Economic Impacts of Environmental Windows Associated with Dredging Operations

Dickerson, Dena D.; Reine, Kevin J.; Clarke, Douglas G.

doi:10.21236/ada361194

Cited by 8 publications

(9 citation statements)

References 1 publication

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“…Consequently, benthic habitats have been explicitly accounted for in management recommendations and plans (Erftemeijer et al ., ; PIANC ). When fish are considered in dredging management plans, there is often limited scientific evidence used to support the recommended management interventions (Dickerson, Reine, & Clarke, ; Suedel et al ., ). The information generated in this meta‐analysis demonstrates that there can also be significant direct effects of dredging on fish, which can compound the indirect effects of habitat loss, leading to further impacts.…”

Section: Summary and Recommendationsmentioning

confidence: 99%

A critical analysis of the direct effects of dredging on fish

et al. 2017

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Dredging can have significant impacts on aquatic environments, but the direct effects on fish have not been critically evaluated. Here, a meta-analysis following a conservative approach is used to understand how dredging-related stressors, including suspended sediment, contaminated sediment, hydraulic entrainment and underwater noise, directly influence the effect size and the response elicited in fish across all aquatic ecosystems and all life-history stages. This is followed by an in-depth review summarizing the effects of each dredging-related stressor on fish. Across all dredging-related stressors, studies that reported fish mortality had significantly higher effect sizes than those that describe physiological responses, although indicators of dredge impacts should endeavour to detect effects before excessive mortality occurs. Studies examining the effects of contaminated sediment also had significantly higher effect sizes than studies on clean sediment alone or noise, suggesting additive or synergistic impacts from dredging-related stressors. The early life stages such as eggs and larvae were most likely to suffer lethal impacts, while behavioural effects were more likely to occur in adult catadromous fishes. Both suspended sediment concentration and duration of exposure greatly influenced the type of fish response observed, with both higher concentrations and longer exposure durations associated with fish mortality. The review highlights the need for in situ studies on the effects of dredging on fish which consider the interactive effects of multiple dredging-related stressors and their impact on sensitive species of ecological and fisheries value. This information will improve the management of dredging projects and ultimately minimize their impacts on fish. K E Y W O R D Scontaminated sediment, dredging impacts, fisheries, meta-analysis, noise pollution, suspended sediment

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Section: Summary and Recommendationsmentioning

confidence: 99%

A critical analysis of the direct effects of dredging on fish

et al. 2017

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“…Moreover, the use of robust and transparent evidence-based information as the basis for management interventions or regulations can reduce controversy and lead to better compliance and actually reduce the overall cost of dredging. This is due to having seasonal restrictions more appropriately set to times of year when risks are actually high and having threshold reference values for multiple endpoints, which can allow dredging activities to be modified or reduced, rather than halted (CEDA, 2015;Dickerson et al, 1998;U.S. Army Corps of Engineers, 2015).…”

Section: Discussionmentioning

confidence: 99%

“…The use of seasonal restrictions has been encouraged during sensitive life history events, such as spawning, flowering, or migration (Commonwealth of Australia, 2009;Erftemeijer et al, 2013). Seasonal restrictions remain controversial because they are perceived not to be based on robust scientific evidence and are inconsistently applied (Dickerson, Reine, & Clarke, 1998;Suedel et al, 2008;U.S. Army Corps of Engineers 2015).…”

Section: Introductionmentioning

confidence: 99%

Management strategies to minimize the dredging impacts of coastal development on fish and fisheries

Wenger

Rawson

Wilson

et al. 2018

CONSERVATION LETTERS

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Accelerating coastal development and shipping activities dictate that dredging operations will intensify, increasing potential impacts to fishes. Coastal fishes have high economic, ecological, and conservation significance and there is a need for evidencebased, quantitative guidelines on how to mitigate the impacts of dredging activities. We assess the potential risk from dredging to coastal fish and fisheries on a global scale. We then develop quantitative guidelines for two management strategies: threshold reference values and seasonal restrictions. Globally, threatened species and nearshore fisheries occur within close proximity to ports. We find that maintaining suspended sediment concentrations below 44 mg/L (15-121 bootstrapped CI) and for less than 24 hours would protect 95% of fishes from dredging-induced mortality. Implementation of seasonal restrictions during peak periods of reproduction and recruitment could further protect species from dredging impacts. This study details the first evidence-based defensible approach to minimize impacts to coastal fishes from dredging activities.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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“…Constraint (1) ensures that job j is satisfied by at most one piece of dredging equipment d, whereas Constraint (2) states that the total cost incurred by such assignment cannot exceed the total budget. Constraint (3) requires that if job j is satisfied by equipment d, exactly one start day for that work must be specified for that assignment. Constraint (4) specifies that if job j is started in period t, by equipment d, then equipment d cannot begin another job, j', until t jj' + t jd periods have passed (i.e.…”

Section: Analytical Approachmentioning

confidence: 99%

Optimal Dredge Fleet Scheduling within Environmental Work Windows

Nachtmann

Mitchell

Rainwater

et al. 2014

Transportation Research Record

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The U.S. Army Corps of Engineers (USACE) annually dredges hundreds of navigation projects through its fleet of government dredges and individual contracts with private industry. The research presented here seeks to examine the decision of allocating dredge resources to projects system-wide under necessary constraints including environmental restrictions concerning when dredging can take place due to migration patterns of turtles, birds, fish, and other wildlife, dredge equipment resource availability, and varying equipment productivity rates that affect project completion times. Our problem definition and model formulation of optimal dredge fleet scheduling within environmental work windows are discussed. In addition, sensitivity analysis is conducted to provide decision makers with quantitative insights into dredging efficiency gains that could be realized system-wide if environmental restrictions were relaxed. Such information can be used to guide USACE research efforts focused on understanding the true impacts of dredging operations on threatened, endangered, and sensitive species.

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Economic Impacts of Environmental Windows Associated with Dredging Operations

Cited by 8 publications

References 1 publication

A critical analysis of the direct effects of dredging on fish

A critical analysis of the direct effects of dredging on fish

Management strategies to minimize the dredging impacts of coastal development on fish and fisheries

Optimal Dredge Fleet Scheduling within Environmental Work Windows

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