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Strategic Approaches to Reduce Uncertainties of Sediment Cleanup Costs

Strategic Approaches to Reduce Uncertainties of Sediment Cleanup Costs. Presented by: Howard L. Cumberland Director of Ports and Harbors, Western Region Darrell Nicholas, P.E. Sr. Project Manager, Ryba -Terra Joint Venture. Presented to : Dredging 2012. Sediment Remediation 101.

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Strategic Approaches to Reduce Uncertainties of Sediment Cleanup Costs

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  1. Strategic Approaches to Reduce Uncertainties of Sediment Cleanup Costs Presented by: Howard L. Cumberland Director of Ports and Harbors, Western Region Darrell Nicholas, P.E. Sr. Project Manager, Ryba-Terra Joint Venture Presented to: Dredging 2012

  2. Sediment Remediation 101 • Characterize Sediment Chemical Concentrations and Risk • Determine Amount of Sediment on Horizontal and Vertical Extent • Determine Remedy • Design Remedy • Execute Remedy • Validate or Monitor Remedy • Regulatory Closure

  3. Optimal Remedy Selection is Crucial • Monitored Natural Recovery • Dredging (Mechanical or Hydraulic) • Capping • Disposal • Contained Aquatic Disposal (CAD) • Confined Disposal Facilities (CDFs) • Open Water Disposal (Clean only) • Beneficial Use Applications (Broadly Defined) • Landfill • Ex-Situ Treatment

  4. Premise of Today’s Talk (1) • Contaminated Sediment Remediation Projects Costs range from $150 to over $600 per CY • Cost estimates are highly uncertain and often vary by 1000% (10x) and do not necessarily include all costs (management, permitting, legal, etc.) • The highest costs of a Sediment Remediation Project fall into remedial design and implementation

  5. Project Cost BreakdownMechanical Dredging, Cement Stabilization, and Offsite Disposal of 150,000 CY

  6. Premise of Today’s Talk (2) • The high cost of sediment remediation requires: • robust characterization sufficient to accurately identify the horizontal and vertical extent of contamination • evaluation of the impact of sediment characteristics (e.g. debris, geotechnical properties) on removal and technologies • accurate estimates of the volume for removal • accurate location of the contaminants AND their concentrations within the dredge prism

  7. Premise of Today’s Talk (3) • Increased tendency to minimize additional investigations after the initial results are obtained • This tendency to try to save money on the CHARACTERIZATION and move to remedial design and implementation, typically before enough facts are known regarding project uncertainties and a complete understanding of the project risks moving forward

  8. Problems with Sediment Sites • Waterfronts are Active -Multiple Sources • Co-Mingled COPCs • Hydrologic and Hydrodynamics • Competing Objectives: • Business, Regulatory, Trustees • Highly Emotional • Typically Multiple Years until Remedy • Typically High Costs • Not Just In-Water Work

  9. Source Conceptual Site Model From: US EPA 2008 RI/FS Summary

  10. Shipping and Commerce Must Continue

  11. Sediments Vary Young Bay Mud 252 ppm ΣDDT 12’’ Young Bay Mud 15 ppm ΣDDT 24’’ No sand Sand 15 ppm ΣDDT 3’’ Young Bay Mud 150 ppm ΣDDT 28’’ Old Bay Mud 7’’ Old Bay Mud 0.9 ppm ΣDDT 14’’

  12. Characterization Risks Inadequate Data Leads to: • Wrong Equipment that Cannot Do the Job • Undersize Equipment that Takes Too Long • Oversize Equipment that is Too Costly • Running Equipment at Redline • Underestimating the Impact of Cascading Downtime

  13. Excavation Risks Dig Too Deep: • Unnecessarily Remove Material • Wasted Money – Increased Costs of Removal and Disposal • Extends Schedule Dig Too Shallow: • Discovered by Validation • Inadequate Budget and Schedule Allowances • Insufficient Landfill Capacity • Impact on Stakeholder Confidence

  14. Reducing Risk - Sample Variability

  15. Reducing Risk - Sample Numbers

  16. Volume Depth of Excavation (below mudline)

  17. Conclusions • Significant cost-benefits by performing robust site characterization prior to remedial design and implementation • Reduces uncertainties and optimizes “big dollar” expenditures of remedy implementation • Added benefit of improving management and stakeholder confidence in overall project

  18. THANK YOU 1. Rosengard, John; Wallace, Jeff; Otten, Mark; MacDonald, Ashley; and Lafrenz, Ryan (2010) "A Parametric Model for Estimating Costs for Remediating Contaminated Sediment Sites Using a Dredging Method - A Budgetary & Planning Tool for Decision-Makers," International Journal of Soil, Sediment and Water: Vol. 3: Iss. 2, Article 9. Available at: http://scholarworks.umass.edu/intljssw/vol3/iss2/9

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