In deciding how thick an in-situ cap must be, construction
constraints in most cases will be the determining factor. The
placement accuracy of conventional equipment is such that the
narrowest cap can be 50 to 60 centimeters. Other factors, such as
the need to insure chemical isolation and the presence
of bioturbators, require caps of considerably smaller widths.
In practice, caps have ranged from two to five feet in thickness
to compensate for erosion in the cap layer and the possibility of
cap consolidation. Recent research indicates that much thinner caps
can be successful in sequestering contaminants for long periods of
time. A laboratory study at Louisiana State University found that
caps as thin as 5 to 7 millimeters drastically reduced the flow of
TCP from sediment to water.
You have completed the section on "Cap Design." To continue this primer, select the link to "Cap Placement" in the navigation bar to the left.
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