4.1.5 Data Requirements

consideration of mixing in evaluating dredged material releases, as does the

MPRSA.

Mixing calculations describe the spatial and temporal boundaries within

which the discharge will reach the water quality standards (WQS). If these

boundaries are within the established mixing zone limits, there should not be an

effect. If these boundaries exceed the established mixing zone limits, there may

be an effect.

Procedures for evaluation of initial mixing are presented in Appendix E.

4.1.5 Data Requirements

Data requirements for effluent evaluations include those pertaining to

operational considerations (i.e., CDF site characteristics and dredge

characteristics) and those pertaining to the properties of the dredged material (i.e.,

contaminant release characteristics and sedimentation characteristics). Data

relating to operational considerations are usually determined by the disposal area

design and by experience in dredging and disposal activities for the project under

consideration or for similar projects. Data relating to the dredged material

characteristics are obtained by sampling and testing the sediments to be dredged.

The process described in Section 3.4 should identify the case-specific effluent

COC for effluent quality evaluations in all tiers. In addition to typical

contaminants, WQS may exist for nutrients and physical parameters such as

temperature, dissolved oxygen, pH, and turbidity or total suspended solids (TSS).

Chlorides should be considered a potential COC whenever there is the potential

for effluent from saline dredged material to enter a fresh water system. If the

effluent pathway is of concern from the standpoint of contaminants, the retention

of TSS within the CDF is of paramount importance, and TSS and/or turbidity

should be considered a COC for the effluent pathway. Effluent elutriate tests and

column settling tests provide the remaining data required for prediction of the

quality of the effluent in Tier III. A summary of the data requirements for effluent

quality prediction is given in Table 4-1.

4-4

Chapter 4

Effluent During Disposal Operations