The Water Report Nov 2005

• Year: 2005
• Title: The Water Report
• Author: Envirotech Publications
• Description: Issue #21
• Publications - Doc Type: Other

Issue #21
The Water Report
The Draft SEF has been designed with levels to encourage investigations that optimize the amount of
Sediments
effort expended in the assessment with respect to the complexity of both the project /site and assessment
questions that must be answered to reach management decisions. A level in this sense is a stage in the
assessment process that concludes with a decision to either: 1) exit the assessment process because
Assessment
sufficient information has been collected to answer questions about the need for management; or 2)
Levels
continue the assessment because insufficient information exists to reach a management decision for the
proposed action.
In many cases management decisions may be possible during the initial phase of an assessment when
Management
there is convincing evidence for or against the presence of risk or whether or not an appropriate disposal
Decisions
option exists for dredged materials. In more ambiguous circumstances, or where the complexity of the
site requires it, more comprehensive assessments and data collection may be required in a subsequent
level before credible management decisions can be made. The strength of a phased assessment
framework is that the framework includes clear decision points where the need to continue the evaluation
is addressed.
This risk -based framework is also structured to allow for iteration. As information is collected and
Adaptation
analyzed during an evaluation, the assessment process must allow for making additions and refinements
to the conceptual model and assessment questions that are formulated during the initial stages of
assessment. Such iteration allows the assessment to become more focused as the evaluation proceeds.
Figures 2 and 3 present the
assessment and management framework
Figure 3. Detail of Level I Tasks
for sediments. Figure 3 provides
additional details for what is included in a
Level 1 evaluation. As shown on these
Define Project Scope
figures, Level 1 includes pre- assessment
Establish Project Goals and initial assessment tasks, while Level 2
• Develop Project Conceptual Model
. identify contaminants of concern can include sediment - dredged material/
Initial
Assessment
. Identify resources of concern site assessment, additional chemical and/
. Describe relevant exposure pathways
or biological testing, or modeling tasks.
Define available management options The levels or sate ories of
Develop assessment questions/ g
hypotheses information /data needs described below
°
are used in a sequential manner for
,i
evaluating the risk of in -place sediments
o ;
Review Existing Information Is the collected and the suitability of dredged material for
es
E
Physical information sufficient unconfined aquatic disposal. This
a
chemical for a management sequential approach is called a tiered
°
Primary
i i ?
. Biological decson
evaluation process. At each level a
Assessment N
decision is made regarding the adequacy
of the existing data to make a suitability
determination. If the existing data are
Conduct Screening Assessment
Collect initial Data adequate for management decision
— • Compare to Screening Guidelines making purposes, then there is no need to
. Physical proceed to the next level. If not, data at
• Chemical the next level are required before a
Biological
management decision can be made.
!
x, Transition to Subsequent Levels
The compilation and review/
Is the collected , — screening of existing information and
i
information sufficient \ Y Management other locational factors comprise the
for a management i Decision initial tasks in Level 1. In some instances,
decision?
the existing information may be sufficient
to make a management decision. For
example, for a navigational dredging
N project, if existing information adequately
-- supports a decision for unconfined aquatic
Level 11 Tasks disposal, no additional data are needed.
However, if there is no existing
information or it is not adequate for
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