Innovative Capping Procedures - Puget Sound Region

Category:

Operating Procedures

Description:

Several innovative capping procedures have been developed by the USACE Seattle District for

placement of sand cap over contaminated or remediated marine sediments. These systems have

been developed under Corps supervision and with Corps funding:

Sand Box Diffusers

Uses a standard split-hull scow, pushed sideways with controlled positioning and opening.

Washing sand off deck barge for thin layer capping.

Reviewer:

C. Woolley

Company / Organization(s):

Projects Completed:

Denny Way Combined Sewer Overflow Capping

Location:

Seattle, WA

Comments:

Beneficial use of Corps maintenance dredge material for the City of

Seattle. Sand placed by sprinkling uniformly graded sand (~0.4mm)

dredged from upper Duwamish River Navigation Project. A barge sand

spreading system was used.

Eagle Harbor Superfund Capping

Location:

Bainbridge Island, WA

Completion Date:

3/94

Random towed barge sprinkling and hosing sand off flat deck barges with

Comments:

2,100-gpm pump. Barge speed over 3 ft/sec. Dump less than 10 cy/sec.

Pier 51Washington Dept. of Transportation Ferry Terminal Expansion

Location:

Elliott Bay, Seattle, WA

Completion Date:

11/89

Commercial sand spread with clamshell from barge

Comments:

Pier 53 Capping of Outfall Area

Location:

Seattle, WA

Beneficial use of Corps maintenance dredge material for the City of

Comments:

Seattle. Seven-compartment barge used to sprinkle uniformly graded sand

(~0.4mm) dredged from upper Duwamish River Navigation Project. A

barge sand spreading system was used.

(Continued)

Chapter 5 Other Technologies Reviewed