A02.12 PWS Exhibit B - Charge Questions - IEPR Wilmington Harbor.docx

WILMINGTON HARBOR 403 LETTER REPORT &

ENVIRONMENTAL IMPACT STATEMENT

INDEPENDENT EXTERNAL PEER REVIEW

CHARGE TO REVIEWERS

The following Charge to Reviewers outlines the objective of the Independent External Peer Review (IEPR) for the subject study and the specific advice sought from the IEPR panel.

The objective of the IEPR is to obtain an independent evaluation of whether the interpretations of analysis and conclusions based on analysis are reasonable for the subject study. The IEPR panel is requested to offer a broad evaluation of the overall study decision document in addition to addressing the specific technical and scientific questions included in the charge. The panel has the flexibility to bring important issues to the attention of decision makers, including positive feedback or issues outside those specific areas outlined in the charge.

The panel review is to focus on scientific and technical matters, leaving policy determinations for USACE and the Army. The panel should not make recommendations on whether a particular alternative should be implemented or present findings that become “directives” in that they call for modifications or additional studies or suggest new conclusions and recommendations. In such circumstances the panel may have assumed the role of advisors as well as reviewers, thus introducing bias and potential conflict in their ability to provide objective review.

Panel review comments are to be structured to fully communicate the panel’s intent by including the comment, why it is important, any potential consequences of failure to address, and suggestions on how to address the comment. The IEPR Performance Work Statement provides additional details on how comments should be structured.

Broad Evaluation Charge Questions Is the need for, scope, and intent of the decision document clearly stated?

Does the decision document adequately address the stated need and intent relative to scientific and technical information?

Given the need for and intent of the decision document, assess the adequacy and acceptability of the following:

Project evaluation data used in the study analyses, Economic, environmental, and engineering assumptions that underlie the study analyses, Economic, environmental, and engineering methodologies, analyses, and projections, Models used in the evaluation of existing and future without-project conditions and of economic or environmental impacts of alternatives, Methods for integrating risk and uncertainty, Formulation of alternative plans and the range of alternative plans considered, Quality and quantity of the surveys, investigations, and engineering sufficient for conceptual design of alternative plans, and Overall assessment of significant environmental impacts and any biological analyses.

Further, Evaluate whether the interpretations of analysis and the conclusions based on analysis are reasonable, and Assess the considered and tentatively selected alternatives from the perspective of systems, including systemic aspects being considered from a temporal perspective, including the potential effects of climate change.

For the tentatively selected plan, assess whether:

The models used to assess environmental impacts are appropriate, The assumptions made for the engineering and economics analyses are appropriate, The quality and quantity of the surveys, investigations, and engineering are sufficient, and The analyses adequately address the uncertainty and residual risks.

Specific Technical and Scientific Charge Questions Has the study used appropriate, up-to-date data and scientific methodologies?

Are data gaps and limitations clearly identified and their implications explained?

Are cumulative impacts from this and other nearby or connected projects sufficiently addressed?

Is there a robust analysis of potential long-term environmental degradation from increased vessel traffic?

General Engineering Is the quantity of dredged material estimated accurate (new work and operations and maintenance (O&M)), the channel design and placement areas technically sound (e.g., beneficial use placement sites, offshore placement sites, and confined disposal facilities)?

Are mitigation measures clearly defined, designed appropriately, feasible, and likely to be effective?

Are the proposed channel dimensions (depth, width, side slopes) appropriate based on sound engineering judgement, vessel traffic, and sediment characteristics?

Are there any aspects of the civil design that raise concerns about feasibility, performance, or longevity of the project?

Hydrology, Hydraulics, and Coastal Engineering Are the engineering assumptions and methodologies used in channel deepening (e.g., hydrodynamic modeling, sediment transport) appropriate and defensible?

Does the study account for changes in wave climate or longshore transport processes resulting from the deeper channel?

Are impacts to adjacent shorelines and coastal infrastructure from waves due to the deeper channel adequately addressed?

Does the hydrodynamic model ( Delft3D and GenCade) accurately simulate tidal range, salinity intrusion, and current velocities for existing, future without project, and future with project?

Are the boundary conditions, model calibration, and validation methods used in H&H modeling appropriate and documented clearly?

Does the hydrodynamic modeling sufficiently represent existing, future without project, and future with project conditions?

Are the predicted changes in shoaling, groundwater, erosion, vessel wake, tidal impacts, and water quality reasonable given the input data and assumptions?

Have seasonal and extreme weather conditions (e.g., hurricanes, low river flow events) been adequately accounted for in sediment transport modeling?

Are the assessments of potential water quality impacts from dredging and disposal activities modeled appropriately?

Does the study adequately incorporate sea level change and climate change projections into the design and impact analysis?

Does the hydrodynamic model accurately represent the changes in water quality (specifically dissolved oxygen, temperature, salinity) standards defined by the State of North Carolina and are model results presented in a way to evaluate?

Geotechnical and Geological Does the geotechnical analysis adequately address the stability of channel slopes and potential impacts from deepening?

Are subsurface investigations (e.g., boring logs, Cone Penetration Tests, washprobes, geophysical surveys, sediment characterization) sufficient in spatial extent and depth to support channel deepening design?

Is the dredged material properly classified and characterized for suitability of disposal (open water, beneficial use, or confined)?

Are the confined underwater blasting assumptions related to current available geotechnical data and execution adequate?

Are the modeling tools (MODFLOW and SEAWAT) appropriate for the site conditions and objectives of the study?

Does the groundwater model address the potential mobilization of containments from adjacent industrial areas due to the deepening?

Is the conceptual model of the site’s hydrogeology (aquifer systems, confining layers, recharge areas) well developed and supported by data?

Are subsurface conditions (e.g., lithology, permeability, aquifer boundaries) adequately characterized to support model inputs and assumptions?

Does the groundwater model adequately address the potential for saltwater intrusion due to the deepened channels?

Does the groundwater modeling accurately depict the existing, future without project, and future with project while incorporating the correctly the various sea-level change scenarios?