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Taking Marine Mammals Incidental to Specified Activities; Construction of the Knik Arm Bridge

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National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce.


Notice of receipt of application for an incidental take authorization; request for comments.


NMFS has received a request from the Knik Arm Bridge and Toll Authority (KABATA) for an authorization to take small numbers of marine mammals, by harassment, incidental to construction of the Knik Arm Bridge at the Knik Arm Crossing in Alaska during the period 2007 through 2012. In order to promulgate regulations and issue annual Letters of Authorization (LOAs) to KABATA, NMFS must determine that these takings will have a negligible impact on the affected species and stocks of marine mammals and not have an unmitigable impact on subsistence uses of marine mammals. NMFS invites comment on the application and suggestions on the content of the regulations.


Comments and information must be received no later than September 22, 2006.


Comments on the application should be addressed to Michael Payne, Chief, Permits, Conservation and Education Division, Office of Protected Resources, National Marine Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910-3225. The mailbox address for providing email comments is PR1.080806A Comments sent via e-mail, including all attachments, must not exceed a 10-megabyte file size. A copy of the application (which includes the reference citations found in this Federal Register document) may be obtained by writing to this address or by telephoning the contact listed here and are also available at:​pr/​permits/​incidental.htm#iha.

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Kenneth Hollingshead, Office of Protected Resources, NMFS, (301) 713-2289, ext 128.

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Section 101(a)(5)(A) of the Marine Mammal Protection Act (16 U.S.C. 1361 et seq.) (MMPA) directs the Secretary of Commerce (Secretary) to allow, upon request, the incidental, but not intentional taking of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified geographical region if certain findings are made and regulations are issued.

Permission may be granted for periods of 5 years or less if the Secretary finds that the taking will have a negligible impact on the species or stock(s) and will not have an unmitigable adverse impact on the availability of the species or stock(s) for subsistence uses, and if regulations are prescribed setting forth the permissible methods of taking and the requirements pertaining to the mitigation, monitoring and reporting of such taking.

NMFS has defined “negligible impact” in 50 CFR 216.103 as “an impact resulting from the specified activity that cannot be reasonably expected to, and is not reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or survival.” An authorization may be granted for periods of 5 years or less if the Secretary finds that the total taking will have a negligible impact on the species or stock(s), will not have an unmitigable adverse impact on the availability of the species or stock(s) for subsistence uses, and regulations are prescribed setting forth the permissible methods of taking and the requirements pertaining to the monitoring and reporting of such taking.

Except for certain categories of activities not pertinent here, the MMPA defines “harassment “as any act of pursuit, torment, or annoyance which

(i) has the potential to injure a marine mammal or marine mammal stock in the wild [Level A harassment]; or (ii) has the potential to disturb a marine mammal or marine mammal stock in the wild by causing disruption of behavioral patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering [Level B harassment].

Summary of Request

On May 6, 2006, NMFS received an application, under section 101(a)(5)(A) of the MMPA, from KABATA to take marine mammals, by harassment, incidental to construction of the Knik Arm Bridge in Alaska. KABATA proposes to construct an 8,180 ft (2,493 m) pile-supported steel bridge spanning Knik Arm in Upper Cook Inlet, in Alaska. The project area is located north of Anchorage and west of Elmendorf Air Force Base in the southern portion of Knik Arm. The crossing would traverse Knik Arm over waters between zero and 70 ft (0-20 m) in depth.

According to KABATA, the bridge would be used for vehicular traffic in order to: (1) Move freight and goods between the Port of Anchorage/Ship Creek industrial areas and the Port MacKenzie district; (2) provide safety and redundant overland routes connecting area airports, military bases, ports and hospitals for emergency response; (3) provide transportation infrastructure to meet projected local population and economic growth forecasts; and (4) support economic advancement in the region.

Three alternatives for the crossing alignment have been proposed. A complete description of these alternatives are discussed in the Draft Environmental Impact Statement (Draft EIS) for the Knik Arm Crossing that will be released to the public shortly. A bridge across lower Knik Arm in the southern alignment is KABATA's preferred alternative identified in that document. For the southern alignment, causeways approximately 3,600 ft (1,100 m) and 2,100 ft (640 m) in length would be constructed from the east and west shores, respectively. During year one for construction (presently scheduled for 2007), the east and west bridge causeway foundations and abutments would be constructed in April-May following the establishment of access roads.Start Printed Page 49434

Pile driving may begin as early as the first year, but is expected to occur primarily during years 2 and 3 of the proposed 3-year construction program. The bridge design requires approximately 132 pilings at 33 locations with an abutment at each end where the bridge meets the east and west causeways. Water depths at the piling sites range from 60 to 80 feet (18 to 24 m) MLLW. Piles will be constructed of pre-stressed steel, approximately 150 ft (46 m) in length, 4 ft (1.2 m) in diameter, and of 1-2 inches (2.54-5.08 cm) wall thickness. Initially, a vibratory hammer will be used to drive each pile approximately 40 percent or more of the way to its final position. Impact hammering will be used to drive the pile the remainder of the way or to refusal (i.e., when further impact pile driving is unproductive). Pilings will be driven one or possibly two at a time and are expected to require 1-2 hours of actual impact hammering per pile to install. On any given day approximately 2-4 hours of impact hammering would be expected. Pile driving will require up to 220 days. A hydraulic impact hammer, or similar equipment, would be used to drive piles during the Knik Arm crossing construction. The proposed impact hammer delivers 30 blows per minute at maximum stroke with a ram weight of 80,000 lb (36,287 kg). Pile driving is planned to take place primarily during the ice-free months from April to November of each year. No piling emplacement is currently planned for months when ice is present due to increased cost and personnel safety limitations. However, KABATA has requested that its incidental take authorization include incidental harassment takings that might occur during pile driving at any time of year.

Construction and installation of the superstructure roadbed is proposed to occur over a 2-year period following placement of piles and installation of support framework. Superstructure installation would occur immediately after completion of construction of support structures for a given section of superstructure, and prior to installation of pilings for subsequent sections. Superstructure construction will involve the use of tug and barge combinations fitted with cranes for lifting and placement of roadbed components.

Because pile driving, support vessel activities, and general construction noise have the potential to result in behavioral harassment of marine mammals located in Knik Arm, an authorization under section 101(a)(5)(A) of the MMPA is warranted. KABATA believes that the potential taking of marine mammals associated with the construction of the Knik Arm crossing are unlikely to be lethal or have any long-term negative consequences for the affected marine mammal populations, and any short-term impact on the marine mammals would be negligible. In addition, there would be no adverse impact on the availability of marine mammals for subsistence uses. KABATA is requesting a multi-year LOA for incidental harassment takings issued commencing on 1 April 2007. KABATA plans to construct the crossing during a 2-3 year construction program; however, potential delays associated with a project of this size and scope may require a longer construction period. Therefore, KABATA has requested that the multi-year LOAs cover the period 2007 through 2012, should an additional year or more be required to complete construction of the crossing.

Marine Mammals Affected by the Activity

Knik Arm, including the area of bridge construction, is used by several species of marine mammals. The Cook Inlet beluga whale is the most abundant marine mammal in the area and harbor seals are occasionally present. Harbor porpoises and killer whales have also been sighted in Knik Arm, but are considered rare and are unlikely to be encountered during bridge construction. There have been no published sightings of Steller sea lions in Knik Arm, but a single adult male was documented in the Susitna Flats area. Detailed information on these species and the number of marine mammals within the project area can be found in KABATA's application (see ADDRESSES) and Draft EIS. Additional information on Alaskan marine mammals can be found in NMFS' Stock Assessment Reports. The Alaska Stock Assessment Report is available at:​pr/​sars/​region.htm. Please refer to those documents for information on these species.

Sounds and non-acoustic stimuli will be generated by vehicle traffic, vessel operations, roadbed construction, and vibratory and impact pile driving. The sounds generated from construction operations and associated activities will be detectable underwater and/or in air some distance away from the area of activity. The distance will depend on the nature of the sound source, ambient noise conditions, and the sensitivity of the receptor to the sound (Richardson et al., 1995). However, as explained in the application, animals that hear the sound will not necessarily react to it. At times, some of these sounds are likely to be strong enough to cause localized avoidance or other disturbance reactions by small numbers of marine mammals. Harassment will potentially result when marine mammals near the activity have a significant behavioral response to the sounds generated. The type and significance of behavioral reaction is likely to depend on the activity of the animal at the time it receives the stimulus, as well as the distance from the sound source and the level of the sound relative to ambient conditions. Noise from pile driving, in particular, may result in marine mammals near the activity changing their behaviors or activities. In addition to disturbance, some limited masking of whale calls or other sounds potentially relevant to whales could occur. Vessel traffic is also known to cause avoidance reactions by beluga whales at certain times (Richardson et al., 1995). However, Cook Inlet belugas are regularly sighted in and around the Port of Anchorage (NMFS, 2005a) passing near or under vessels (Blackwell and Greene, 2002), and they appear to have high tolerance to vessel traffic. It is possible that belugas exposed to repetitious construction sounds from the proposed construction activities will, after initial exposure to these sounds, tolerate them as they have learned to tolerate vessel traffic.

Harbor seals, beluga whales, and harbor porpoises could be exposed to vessel or construction noise and to other stimuli associated with the planned construction. Construction activities are expected to occur seasonally and incidental harassment of marine mammals could potentially occur intermittently when construction occurs. To some extent, beluga whales and harbor seals will likely be in the area throughout the proposed authorization period (2007-2012). Based on sighting rates and telemetry studies, few beluga whales are likely to be in the project area between December and late May, they will be present infrequently from May through July, and highest numbers will occur in August through November (Rugh et al., 2004; NMFS 2005a, Funk et al. 2005a). Only a few harbor seals have been reported near the planned construction site (LGL, unpublished data). With the mitigation and monitoring measures that are planned (see next section), it is very unlikely that any marine mammal will be injured or killed.

KABATA believes that the construction activities outlined in its application and described in detail in the Draft EIS have the potential to disturb or displace small numbers of marine mammals. These potential takes Start Printed Page 49435would be by Level B harassment (behavioral disturbance) as defined in the 1994 amendments to the MMPA. No take by serious injury or death is likely, given the planned monitoring and mitigation procedures described in the application and summarized in this document. These measures are designed to minimize the possibility of injury to marine mammals and to reduce disturbance caused by construction activities. However, KABATA has requested that the LOA authorize a very small number (1-2 animals) of incidental, non-intentional Level A harassment (injury) takings be authorized in the unlikely event that they might occur. Should a Level A harassment take occur that involves serious injury (or mortality) of a marine mammal occurs, construction activities would be suspended, NMFS would be notified, and a review of the conditions under which construction activity could resume would be immediately undertaken.


KABATA proposes the following mitigation and monitoring measures to reduce impacts on marine mammals:

Scheduling of construction activities to avoid periods of high whale use of Knik Arm

Construction activities are planned to occur when beluga whale use of Knik Arm is low. Specifically, construction will occur to the greatest extent practicable during the December through mid-August time period when beluga whale abundance in Knik Arm are generally low. During the fall period when beluga whales are present in the Arm in greater numbers (15 August to 15 November), impact pile driving activities will not occur during the three hour period around low tide when whales are most likely to be in or near the construction area. These measures will greatly reduce the number of beluga whales potentially affected by construction and will assure that impacts on beluga whales are negligible.

Soft start to pile driving activities

A “soft start” technique will be used at the beginning of each pile installation to allow any marine mammal that may be in the immediate area to leave before impact piling reaches full energy. The soft start requires an initial set of 3 strikes from the impact hammer at 40 percent energy with a one minute waiting period between subsequent 3-strike sets (NMFS, 2003). If marine mammals are sighted within the safety zone prior to pile-driving, or during the soft start, the Resident Engineer (or other authorized individual) will delay pile-driving until the animal has moved outside the safety zone. The safety zone will be defined by the 190 dB re 1 microPa (rms) radius in the case of pinnipeds and 180 dB rms in the case of odontocetes. Piling will resume only after the marine mammal is determined to have moved outside the safety zone by a qualified observer or after 15 minutes have elapsed since the last sighting of the marine mammal within the safety zone.

Acoustic monitoring to determine appropriate safety zones

Sound generated by the pile driver will be measured and used to refine the radii of the safety zones for marine mammals. Initially the safety zones will be defined based on measurements made by Blackwell (2005) at the nearby Port MacKenzie dock reconstruction with allowances for differences in pile size and pile driver energy. Initial safety radii will be 1.5 times the size of those estimated by Blackwell (2005) until actual safety radii can be determined. Safety zones appropriate to the conditions and equipment used for the Knik Arm Bridge will be empirically determined and implemented as soon as practicable.

Observer Monitoring and shut down procedures

The safety zone around the pile driving activity will be monitored for the presence of marine mammals before, during, and after any pile driving activity. The safety zone will be monitored for 30 minutes prior to initiating the soft start for pile driving. If the safety radius is obscured by fog or poor lighting conditions, pile driving will not be initiated until the entire safety radius is visible for the 30 minute period. If marine mammals are present within the safety zone, the start of pile driving will be delayed until the animals leave the area. The safety zone will also be monitored throughout the time required to drive a pile. If a marine mammal is observed entering the safety zone, pile driving operations will be discontinued until the animal is clear of the safety zone. Monitoring of the safety zone will continue for 30 minutes following pile driving.


Land-based Visual Monitoring

Two experienced marine mammal observers will be positioned at sites appropriate for monitoring whales and seals within and approaching the safety zone and the larger area where marine mammals might be disturbed by pile-driving operations. Established observation sites near Cairn Point and Sixmile Creek will be used initially. Based on measurements by Blackwell (2005), observers at those sites will be able to see the area within the 180 dB safety radius and the area within which behavioral disturbance may potentially occur (160 dB). These observers will monitor the safety radius and the surrounding areas commencing 30 minutes prior to the beginning of pile-driving operations, during pile driving, and for 30 minutes after pile driving is completed. If whales or other marine mammals are sighted within the safety zone, pile driving operations will be halted until the animals are outside of the area.

Boat-based Monitoring

Two trained boat-based observers will survey Knik Arm and adjacent areas once per week during pile driving operations. The primary purpose of these observers will be to inform construction and shore-based observation personnel of whale group locations and the potential of these groups to approach and/or enter the safety zone. The boat based observers will also obtain information on the distribution and movements of belugas, noting especially any apparent blockage or delay of normal whale movement within Knik Arm over tidal cycles.


During the period of bridge construction, KABATA proposes to submit brief progress reports concerning recent construction activities, marine mammal and acoustic monitoring work, and any other information required under an LOA will be provided to NMFS on a weekly, monthly or such other schedule as may be specified in the LOA. Any significant observations concerning impacts on marine mammals will be transmitted to NMFS within 48 hours. Any Level A takes observed will be required to be immediately reported to NMFS.

Preliminary results of the acoustical measurements, as necessary to refine and validate the safety radii, will be reported to NMFS as soon as the relevant data can be obtained and analyzed. These data will be available no later than 1 month after the onset of pile driving.

During construction, KABATA proposes to submit a preliminary report on activities and results (acoustical and mammal) to NMFS within 90 days after the termination of the fall construction season-the season when most belugas are likely to be present in the area. This report will provide summaries of the Start Printed Page 49436dates and locations of construction operations, details of marine mammal sightings (dates, times, locations, activities, associated construction activities), estimates of the amount and nature of marine mammal takings, and any apparent effects on accessibility of marine mammals to subsistence hunters. It will also provide a fuller account of the levels, durations, and spectral characteristics of the impact and vibratory pile driving sounds. For the impact pile driving, the peak, rms, and energy levels of the sound pulses and their durations will be reported as a function of distance, water depth, and tidal cycle.

In addition to the 90-day reports, KABATA proposes to submit a draft technical summary report to NMFS 60-120 days before the LOA expires. All technical reports will provide full documentation of methods, results and interpretation of all monitoring tasks. The draft final report may be subject to a review process determined by NMFS, and will then be finalized if comments are received from NMFS. The final comprehensive report will be submitted within 90 days following expiration of the final LOA.

Request for Information

As this document is being published in conformance with NMFS regulations implementing the incidental take program (50 CFR Part 216 Subpart I), NMFS requests interested persons to submit comments, information, and suggestions concerning the request and the possible structure and content of the regulations to allow the taking. As provided by 50 CFR 216.105, NMFS will consider this information in developing any proposed regulations to authorize the taking. Comments regarding activities that do not relate to the incidental taking of marine mammals will not be considered by NMFS in its decision-making process. Prior to submitting comments, NMFS recommends reviewers of this document read KABATA's MMPA application as that document contains information necessary to respond appropriately to this action. If NMFS proposes regulations to allow this take, interested parties will be provided with a 30-day comment period within which to submit comments on the proposed rule.

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Dated: August 16, 2006.

James H. Lecky,

Director, Office of Protected Resources, National Marine Fisheries Service.

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[FR Doc. E6-13970 Filed 8-22-06; 8:45 am]