6.1.3 Consideration of Attenuation

supplies. Chlorides should be considered as a COC for leachate whenever there is

the potential for leachate from saline dredged material to enter a fresh water

system.

6.1.3 Consideration of Attenuation

The evaluation of leachate should consider the effects of attenuation, mixing,

and dispersion in the dikes, foundation materials, and aquifer between the dredged

material and the leachate receptors. The point of compliance for leachate in the

groundwater is normally defined by the State regulatory agency.

6.1.4 Data Requirements

Data requirements for prediction of leachate quality, summarized in

Table 6-1, include those pertaining to:

1. Operational considerations (i.e., CDF site characteristics, site

management and dredge 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.

2. Properties of the dredged material (i.e., contaminant release

characteristics). Data relating to the dredged material characteristics

should be obtained by sampling and testing the sediments to be dredged.

3. Foundation, dikes, and aquifer. Data relating to the foundation, dikes,

and aquifer are usually determined by site investigation and are typically

available from the site selection and design evaluation.

4. Climate. Climatic data are available from the U.S. National Weather

Service.

6-5

Chapter 6

Leachate to Groundwater