The Use of Dispersants in Marine Oil Spill Response (2020) / Chapter Skim
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5 TOOLS FOR DECISION MAKING
5 TOOLS FOR DECISION MAKING
Pages 141-164
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From page 141... ...
Often these response options are used in combination to effectively mount a comprehensive spill response. "As the potential use of dispersants is expanded into nearshore, estuarine, and perhaps even freshwater systems, the trade-offs become even more complex" (NRC, 2005)
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From page 142... ...
DECISION-MAKING TOOLS As previously discussed, making the best decision possible during an oil spill incident requires a balanced consideration of the potential environmental consequences of the spill under a natural recovery scenario versus the consequences associated with each response strategy. In any spill response, the first priority is the protection of human life, and the Federal On-Scene Coordinator and Area Contingency Plans place the highest priority on decisions that may affect response worker health and safety or public health (in the case of a nearshore release)
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From page 143... ...
In 2000, IPIECA (formerly the International Petroleum Industry Environmental Conservation Association) published a report titled Choosing Spill Response Options to Minimize Damage: Net Environmental Benefit Analysis (IPIECA, 2000)
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From page 144... ...
There are differences between these tools and how they are best used in spill responses. Consensus Ecological Risk Assessment CERA utilizes a detailed semiquantitative risk ranking square to perform comparative analyses of available response methods.
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From page 145... ...
concentration fields of oil pseudo-components coupled with toxicity thresholds and spatial distributions of important biota to calculate mortality and recovery rates. Another benefit of integrated models is that they can be used to quantify and understand the sensitivity of the results to changes and uncertainties in inputs and sub-model formulations and the effectiveness of the various response options.
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From page 146... ...
Science • Pre-existing contingency plans • Biological Assessments • Historical databases • NEPA Studies • Environmental Sensitivity Index maps • Subject matter expertise FIGURE 5.2 CERA, SIMA, and CRA bring together elements of regulations, policies, and current scientific information. This figure provides some examples for illustrative purposes.
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From page 147... ...
On a positive note, however, integrated models are composed of sub-models simulating the major processes, and these sub-models have typically been validated. Nevertheless, results from even the best integrated model should be viewed with caution and results with uncertainty bounds should always be presented to decision makers, a point reinforced by ASTM F2067-13 (ASTM, 2013b)
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From page 148... ...
In other words, the inability of an integrated model to accurately forecast spill fates days in advance during an actual spill should not be taken as proof that the model cannot be trusted to develop a reasonable contingency plan. Even if the uncertainty in integrated models was thoroughly studied and quantified, there would still be a major challenge: ensuring that decision makers take adequate account of this added information.
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From page 149... ...
Table 5.1 summarizes several of the more widely used integrated models as well as the Texas A&M Oilspill Calculator (TAMOC) model.
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From page 150... ...
1st order decay, Brakstad and 1st order decay with droplet size 1st order decay but not used in Gros (2015) ; Spaulding et al.
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From page 151... ...
Spreading French-McCay (2004) ; Hoult (1972)
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From page 152... ...
calculate dissolved concentrations of hydrocarbons in pore water from Shoreline -- Considers the National Oceanic and Atmospheric Administration's sedimented oil. The aquatic toxicity model is applied to pore water Environmental Sensitivity Index along with the average thickness of the oil, a concentration estimates.
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From page 153... ...
Restitution time is based on recovers to within 1% of the pre-spill condition. For habitats, recovery historical data for each Environmental Sensitivity Index where lethality has been time is based on literature observations of productivity over time.
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(2015) compared 5 integrated models for 14 scenarios of a continuous 20,000 barrels (bbl)
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From page 155... ...
developed an approach to evaluate the ecological effects from various response options, which included input from several state and federal agencies. The effort was spurred by an article on the application of ecological risk analysis in dispersant use (Aurand, 1995)
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From page 156... ...
SOURCE: Walker et al., 2018b. sons between response options and within particular habitats or resource groups.
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From page 157... ...
Habitat Intertidal NEARSHORE - Water Surface OFFSHORE - Water Surface Resources of Concern Vegetation Crustose Coraline Algae Sponges Coral and Live Rock Non-T/E Birds Non-T/E Mammals - feral cat, mongoose Non-T/E Fish Non-T/E Shellfish & Other Invertebrates T/E Species or Rare - ANIMALS T/E Species or Rare - PLANTS Critical Habitat Vegetation, Floating Algae Crustose Calcified Algae on the bottom Sponges on the bottom Coral and Live Rock on the bottom Non-T/E Birds Non-T/E Mammals Non-T/E Fish Non-T/E Shellfish & Other Invertebrates T/E Species or Rare - ANIMALS Critical Habitat Plankton Non-T/E Birds Non-T/E Mammals Non-T/E Fish Non-T/E Shellfish & Other Invertebrates T/E Species or Rare - ANIMALS Critical Habitat 3B 2A 2B N/A N/A N/A 2A 2A 2A N/A N/A N/A Natural Attenuation and Monitoring 3B 3B 4C 2B 3B 4D 3C 3C N/A N/A 3C 3C 4C 2C 3B 2B 4C 4C N/A 4C 2B 2B 4C 4C 1B 4B 4C N/A 2B 1A 2B N/A N/A 4B N/A 2C 3C Summary Risk for Sub-habitat 4D 4D N/A N/A 4D 4D N/A N/A Mechanical Containment and Recovery N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 3C N/A N/A N/A 4D 4D 4D 4D N/A 4D 4D 4D 4D 4D 4D 4D N/A 4C 4C N/A 4D 4D 4D Summary Risk for Sub-habitat 3C 2A 2C N/A N/A N/A 2B 2A 2A 3B N/A N/A N/A Chemical Dispersion 3B 3C 4B 2A 3C 4D 3B N/A N/A 3C 3B 3B 1B 3C 2B 4B 4B N/A 4B 2C 2B 4B 4C 1B 3B 4C 4C N/A 2B 1B 2B N/A N/A 4B N/A 2C 3B Summary Risk for Sub-habitat 3B N/A 4C N/A Resource Protection 3C 3C 4B 2B 3B N/A 4C 3C N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 4B 2B N/A N/A Summary Risk for Sub-habitat Shoreline Clean Up N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A Summary Risk for Sub-habitat T/E species – ANIMALS Critical Habitat Reporting order: Reporting order: Birds Insects CH Marine Mammal – HI Monk Seal Plants CH Marine Mammal – cetaceans HI Monk Seal CH Reptiles – Sea Turtles HI Monk Seal CH Insular False Killer Whale Fish - Manta Ray FIGURE 5.5 Example of a risk ranking matrix specific for resources inhabiting surface waters (0-2 m depth) in Hawaii, including threatened and endangered species, potentially affected by response options.
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From page 158... ...
Although the USCG had already developed the CERA process for contingency planning purposes, many believed that it could not be realistically applied at the onset of a spill response, nor tactically during an ongoing event. Simply put, the time, cost, and logistics coordination to achieve a consensusbased approach for contingency planning, while appropriate for contingency planning, was believed by many to be too constraining when faced with an actual spill.
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From page 159... ...
. Data linked directly to planning scenarios under consideration primarily include oil properties, oil spill trajectory modeling, environmental sensitivity maps, and identification of appropriate response options for that particular site.
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From page 160... ...
160 NO CONTAINMENT SURFACE SUBSEA CONTROLLED SHORELINE INTERVENTION AND RECOVERY DISPERSANT DISPERSANT IN-SITU BURNING BOOMING Not feasible for a surface spill Potential relative impact Impact modification factor Impact modification factor Impact modification factor Impact modification factor Relative impact mitigation score Relative impact mitigation score Relative impact mitigation score Relative impact mitigation score RESOURCE COMPARTMENTS A B1 A x B1 B2 A x B2 B4 A x B4 BS A x BS Seabed None 1 0 0 0 0 0 0 0 0 Lower water column None 1 0 0 0 0 0 0 0 0 Upper water column Low 2 1 2 -2 -4 0 0 0 0 Water surface Medium 3 1 3 3 9 2 6 0 0 Air Medum 3 1 3 2 6 1 3 0 0 Shorelines 3 1 3 3 9 2 6 1 3 Saltmarsh High 4 1 3 2 1 Estuarine mudflats High 4 1 3 2 1 Sandy beaches Low 2 1 3 2 2 High value resources Low 2 0 0 1 2 0 0 1 2 Socio-economic 4 1 4 2 8 1 4 3 12 Boat harbour Medium 3 1 2 1 2 Water recreation High 4 1 2 1 3 Cultural None 1 0 0 2 2 1 1 1 1 Total impact mitigation score: 1S 32 20 18 Ranking: 4th 1st 2nd 3rd FIGURE 5.8 Overview of Step 2 and Step 3.
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From page 161... ...
. Two trade-off aspects are balanced in this step (i.e., protection and response and the benefits and drawbacks of selected response options)
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From page 162... ...
. As a newly developed framework, a key rationale of the CRA is that it attempts to reduce uncertainties introduced through the use of integrated models, whose predicted results may not reflect actual occurrences in the environment, by comparing the relative risks and benefits of various response options.
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From page 163... ...
process is to conduct an evaluation that will allow spill responders and stakeholders to evaluate the trade-offs involved with the various response options and choose the option(s) that will result in a reduction of potential adverse impacts and/or the best overall recovery of the ecological, socioeconomic, and cultural resources of concern, while satisfying the primary goal of minimizing immediate risks to response workers and public health and safety.
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From page 164... ...
Recommendation: A controlled field experiment or spills of opportunity should be used to collect comprehensive field observations for validating the entire integrated model. Recommendation: Integrated models should be used to evaluate and optimize combinations of response options.
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