07 - Attachment N -USACE Shrewsbury River ESA BA.pdf

DEPARTMENT OF THE ARMY

U.S. ARMY CORPS OF ENGINEERS, NEW YORK DISTRICT

JACOB K. JAVITS FEDERAL BUILDING

26 FEDERAL PLAZA

NEW YORK, NEW YORK 10278-0090

Operations Division Operations Support Branch

SUBJECT: Maintenance Dredging of Shrewsbury River, New Jersey - Endangered Species Act concurrence

NOAA National Marine Fisheries Service Protected Resource Division 55 Great Republic Drive Gloucester, MA 01930

Attn: Jennifer Anderson

Dear Ms. Anderson, Pursuant to Section 10 of the Rivers and Harbors Act of 1899 and Section 404 (33 U.S.C. 1344) of the Federal Water Pollution Control Act (amended in 1977 and commonly referred to as the Clean Water Act), the U.S. Army Corps of Engineers, New York District (USACE), is proposing to perform maintenance dredging of the Shrewsbury River, New Jersey, Federal Navigation Project, with subsequent placement of the dredged sand for beneficial reuse at Monmouth Beach, a nearshore placement site, and/or Sea Bright Offshore Borrow Area (SBOBA) and placement of the dredged silt/clay material at a contractor furnished, state-permitted upland site(s). This letter is to request Endangered Species Act (ESA) concurrence from your office for the above project.

We have made the determination that the proposed activity may affect, but is not likely to adversely affect, any species listed as threatened or endangered by NMFS under the ESA of 1973, as amended. Our supporting analysis is provided below.

1) Proposed Project

The proposed project is designed to maintain the authorized dimensions of the Shrewsbury River, New Jersey, Federal Navigation Project, thereby assuring safe and economical use of the waterway by recreational and commercial maritime interests while providing beneficial use of the dredged sand. The dredged sand will be used for beneficial reuse at Monmouth Beach, a nearshore placement site, and/or Sea Bright Offshore Borrow Area (SBOBA) and the remaining dredged silt/clay material will be used for beneficially re-use at a contractor furnished, state-permitted upland site(s).

The existing Federal Navigation Project at Shrewsbury River, New Jersey provides for:

a. An entrance channel about 2.2 miles long, 12 feet below Mean Lower Low Water (MLLW) and 300 feet wide, following the westerly shore from deep water in Sandy Hook Bay to approximately the Route 36 bridge.

b. A channel (South Branch) about 6.8 miles long, 9 feet below MLLW and 150 feet wide, widened at bends, ending at Branchport Ave in Branchport.

c. A tributary channel (North Branch) 6 feet below MLLW and width of 150 feet, connected to the South Branch channel at Normandie, which extends up the Navesink River approximately 6.1 miles to Red Bank.

CENAN OP-S

SUBJECT: Maintenance Dredging of Shrewsbury River, New Jersey Endangered Species Act concurrence

The USACE, New York District, proposes to perform dredging of Shrewsbury River Federal Navigation Project. The channel was last maintenance dredged in 2014 by the USACE special use Dredge Currituck (315 CY max bin capacity) and contractor pipeline dredge with the removal of approximately 100,000 cubic yards (CY) of sand. The dredged sand was beneficially used at a nearshore placement location on the oceanside of Sandy Hook, NJ and as beach nourishment on Monmouth Beach, New Jersey. The proposed dredging would involve the removal of approximately 150,000 CY of material from Shrewsbury River, NJ.

The proposed dredging of the entrance channel would remove approximately 55,000 CY of sand to a depth of 12 feet below MLLW plus 2 feet of allowable overdepth with subsequent placement at a nearshore placement area, or SBOBA. Maintenance dredging of the entrance channel can be accomplished using the USACE Hopper Dredge Murden and is anticipated to occur in the summer/fall of 2023. The proposed dredging of the sandy portions of the North and South Branches would remove approximately 45,000 CY of sand to a project depth of 8 feet below MLLW plus 2 feet of allowable overdepth, and 6 feet below MLLW plus 2 feet allowable overdepth.

Maintenance dredging of this portion of the river can be accomplished by a pipeline dredge or similar plant and is anticipated to occur in the fall/winter of 2023/2024. The proposed dredging of the remaining silt/clay material from the North and South Branches would remove approximately 50,000 CY of material to a project depth of 8 feet below MLLW plus 1 foot of allowable overdepth, and 6 feet below MLLW 1 foot allowable overdepth. Maintenance dredging of this portion of the river can be accomplished by a mechanical dredge with clamshell bucket or similar plant and is anticipated to occur in the fall/winter of 2023/2024. The entire river will generally not require maintenance dredging; only areas where shoaling has reduced the depth of the channel will require dredging. The proposed dredging is to maintain the approved project dimensions to provide safe and economical use of the river and will not deepen any portion of the river beyond authorized depths.

Grain size analysis was performed in 2023 on sediment samples taken from the shoals in Shrewsbury River. Based on this analysis, the proposed dredge material is greater than 99% sand and gravel in the entrance channel and portions of the North and South Branches. The remaining material in the North and South Branches is silt and clay. The proposed dredged sand is suitable for placement along the shoreline at Monmouth Beach, at the nearshore placement area or at Sea Bright Offshore Borrow Area.

We request that this consultation cover anticipated dredging operations from 2023 to 2033. During this time frame, it is expected that 2 dredging events (including the proposed 2023 operation) would be necessary. Future dredging operations would be structured in the same manner as the proposed 2023 operation with the exception of quantity of sediment (estimated 100,000–300,000 CY per event). Future dredge events would be expected to overlap and encompass a similar footprint to that of the proposed 2023 operation (Figure 1) as this is the typical location of general shoal formation of Shrewsbury River. Future dredge events would require placement at the same proposed placement site(s).

Figure 1. General Vicinity Map (2023 Project)

Red indicates sand shoals to be dredged in 2023 in the entrance channel by USACE Hopper Dredge Murden and placed at the nearshore placement area or Sea Bright Offshore Borrow Area (SBOBA) Green indicates sand shoals to be dredged in 2023 in the North and South Branches by contractor pipeline dredge and placed along the Monmouth Beach, NJ shoreline Orange indicates silt/clay shoals to be dredged in 2023 in the North and South Branches by contractor mechanical dredge and placed at a contractor furnished, state permitted, upland placement site.

Yellow line outlines the channel.

Green indicates sand shoals to be dredged in 2023 in the North and South Branches by contractor pipeline dredge and placed along the Monmouth Beach, NJ shoreline Orange indicates silt/clay shoals to be dredged in 2023 in the North and South Branches by contractor mechanical dredge and placed at a contractor furnished, state permitted, upland placement site.

Yellow line outlines the channel.

Figure 2. Potential Placement Sites

Nearshore Placement Location - red polygon, Shrewsbury River, NJ entrance channel –green polygon, Shrewsbury River, NJ outline – yellow polygon.

Sea Bright Offshore Borrow Area (SBOBA)- red polygon

Monmouth Beach placement area- red polygon

Project Vessels

To safely and effectively complete the scope of work for the subject project, it is anticipated that the USACE shallow draft special purpose Hopper Dredge Murden, would be mobilized to accomplish the dredging within the proposed dredge areas located in the entrance channel of the Federal Navigation Project (FNP). The USACE Dredge Murden has a hopper capacity of 512 CY.

The Murden has draghead openings of 2" x 2" to 2” x 3”. In addition, operational speeds with the draghead engaged are typically 1.15 - 2.3 mph. We are unable to obtain a value for the dredge’s suction velocity but based on analysis of the USACE Hopper Dredge Currituck, which utilizes the same dragheads and HP pumps, it is determined that velocity would not be greater than that of large hopper dredges (11ft/s) for a project like the one proposed herein (also discussed in the Effects Analysis). Optimal suction velocities vary according to numerous project parameters (depth, salinity, grain size, etc.) but the desired suction velocity for any hydraulic dredging operation, regardless of the type of hydraulic dredge, is that which efficiently overcomes the project specific (local) forces, and lifts sediment from the bottom. The USACE Hopper Dredge Murden utilizes the same dragheads, HP pumps and operational procedures as the USACE Hopper Dredge Currituck. The only difference between the two USACE Hopper dredges is the bin capacity size.

Additional incidental vessels may be used for specific dredging operation needs such as hydrographic surveying. In total, it is estimated that no more than two (2) vessels will be temporarily added to the project area. Vessel speeds will be restricted to no greater than 10 knots throughout the duration of the project. Given the volume of material to be dredged in the 2023 project cycle, and the likely hopper capacity, it is estimated that approximately 110 trips from dredging area to placement area will be required. Future dredge events would be expected to require a similar number of trips.

To safely and effectively complete the remaining scope of work for the subject project, it is also anticipated that a small pipeline dredge and mechanical dredge would be mobilized to accomplish the dredging within the proposed dredge areas located in the North and South Branches of the Federal Navigation Project (FNP). Based on historical information for this project and project of similar scope, a small/medium (~16” diameter) cutterhead dredge and a mechanical dredge with clamshell bucket would be used to complete this work. Optimal suction velocities for pipeline dredges vary according to numerous project parameters (depth, salinity, grain size, etc.) but the desired suction velocity for any hydraulic dredging operation, regardless of the type of hydraulic dredge, is that which efficiently overcomes the project specific (local) forces, and lifts sediment from the bottom. In addition, a contractor will likely mobilize a support crew boat, and multiple scows and tugs, ranging in sizes from 25 to 100 feet in length. Additional incidental vessels may be used for specific dredging operation needs such as hydrographic surveying. In total, it is estimated that no more than twelve (12) vessels will be temporarily added to the project area.

Vessel speeds will be restricted to no greater than 10 knots throughout the duration of the project.

Given the volume of material to be dredged in the 2023 project cycle, and the likely scow capacity for the mechanical dredge portion of the dredging area, it is estimated that approximately 30 trips from dredging area to the processing area will be required. Future dredge events would be expected to require a similar number of trips.

Specific information pertaining to the capacity and size of the pipeline dredge, mechanical dredge and scows accompanying a mechanical dredge, project vessel points of origin (mobilization), post work destination (demobilization), the array of attendant plant and other project vessels, in-water work schedule, etc., is indeterminate until the project has been awarded to a contractor. It is anticipated that the work for the entrance channel will be performed from the summer of 2023, with intent to complete the work as early within that period as possible. It is anticipated that the remaining work in the North and South Branches will be performed in the fall/winter of 2023/2024.

Future dredge events would target the same time period for dredging and placement activities.

USACE does not perform any surveillance on, or have any control of the project vessels movements, until the vessels arrive on the jobsite (project area).

A description of the typical dredging and placement cycle using a hopper dredge is as follows:

The dredge takes on ballast water and sails to the dredge reach. Once at the dredge reach the dredge will drain the ballast water, lower the drag arm to the shoal depth and begin making it's cut, pumping the material (70-80%) and water (30-20%) slurry into the hopper. In Shrewsbury River, the dredge typically will move longitudinally in the dredge reach, making a 180 degree turn at the end of each cut. During the loading process sedimentation of the dredged materials is occurring in the hopper. The hopper is eventually filled with this slurry mixture and must begin to decant the effluent surface water in the hopper through a skimmer system. Once the dredge reaches its maximum economic load, it sails back to the placement area, a nearshore placement location, or SBOBA. The dredge will offload the dredged sand via the bottom dumping process.

Best Management Practices (BMPs)

The dredge cannot be equipped with turtle/sturgeon deflectors due to the small size of the dragheads and low HP pumps.

The draghead will remain on the bottom at all times during pumping action except when: the dredge is not in pumping operation, or, the pumps are completely shut off; or the vessel’s safety is at risk. Due to the small pump capacity, pumps will be primed right before the draghead touches the bottom, however suction into the hopper bin does not begin until draghead is fully on the bottom. Draghead distance from the bottom (approximately 1-2 inches) and length of time (approximately 1-2 seconds) pump is priming is negligible. The pump velocity and operational procedures are the same as USACE Hopper Dredge Currituck.

USACE will install baskets or screens over the hopper inflow and overflow, and any openings that are present along the inflow pipe infrastructures to ensure one hundred (100) percent screening of dredged sand. Baskets or screens or inflow openings shall have openings that do not exceed four (4) inches by four (4) inches.

Upon completion of the dredge track line, the drag tender will throttle back on the RPMs of the suction pump engine to idle speed prior to raising the draghead off the bottom so that no flow of material is coming through the pipe into the hopper. Prior to raising the draghead, no suction will remain in the draghead or the dragarm in order to prevent impingement during the dragarm listing phase. Prior to actual lifting of the dragarm from the bottom, the draghead will be held firmly on the bottom for 10 to 15 seconds (with no suction) then lifted rapidly to midwater to further reduce the potential for an interaction with an ESA-listed species. The dredge will then be re-oriented quickly to the next dredge line and the draghead will be firmly repositioned on the bottom before bringing the suction pump up to speed.

Vessel speeds will be restricted to no greater than 10 knots throughout the duration of the project.

The USACE Murden will be required to conduct sea turtle, and Atlantic sturgeon monitoring on board the dredge during all dredging operations. Starting immediately upon project commencement, the dredge will have an on-deck observer to monitor for sea turtles, whales, and Atlantic sturgeon. The endangered species monitors will be knowledgeable in endangered species identification and will be present onboard the dredge at all times to inspect the draghead screen, every time it is removed from the water, for turtles or sturgeon (whole or parts) impinged on the draghead, in the hopper, swimming/present at or near the surface.

A dredge observer form shall be completed every cycle (load), whether sea turtles or Atlantic sturgeon are present or not. The completed forms will be submitted to the USACE.

Should an incidental take of an Atlantic sturgeon or a sea turtle occur, dredging operations will immediately cease, and NOAA Fisheries will be notified (978-281-9328). USACE will then start the process to request the reinitiation of consultation.

Based on the expected species presence in the dredging area and designated disposal site, we have identified the following special conditions:

i. Year-round, disposal vessels including tugs, barges, and scows transiting between the dredge site and the disposal site shall operate at speeds not to exceed 10 knots. For unanticipated conditions, a vessel may operate at a speed necessary to maintain safe maneuvering speed instead of the required 10 knots. The intent of this condition is to reduce the potential for vessel collisions with endangered turtles, fish, and whales

ii. A marine mammal/turtle observer with written approval from the National Marine Fisheries Service (NMFS) (https://www.fisheries.noaa.gov/new-england-mid-atlantic/careers-and-opportunities/protected-species-observers), hereafter referred to as the “endangered species observer”, and contracted and paid for by the USACE must be present aboard disposal vessels for transportation and disposal activities to and from the disposal site. The name of the endangered species observer must be recorded in the logbook and is required to be on lookout for marine mammals and sea turtles for the duration of the trip.

iii. The captain or endangered species observer shall:

a. Check communication media for the latest information regarding North Atlantic right whale sighting locations. These media may include, but are not limited to, the Whale Alert app (https://www.fisheries.noaa.gov/resource/tool-app/whale-alert-smartphone-app), https://portal.nrwbuoys.org/ab/dash/ or https://www.nefsc.noaa.gov/psb/surveys. Check communication media before the initial disposal operation to determine the potential presence of whales in the area;

and

b. Lookout for turtles and whales and advise the captain of turtle or whale sightings.

c. Report any interactions (i.e., vessel strikes, captures, etc.) with any ESA-listed species as soon as possible (within 24-hours) to the NMFS Marine Animal Response Hotline at (866) 755-NOAA or USCG via CH-16 and immediately report any injured or dead marine mammals or sea turtles to NMFS at (866) 755-NOAA.

d. Every three months after the initial dredge action for as long as the dredging and disposal continues and at the end of a disposal operation, submit a report by email to Alexander.F.Gregory@usace.army.mil, Robert.J.Smith@usace.army.mil, and incidental.take@noaa.gov, summarizing the vessel route taken, number of trips, sightings of ESA-listed species, and any action taken to avoid interactions with ESA-listed species.

iv. The vessel captain shall:

a. Lookout for turtles and whales; and

b. Avoid transit and disposal when visibility is lessened (e.g., at night, fog) to an extent that would preclude an endangered species observer from spotting a whale within 1,500 feet or a sea turtle within 600 feet. Disposal shall not be permitted if these requirements cannot be met due to weather or sea conditions. In that regard, the permittee and contractor should be aware of predicted conditions before departing for the disposal site. The intent of this condition is to reduce the potential for vessel collisions with endangered species, including right whales.

c. Avoid harassment of or direct impact to turtles and whales except when precluded by safety considerations; and

d. Ensure that the disposal vessel adheres to the enclosed NMFS regulations for approaching right whales, 50 CFR 224.103(c), which restrict approaches within 1,500 feet (500 yards) of a right whale and specify avoidance measures for vessels that encounter right whales; and

e. Ensure that dredged material is not released if whales are within 1,500 feet or turtles are within 600 feet of the specified disposal point. The captain must check in with the endangered species observer prior to releasing the dredged material. If whales or turtles are within these distances and appear to be moving away from the specified disposal point, within these distances and appear to be remaining stationary, or outside these distances but appear to be moving towards the specified disposal point, the vessel captain shall wait until they have cleared the specified disposal point by these distances and are not moving towards it, and then proceed with disposal at the specified disposal point.

2) Description of the Action Area

The action area is defined as “all area to be affected directly or indirectly by the Federal action and not merely the immediate area involved in the action” (50 CFR §402.02). For this project, the action area includes (see Figures 1 & 2): the dredge area footprints, the area between the dredge area (Shrewsbury River, NJ) and the placement sites (nearshore placement location, SBOBA, and Monmouth Beach), the underwater areas experiencing effects of dredging (i.e., increase in suspended sediment - Figure 2), and all routes travelled by the project vessels. This area is expected to encompass all of the effects of the proposed project. The dredge area footprint for the proposed 2023 project (highlighted in red, green, and orange on Figure 1) is centered at approximately 40.401303N, -73.980447W, encompassing a total area of approximately 40 acres.

The dredge area footprint for the entrance channel encompasses a total area of approximately 13 acres. The potential nearshore placement area is centered 40.4339N, 73.97945W and encompasses a total area of approximately 10 acres. The potential SBOBA placement area is centered around 40.4253N, 73.94092W and encompasses a total area of approximately 42 acres.

The dredge area footprint for the sandy portions of the North and South Branches encompasses approximately 7 acres. The remaining dredging area for the silt/lay material encompasses approximately 20 acres. This dredging footprint is typical and would be expected to be similar to the footprint size of future dredging cycles. It is requested that this consultation cover those potential future dredge events provided that your office find the scope of those projects in congruence with that described herein.

Dredging Area Grain size analysis was performed in 2023 on sediment samples taken to project depth. Based upon an analysis of the samples collected, the grain size characteristics of the proposed dredged material consists of predominantly sand in the entrance channel and portions of the North and South Branches. The remaining material in the North and South Branches is mostly silt and clay. The shoals to be dredged have depths that range from -0.5 ft to -12 feet.

There is no evidence of submerged aquatic vegetation (SAV) in the proposed entrance channel and north branch project area. SAV may minimally exist near the south branch project area, however the project site has been maintenance dredged routinely, with the most recent dredging operation taking place in 2014. Therefore, such vegetation would not likely develop within the channel's boundaries. The tide at Shrewsbury River ranges from 3.92 ft MHHW to

0.00 ft MLLW.

Placement Areas The nearshore placement area on the ocean side of Sandy Hook, NJ encompasses approximately 10 acres and is located approximately 700 feet offshore of the Sandy Hook, South Beach – Area E (Figure 2). The nearshore placement area contains depths ranging from 15 to 24 feet (USACE 2023 Survey). There are no sea grasses and no Submerged Aquatic Vegetation (SAV) at the placement site.

The Sea Bright Offshore Borrow Area (SBOBA) is a 3 square mile area and is located approximately 1-3 miles offshore of the southern end of Sandy Hook (USACE -WES 1996).

SBOBA box 1A is within the Borrow Area and contains depths ranging from 43 to 62 feet (USACE 2023 Survey). There are no sea grasses and no Submerged Aquatic Vegetation (SAV) at the placement site.

A September 2002 Biological Opinion for the Atlantic Coast of New Jersey Beach Erosion Control Project Sea Bright to Manasquan, Monmouth County, New Jersey and December 2022 Streamlined Biological Opinion (attached) which encompasses the Monmouth Beach placement site has been conducted and no new information is available which changes the previous conclusion, no further consultation regarding the disposal of material at the Monmouth is necessary and will not be considered further in this document.

The contractor will be required to provide a processing and final upland placement site for the dredged silt/clay material. Specific information pertaining to the transport, processing and final upland placement site(s) utilizing a mechanical dredge, etc., is indeterminate until the project has been awarded to a contractor. All required permits for upland placement with be provided to USACE by the contractor before the time of award.

3) NMFS Listed Species in the Action Area

Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) (77 FR 5880 and 77 FR 5914)

Loggerhead turtle (Caretta caretta) (76 FR 58868; Recovery plan: NMFS & USFWS 2008)

Leatherback turtle (Dermochelys coriacea) (35 FR 8491; Recovery plan: NMFS & USFWS 1992)

Green turtle (Chelonia mydas) (81 FR 20057; Recovery plan: NMFS & USFWS 1991)

Kemp’s ridley turtle (Lepidochelys kempii) (35 FR 18319; Recovery plan: NMFS et al. 2011)

North Atlantic right whale (Eubalaena glacialis) (73 FR 12024; Recovery plan: NMFS 2005)

Fin whale (Balaenoptera physalus) (35 FR 18319; Recovery plan: NMFS 2010)

No designated critical habitat is present in the action area.

Whales

Federally endangered North Atlantic right whales and fin whales are expected to occur year round in New Jersey nearshore and coastal waters of New Jersey. Fin and right whales use the coastal waters of the Atlantic Ocean as they migrate to and from calving and foraging grounds. Because the dredge site has shallow depths that range from -0.5 ft to -12 ft, no whales will be present at the dredge site. Due to the shallow, nearshore location of both the nearshore placement area and SBOBA, we do not expect listed whales to occur in the action area; therefore, no whales will be exposed to any effects of the proposed action, and we will not consider these species further in this consultation.

Atlantic Sturgeon

There are five Distinct Population Segments (DPSs) of Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) listed as threatened or endangered. Atlantic sturgeon originating from the New York Bight, Chesapeake Bay, South Atlantic and Carolina DPSs are listed as endangered; the Gulf of Maine DPS is listed as threatened. The marine range of all five DPSs extends along the Atlantic coast from Canada to Cape Canaveral, Florida. Therefore, Atlantic sturgeon from any DPS could be present in the action area.

At around three years of age, subadults exceeding 70 centimeters in total length begin to migrate to marine waters (Bain et al. 2000). After emigration from the natal river/estuary, subadults and adult Atlantic sturgeon travel within the marine environment, typically in waters less than 50 m in depth, using coastal bays, sounds, and ocean waters (ASSRT 2007). In rivers and estuaries, Atlantic sturgeon typically use the deepest waters available; however, Atlantic sturgeon also occur over shallow (2.5 m), tidally influenced flats and mud, sand, and mixed cobble substrates (Savoy and Pacileo 2003). Occurrence in these shallow waters is thought to be tied to the presence of benthic resources for foraging.

As Atlantic sturgeon spawn in freshwater portions of large rivers and early life stages are not tolerant of salinity, spawning, eggs and early life stages will not occur in any part of the action area. Because the action area is not located in a river where sturgeon spawn, no juveniles will be present as this life stage remains in the natal river. Adult and subadult Atlantic sturgeon from any of the five DPSs may occur in any part of the action area. While in the marine environment, Atlantic sturgeon are known to aggregate in several distinct areas along the Mid-Atlantic coastline, including an area off of Sandy Hook, New Jersey (Stein et al. 2004; Laney et al. 2007; Erickson et al. 2011; Dunton et al. 2010). The aggregation area off Sandy Hook is believed to be used primarily during the late fall and spring, although some sturgeon can still be found in this area during the winter and the summer months (Dunton et al. 2010; Erickson et al. 2011). The action area does not overlap with the Sandy Hook concentration areas. Use of the action area is expected to be limited to transient Atlantic sturgeon moving along the coast or opportunistically foraging. Thus, Atlantic sturgeon may occur in the Shrewsbury River and at the nearshore placement area and SBOBA. Based on the known presence of Atlantic sturgeon year-round in other parts of the Sandy Hook area, we also assume adult and sub-adult Atlantic sturgeon could be in these action areas year-round.

Sea Turtles

Four species of federally listed threatened or endangered sea turtles are found seasonally in the coastal waters of New Jersey, including the action area: the threatened Northwest Atlantic Ocean DPS of loggerhead (Caretta caretta), North Atlantic DPS of green (Chelonia mydas), and the endangered Kemp's ridley (Lepidochelys kempi), and leatherback (Dermochelys coriacea) sea turtles. In general, listed sea turtles are seasonally distributed in coastal U.S. Atlantic waters, migrating to and from habitats extending from Florida to New England, with overwintering concentrations in southern waters. As water temperatures rise in the spring, these turtles begin to migrate northward. As temperatures decline rapidly in the fall, turtles in northern waters begin their southward migration. Sea turtles are expected to be in the action area in warmer months, typically when water temperatures are at least 15°C. This generally coincides with the months of May through November, with the highest concentration of sea turtles present from June through October (Shoop and Kenney 1992; Morreale and Standora 2005).

No studies of sea turtles near the action area are available to estimate the depth at which they typically occur; however, studies of sea turtles near Long Island, NY have shown that the species typically occur in waters with depths between 16 and 49 feet deep and in areas where the waters are slow-moving or still (i.e., less than 2 knots) (Ruben and Morreale 1999). Thus, based on the best available information, we assume their preferred foraging depth is between 16 and 49 feet deep. Sea turtles are known to occur in Sandy Hook Bay; however, this is not a high use area for sea turtles. In 1999, the USACE and Dr. Stephen Morreale of Cornell University completed an analysis of habitat suitability of the New York Bight complex, including Sandy Hook Bay, for listed sea turtles. Habitat suitability was based on seasonal temperature, depth, benthic biota and substrate. Based on this analysis, the habitats found in Sandy Hook Bay were considered only marginally suitable for listed sea turtles. This finding is consistent with the only occasional sightings of sea turtles in that area. Thus, sea turtles may occur in Shrewsbury River and at the nearshore placement area and SBOBA. Based on the best available information, we have determined that occasional sea turtles are likely to occur in the action area between May and November. These turtles may be foraging opportunistically or migrating to other coastal waters.

4) Effects Determination

Impingement / Entrapment / Capture

Mechanical Dredging Mechanical dredging entails lowering the open bucket or clam shell through the water column, closing the bucket after impact on the bottom, lifting the bucket up through the water column, and emptying the bucket into a barge or truck. The bucket operates without suction or hydraulic intake, moves relatively slowly through the water column, and impacts only a small area of the aquatic bottom at any time. In order to be captured in a dredge bucket, an animal must be on the bottom directly below the dredge bucket as it impacts the substrate and remain stationary as the bucket closes. Species captured in dredge buckets can be injured or killed if entrapped in the bucket or buried in sediment during dredging and/ or when sediment is deposited into the dredge scow.

Species captured and emptied out of the bucket can suffer stress or injury, which can lead to mortality.

Entrapment of sturgeon during the temporary performance of dredging operations is considered extremely unlikely. For entrapment to occur, an individual sturgeon would have to be present directly below the dredge bucket at the time of operation. Based on past interactions between mechanical dredges and sturgeon, the greatest risk of capture is when dredging occurs in areas where sturgeon are densely aggregated such as when they experience sedentary behavior in spawning or overwintering areas. However, the area to be dredged is not a known spawning or overwintering area and only migrating and opportunistically foraging adult sturgeon would potentially be present within the action area. Any such individuals would likely use adjacent open water areas in the waterway that provide for sufficient safe passage to avoid the work area during construction.

Sea turtles are not known to be vulnerable to entrapment in mechanical dredges, presumably because they are able to avoid the dredge bucket. Thus, if a sea turtle were to be present at the dredge site, it would be extremely unlikely to be injured or killed as a result of dredging operations carried out by a mechanical dredge.

Pipeline Dredging The hydraulic cutterhead dredge (also commonly called pipeline dredge) consists of a rotating cutterhead positioned at the end of a ladder that excavates the bottom sediment. The excavated material is picked up through a suction pipe and transferred by means of a centrifugal pump to a designated disposal area through a pipeline as a slurry. The typical solids content of the slurry is 10 to 20 percent by weight. The typical cutterhead dredge is swung in an arc from side to side as the dredge is stepped forward on pivoting spuds at the stem of the dredge. Operation of this type of dredge is nearly continuous, and production rates are generally high. Cutterhead dredges are used extensively for removal of large quantities of material during channel excavation and maintenance operations with relatively short distances to the disposal site (1.5 to 5 km).

Pipeline dredges operate with the dredge cutterhead intake buried in the sediment, where sturgeon feed on benthic invertebrates (e.g., amphipods, gastropods, annelids, decapods) and occasionally on small fish. Atlantic sturgeon may occur in the entrance channel of Shrewsbury River opportunistically foraging, therefore there could be interaction with the dredge. However, because the dredge moves very slowly, it is likely that sturgeon would be able to easily avoid the dredge. This assumption is supported by monitoring work, completed in the James River (Virginia) and the Delaware River (New Jersey) (Cameron 2010; ERC 2011), as well as work undertaken on a related species, the white sturgeon, in the Columbia River (Parsley and Popoff 2004). During these three studies, the movements of tagged sturgeon were tracked near the dredge: no interactions between sturgeon and the dredge occurred. Some tagged sturgeon moved through the area where the dredge was operating multiple times during the study. The risk of interaction between sturgeon and pipeline dredges is thought to be highest in where large numbers of sturgeon are known to aggregate, such as when they experience sedentary behavior in overwintering areas. However, the area to be dredged is not a known overwintering area and only migrating and opportunistically foraging adult sturgeon would potentially be present within the action area. Any such individuals would likely use adjacent open water areas in the waterway that provide for sufficient safe passage to avoid the work area during construction.

Sea Turtles are not known to be vulnerable to entrainment in cutterhead dredges, presumably because they are able to avoid the relatively small intake and low intake velocity. Thus, if a sea turtle were to be present at the dredge site, it would be extremely unlikely to be injured or killed as a result of dredging operations. Based on this information, effects to sea turtles from the pipeline dredge are discountable.

Hopper Dredging With the use of a hopper dredge, dredged material is raised by dredge pumps through dragarms connected to dragheads in contact with the channel bottom and discharged into hoppers built in the vessel. Hopper dredges are equipped with large centrifugal pumps similar to those employed by other hydraulic dredges. Suction pipes (dragarms) are hinged on each side of the vessel with the intake (drag) extending downward toward the stern of the vessel. The drag head is moved along the bottom as the vessel moves forward at speeds up to three knots. The dredged material is sucked up the pipe and deposited and stored in the hoppers of the vessel.

Most sturgeon are able to escape from the oncoming draghead due to the slow speed that the draghead advances (up to 3 mph or 4.4 feet/second). Interactions with a hopper dredge result primarily from crushing when the draghead is placed on the bottom, or when an animal is unable to escape from the suction of the dredge and becomes stuck on the draghead (i.e., impingement).

Entrainment occurs when organisms are sucked through the draghead into the hopper. Mortality most often occurs when animals are sucked into the dredge draghead, pumped through the intake pipe and then killed as they cycle through the centrifugal pump and into the hopper.

Interactions with the draghead can also occur if the suction is turned on while the drag head is in the water column (i.e., not seated on the bottom). However, the Biological Assessment for the Use of sidecast dredges Fry, Merritt, and Schweizer and the Split-Hull Hopper Dredge Currituck in Coastal United States Waters (attached) determined that based on the low suction forces of these vessels and the small size of the draghead openings, direct impingement is considered unlikely. The USACE Hopper Dredge Murden, used in the 2023 cycle for this project, utilizes the same dragheads and pumps as the USACE Hopper Dredge Currituck, therefore these conclusions and biological assessment apply to the use of the Dredge Murden.

Sturgeon are vulnerable to interactions with hopper dredges. The risk of interactions is related to both the amount of time sturgeon spend on the bottom and the behavior the fish are engaged in (i.e., whether the fish are overwintering, foraging, resting or migrating), as well as the intake velocity and swimming abilities of sturgeon in the area (Clarke, 2011). The USACE Special Use Hopper Dredge Murden operates at a low intake velocity , the same as that of USACE Hopper Dredge Currituck and below 11ft/s, therefore any Atlantic sturgeon present near these dredges are likely to be able to swim away and avoid the intake. Exposure to the suction of the draghead intake is minimized by not turning on the suction until the draghead is properly seated on the bottom sediments and by maintaining contact between the draghead and the bottom.

In general, entrainment of large mobile animals, such as the sturgeon, is relatively rare. Several factors are thought to contribute to the likelihood of entrainment. One factor influencing potential entrainment is the swimming stamina and size of the individual fish at risk (Boysen and Hoover 2009), Swimming stamina is positively correlated with total fish length. Entrainment of larger sturgeon, such as the subadults and adults that may occur in the action area, is less likely due to the increased swimming performance by the fish. The estimated minimum size for sturgeon that out-migrate from their natal river is approximately 30-36 inches (Murawski and Pacheco, 1977;

ASSRT, 2007); therefore, that is the minimum size of sturgeon anticipated in the action area.

In areas where animals are present in high density, the risk of an interaction is greater because more animals are exposed to the potential for entrainment. The hopper dredge draghead operates on the bottom and is typically at least partially buried in the sediment. Sturgeon are benthic feeders and are often found at or near the bottom while foraging or while moving within rivers.

Sturgeon at or near the bottom could be vulnerable to entrainment if they were unable to swim away from the drag head. Information suggests that Atlantic sturgeon migrating in the marine environment do not move along the bottom but move further up in the water column (Sarah Cameron, submission of comments on 75 FR 61872, 2011 in letter from NMFS for Duxbury Harbor September 9, 2011). If sturgeon are up off the bottom while in marine areas, such as Shrewsbury River, the potential for interactions with the dredge are further reduced. We expect the occurrence of sturgeon in the dredging area to be limited to rare transients. Furthermore, the Shrewsbury River, Federal Navigation Project entrance channel has been dredged with relative frequency and there has never been an observed interaction with sturgeon. Because the entrance channel project is occurring in coastal waters, sturgeon will have plenty of room in the waterway to swim away and avoid the dredge. Given the above information, an interaction of a sturgeon with the USACE Dredge Murden in the action area is extremely unlikely.

Furthermore, hydraulic pumps will only be primed once the draghead is a negligible distance from the bottom and fully suctioning when in contact with the sediments, thereby, directing and maintaining the suction velocity to the bottom, and thus, within an area where sturgeon are not expected to occur. We expect the occurrence of sturgeon in the area to be limited to rare transients during the time of year dredging is scheduled to occur. Given the precautionary measures ensuring that suction of the draghead is only on when in contact with the bottom, an interaction of a sturgeon with the USACE Dredge Murden in the action area is extremely unlikely.

Loggerhead, Kemp's ridley, and green sea turtles are known to be vulnerable to entrainment and/or impingement in hopper dredges. Due to the large size of leatherback sea turtles, leatherback sea turtles are not vulnerable to entrainment in hopper dredges. Factors that are believed to contribute to the likelihood of sea turtle entrainment include: 1) dredge duration (e.g., greater number of interactions associated with longer duration dredging); 2) Hydraulic pump operation (i.e., interactions rates increase with hydraulic pumps operating during the placement/removal of draghead); 3) the location, habitat, and geography of the project site (e.g., open estuarine environment versus confined channel areas); and, 4) the species' use of, and behavior within, the affected location (e.g., foraging, brumating, breeding, resting, transiting).

As the draghead of a hopper dredge operates on the bottom, interactions with sea turtles primarily occur when a sea turtle is foraging or resting on the bottom; these interactions occur more frequently in areas where sea turtle forage is abundant, and thus, sea turtle densities are high.

Habitat conditions in the dredging area are not consistent with the areas where brumation has been documented; therefore, we do not anticipate that brumating sea turtles are present in the project area. Sea turtles are not known to concentrate in or use the waters of the area affected by dredging operations as an essential foraging or resting ground; instead it is believed that they use these waters to transit to other waterways of New Jersey and New York. Although sea turtle forage exists within the United States coastal waters of the Atlantic Ocean (e.g., crabs, mollusks, submerged aquatic vegetation (SAV), there is no optimal foraging habitat within the portion of the action area affected by hopper dredging. There is no evidence of SAV in the Shrewsbury River entrance channel. Based on the best available information, sea turtle species are not expected to be foraging or resting in this portion of the action area and thus, are not expected to be on the benthos where the draghead of the hopper dredge will be operating. Instead, within the project area, these species of sea turtles are expected to be found in the water column, migrating to and from foraging, breeding, or resting grounds found in nearshore coastal bays and estuaries located outside of the action area. As sea turtles are not expected to occur within the vicinity of the draghead, the likelihood of an interaction between a sea turtle and the dredge head is extremely unlikely.

In addition to the habitat characteristics of the project area, the location and geography of a project may also affect the likelihood of entrainment. The risk of entrainment is believed to be highest in areas where the movements of animals are restricted (e.g., rivers, narrow confined channels) and therefore, where the animal has limited opportunity to move away from the dredge. If these restricted areas also occur within sites in which species are known to concentrate, the likelihood of an interaction further increases. These characteristics; however, are not present within the project area. The hopper dredge project area is situated at the widest entry point to Shrewsbury, an area we consider a predominately open environment; that is, a body of water in which the shorelines of the surrounding land masses do not encroach on the body of water to an extent that shallow, narrow waterways are created due to the presence of project related vessels or equipment. Based on the best available information, the presence of sea turtle is more unlikely the further upstream in the river. This is confirmed by no records of sea turtles in the upstream river, and habitat (shallow, sandy) is not optimal foraging habitat for sea turtles. The minimum width of the entrance channel dredge site where sea turtles may be present is approximately 1,000 feet. As dredging operations will occur in a predominately open environment, sea turtle movements will be unrestricted, with ample space surrounding the dredging area for sea turtles to move and avoid the dredge or dredge site and continue normal behaviors in other waterways of New Jersey. Further, because sea turtles are only expected to transit the project area, and not congregate, the density of sea turtles in any portion of the project area is expected to be low.

Based on this information, combined with the fact that sea turtles are not expected to occur on the benthos to forage or rest, the potential for an interaction with a dredge is further reduced.

Based on the information above, and the following factors, we conclude that the risk factors that increase the likelihood for sea turtle entrainment are not present. First, hydraulic pumps will be only turned on once the draghead is a negligible distance from the bottom; thereby, directing and maintaining the suction velocity to the benthos of the borrow areas, and thus, within an area where sea turtles are not expected to occur. Second, prior to the actual lifting of the dragarm from the bottom, the draghead will be held firmly on the bottom for 10 to 15 seconds (with no suction) then lifted rapidly to mid water. Based on this information, it is extremely unlikely that there will be any impingement or entrainment of sea turtles. This conclusion is supported by the lack of any observed impingement or entrainment of sea turtles on the Murden dredge operating several times per year in areas where sea turtles are likely to be present.

Based on this information, and information presented in the Biological Assessment referenced above for the USACE Hopper Dredge Currituck, the effects of impingement or entrainment on sturgeon and sea turtles are extremely unlikely and are, therefore, discountable.

Turbidity / Water Quality

Dredging impacts on water quality are largely restricted to the plume, with impacts localized in the dredging area. Hopper dredges re-suspend sediment when the suction draghead(s) make contact with the substrate and during release of overflow waters, which generally occurs through the bottom of the vessel’s hull. Hopper dredges have a large range in capacities and different draghead configurations. Plumes generated during hopper dredging of sandy entrance channels will have very different spatial and temporal characteristics than those created in silt-laden harbors. Near-bottom plumes caused by hopper dredges may extend approximately 2,300 to 2,400 feet (701-731 meters) down-current from the dredge (ACOE 1983). According to Wilber and Clarke (2001), suspended sediment plumes can extend 3,937 ft (1,200 m). TSS concentrations may be as high as several hundred mg/L near the discharge port and as high as several tens of mg/L near the draghead. In a literature review conducted by Anchor Environmental (2003), near-field concentrations ranged from 80.0-475.0 mg/L. TSS and turbidity levels in the near-surface plume usually decrease exponentially with increasing time and distance from the active dredge due to settling and dispersion, quickly reaching ambient concentrations and turbidities. In almost all cases, the majority of re-suspended sediments resettle close to the dredge within one hour, although very fine particles may settle during slack tides only to be re-suspended by ensuing peak ebb or flood currents (Anchor Environmental 2003). The TSS levels expected for hopper dredging (up to 475.0 mg/L) are below those shown to have adverse effect on fish (typically up to 1,000.0 mg/L; see summary of scientific literature in Burton 1993; Wilber and Clarke 2001).

Mechanical dredges include many different bucket designs (e.g., clamshell, closed versus open bucket, level-cut bucket) and backhoe dredges, representing a wide range of bucket sizes.