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| High cost | Low cost |
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Indicator(s) of the impact |
Scour: increase in median grain size, decrease in organic content, decrease in seabed volume |
Deposition: decrease in median grain size, increase in organic content, increase in seabed volume |
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Methodology or technique to collect data |
Particle size analysis, multibeam/interferometric bathymetry |
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Description of methodology or technique(s) for collecting data | Seasonal surveys, 5 years | Annual surveys, 3 years |
Grain size: *5-sample transect at 3 devices out to 200 m | Grain size: *3-sample transect at 3 devices out to 200 m |
Bathymetry: overlapping transects for 100% coverage (at least 0.5 m pixels) 1 km radius at 3 devices | Bathymetry: overlapping transects for 100% coverage (at least 0.5 m pixels) 500 m radius 3 devices |
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Methodology for analyzing data |
ANOVA on median grain size, volume change estimate using mosaicked bathymetry models |
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Frequency and duration | 1 preconstruction survey, seasonal operation, 1 postconstruction survey | 1 preconstruction survey, annual operation, 1 postconstruction survey |
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Spatial scale | 200 m–1 km radius around 3 devices | 500 m radius around 3 devices |
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How well does this methodology account for environmental variability? | Seasonal and interannual variability | Interannual variability |
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Cost | $25 k/year, 5 years | $15 k/year, 3 years |
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Other considerations (e.g., advantages or disadvantages) |
Can be combined with benthic community composition monitoring protocol |
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