Alternative Sediment Remediation Authorities to CERCLA ...

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

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 Sediment – Water Interface

Focus for health benchmarks

Mixed Bioturbation Layer

Protection Cap Isolation Cap Contaminated Sediments Clean Sediments

Cap thicknesses for erosion protection and chemical isolation

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

Alternative 1 Dredge + Cap Dredge Volume 172,460 cy

Dredge to El -42’ 2’ Sand Cap Dredge 2’ w/ Armored Cap

Dredge to El -39’ w/ Armored Cap

Dredge 2’ Cap 2’

Dredge 2’ Cap 2’ Armored Cap

2’ Sand Cap / Wetlands