Section 1 Introduction - National Marine Fisheries Service - NOAA

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NBK at Bangor EHW-1 Pile Replacement Project Final Marine Mammal Monitoring Report The monitoring boat stationed outside the WRA and monitoring the 120 dB RMS zone (see Figure 3) looked for the presence of marine mammals and radioed to near-field observers if marine mammals were traveling toward the WRA/shutdown zone. Marine mammal sighting forms were used to document observations (Appendix C). During Activity Monitoring. The shutdown and buffer zones were monitored throughout the time required to install or remove a pile. The following monitoring methodology was implemented during pile operations: No impact pile driving was conducted during EHW-1 repairs. During vibratory pile driving, if a marine mammal was observed entering the 1.5 miles (2.4 km) vibratory behavioral disturbance zone, a “take” was recorded and behaviors documented. However, that pile segment would be completed without cessation unless the animal entered or approached the shutdown (injury) zone, at which point all pile installation and removal activities were halted. The observers immediately radioed to alert the Pile Driving Lead Engineer and/or raised a red flag. This action required an immediate “all-stop” on pile operations. In the event that a pile was being driven and initiation of the shutdown procedures (if a marine mammal was sighted approaching or entering the 50 m [164 ft] shutdown zone) would pose an imminent human safety hazard, the shutdown procedures were temporarily waived by the MC, and pile driving was allowed to continue. The marine mammal was closely watched and pile driving would have been stopped if the marine mammal showed any signs of distress; however no such behavior was noted. After initiation of a shutdown, pile installation and removal activities were delayed until the animal voluntarily left the shutdown zone and had been visually confirmed beyond the shutdown zone, or 30 minutes had passed without re-detection of the animal. During the pile driving delay, monitoring continued and pile driving did not resume until the shutdown zone had been deemed clear of all marine mammals. If marine mammals were detected outside the shutdown zone after the pile driving was initiated, the MMOs continued to monitor these individuals and recorded their behavior, but pile driving proceeded. Marine Mammal Sighting Forms were used to document observations (Appendix C). Any monitoring boats engaged in marine mammal monitoring maintained speeds equal to or less than 10 knots. Experienced MMOs were trained to accurately verify species sighted. MMOs used binoculars and the naked eye to search continuously for marine mammals. In case of fog or reduced visibility, the MMOs had to be able to see the shutdown and buffer zones, or pile driving was not initiated until visibility in these zones improved to acceptable levels. Post-Activity Monitoring. Monitoring of the shutdown and buffer zones continued for 30 minutes following completion of pile installation and/or removal activities. These monitoring Bangor, Washington 14
NBK at Bangor EHW-1 Pile Replacement Project Final Marine Mammal Monitoring Report efforts focused on observing and reporting unusual or abnormal behavior of marine mammals. During these efforts, if any injured, sick, or dead marine mammals were observed, the U.S. Navy was to notify NMFS immediately. Monitoring results were noted on the Marine Mammal Sighting Form (Appendix C). Piles and Pile-Driving Equipment Pile driving operations were conducted October 4-27, 2011. During the EHW-1 repairs a total of 45 steel piles were subject to installation or extraction. This 45 pile total consisted of 36 piles installed (28 new permanent piles and 8 temporary falsework piles), and 9 piles extracted. There were 55 pile driving events (36 piles installed) and 10 pile removal events (9 piles were removed) all conducted with a vibratory hammer. The new permanent production piles were 30" OD (Outside Diameter) open ended steel piles with wall thicknesses of 0.50" and lengths of 140 to 190 ft. In subsequent tables and text, production piles supporting the new walkway are denoted by the prefix “W” (W1 - W12) and replacement wharf piles are denoted by the prefix “EHW” (EHW1 - EHW16). Falsework piles are denoted by the prefix “FW” (FW1 - FW8) and were 16" OD open-end steel piles with variable and undetermined wall thickness. Some original walkway piles were extracted and those and other piles extracted were 12” and 24” piles and may be denoted by the prefix “RX” or “EX” in the pile name. Falsework piles are intended for temporary use to support scaffolding to guide installation of permanent piles. Table 3 provides the pile specification information for the piles installed and removed at the EHW-1. No impact pile driving occurred during this first year of construction activities associated with EHW-1 repairs. Pile-driving equipment was provided and operated by Manson Construction Co. One vibratory hammer (APE 200-6) was utilized during the project. The APE 200-6 has a drive force of up to 542 kips or 271 tons. Acoustic Monitoring Acoustic monitoring was conducted during vibratory installation and removal activities associated with the EHW-1 PRP in order to determine the actual distances to the underwater and airborne thresholds for marine mammals and pinnipeds. These included the 190-dB re 1μPa RMS, 180-dB re 1μPa RMS, and 120-dB re 1μPa RMS underwater isopleths, and the 100-dB re 20 μPa and 90-dB re 20 μPa unweighted airborne isopleths. Unless otherwise stated, underwater sound pressure is defined as SPL in dB re 1 µPa. Airborne sound pressure is defined as SPL in dB re 20 µPa. The injury and behavioral harassment thresholds for marine mammals are defined as follows: Underwater Injury Zones: a. 180 dB RMS isopleth for cetaceans b. 190 dB RMS isopleth for pinnipeds Underwater Behavioral Harassment Zones: a. 120 dB RMS for marine mammals during vibratory driving Bangor, Washington 15
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APPENDIX A U.S. Navy EHW-1 Pile Rep
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