2.1.6 Decisions after Each Tier

all relevant available information and identify COC (Section 2.2.2) and ROC

(Section 2.2.3) for the CDF and dredged material being investigated, even though

it may be clear without formal Tier I evaluation that further assessment will be

necessary. It may be possible to skip some Tier II evaluations if it appears likely

that it will ultimately be necessary to go to Tier III. As evaluation of a pathway

progresses through the tiers, more and more information becomes available, so

that in most cases there is sufficient information for a decision by the end of Tier

III or earlier. If it is necessary to go to Tier IV, only a few specific and well-

defined questions should remain to be addressed at the Tier IV level of intensity.

The procedures in this manual can be applied within a given tier using several

levels of sophistication with respect to the data required. Pathway evaluations

require consideration of several types of site and CDF information to include

physical and chemical characteristics of the material proposed for disposal in the

CDF, the characteristics of the CDF itself, operational variables regarding the

dredging and disposal process, and characteristics of the receiving environments

for the pathways. These data can be derived from simple estimates to extensive

prediction or modeling efforts and should be considered in conjunction with data

on dredged material pathway behavior. These data may vary from conservative

estimates based on simple partitioning principles to data derived from detailed

pathway testing. A given evaluation for a given pathway could therefore employ a

range of site and CDF data sources and levels of detail. Use of existing

information or conservative estimates of the needed site variables is most

appropriate for evaluations in the early tiers. Use of case-specific data is more

appropriate for later tiers.

2.1.6 Decisions after Each Tier

After completion of the technical evaluation in each tier, a decision

concerning the next step is made in the following manner:

1. If the available information is sufficient for a decision regarding the need

for management actions, evaluation of the pathway under consideration

stops at this point and management actions, if appropriate, are considered.

The evaluation then proceeds to the next pathway of concern. This

generic decision process is described in detail for every tier of each

pathway in Chapters 4 through 9.

2. If the information available at the completion of a particular tier is not

sufficient to make a decision regarding the need for management actions,

the evaluation of the pathway under consideration may proceed to the

next tier, or appropriate management actions may be considered as an

alternative to further testing.

2.1.7 Management Actions

If a decision is made that management actions are needed for a given

pathway, the influence of the management actions on other pathways should be

considered. For example, the placement of a surface cover of clean material to

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Chapter 2 Structure and Approach of the UTM