Life cycle assessment for dredged sediment placement strategies

Area of Science:

• Environmental Science
• Civil Engineering
• Sustainability Studies

Background:

• Dredging is crucial for maintaining navigable waterways, supporting trade and economic sustainability.
• Managing dredged sediments involves balancing regulatory standards, costs, and risks, often leading to stakeholder conflicts.
• Current decisions prioritize local, immediate environmental effects, overlooking broader, long-term impacts of transportation and placement.

Purpose of the Study:

• To apply a cradle-to-use Life-Cycle Assessment (LCA) to dredged sediment placement.
• To quantitatively analyze a wider range of impacts and benefits across all project stages and time horizons.
• To compare potential upland, open water, and containment-island placement alternatives in the Long Island Sound region.

Main Methods:

• Utilized a cradle-to-use Life-Cycle Assessment (LCA) framework.
• Conducted a comparative analysis of different sediment placement alternatives.
• Focused on the Long Island Sound region (NY/CT) for case study analysis.

Main Results:

• Upland placement of uncontaminated sediments may be the most environmentally burdensome alternative on a per-ton-kilometer basis.
• This increased burden is attributed to emissions from diesel fuel combustion and electricity consumption during handling and transportation.
• Results indicate that transportation impacts can be significant and should be weighed against the ecosystem impacts of the sediments themselves.

Conclusions:

• Sediment management decisions should incorporate a comprehensive Life-Cycle Assessment (LCA) approach.
• Considering distributed and long-term effects, including transportation, is essential for sustainable sediment management.
• A holistic decision-making framework is needed to balance various environmental impacts and stakeholder considerations.