
Cap 2’
2’ Sand Cap / Wetlands
2’ Sand Cap
/ Wetlands Dredge to El -42’ 2’ Armored Cap
Dredge Volume 0 cy
Republic Cost Estimate
Unit Cost Alt 1 Alt 2 Alt 3 Alt 4
Dredging/Disposal $135-
$188/cy
$17.1M $7.9M $54.3M -
Sand Cap $70/cy $7.5M $7.5M $0.1M $7.5M
Rock Cap $112/cy $3.3M $3.3M $0.9M $3.3M
Rock Breakwater $125/ton $0.9M $0.9M - $0.9M
Mobilization 10% $2.8M $2.0M $5.5M $1.2M
Contingency 20% $5.6M $3.9M $11.1M $2.4M
Total $36.3M $25.5M $71.9M $15.3M
Alternative 2 Selected
Upland Sources
Coordinated by Other Agencies
McLean – Entered Volunteer Clean Up
Allied – EPA in Discussions with Owners
Shotmeyer and Southern Aggregates – No Known Upland
Source
Institutional Controls to Prevent
Recontamination
Recommended Controls for Future Activities
Landside Shoreline Construction Control
In-Water Construction Controls
Control Navigation Dredging in Mitigation Areas