An Overview of Pile Driving Effects on Fish For the: Oregon Department of Transportation By: Robert R. Abbott, Ph. D. May14, 2009

Presentation Overview  How did we get here?  Why Pile Driving Impacts Fish  Introduction to Underwater Sound  The California Experience

At the Pile Installation Demonstration Project for the Bay Bridge in San Francisco Bay, NOAA noted birds and dead fish.

Gulls Quickly Flocked to the Area

A Typical Gull Pattern

Occasionally There Were Very Large Flocks (> 500 gulls)

Benicia-Martinez Bridge killed many fish including salmon and sturgeon, and resulted in millions of dollars of compensatory mitigation. “We are too busy building American to be concerned about this****”

What Is The Big Deal about a few dead fish?  Fish floating up to the surface are now noticed  Dead fish get advocacy groups involved  Some are threatened and endangered species  Some fish are recreationally important  Some fish are commercially important  Lots of dead fish: bad media attention

Richmond-San Rafael Bridge. There was no mitigation on this project and it also resulted in millions of dollars of compensatory mitigation.

San Francisco Bay Area Studies  Piscivorous bird studies  Hydroacoustic monitoring of fish schools  Fish salvage  Necropsies  Caged fish studies  Behavioral Studies

Berth 22 for Port of Oakland

Cushion Block

Concrete Piles

Pile Installation Demonstration Project

How underwater sound affect fish?  Temporary -hearing threshold shift  Startle response  Compression and expansion of swim bladder  Kidney damage  Injury to the inner ear hair cells  Ruptured capillaries  Ruptured heart

Air pockets in fish  Swimbladder – Physostomous - salmonids, sturgeon – Physoclistous - Carp, perch, rockfish  Air pockets leading to the ear  Micro air bubbles in tissues and capillaries  Intestinal gas

Inner Ear of Fish

Piscivorous Bird Studies  Circling, diving  Some coming up with a fish  Many big fish recover and swim away  Only gulls, no other species  No birds injured to date

Competition with Gulls

Fish Salvage Taught Us:  Only swim bladder fish  No sharks or flat fish  Tough to beat the gull at collecting fish  Most small fish never surface  All sizes killed  Easy pickings for predators below

Hydroacoustic Monitoring of Fish Schools  They do not move away  Small fish appear to be entrained  Some species attracted to physical structures  Some species may actually be attracted to vibrations in the water

Why Don’t They Move Away?  Some probably do  Some can not tell which way to go  Some can not get out of the way even if they can tell which way the sound is coming form  Some are attracted  Some not adversely affected

Necropsies: External Indications  Red eye  Red belly  Protruding organs  Red fins  Scale loss along the abdomen

Traces of Blood in the Eye

Loss of Scales Along the Abdomen

Slight reddening around the belly

Red Head

Rupture of the Body Cavity

Protruding Internal Organs

Necropsies: Internal Indications  Internal bleeding  Ruptured swim bladder  Ruptured heart chambers  Smashed kidney  Pulverized internal organs

Massive Internal Bleeding

Ruptured Swim Bladder

Hole in the Posterior Swim Bladder

Rupture of the Kidney

Behavioral Observations  Short term erratic swimming pattern  Whirling behavior  Startle response  Twitch response  Delayed mortality

Zone of Impact  Near-term mortality zone  Delayed mortality zone  Non-lethal effects on behavior Adverse effect on hearing May affect fish migration routs May affect spawning success Reduce survival rate

Pile Near-term Mortality Zone Delayed Mortality Zone Zones of Impact

Introduction to Underwater Noise  Frequency  Wave form  Amplitude  Pulse  Peak Sound Pressure Level & RMS  Energy flux density  Shallow water distortion

Frequency Characterization

Frequency: Pile Impulse Histogram  Most energy is below 1 KHz  Low frequency = long wave length  Propagate a long distance

Bubble Curtain 30 m Peak Pressure = 209 dB or 28 kPa

30m Bubble Curtain ON Peak Pressure = 198 dB or 8 kPa

Wave Form  Under pressure spike  Time in ms to peak under-pressure  Time in ms to peak over-pressure

Rate of propagation loss

Amplitude Measurements  Measured in terms of dB re 1 µ Pa  Peak and RMS  Measured at a reference distance  At least two meters below the surface  Not the same as measuring sound in air  Very few experts around

Pulse Pulse Pulse Pulse  Relatively long impulse  Repetition for hours  Cumulative effect

Shallow Water Distortion  Accelerated rate of attenuation  Pressure relief at the surface  Reflection off the surface  Reflection off the bottom  Standing waves  Doppler effects due to tidal currents  Wave guide phenomena

Mitigation Strategies  Bubble curtains  Fabric barriers  Isolation casings  Construction windows  Fish distribution monitoring  Compensatory mitigation

LET THERE BE LOTS OF BUBBLES

Bubble Curtain Schematic

Key Concepts in Bubble Curtain Technology  Metric is bubble flux density  Decouple pile from water  The closer the better  Filter out higher frequencies  Reduce amplitude from 6-30 dB  Increase rise time to peak  Delays arrival of peak

PRESSURE WAVE PILE BUBBLE CURTAIN EXPANSION WAVES HEAT RADIATION DISTORTED PRESSURE WAVE How Bubble Curtains Work

Primary Feed Lines

PRIMARY DISTRIBUTION LINES

ON DECK MONITORING Digital flow meters and analog gauges to monitor air flow rate and distribution

Bubble Curtain Deployment Pile driving operations at Pier E6E. Water depth is 26 feet.

Bubble Curtain On

Bubble Curtain off

Placing the hydrophone in the cage

Hydroacoustic monitoring equipment

Placing fish in a cage

Post exposure observations

Loading fish onto the research vessel

Up to 10 batches of fish

Retrieving the cage while keeping the fish in water at all times

ACKNOWLEDGEMENTS  Manson Construction  Caltrans: District 4  Illingworth and Rodkin  Charles Greene  Art Popper  Glenn Fleming  Robert Blizard