1. Piers 24 & 25 Sediment Remediation Project Tacoma, Washington or… Adventures in Underpier Capping
Rick Moore, Hart Crowser
WEDA Pacific Chapter Conference November 5, 2009
A couple things came to mind when developing presentation:
The first is how far we’ve come in 20 years on sediment cleanup projects in Commencement Bay – well north of $100M spent since the mid-1980s
And secondly the challenges of underpier capping on relatively steep slopes with lots of obstructions with the added fun of trying to do the work in an intertidal zone in the Winter time.
This was a Superfund cleanup project sponsored by the Port of Tacoma. Unfortunatley, Bill Evans, the Port’s project manage could not be here today to copresent the talk.

2. Acknowledgments Port of Tacoma US EPA US Army Corps of Engineers
Washington State Department of Ecology
Bergerson Construction
Berger/ABAM

3. Presentation Overview
Project Setting and Background
Commencement Bay CERCLA Actions
How Did We Get Here? When Will We Be Done?
Remediation Elements
Why Do These Projects Always Happen in the Winter?
Lessons Learned
The Good, the Challenged, and the Long-Term.

4. There are probably a number of folks here who are familiar with the general setting of sediment cleanup projects that have been going in in Commencement Bay.
The Piers 24 & 25 project site is located here at the mouth of the Hylebos Waterway

5. Historical Tideflat Filling
A little bit of background on how we got here for the current project

6. Commencement Bay Nearshore/ Tideflats Superfund Site Modified From Port of Tacoma Photo Slide
Sitcum
St. Paul
Hylebos
Middle
Piers 24 & 25 Project Site
Thea Foss 6

7. CERCLA Background Commencement Bay/Nearshore Tideflats Superfund Site
Work Began Mid-1980s
1989 EPA Record of Decision
20+ Year Cycle to Complete Remediation
Piers 24 & 25
Part of Mouth of Hylebos Remedial Action
One of the Last CB/NT Remediation Efforts
First provide a bit of an overview of the CERCLA background in Commencement Bay
Piers 24/25 part of a lengthy CERCLA history work beginning with initial site characterization in mid-1980s, leading to EPA ROD in 1989.
Part of 20+ year cycle through construction for the remedial action typical for many of the in-water projects of this complexity including Piers 24 & 25.

8. Site Vicinity and Project Area
2006 Aerial Photo
Source: City of Tacoma
Piers 24 and 25 Project Site
Blair Waterway
Hylebos Waterway
The project site is located adjacent to land owned by the Port of Tacoma at the end of the peninsula between the Hylebos and Blair Waterways. This currently includes a seafood processing facility that uses the adjoining Pier 25 and Pier 24 for their vessels. Adjacent areas are operated by other Port tenants in the upland and by the Army Reserve at

9. Site Contaminants
PAH, Metals, and PCB Contamination from Historical Shipyard Waste Disposal
A Convenient Place to Dump Waste
A Difficult Place to Clean Up

10. 1940s Shipyard
Piers 24 & 25 Project Site

11. 1946 Aerial Photo

12. Piers 24 & 25 Project Timeline
1998 to 2000 Remedial Design
EPA AOC 2002 and CD 2005
2000 to 2007 Revise/Finalize Design
10/07 and 2/08 Complete Construction
Following completion of site characterzation for Pre-Remedial Design in the mid-1990s, project progressed to the design phase, with an AOC and CD issued in 2002 and 2005, respectively. At the same time the design went through several additional phases and EPA review cycles. Construction originally scheduled for the beginning of the in-water work window during the summer of 2007 with an anticipated 4 to 5 month duration. Startup delays and additional EPA review items eventually pushed start into October and significantly compressed the schedule to complete the work by the close of the in-water work window or “fish window” by February of Further acknolwedgement to the work team and EPA on the degree of cooperation needed to make this happen.
Next time will plan for a winter start up assuming that will be delayed into the summer.

13. Remediation Elements Embankment Capping on 2V:1H Slopes
Hot Spot Dredging for As Contamination
Debris Pile Removal
Hot Spot PCB Removal

14. A Difficult Place to Work
Limited Access
Forest of Pilings
Steep, Slippery Rock Slopes

16. Barge-Mounted Placement of Capping Materials

17. Pier-Mounted Placement of Capping Materials

18. Sand Cap and Armor Rock Placement

19. Sand Cap and Armor Rock Placement

20. Toe Berm Riprap Placement

21. Sand Cap and Armor Rock

22. Lead Line Survey Control

23. Project Area - Post-Capping

24. Shotcrete Application

25. Photo Courtesy of the Port of Tacoma

26. Shotcrete Application

27. Piers 24 & 25 Project Area
A more detailed project map shows the affected area and several features of interest….steep embankment, subtidal component, previous dredging areas, 0 elevation – keep this in mind as
The remediation elements included:
Embankment Capping on 2V:1H Slopes
Hot Spot Dredging for As Contamination
Debris Pile Removal
Hot Spot PCB Removal

28. Debris Pile Removal

29. PCB Hot Spot Removal

30. PCB Hot Spot Removal

31. Lessons Learned – The Good
Construction Methods Successful for Steep Slope Capping
Sand Cap to 700 CY/Shift
Crushed Armor Rock to 600 CY/Shift
Shotcrete to 10 CY/Shift
Total Construction Cost $4.6M
Within 1% of Engineering Estimate Excluding Change Orders

32. The Challenged
PCB Hot Spot and Deeper Debris Excavation Were Unexpected and Costly
Difficult Setting to Obtain Good Sampling Data
50% Toe Berm Riprap Quantity Over-Run
Difficult to Estimate Riprap Repose Angle and Settling
Toe Berm overrun was about $70K in rock materials
Shotcrete $250K
PCBs and deeper debris pile removal $250K

33. And The Long Term… Piers 24 & 25 Cap Performing as Intended
Remediation Complete:
Sitcum, Milwaukee, St. Paul, Thea Foss/Wheeler Osgood Waterways, and ASARCO
Remediation Pending: OXY/Area 5106
CB/NT In Post-Construction Monitoring
Portions of the Blair and St. Paul Waterways Delisted/Deleted from NPL

34. Thanks to WEDA Rick Moore Hart Crowser rick.moore@hartcrowser.com
(206)
Bill Evans
Port of Tacoma
(253)

35. 5106 and “OXY” In-Water Areas

36. Commencement Bay Waterways