2010-16370. Takes of Marine Mammals Incidental to Specified Activities; Manette Bridge Replacement in Bremerton, Washington

AGENCY:

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

ACTION:

Notice; issuance of incidental harassment authorization.

SUMMARY:

In accordance with the regulations implementing the Marine Mammal Protection Act (MMPA) as amended, notification is hereby given that NMFS has issued an Incidental Harassment Authorization (IHA) to the Washington State Department of Transportation (WSDOT), to incidentally harass, by Level B harassment only, small numbers of marine mammals during the specified activity.

DATES:

This authorization is effective from June 29, 2010, through June 28, 2011.

ADDRESSES:

A copy of the IHA and the application are available by writing to P. 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. A copy of the application may be obtained by writing to this address, by telephoning the contact listed here (FOR FURTHER INFORMATION CONTACT) or online at: http://www.nmfs.noaa.gov/​pr/​permits/​incidental.htm#applications

Documents cited in this notice may be viewed, by appointment, during regular business hours, at the aforementioned address.

FOR FURTHER INFORMATION CONTACT:

Shane Guan, Office of Protected Resources, NMFS, [phone], ext 137.

SUPPLEMENTARY INFORMATION:

Background

Section 101(a)(5)(D) of the MMPA (16 U.S.C. 1371 (a)(5)(D)) directs the Secretary of Commerce to authorize, upon request, the incidental, but not intentional, taking by harassment of small numbers of marine mammals of a species or population stock, for periods of not more than one year, by United States citizens who engage in a specified activity (other than commercial fishing) within a specific geographic region if certain findings are made and, a notice of a proposed authorization is provided to the public for review.

Authorization for incidental takings shall be granted if NMFS finds that the 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 (where relevant), and if the permissible methods of taking and requirements pertaining to the mitigation, monitoring and reporting of such takings are set forth. 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.”

Section 101(a)(5)(D) of the MMPA established an expedited process by which citizens of the United States can apply for an authorization to incidentally take small numbers of marine mammals by harassment. Section 101(a)(5)(D) establishes a 45-day time limit for NMFS review of an application followed by a 30-day public notice and comment period on any proposed authorizations for the incidental harassment of marine mammals. Within 45 days of the close of the comment period, NMFS must either issue or deny the authorization.

Except with respect to certain 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

NMFS received an application on December 24, 2009, from WSDOT for the taking, by harassment, of marine mammals incidental to construction and demolition work related to the Manette Bridge replacement in Bremerton, Washington, starting in early June 2010.

The Manette Bridge is located within the Puget Sound of Washington State, at the outlet to the Port Washington Narrows. The Port Washington Narrows provides the only outlet from Dyes Inlet to Sinclair Inlet, and connection to the greater Puget Sound. The Manette Bridge is determined to be a functionally obsolete and structurally deficient bridge that requires replacement, and the WSDOT is planning to have it replaced. The proposed bridge replacement work includes the following activities:

• Construction of temporary work trestles, which involves steel pile installation using both vibratory and impact driving methods;
• Construction of new bridge piers, which involves excavation of benthic material;
• Barge anchoring and usage;
• Removal of existing bridge; and
• Removal of temporary work platforms.

Since marine mammal species and stocks in the proposed action area could be affected by the proposed bridge replacement activities, the WSDOT is seeking an IHA that would allow the incidental, but not intentional, take of marine mammals by Level B behavioral harassment during the construction of the new Manette Bridge and removal of the existing bridge. The WSDOT states that small numbers of three species of marine mammals could potentially be taken by pile driving or other construction activities associated with the bridge replacement work. However, with the required mitigation and monitoring measures, the numbers and levels of marine mammal takes would be reduced to the least amount practicable.

Description of the Specific Activity

WSDOT will conduct construction and demolishing activities associated with the Manette Bridge replacement project in Bremerton, WA, starting from June 2010 and lasting for approximately three years. However, no in-water activities will be planned between March 1 and June 14 in water below the ordinary high water line.

NMFS provided a detailed overview of the activity in the notice of the proposed IHA (75 FR 13502, March 22, 2010) and in the WSDOT's IHA application. No changes have been made to the proposed activities.

The following is a summarized description of the sequence of anticipated work activities associated with the Manette Bridge replacement project.

1. Construction of Work Trestles and Falsework Towers

Separate work trestles would be constructed for the new bridge construction and existing bridge removal processes. The south trestles for access to the new bridge site would be constructed prior to the installation of the north trestles for bridge removal. The work trestles and associated falsework towers would be supported on steel pilings with diameters of 24 to 36 in. (0.61 to 0.91 m). The construction of the work trestles is estimated to take up to 9 months. The work trestles and falsework towers would be in place throughout the project duration, approximately 3 years.

The trestles would be located a few feet above the high water mark, with the exact height determined by the contractor and work site conditions. The trestles would be supported by steel girders attached to the piles and the deck would be composed of timbers. The new bridge construction work trestle would be supported by up to 360 piles and could cover an area of up to 40,000 ft² (3,716 m²). The bridge removal work trestle will be supported by up to 170 piles and could cover an area of up to 15,900 ft² (1,477 m²). Up to 12 additional piles may be used for project related moorage.

All piles would be installed using a vibratory hammer unless an impact hammer is needed to drive a pile through consolidated material or meet bearing. Currently, pile driving is scheduled to occur July 1 to August 20, 2010, and October 6, 2010, to January 31, 2011, with an estimated 45 minutes per pile and 410 total hours of pile driving using a vibratory hammer. Pile driving activities would occur daily two hours after sunrise to two hours before sunset between April 1 and September 15, 2010. No pile driving will occur during nighttime hours.

2. Barge Anchoring and Usage

Barges would be used extensively throughout the project duration to provide access to work areas, support machinery, deliver and stage materials, and as a collection surface for spoils, construction debris, and materials from demolition. The actual number and dimensions of barges to be used would be determined by the contractor and work site conditions. However, it is estimated that up to 6 barges would be used at one time. A typical barge dimension is approximately 290 ft (88.4 m) in length and 50 ft (15.2 m) in width. Typical barge draft is 4 to 8 ft (1.22 to 2.44 m) and typical freeboard is 3 to 6 ft (0.91 to 1.83 m). Barges would be used throughout the construction period, approximately 3 years.

During working hours, barges would be attached to mooring lines, the work trestles, or to other portions of the project area, depending on the construction and access needs. Up to 6 temporary buoys may be installed to moor barges during non-working hours. These buoys would be attached to one or more anchors, which may need to be driven, or excavated, due to hard ground and strong currents in the project area. If the contractor chooses to deploy a dynamic barge positioning system, it is expected that the hours the system is in use would coincide closely with pile driving activities.

3. Construction of New Piers

Eight piers would support the new bridge, six in-water and two upland. The existing bridge has 13 piers, nine in-water and three upland. The total footprint of the piers would be 1,416 ft² (131.6 m²). The footprint of the nine in-water piers supporting the existing bridge is 8,726 ft² (810.7 m²).

Piers 1 and 8 are the bridge abutments and are located well above the mean high water line (MHW). Piers 2 through 7 are located below the MLLW line. The construction of the in-water piers (2 through 7) would take up to 18 months. The construction of the abutment piers (1 and 8) would occur during the bridge closure period (targeted duration of 3 months). The construction of each would include excavation of up to 3 shafts to support each pier, concrete pouring of each shaft, and construction of piers on top of new shafts.

Shaft casings would be installed and the shafts will be excavated using equipment positioned on the work trestles or barges.

To create a drilled shaft, a steel casing approximately 6 to 10 ft (1.8 to 3 m) in diameter is driven into the substrate using a vibratory hammer, and the material inside the casing is excavated using an auger or a clamshell dredge. During excavation a premixed bentonite or synthetic polymer slurry is sometimes added to stabilize the walls of the shaft. Spoils from shaft excavation would be placed in a large steel containment box located on a barge or on the work trestle for offsite transport. During the drilling, polymer slurry is typically placed into the hole to keep side walls of the shaft from caving.

After completion of the excavation, a steel reinforcing cage is placed into the hole to specified elevations. Concrete is then pumped into the hole using a tremie tube placed at the bottom of the excavation. As concrete is placed the tremie tube is raised but is maintained within the concrete. As the concrete is pumped into the hole, the slurry is displaced upward and removed from the top concrete using a vacuum hose. The slurry is pumped from the hole into large tanks located on the work trestle or on a barge, which is either recycled for use in the next shaft or transported off site. This procedure would be used on all shafts at each pier.

After shafts are completed, pre-cast concrete, stay-in-place forms would be stacked on top of the shafts up to the crossbeam elevation. A steel reinforcing cage would be placed inside the concrete forms and the columns would be filled with concrete. A pre-cast concrete crossbeam or a cast-in-place crossbeam, or some combination of both would be constructed on top of the columns. Girders would be fabricated off site and would be shipped to the site on barges. The girders would then be placed on the piers and falsework towers between piers 2 and 7.

After completion of the girder placement and casting of diaphragms connecting the girders, post-tensioning strands would be placed into ducts cast in the girders. The post-tensioning strands will then be stressed. The roadway deck would then be formed and cast between piers 2 and 7.

4. Installation of Girders and Decking

Girders and decking would be installed using the work trestles, falsework towers, and cranes deployed on work barges. The roadway deck would be made of concrete and would be poured in place. This work is expected to take 3 to 4 months.

5. Reconfiguration of Abutments and Roadway Approaches

The existing bridge abutments would be removed, along with the associated retaining walls. New retaining walls and abutments would be constructed. These activities, and associated construction access would require the temporary disturbance of 0.75 acre of land, of which 0.15 acre are vegetated, and permanent removal of 0.15 acre of vegetation. This work, all in upland areas, includes 2000 cubic yards of fill. Once the abutments are complete, the new bridge approach roadways will be constructed. Disturbed areas on the east shore of the Port Washington Narrows would be restored with a mix of native trees and shrubs including marine riparian vegetation and shoreline enhancement.

6. Demolition of Existing Bridge

The demolition of the existing bridge would occur in phases over a period of 18 months. After the central portion of the new bridge is constructed, the outermost spans and abutments of the existing bridge would be demolished. Once the new abutments and outer spans are constructed, the demolition of the remainder of the existing bridge will proceed. Conceptual demolition plan sheets are included in Appendix D of the WSDOT IHA application.

The bridge structure above the water line would be cut into manageable sections, using conventional concrete and metal cutting tools, or a wire saw, and placed on barges for transport to approved waste or recycling sites. The portions of the piers below the water line would be cut into pieces using a wire saw. All slurry from wire cutting operations above the water line would be contained and removed. All slurry from wire cutting operations below the water line would be dispersed by the current. Piers would be cut off at the ground level except for one, Pier 4. Pier 4 was built up to encapsulate original creosote treated timbers. Complete removal of the pier is not feasible and if it is cut at the ground level, many creosote treated timbers may be exposed. To minimize the risk of contamination, Pier 4 would be cut two feet above ground level.

7. Removal of Falsework Towers and Work Trestles

Once the demolition of the existing bridge is complete, the falsework towers and work trestles would be removed. Decking and girders would be placed on barges for transportation off-site. Piles would be removed using vibratory hammers, based on barges. The removal of the falsework towers and work trestles is expected to occur over 4 to 6 months.

Vibratory extraction is a common method for removing steel piling. The pile is unseated from the sediments by engaging the hammer and slowly lifting up on the hammer with the aid of the crane. Once unseated, the crane would continue to raise the hammer and pull the pile from the sediment. When the pile is released from the sediment, the vibratory hammer is disengaged and the pile is pulled from the water and placed on a barge for transfer upland.

Comments and Responses

NMFS published a notice of receipt of the WSDPT application and proposed IHA in the Federal Register on March 22, 2010 (75 FR 13502). During the 30-day comment period, NMFS received a letter from the Marine Mammal Commission (Commission) and a private citizen. Both the Commission and the private citizen recommended that NMFS issue the requested authorization. The Commission further states that the authorization should be issued provided that the required monitoring and mitigation measures are carried out (e.g., establishing of the safety zones and take zones, marine mammal monitoring during in-water construction activities, and ramp-up for pile driving) as described in NMFS' March 22, 2010 (75 FR 13502), notice of the proposed IHA and the application. All measures proposed in the initial Federal Register notice are included in the authorization and NMFS has determined that they will effect the least practicable impact on the species or stocks and their habitats.

Description of Marine Mammals in the Area of the Specified Activity

Six marine mammal species/stocks occur in the area where the proposed Manette Bridge replacement work is planned. These six species/stocks are: Pacific harbor seal (Phoca vitulina richardsi), California sea lion (Zalophus californianus), Steller sea lion (Eumetopias ubatus), transient and Southern Resident killer whales (Orcinus orca), and gray whale (Eschrichtius robustus). All these marine mammals have been observed in southern Puget Sound during certain periods of the year and may occur in Sinclair Inlet, Port Washington Narrows and Dyes Inlet, although direct observation in the vicinity of the Manette Bridge may not be documented. General information on these marine mammal species can be found in Caretta et al. (2008), which is available at the following URL: http://www.nmfs.noaa.gov/​pr/​pdfs/​sars/​po2009.pdf. Refer to that document for information on these species.

To further gather information on the occurrence of these marine mammal species in the vicinity of the proposed project area, the WSDOT contracted ten surveys between the months of July 2006 and January 2007. This time period was chosen for sampling because it represents the time period when most in-water work activities would occur. Two pinniped species and zero cetaceans were observed. Thirty four harbor seals, one California sea lion and one unidentified pinniped, likely a California sea lion, were observed over the six month period. In general, cetacean observations are infrequent in the Puget Sound (Calambokidis and Baird 1994, Jefferies 2007). During ten surveys for marine mammals in Sinclair Inlet and Port Washington Narrows between July 2006 and January 2007, no cetaceans were observed. No marine mammals were observed during two of the ten surveys. Detailed results of the surveys are provided in a final report, which is included in Appendix E of the WSDOT IHA application.

Additional information on these species, particularly in relation to their occurrence in the proposed project area, is provided in the March 22, 2010, Federal Register notice (75 FR 13502). Please refer to that document for this information.

Potential Effects on Marine Mammals and Their Habitat

Anticipated impacts resulting from the Manette Bridge Replacement project include disturbance from increased human presence and marine traffic if marine mammals are in the vicinity of the proposed project area, Level B harassment by noises generated from the construction work such as pile driving and dredging activities, and the effect of the new bridge and stormwater system on water quality. A detailed discussion of these effects from various construction and demolishing activity components is provided in the March 22, 2010, Federal Register notice (75 FR 13502). These potential effects are expected to be localized and short-term. In addition, none of these potential impacts is believed to be biologically significant to the survival and reproduction of marine mammals and their habitat in the vicinity of the proposed project. Please refer to that document for this information.

Mitigation Measures

In order to issue an incidental take authorization under Section 101(a)(5)(D) of the MMPA, NMFS must set forth the permissible methods of taking pursuant to such activity, and other means of effecting the least practicable adverse impact on such species or stock and its habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance, and on the availability of such species or stock for taking for certain subsistence uses.

For the proposed Manette Bridge replacement project, the WSDOT worked with NMFS and formulated the following mitigation measures to minimize the potential impacts to marine mammals in the project vicinity as a result of the construction activities.

1. Overall Construction Activities

All construction shall be performed in accordance with the current WSDOT Standard Specifications for Road, Bridge, and Municipal Construction. Special Provisions contained in contracts are used in conjunction with, and supersede, any conflicting provisions of the Standard Specifications.

WSDOT activities are subject to state and local permit conditions. WSDOT shall use the best guidance available (e.g., best management practices and conservation measures) to accomplish the necessary work while avoiding and minimizing environmental impacts to the greatest extent possible.

The WSDOT contractor is expected to be responsible for the preparation of a Spill Prevention, Control, and Countermeasures plan to be used for the duration of the project. The plan would be submitted to the WSDOT Project Engineer prior to the commencement of any construction activities. A copy of the plan with any updates will be maintained at the work site by the contractor. A detailed discussion of the plan is provided in the WSDOT's IHA application.

2. Equipment Noise Standards

To mitigate noise levels and, therefore, impacts to marine mammals, all the construction equipment shall comply with applicable equipment noise standards of the U.S. Environmental Protection Agency, and all construction equipment shall have noise control devices no less effective than those provided on the original equipment.

3. Timing Windows

Timing restrictions are used to avoid construction activities that generate relatively intense underwater noises (i.e., pile driving, dredging, and dynamic positioning) when ESA-listed species are most likely to be present. If an ESA-listed marine mammal species is detected in the vicinity of the project area, pile driving and dredging operations shall be halted and stationing construction vessels will turn off dynamic positioning systems. WSDOT shall comply with all in-water timing restrictions as determined through the MMPA take authorization. Pile driving activities shall only be conducted during daylight hours. If the safety zone (see below) is obscured by fog or poor lighting conditions, impact pile driving will not be initiated until the entire safety zone is visible. In addition, no in-water work shall be conducted between March 1 and June 14 in water below the ordinary high water line.

4. Establishment of Zones of Safety and Influence

For impact pile driving, the safety zones are defined as the areas where received SPLs from the noise source exceed 180 dB re 1 μPa (rms) for cetaceans or 190 dB re 1 μPa (rms) for pinnipeds. Repeated and prolonged exposure to SPLs above these values may cause TTS to cetaceans and pinnipeds, respectively. The radii of the safety zones shall be determined through empirical measurements of acoustic data. Prior to acquiring acoustic data, the safety zones shall be established based on the worst-case scenario measured from impact pile driving of 36-inch (0.91 m) steel pile conducted elsewhere, such as the Anacortes or Mukiteo ferry terminals. Acoustic measurements indicate that source levels are approximately 201 dB re 1 μPa (rms) at 10 m for both pile driving activities for Anacortes and Mukiteo ferry terminal constructions when the 36-inch (0.91 m) piles were hammered in (Laughlin 2007; Sexton 2007). Approximation of the received levels of 180 and 190 dB re 1 μPa (rms) by using an acoustic propagation spreading model between spherical and cylindrical propagation,

TL = 15log(R]/RSL),

where TL is the transmission loss (in dB), RRL is the distance at received levels (either 180 or 190 dB), and RSL is the distance (10 m) at source level (201 dB). The results show that the distances for received levels 180 and 190 dB re 1 μPa (rms) are approximately 251 m and 54 m, respectively. NMFS expects that the modeled safety zones are reasonably conservative as the propagation model does not take into consideration other transmission loss factors such as sound absorption in the water column.

Once impact pile driving begins, NMFS requires that the contractor adjust the size of the safety zones based on actual measurements of SPLs at various distances to determine the most conservative (the largest) safety zones at which the received levels are 180 and 190 dB re 1 μPa (rms).

Since the source levels for vibratory pile driving are expected to be under 180 dB re 1 μPa (rms) at 10 m, no safety zones would be established for vibratory pile driving.

In addition, WSDOT and its contractor shall establish zones of influence (ZOIs) at received levels of 160 and 120 dB re 1 μPa (rms) for impulse noise (noise from impact pile driving) and non-impulse noise (such as noise from vibratory pile driving and dynamic positioning system), respectively. These SPLs are expected to cause Level B behavioral harassment to marine mammals. The model based approximation for the distance at 160 dB received level is 5,412 m from pile driving based on the most conservative measurements from the Anacortes or Mukiteo ferry terminal construction (201 dB re 1 μPa (rms) at 10 m; Laughlin 2007; Sexton 2007), using the same spreading model discussed above. Once impact pile driving starts, the contractor shall conduct empirical acoustic measurements to determine the most conservative distance (the largest distance from the pile) where the received levels begin to fall below 160 dB re 1 μPa (rms).

As far as non-pulse noises are concerned, for which the Level B behavioral harassment is set at a received level of 120 dB re 1 μPa, no simple modeling is available to approximate the distance (though direct calculation using the spreading model puts the 120 dB received level at 100 km, this simple approximation no longer works at this long distance due to range-dependent propagation involving complex sound propagation behavior that cannot be ignored). NMFS uses the empirical underwater acoustic measurements from vibratory pile driving of 42 48-inch (1.06 1.22 m) diameter piles at the San Francisco-Oakland Bay Bridge construction as a model and expects that the distance at a received level of 120 dB is less than 1,900 m from the pile (CALTRANS 2009). Likewise, WSDOT and its contractor shall conduct empirical acoustic measurements to determine the actual distance of 120 dB re 1 μPa (rms) from the pile.

All safety and influence zones shall be monitored for marine mammals prior to and during construction activities. Please refer to the Monitoring and Reporting Measures section for a detailed description of monitoring measures.

5. Shutdown Measures

To prevent marine mammals from exposure to intense sounds that could potentially lead to TTS (i.e., received levels above 180 dB and 190 dB re 1 μPa (rms) for cetaceans and pinnipeds, respectively), no impact pile driving shall be initiated when marine mammals are detected within these safety zones. In addition, during impact driving, when a marine mammal is detected within the respective safety zones or is about to enter the safety zones, impact pile driving shall be halted and shall not be resumed until the animal is seen to leave the safety zone on its own, or 30 minutes has elapsed until the animal is last seen.

Pile driving and dredging activities shall be suspended when ESA-listed marine mammals (Steller sea lion and killer whale) are detected within the zone of behavioral harassment (160 dB re 1 μPa for impulse sources and 120 dB re 1 μPa for non-impulse sources) and that all vessels' dynamic positioning systems would be turned off. Therefore, no take of ESA-listed marine mammal species or stocks is expected.

6. “Soft Start” Impact Pile Driving or Ramp-up

Although marine mammals will be protected from Level A harassment by establishment of an air-bubble curtain during impact pile driving and marine mammal observers monitoring a safety zone, monitoring may not be 100 percent effective at all times in locating marine mammals. Therefore, a “soft-start” technique shall be used at the beginning of each day's in-water pile driving activities or if pile driving has ceased for more than one hour to allow any marine mammal that may be in the immediate area to leave before pile driving reaches full energy.

For vibratory pile driving, the soft start requires contractors to initiate noise from vibratory hammers for 15 seconds at reduced energy followed by a one minute waiting period. The procedure shall be repeated two additional times. If an impact hammer is used on a pile greater than 10 inches in diameter, contractors shall be required to provide an initial set of three strikes from the impact hammer at 40 percent energy, followed by a one minute waiting period, then two subsequent 3-strike sets. This should expose fewer animals to loud sounds both underwater and above water noise. This would also ensure that, although not expected, any pinnipeds and cetaceans that are missed during safety zone monitoring will not be injured.

7. Sound Attenuation Measures

All steel piles shall be installed using a vibratory hammer until an impact hammer is needed for bearing or if a pile encounters consolidated material. If vibratory installation is not possible due to the substrate, an impact pile driver would be used. An air bubble curtain(s) shall be employed during impact installation of all steel piles. Detailed description and specification of the air bubble curtain system is provided in Appendix C of the WSDOT's IHA application.

WSDOT shall provide bubble curtain performance criteria to the contractor, which include:

• Piling shall be completely engulfed in bubbles over the full depth of the water column at all times when an impact pile driver is in use.
• The lowest bubble ring shall be in contact with the mud line for the full circumference of the ring. The weights attached to the bottom ring shall ensure complete mud line contact. No parts of the ring or other objects shall prevent the full mud line contact.
• Bubblers shall be constructed of minimum 2-inch (5.1-cm) inside diameter aluminum pipe with 1/16-inch (0.16-cm) diameter bubble release holes in four rows with 3/4-inch (1.9-cm) spacing in the radial and axial directions. Bubblers shall be durable enough to withstand repeated deployment during pile driving and shall be constructed to facilitate underwater setup, knockdown, and reuse on the next pile.
• One or more compressors shall be provided to supply air in sufficient volume and pressure to self-purge water from the bubblers and maintain the required bubble flux for the duration of pile driving. Compressors shall be of a type that prevents the introduction of oil or fine oil mist by the compressed air into the water. If there is presence of oil film or sheen on the water surface in the vicinity of the operating bubbler, the contractor shall immediately stop work until the source of oil film or sheen is identified and corrected.
• The system shall provide a bubble flux of 3.0 cubic meters (m3) per minute per linear meter of pipe in each layer (32.91 cubic feet, or 0.93 m3, per minute per linear foot of pipe in each layer). The total volume of air per layer is the product of the bubble flux and the circumference of the ring:

Vt=3.0 m³/min/m x Circum of the aeration ring in meters.

or

Vt=32.91 ft³/min/ft x Circum of the aeration ring in meters.

• The bubble ring manifold shall incorporate a shut off valve, flow meter, and a throttling globe valve with a pressure gauge for each bubble ring supply.
• Prior to first use of the bubble curtain during pile driving, the fully-assembled system shall be test-operated to demonstrate proper function and to train personnel in the proper balancing of the air flow to the bubblers. The test shall also confirm the calculated pressures and flow rates at each manifold ring. The Contractor shall submit an inspection/performance report to WSDOT within 72 hours following the performance test.

The WSDOT Office of Air Quality and Noise has prepared a noise monitoring plan for the Manette Bridge Replacement Project (Appendix H). To comply with the provisions of the plan, the State will conduct hydroacoustic monitoring during construction to evaluate in water noise levels.

8. Ensure Regulation Compliance

Finally, a WSDOT inspector shall be on site during construction. The role of the inspector is to ensure contract compliance. The inspector and the contractor each have a copy of the Contract Plans and Specifications on site and are aware of all requirements. The inspector is also trained in environmental provisions and compliance.

NMFS has carefully evaluated the applicant's proposed mitigation measures and considered a range of other measures in the context of ensuring that NMFS prescribes the means of effecting the least practicable adverse impact on the affected marine mammal species and stocks and their habitat. Our evaluation of potential measures included consideration of the following factors in relation to one another:

• the manner in which, and the degree to which, the successful implementation of the measure is expected to minimize adverse impacts to marine mammals
• the proven or likely efficacy of the specific measure to minimize adverse impacts as planned
• the practicability of the measure for applicant implementation, including consideration of personnel safety, and practicality of implementation.

Based on our evaluation of the applicant's proposed measures, as well as other measures considered by NMFS or recommended by the public, NMFS has determined that the required mitigation measures provide the means of effecting the least practicable adverse impacts on marine mammals species or stocks and their habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance.

Monitoring and Reporting Measures

In order to issue an ITA for an activity, Section 101(a)(5)(D) of the MMPA states that NMFS must set forth “requirements pertaining to the monitoring and reporting of such taking”. The MMPA implementing regulations at 50 CFR § 216.104 (a)(13) indicate that requests for IHAs must include the suggested means of accomplishing the necessary monitoring and reporting that will result in increased knowledge of the species and of the level of taking or impacts on populations of marine mammals that are expected to be present. The requireed monitoring and reporting measures for the Manette Bridge replacement project are provided below.

1. Marine Mammal Observers

A minimum of two qualified and NMFS-approved marine mammal observers (MMOs) would be present on site at all times during steel pile driving. In order to be considered qualified, WSDOT lists the following requirements for prospective MMOs:

• Visual acuity in both eyes (correction is permissible) sufficient for discernment of moving targets at the water's surface with ability to estimate target size and distance. MMOs shall use binoculars to correctly identify the target.
• Advanced education in biological science, wildlife management, mammalogy or related fields (Bachelors degree or higher is preferred).
• Experience and ability to conduct field observations and collect data according to assigned protocols (this may include academic experience).
• Experience or training in the field identification of marine mammals (cetaceans and pinnipeds), including the identification of behaviors.
• Sufficient training, orientation or experience with the construction operation to provide for personal safety during observations.
• Writing skills sufficient to prepare a report of observations.
• Ability to communicate orally, by radio or in person, with project personnel to provide real-time information on marine mammals observed in the area as necessary.

2. Marine Mammal Monitoring

WSDOT has developed a monitoring plan (Appendix G of the WSDOT IHA application) in conjunction with NMFS that will collect sighting data for each distinct marine mammal species observed during the proposed Manette Bridge replacement construction activities that generate intense underwater noise. These activities include, but are not limited to, impact and vibratory pile driving, use of dynamic positioning system by construction and supporting vessels, and sediment dredging. Marine mammal behavior, overall numbers of individuals observed, frequency of observation, and the time corresponding to the daily tidal cycle will also be included. An example of a marine mammal sighting form is included in Appendix I of the WSDOT's IHA application.

In addition, for impact pile driving, the following Marine Mammal Monitoring Plan and shut down procedures shall be implemented:

• At least two MMOs shall be on site to monitor the safety and influence zones by using a range finder or hand held global positioning system (GPS) device. The zone will be monitored by driving a boat along and within the radius while visually scanning the area, and/or monitored from shore if there is a vantage point that will allow full observation of the zone.
• If the safety zone is obscured by fog or poor lighting conditions, pile driving shall not be initiated until the entire safety zone is visible.
• The safety zone shall be monitored for the presence of marine mammals for 30 minutes prior to impact pile driving, during pile driving, and 20 minutes after pile driving activities.
• No impact pile driving shall be started if a marine mammal is detected within the respective safety zones. Pile driving may begin if a marine mammal is seen leaving the safety zone, or 30 minutes has elapsed since the marine mammal is last seen inside the safety zone.
• If marine mammals are observed, their location in relation to the safety and influence zones, and their reaction (if any) to pile driving activities shall be documented.

3. Reporting

WSDOT shall submit weekly marine mammal monitoring reports from the time when in-water construction activities are commenced to NMFS Office of Protected Resources (OPR). These weekly reports shall include a summary of the previous week's monitoring activities and an estimate of the number of marine mammals that may have been disturbed as a result of in-water construction activities.

In addition, WSDOT shall provide NMFS OPR with a draft final report within 90 days after the expiration of the IHA. This report should detail the in-water construction and demolishing activities being conducted, empirically measured safety zones for pile driving, and the monitoring protocol; summarize the data recorded during monitoring; and estimate the number of marine mammals that may have been harassed due to the construction activities. If no comments are received from NMFS OPR within 30 days, the draft final report will be considered the final report. If comments are received, a final report must be submitted within 30 days after receipt of comments.

Estimated Take by Incidental Harassment

As mentioned earlier in the March 22, 2010, Federal Register (75 FR 13502), the potential effects to marine mammals from the proposed activities include disturbance from increased human presence and marine traffic and from noises generated from the construction work such as pile driving and dredging activities. The required mitigation measures of using air bubble curtain systems would prevent marine mammals from onset of TTS by impact pile driving and reduce Level B behavioral harassment due to the effective attenuation by the air bubble systems. Therefore, the following analyses focus on potential noise impacts that could cause Level B behavioral harassment, based on the WSDOT contracted surveys for the entire proposed project area (WSDOT 2009).

1. Harbor Seal

There are no harbor seal haulouts within 3 miles (4.8 km) of the project. The nearest haulout is in Dyes Inlet and animals must move through the Port Washington Narrows to access Sinclair Inlet and the greater Puget Sound. Individual harbor seals moving between Sinclair and Dyes Inlets would be exposed to project activities.

A total of 34 harbor seals were detected during ten surveys conducted during the same time of year pile driving will occur, between July and January. The age, sex and reproductive condition of the animals was not determined. For the proposed Manette Bridge replacement activities, it is reasonable to assume that similar numbers of animals would be encountered during an average 10-day period. WSDOT anticipates that for every day of construction activities, between 3 and 4 harbor seals may be encountered, although it is possible that some of these animals will be the same individuals. If in-water construction activities occur every day of the year (258 days between June 15 and February 28), approximately 877 harbor seals (or about 6% of the Washington inland waters stock of harbor seals) could be encountered in the vicinity of the proposed bridge replacement work. However, it is not likely that every harbor seal would be taken by Level B behavioral harassment since not every animal would be exposed to received levels above 160 dB re 1 μPa (rms) from an impulse source (such as impact pile driving) or above 120 dB re 1 μPa (rms) from a non-impulse source (such as vibratory pile driving or dredging). Likewise, not every single harbor seal would respond to the sight of human or vessel traffic in the vicinity of the project area. Therefore, the estimated number of 877 represents the upper-limit of the number of harbor seals that could be affected by Level B behavioral harassment as a result of exposure to Manette Bridge replacement related construction activities.

2. California Sea Lion

There are no California sea lion haulouts within three miles of the project. The nearest haulout is in Rich Passage, east of the Port Washington Narrows in more open water. Individual California sea lions moving between Sinclair and Dyes Inlets could be exposed to project activities.

A total of one, possibly two California sea lions were detected during ten surveys conducted during the same time of year pile driving would occur, between July and January. The age, sex and reproductive condition of the animals was not determined. For the proposed Manette Bridge replacement activities, it is reasonable to assume that similar numbers of animals would be encountered during an average 10-day period. WSDOT anticipates that for every 10 days of construction activities, between 1 and 2 California sea lions may be encountered, although it is possible that some of these animals will be the same individuals. If in-water construction activities occur every day of the year (258 days between June 15 and February 28), up to 516 California sea lions (or about 0.2% of the US stock of California sea lions) could be encountered in the vicinity of the proposed bridge replacement work. However, it is not likely that every California sea lion would be taken by Level B behavioral harassment since not every animal would be exposed to received levels above 160 dB re 1 μPa (rms) from an impulse source (such as impact pile driving) or above 120 dB re 1 μPa (rms) from a non-impulse source (such as vibratory pile driving or dredging). Likewise, not every single California sea lion would respond to the sight of human or vessel traffic in the vicinity of the project area. Therefore, the estimated number of 516 represents the upper-limit of the number of harbor seals that could be affected by Level B behavioral harassment as a result of exposure to Manette Bridge replacement related construction activities.

3. Steller Sea Lion

As stated earlier, the nearest Steller sea lion haulout is approximately 12 miles (19.3 km) northeast of the proposed project area in Shilshole Bay on the east side of the Puget Sound, adjacent to the city of Seattle. No Steller sea lions were sighted during the ten surveys contracted by WSDOT, and NMFS considers it is very unlikely that a Steller sea lion would occur in the vicinity of the proposed project area. The implementation of the aforementioned mitigation measures, including halting all pile driving and dredging activities and turning off construction vessels' dynamic positioning systems when a Steller sea lion is detected about to enter the zone of influence (received levels at or above 160 dB re 1 μPa (rms) for impulse noise or 120 dB re 1 μPa (rms) for non-impulse noise). Therefore, NMFS does not believe Steller sea lions would be affected.

4. Killer Whale

Killer whales (southern resident) have been documented in the project vicinity once in the last ten years (WSDOT 2009). No killer whales were sighted during the ten surveys contracted by WSDOT, and NMFS considers it rare that a killer whale would occur in the vicinity of the proposed project area. The implementation of the aforementioned mitigation measures, including halting all pile driving and dredging activities and turning off construction vessels' dynamic positioning systems when a killer whale is detected about to enter the zone of influence (received levels at or above 160 dB re 1 μPa (rms) for impulse noise or 120 dB re 1 μPa (rms) for non-impulse noise). Therefore, NMFS does not believe killer whales would be affected.

5. Gray Whale

Individual gray whales have been observed near the project area in four of the last eight years (WSDOT 2009). No gray whales were sighted during the ten surveys contracted by WSDOT, and NMFS considers it rare that a gray whale would occur in the vicinity of the proposed project area. Most grays whales spend winters in their breeding/calving grounds around Baja California and summers in feeding grounds around the Bering Sea and the Arctic. The few gray whales that occur in the vicinity of the proposed project area are likely the ones visiting the area on their north-south migration route. Based on past occurrence of gray whales in the area and using conservative probability estimate, NMFS considers that no more than 2 individuals of gray whales (0.01% of the Eastern North Pacific gray whale population) would be exposed to underwater construction noise SPL that could cause Level B behavioral harassment annually as a result of the proposed Manette Bridge replacement project.

Negligible Impact and Small Numbers Analysis and Determination

Pursuant to NMFS' regulations implementing the MMPA, an applicant is required to estimate the number of animals that will be “taken” by the specified activities (i.e., takes by harassment only, or takes by harassment, injury, and/or death). This estimate informs the analysis that NMFS must perform to determine whether the activity will have a “negligible impact” on the species or stock. Level B (behavioral) harassment occurs at the level of the individual(s) and does not assume any resulting population-level consequences, though there are known avenues through which behavioral disturbance of individuals can result in population-level effects. A negligible impact finding is based on the lack of likely adverse effects on annual rates of recruitment or survival (i.e., population-level effects). An estimate of the number of Level B harassment takes alone is not enough information on which to base an impact determination.

In addition to considering estimates of the number of marine mammals that might be “taken” through behavioral harassment, NMFS considers other factors, such as the likely nature of any responses (their intensity, duration, etc.), the context of any responses (critical reproductive time or location, migration, etc.), as well as the number and nature of estimated Level A takes, the number of estimated mortalities, and effects on habitat.

The WSDOT's specified activities have been described based on best estimates of the planned Manette Bridge replacement project within the proposed project area. Some of the noises that would be generated as a result of the proposed bridge replacement project, such as impact pile driving, are high intensity. However, WSDOT plans to use vibratory pile driving and to avoid using impact pile driving as much as possible, therefore eliminating the intense impulses that could cause TTS to marine mammals when repeatedly exposed in close proximity. In addition, WSDOT indicates that if impact pile driving is to be conducted, an air bubble curtain system would be used to attenuate the noise level. Furthermore, shutdown of pile driving would be implemented when a marine mammal is spotted within the 180 dB and 190 dB re 1 μPa (rms) safety zones for cetaceans and pinnipeds, respectively. Therefore, NMFS does not expect that any animals would receive Level A (including injury) harassment or Level B TTS from being exposed to intense construction noise.

Animals exposed to construction noise associated with the proposed bridge replacement work would be limited to Level B behavioral harassment only, i.e., the exposure of received levels for impulse noise between 160 and 180 dB re 1 μPa (rms) (from impact pile driving) and for non-impulse noise between 120 and 180 dB re 1 μPa (rms) (from vibratory pile driving, dredging, and dynamic positioning of construction vessels). In addition, the potential behavioral responses from exposed animals are expected to be localized and short in duration. The modeled 160 dB isopleths from impact pile driving is 5,412 m from the pile, and the estimated 120 dB isopleths from vibratory pile driving is approximately 1,900 m from the pile. However, the actual zone of influence from impact pile driving is expected to be much smaller due to other sound attenuation factors not considered in the spreading model. Furthermore, although in-water construction activities are expected to be conducted everyday during daylight hours between June 15 and February 28, the total duration for pile driving is expected to be approximately 410 hours, or 41 working days based on 10 hours of daylight for each working day. WSDOT also plans to use barge anchoring instead of dynamic positioning systems for construction vessels, thus further reducing noise input into the water column. Therefore, the underwater noise impacts from the proposed Manette Bridge replacement construction is expected to have a low level of noise intensity, and be of short duration and localized. These low intensity, localized, and short-term noise exposures, when received at distances of Level B behavioral harassment (i.e., 160 dB re 1 μPa (rms) from impulse sources and 120 dB re 1 μPa (rms) from non-impulse sources), are expected to cause brief startle reactions or short-term behavioral modification by the animals. These brief reactions and behavioral changes are expected to disappear when the exposures cease. Therefore, these levels of received underwater construction noise from the proposed Manette Bridge replacement project are not expected to affect marine mammal annual rates of recruitment or survival.

Based on the analysis contained herein of the likely effects of the specified activity on marine mammals and their habitat, and taking into consideration the implementation of the required mitigation and monitoring measures, NMFS finds that the Manette Bridge replacement project will result in the incidental take of small numbers of Pacific harbor seals, California sea lions, and gray whales by Level B harassment only, and that the total taking from harassment will have a negligible impact on the affected species or stocks.

Impact on Availability of Affected Species for Taking for Subsistence Uses

There are no relevant subsistence uses of marine mammals implicated by this action.

Endangered Species Act (ESA)

There are two marine mammal species and two fish species that are listed as endangered or threatened under the ESA with confirmed or possible occurrence in the study area: Eastern North Pacific Southern Resident killer whale, Eastern U.S. Steller sea lion, Chinook salmon, and steelhead trout. Under section 7 of the ESA, the Federal Highway Administration (FHWA) and WSDOT have consulted with NMFS Northwest Regional Office (NWRO) on the proposed Manette Bridge replacement project. In a memo issued with its August 3, 2009, Biological Opinion, NMFS NWRO stated that the proposed bridge replacement may affect, but is not likely to adversely affect the listed marine mammal species and stocks. On May 28, 2010, FHWA requested the reinitiation of section 7 consultation with NMFS NWRO on the newly ESA-listed three Puget Sound rockfish species. The consultation is expected to be completed in July 2010.

The issuance of an IHA to WSDOT constitutes an agency action that authorizes an activity that may affect ESA-listed species and, therefore, is subject to section 7 of the ESA. As the effects of the activities on listed marine mammals and salmonids were analyzed during a formal consultation between the FHWA and NMFS, and as the underlying action has not changed from that considered in the consultation, the discussion of effects that are contained in the Biological Opinion and accompanying memo issued to the FHWA on August 3, 2009, pertains also to this action. Therefore, NMFS has determined that issuance of an IHA for this activity would not lead to any effects to listed marine mammal species apart from those that were considered in the consultation on FHWA's action. Although the reinitiation of section 7 consultation by FHWA on three Puget Sound rockfish species is still on-going, NMFS does not expect that the outcome would affect NMFS' action in issuing an IHA for the incidental take of marine mammals.

National Environmental Policy Act (NEPA)

To meet NMFS' NEPA requirements for the issuance of an IHA to the WSDOT, NMFS has prepared an Environmental Assessment (EA) that is specific to the construction and demolishing activities associated with the Manette Bridge replacement project in Bremerton, WA. NMFS has prepared an EA titled Issuance of an Incidental Harassment Authorization to the Washington State Department of Transportation to Take Marine Mammals by Harassment Incidental to Manette Bridge Replacement Project in Bremerton, Washington, that evaluates the impacts on the human environment of NMFS' authorization of incidental Level B harassment resulting from the specified activity in the specified geographic region. The NMFS has made a Finding of No Significant Impact (FONSI) and, therefore, it is not necessary to prepare an environmental impact statement for the issuance of an IHA to WSDOT for this activity. A copy of the EA and the NMFS FONSI for this activity is available upon request (see ADDRESSES).

As a result of these determinations, NMFS has issued an IHA to the WSDOT to conduct construction and demolishing activities associated with the Manette Bridge replacement project in Bremerton, WA, provided the previously mentioned mitigation, monitoring, and reporting requirements are incorporated.

Dated: June 29, 2010.

Helen Golde,

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