Alternative Sediment Remediation Authorities to CERCLA: Elizabeth River

DemonstrationRobert Engler (rengler@moffattnichol.com) Moffatt &

Nichol), Vicksburg, Mississippi, (USA)

Eric Smith (esmith@moffattnochol.com), 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 Assessmento Clean Water Act – CWA (USACE Guidance/Reviewo VA DEQ, DCR, VIMS, DGIF, MRC Guidance/Review

• Dredgingo USACE, Section 10, Rivers and Harbors Act (R&HA),

Clean Water Act 404(b)1 Guidance, Manualso VA DEQ CWA, Water Quality Certificationo VA DCR Oversighto VIMS Review

• Dredge Material Rehandling/Treatment/Disposalo VA Authorized Land Fill Rules; Land Farming/Solidification and

stabilizationo TSCA – VA Rules

• Capping/Wetlands Restoration, Oyster Habitato USACE, Section 10 R&HA, CWA 404(b)1 Guidance, Manualso VA DEQ, CWA – Water Quality Certificationo VA – DCR, DGIF, MRC Oversighto VIMS Review

• Source Control/Air Qualityo VA 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

Landscape Approach

Forested Upland

Wetlands Restoration

Oyster Reef Creation

Sediment Cleanup

Republic ERM

CLEANUP GOALS

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 ModelIncreased 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

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