Environmental Monitoring under DFO’s New Pile Driving Mitigation AdviceMay 10, 2019Jayson Kurtz, Ecofish Research Ltd.
Introduction
• Who we are:• Jayson Kurtz R.P. Bio.• Ecofish Research Ltd.
• Outline:• The environmental concern about pile driving• The regulatory context• What it takes to monitor effects
Environmental Concerns
• Fish and marine mammals• Footprint and construction activity• Loss of habitat• Behavioural disturbance• Physical injury
Disturbance and injury due to construction activity (driving piles)
Mechanism of Concern
• Exposure to underwater sound waves (pressure)• Avoidance of area• Delayed migration• Damage to auditory systems • Rupture of gas-filled organs (fish)• Interference with communication or echo location
(marine mammals)
Regulatory Context
• Fisheries Act (serious harm)• Letter of Advice• Authorization
• Species at Risk Act• CEAA/BCEAA
Regulatory Context
• Fisheries Act - Letter of Advice• Advice to avoid impacts• Often based on proponents suggested mitigation• Advice has evolved over time but typically
referenced BMPs produced by industry
BMP
• Outlined practices by type of pile (focus on impact hammer)• Mitigation measures:
• Timing• Physical exclusion• Bubble curtain• Monitoring
• 30 kPa sound pressure threshold (209.5 dB)
Recent DFO Advice
• Based on latest scientific research on impacts• Includes fish and marine mammals• Includes impact and vibratory hammers• Includes cumulative effects monitoring• New thresholds• Exclusion zones – visual observations
New Thresholds
• Finfish peak sound pressure level (SPL): 206 dB@ 10m• Finfish cumulative sound exposure level (SEL): 187 dB re 1 μPa2s >2g• Finfish cumulative sound exposure level (SEL): 183 dB re 1 μPa2s <2g• Marine mammal exclusion zone 120 dB RMS (vibratory)• Marine mammal exclusion zone 160 dB RMS (impact)
• Confused yet?• All lower than the BMP threshold: 209.5 dB
Monitoring
Monitoring
Monitoring
What Did We Learn?
• New monitoring hardware and software is finicky• SELcum scripts from manufacturer• Stop/start measurements
• Challenges measuring background/ambient noise• Technical support
What Did We Learn?
• New peak SPL are achievable…
…with mitigation:• soft-start• bubble curtain
What Did We Learn?
• New cumulative SEL thresholds are challenging to meet• Required pausing pile driving activities • Required moving to other piles >20m apart• Similar levels for pile install and removal
What Did We Learn?
• Can predict when threshold will be reached
What Did We Learn?
• Marine mammal exclusion zone extended >1km for vibratory
• Adapted our approach for pinnipeds (seals)
Recommendations
• Plan your work• Adequately assess fish and marine mammal species in the area• Secure monitoring equipment in advance• Stagger pile locations and be prepared for time outs
Questions?