Water Resources Issues of the Laurentian Great Lakes
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4.4 Management Options
The main options available for managing sites with contaminated sediments
include: (1) no-action scenario, wait for the system to recover naturally, or at least
for contaminated sediments to be sufficiently buried that there is no concern that
they might be uncovered; (2) uniform or targeted dredging, remove material at
those sites where contaminant concentrations are especially high; (3) artificial
armoring, prevent erosion in specific parts of the bed; and (4) combining parts of
each of options (1) - (3). It is important, however, to have accurate scientific
information when making decisions and choosing between different options. As
noted above, it is often difficult to obtain the required information.
100
p
50
10- 2
Time (days)
increasing n,
increasing particle size,
decreasing porosity
Fig. 3. Variation of time to reach equilibrium in the water column after a resuspension
event; P is percentage of equilibrium concentration attained (adapted from Cheng et al.
1995)