Introduction - trdoer30009

Introduction

Uncertainty about ecological and human health risk associated with dredged

material disposal alternatives can lead to delayed, costly, and unwise decisions.

This report examines sources of uncertainty in evaluating impacts of open-water

disposal with the goal of improving dredged material management decisions.

Uncertainty sources are prioritized to focus U.S. Army Corps of Engineers

(USACE) resources on reducing principal contributors to uncertainty and the

controversy that often accompanies it.

This report begins with a brief description of the USACE tiered evaluation of

dredged material, a summary of uncertainty analysis tools, and an explanation of

how uncertainty analysis can improve USACE dredged material disposal

decisions. Chapters 2 through 6 discuss the following:

a. The approach used to rank uncertainty sources in the tiered evaluation

(including complete risk assessments) of dredged material disposal at

open-water sites.

b. A detailed discussion of uncertainty sources within the tiered evaluation

of dredged material disposal.

c. Results of the preliminary ranking and recommendations for further

refinement of the ranking.

USACE/USEPA Technical Framework for

Evaluating Environmental Effects of Dredged

Material Management Alternatives

The U.S. Environmental Protection Agency (USEPA)/USACE Technical

Framework (USEPA/USACE 1992) for evaluating environmental effects of

dredged material management alternatives includes five major components:

evaluation of dredging project requirements, identification of disposal

alternatives, initial screening of alternatives, detailed assessment of alternatives,

and alternative selection. This report focuses on a portion of this framework to

identify important sources of uncertainty in evaluating dredged material for

disposal in one type of alternative: an open-water site.

Prior to disposal, dredged material undergoes a four-tiered evaluation

designed to match the level of analytical effort with the complexity of the

Chapter 1 Introduction