Record of Decision for the Boston Harbor Inner Harbor Maintenance Dredging Project, 45539-45541 [06-6792]

Agencies

• DEPARTMENT OF DEFENSE
• Department of the Army, Corps of Engineers
• Engineers Corps
• Department of the Army; Corps of Engineers

[Federal Register Volume 71, Number 153 (Wednesday, August 9, 2006)]
[Notices]
[Pages 45539-45541]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 06]


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DEPARTMENT OF DEFENSE

Department of the Army; Corps of Engineers


Record of Decision for the Boston Harbor Inner Harbor Maintenance 
Dredging Project

AGENCY: Department of the Army, U.S. Army Corps of Engineers, DOD.

ACTION: Notice.

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SUMMARY: The U.S. Army Corps of Engineers, New England District 
announces its decision to maintenance dredge the following Federal 
navigation channels in Boston Harbor, Massachusetts: the Main Ship 
Channel upstream of Spectacle Island to the Inner Confluence, the upper 
Reserved Channel, the approach to the Navy Dry Dock, a portion of the 
Mystic River, and a portion of the Chelsea River (previously 
permitted). Maintenance dredging of the navigation channels landward of 
Spectacle Island is needed to remove shoals and restore the Federal 
navigation channels to their authorized depths. Dredged material 
suitable for unconfined open water disposal will be disposed at the 
Massachusetts Bay Disposal Site; material not suitable for unconfined 
open water disposal will be disposed in confined aquatic disposal (CAD) 
cell(s) located within the navigation channels. Major navigation 
channel improvements (deepening) were made in 1999 through 2001 in the 
Reserved Channel, the Mystic River, Inner Confluence, and the Chelsea 
River. A Final Environmental Impact Statement (EIS) prepared in June 
1995 for this previous navigation improvement project (Boston Harbor 
Navigation Improvement Project--BHNIP) identified selected use of CAD 
cells in the Mystic River, Inner Confluence, and Chelsea River for 
disposal. A Supplemental Draft and Final EIS was prepared for this 
maintenance dredging project and built on the lessons learned from the 
previous improvement project. A new CAD cell for the proposed 
maintenance project will be constructed in the Mystic River (previously 
permitted) and in the Main Ship Channel just below the Inner 
Confluence.

FOR FURTHER INFORMATION CONTACT: Mr. Michael Keegan, (978) 318-8087.

SUPPLEMENTARY INFORMATION: The U.S. Army Corps of Engineers is 
authorized by the various River and Harbor Acts and Water Resources 
Development Acts to conduct maintenance dredging of the Federal 
navigation channels and anchorage areas in Boston Harbor.
    Alternatives Considered: The National Environmental Policy Act 
(NEPA) requires a discussion of alternatives to the project, including 
the No Action Alternative. Since a Supplemental EIS was prepared, the 
preferred alternative is evaluated in the context of the alternatives 
addressed in the EIS for the navigation improvement project, including 
alternatives to full maintenance dredging, dredging methods, and 
disposal options.
    Dredging--The Boston Harbor terminal operators, and shipping 
interests were contacted to identify the type and size of vessels 
currently using the navigation channels and if they were experiencing 
any delay or impacts associated with the navigation project. The 
results of the survey were used to determine if maintenance of all or 
just a portion of the currently authorized navigation channels in the 
proposed project is required. Based on the results of the survey, it 
was determined that shoaling in the Charles River channel does not 
affect any of the current operations in that channel and will not be 
dredged.
    Dredging Methods--Various types of dredging methods were considered 
for this project including a hydraulic dredge, a hopper dredge, and a

[[Page 45540]]

mechanical dredge. The type of dredge proposed for a project is 
dependent upon the type of material to be dredged and the disposal site 
selected. Due to the fine nature of the materials to be dredged from 
Boston Harbor, and the aquatic sites selected for disposal, it was 
determined that a mechanical dredge would best suit the needs of the 
project. To minimize turbidity impacts from dredging, an enclosed 
``environmental'' bucket will be used during silt dredging. In 
addition, no overflow from the scows will be allowed to further reduce 
the effects of turbidity on water quality.
    Disposal Alternatives--Over 370 disposal sites were identified and 
evaluated during preparation of the EIS for the previous navigation 
improvement project (BHNIP). The screening process selected in-channel 
CAD cells for disposal of the material unsuitable for unconfined open 
water disposal and the Massachusetts Bay Disposal Site (MBDS) for 
disposal of the suitable material. In addition, seven sites were 
identified in the BHNIP Final EIS as potential disposal sites for 
future maintenance dredged material. The sites included the MBDS, 
Subaqueous B and E, Meisburger 2 and 7, Boston Lightship, and Spectacle 
Island CAD.
    The Subaqueous B and E sites, the Meisburger sites and the 
Spectacle Island CAD are all located in previously undisturbed areas. 
The Boston Lightship is a historic disposal site and would need to go 
through a lengthy site selection process before disposal could be 
considered. This site also recovering from previous disposal events. 
The MBDS is an EPA-designated ocean disposal site that is currently in 
use. Sites that have not been previously disturbed are not as desirable 
for disposal of dredged material. Therefore, the MBDS was selected as 
the preferred site for the suitable material and the in-channel CAD 
cells selected for material unsuitable for unconfined open water 
disposal.
    No Action Alternative--Under a No Action Alternative, the Federal 
navigation channels in Boston Harbor would not be dredged. Failure to 
dredge Boston Harbor will further restrict and delay commercial deep 
draft vessels. Shoaling has reduced depths in the channel as much as 
five feet in some sections of the project area. Without maintenance 
dredging to restore authorized depths in the inner portion of the Main 
Ship Channel, shippers will experience even longer tidal delays and be 
restricted to operating within narrower time periods of higher tidal 
stages. This results in a significant and negative impact to the 
region, and raises significant operational, safety, economic, and 
environmental concerns. With the increase in costs and reduction in 
vessel movement opportunities, it is likely that shippers will by-pass 
the port and will unload their products at other ports and ship the 
products back to the region via trucks. This could impact limited 
roadway capacity, resulting in increased air emissions, traffic, and 
deterioration of highways and bridges. Although the No Action 
Alternative is the environmentally preferred alternative, it does not 
meet the project objectives, and is not considered a viable 
alternative. Therefore the preferred alternative is dredging the above 
described navigation channels to their authorized depth using a 
mechanical dredge with disposal at the MBDS and in-channel CAD cells.
    Environmental Impacts: Potential environmental impacts associated 
with dredging and disposal includes water quality impacts from 
turbidity plumes, potential release contaminants during dredging and 
disposal activities, and impacts to biological resources. In 
particular, concerns about biological resources centered on potential 
blockage of anadromous fish transiting to spawning grounds, sediment 
deposition from suspended solids on winter flounder eggs, and direct 
impacts to lobsters.
    Extensive environmental monitoring was conducted during 
construction of the BHNIP as a requirement of the Water Quality 
Certification (WQC). Environmental monitoring required as part of the 
WQC included: (1) Silt plume tracking during dredging of and after 
disposal into CAD cells, (2) water quality testing after disposal into 
the CAD cells, (3) biological testing, (4) dissolved oxygen (DO) 
testing within and outside the CAD cells, and (5) fisheries monitoring. 
The results of the monitoring showed no water quality violations or 
significant impacts to biological resources.
    Additional investigations (i.e., outside the scope of the WQC) were 
performed during construction to address concerns raised by the 
Technical Advisory Committee (TAC) to address potential impacts from 
changes in operations suggested by the dredging contractor. The TAC met 
periodically to review monitoring results and discuss recommended 
amendments to the WQC. These additional investigations included water 
quality monitoring of disposal at low tide, plume monitoring of the 
contractor's enclosed bucket, monitoring turbidity caused by vessel 
passage over an uncapped and capped CAD cell, bathymetric measurements, 
and lobster monitoring. Monitoring results showed no water quality 
violations or significant environmental impacts from construction of 
the project. One-year surveys and five-year surveys of the CAD cells 
constructed in the Inner Confluence, Mystic River, and Chelsea River 
for the BHNIP have also been completed, as required by the BHNIP WQC. 
The results of the monitoring show that the CAD cells are performing as 
expected. Experience gained from placing a sand cap on the CAD cells 
will be incorporated into this project.
    Mitigation: As a result of the extensive monitoring conducted for 
the BHNIP, and the lack of any water quality violations or significant 
impacts, only confirmatory water quality monitoring during initial 
disposal operations is recommended for this project. It is recommended 
that total suspended solids and turbidity monitoring be performed 
during the initial disposal events at both the Mystic River CAD cell 
and at the Main Ship Channel CAD cell.
    To reduce potential impacts to resources in the project area, based 
on lessons learned, the following mitigation measures will be 
implemented:
     An enclosed ``environmental'' bucket will be used for silt 
dredging. To reduce the effects of turbidity on water quality, no 
overflow from the scows will be allowed.
     Disposal into the CAD cells will occur only around periods 
of slack tide: three hours at low tide and high tide (one hour before 
and two hours after slack tide).
     A three-foot sand cap will be placed in the CAD cells when 
the silt has consolidated enough to support a cap. The cap material 
will be released from a moving as opposed to a stationary platform. No 
spudding over the cap or mechanical disturbance of the cap will be 
allowed.
     To reduce the impact to biological resources from 
blasting, all blasting will be conducted using inserted delays of a 
fraction of a second per hole. Rock or similar material will be placed 
into the top of the borehold to deaden the shock wave reaching the 
water column. A fisheries and mammal observer, and fish detecting sonar 
system, will be used to avoid blasting when mammals are present in the 
area or when significant schools of fish are observed.
     A fisheries observer, sonar detection, and use of a fish 
startle system from February 15 to June 15 will be required for the 
Mystic River and Main Ship Channel CAD disposal activities to avoid 
disposal during the time of anadromous fish migration.
     To reduce potential impacts to egg-bearing lobsters that 
are less mobile in

[[Page 45541]]

the colder months, no dredging or blasting will occur seaward of the 
Third Harbor Tunnel between December 1 and March 31.
     A marine mammal observer will be on board the scows 
transiting to the MBDS from February 1 to May 31 to avoid potential 
ship strikes with marine mammals, and in particular the North Atlantic 
Right Whale.
     Rock removed from the Presidents Road Anchorage area will 
be placed within a new area of the MBDS to increase habitat diversity.
     The dredge contractor will provide advance notice to the 
lobstermen on anticipated significant dredge movements.
     The dredge contractor will maintain a short tow while 
inside Boston Harbor to minimize disruption of lobster pots.
    Based on incorporation of the above mitigation measures, the 
experience gained during construction of the BHNIP, and lack of any 
water quality violations or other significant effects from the BHNIP, 
no significant impacts to the environment are expected from the Boston 
Harbor Inner Harbor Maintenance Dredging Project. All practicable means 
to avoid or minimize adverse environmental effects have been 
incorporated into the recommended plan. The public interest will best 
be served by implementing maintenance dredging as identified and 
described in the Supplemental Environmental Impact Report.

    Dated: August 1, 2006.
Curtis L. Thalken,
Colonel, Corps of Engineers, New England District.
[FR Doc. 06-6792 Filed 8-8-06; 8:45 am]
BILLING CODE 3710-24-M