What are the advantages of a risk-based approach for dredged material management?

Technical Note DOER-R1

September 1998

A number of Federal environmental regulatory programs use some form of risk assessment in their

decision-making process. Regulatory agencies used the risk assessment approach to develop Federal

drinking water standards and ambient water quality criteria, to make decisions regarding

environmentally protective concentrations of contaminants under Resource Conservation and

Recovery Act (RCRA) and Comprehensive Environmental Response, Compensation, and Liability

Act (CERCLA) programs, and to develop discharge limits under Clean Water Act provisions.

The United States Congress has renewed its commitment to integrate risk assessment into the

regulatory process. The Commission on Risk Assessment and Risk Management published its

report on risk assessment in regulatory decision making (Omenn et al. 1997). That the United States

Congress mandated this commission to "make a full investigation of the policy implications and

appropriate uses of risk assessment and risk management in regulatory programs under various

federal laws" reflects governmental concern regarding risk assessment in regulation. The

commission report made recommendations for risk-based approaches to nearly all Federal agencies

including the Department of Defense, USEPA Office of Water, Occupational Safety and Health

Administration, Food and Drug Administration, Department of Agriculture, and Department of

Energy. These recommendations indicate that the engineering and water pollution control

community will depend even more heavily upon an understanding of risk assessment in the future.

What are the advantages of a risk-based approach for dredged material

management? The major advantage of a risk-based approach for dredged material management

decision making is that it provides a consistent framework that integrates a wide variety of data and

information.

The dredged material manager works within a decision-making system framed by regulation and

technical approaches. In their concise review of this framework, Peddicord et al. (1997) note that

there are three principal components of dredged material management: (1) site selection; (2) dredged

material evaluation (permitting); and (3) site monitoring. The intent of these components is to assure

that dredged material management decisions meet the statutory requirement that there be "no

unacceptable or undesirable adverse effects."

Currently, these three components form the basis for data collection and environmental analysis of

potential impacts associated with dredged material management. The site selection process provides

baseline environmental studies of a proposed site. The dredged material evaluation is a four-tiered

process as described in the Dredged Material Testing Manuals. An increasing level of information

is developed in successive tiers until sufficient data are available to reach a determination regarding

the acceptability of the material. Monitoring is a post-site selection and post-dredged material

disposal activity to confirm or validate the decision-making process.

It is fair for the dredged material manager or field operations personnel to ask, "If we are essentially

collecting all the data and going through the general thought processes for risk assessment anyway,

why conduct a formal risk assessment?" The answer is that risk assessment imposes a structure on

the data analysis that integrates the information obtained in the site selection process with the data

collected and/or generated in Tiers I to IV on the properties of the sediments. A risk assessment

further integrates these data with the operational and physical characteristics of the management