2.1.1 Tier I

contamination is not likely to be a concern, further evaluation in subsequent tiers

will not increase the degree of confidence or certainty about the nature of the

material. Evaluation in progressively higher tiers should be conducted only if the

information at a given tier is not sufficient to make a decision regarding the need

for management actions. Once the information necessary and sufficient to make a

decision is available, further evaluation in subsequent tiers will not increase the

confidence in the decision, is a waste of time and resources, and should not be

conducted.

The overall evaluation process is illustrated as a flowchart in Figure 2-1. The

tiered structure for each pathway is illustrated in matrix form in Table 2-1. The

general intent of each of the tiers is described below. More detailed tiered

structures specific to each pathway are discussed in Chapters 4 through 9.

2.1.1 Tier I

Tier I uses readily available existing information. The Tier I evaluation should

determine the need for evaluation of pathways, identify the pathways (if any) that

should be evaluated further, and identify receptors of concern (ROC) and COC (if

any) for further evaluation.

Although gathering such information may require searching libraries,

archives, and similar sources, such as previous project files, the collection of field

data or pathway tests is outside the scope and intentions of this tier. For dredged

material with a readily apparent need for management actions (or lack thereof),

the information collected in Tier I should be sufficient for making management

decisions. However, more extensive evaluation in subsequent tiers will be needed

if Tier I information is inadequate for management decisions.

2.1.2 Tier II

If a decision cannot be made at Tier I, Tier II evaluations consist of

determining the need for management actions derived from very conservative

techniques that use the chemical, physical, and biological characteristics of the

dredged material and basic information about the CDF. Because of their

conservative nature, if these evaluations indicate that management actions are not

needed, it is very unlikely that further evaluations will indicate such a need.

However, because of their conservative nature, "false positives" may occur and,

depending on the magnitude of such results, further evaluation in higher tiers may

be warranted. Tier II includes tests to evaluate the need for management actions to

meet applicable water quality standards, groundwater standards, etc.

2-2

Chapter 2 Structure and Approach of the UTM