Onsite Confinement of Contaminated Dredged Sediments

Category:

Dredged Material Management

Operating Procedures

Description:

Lake Ketelmeer is located between two Polders at the mouth of the Ijssel River, a portion of the

Rhine River system. Over the past 30 years, pollution from industries along the river

contaminated sediments that covered 2,800 hectares of the 3,800-hectare lake with

approximately 0.5 m of contaminated soils.

To contain the contaminated sediment, the Dutch government designed and constructed a

350-hectare site in the middle of the lake with a capacity of 23 million yards. Onsite confinement

was chosen to reduce transportation costs.

The containment facility was built in three phases; 1) removal of the existing contaminants for

placement in a temporary holding area, 2) excavation of underlying peat and organic matter to

create wetland areas along the fringe of the project, and 3) excavation of glacial sand to a depth

of 45 m.

The sand was either sold, stockpiled or used to construct levees around the containment site.

Filling the facility is expected to take up to 20 years. The plan is to use extremely accurate

dredging methods to remove the sediments from the lake bottom and pump it into the

confinement basin. To reduce the chance of seepage of contaminated water into the surrounding

aquifer, the bottom portion of the site has be covered with a clay liner, and the site will not be

filled above the existing water table. In addition, a pumping system will remove water from the

site to ensure that pore pressure within the site remains less than outside the site. The extracted

water will be treated. The site will provide environmental enhancement, such as the construction

of wetlands and a boater destination. The construction cost of the Ketelmeer project is

approximately $150 million (U.S.).

Reviewer:

N. McLellan

Company / Organization(s):

Access Restricted to U.S. Army Corps of Engineers

Projects Completed:

Ketelmeer Lake

Location:

Ketelmeerdijk, Holland

Project Cost:

$150 million (U.S.)

Information Sources:

Interviews:

Interviewee:

W.C.F.H. (Wilbert) van Boldrik

Interviewer:

Neil McLellan, Bob Hopman

Interview Date:

7/30/98

Interview Location:

Ketelmeerdijk, Holland

Field Investigations: Location:

Ketelmeerdijk, Holland

Date:

7/30/98

Photos:

Yes

Photo Location:

Hartman Consulting Corporation, Bellevue, WA

Chapter 5 Other Technologies Reviewed