Attachment_2.pdf

EVALUATION OF FISH PROTECTION MEASURES ASSOCIATED

WITH DISPOSAL OF DREDGED MATERIAL INTO CONFINED

AQUATIC DISPOSAL CELLS IN BOSTON HARBOR

US ARMY CORPS August 2016

OF ENGINEERS

NEW ENGLAND DISTRICT

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Introduction

As detailed in the 2006 Environmental Impact Statement (EIS) and 2013 Final Supplemental Environmental Impact Statement (SEIS) for Boston Harbor (USACE 2013), there are a number of environmental concerns related to the Boston Harbor maintenance and improvement projects, particularly related to the dredging and disposal of the maintenance material. One major concern was the potential for impacts to fisheries resources, specifically winter flounder and Clupeids (alewife and blueback herring), during material placement into confined aquatic disposal (CAD) cells during those times of year when these species are known to be present in or transiting through areas of the harbor where CAD cells are located.

In response to these concerns, the Corps developed a suite of best management practices (BMPs) for use during disposal events at specified times of year to minimize impacts to fisheries resources. These BMPs included the use a fish startle system, the use of a fisheries observer, and the use of sonar during placement events. The fish startle system is an electronic device that emits high amplitude sound at specific frequencies throughout the water column in the vicinity of where it is deployed. The sounds produced and emitted have been demonstrated to deter fish from coming near them (Blaxtera1 and Hossa 1981, Mann et al 2001). A qualified fisheries observer is also used as a BMP to minimize impacts to fisheries resources. The fisheries observer uses a side-scan type sonar (hydroacoustic monitoring equipment) to determine if any fish resources are present in the water column over the placement location. The sonar provides the fisheries observer an indication of the distance between the vessel containing the dredged material and any fish within the project area, and the direction the fish are traveling. Using this information, the fisheries observer can direct the activation of the fish startle system and direct the timing of placement of the dredged material to avoid impacts to fishery resources within and transiting through the project area. In some situations the placement of the material in a particular area of the CAD cell may be also adjusted to avoid impacts. Material from the scows is released into the CAD cell or area of the cell only after the fisheries observer confirms that no significant fish resources are present. The ability to direct placement in one area of the cell or another to avoid impacts will decline as the cell is filled, leading to greater reliance on limiting the timing of placement until fish have moved beyond the cell.

This document serves to document the use of the BMPs stated above in previous Boston Harbor dredging and blasting efforts, to document the standard operation procedures (SOP) for each BMP, and provides an assessment of the BMP’s effectiveness in protecting fisheries resources.

Past Use of Fisheries Best Management Practices

The following section details past construction events in Boston Harbor and the BMPs that were utilized.

Boston Harbor Navigation Improvement and Berth Dredging Project (BHNIP): 1998-2000

The fisheries protection BMPs (startle system, sonar, and observer) were first used in the Boston Harbor Navigation Improvement and Berth Dredging Project (BHNIP) during 1999-2000 and 2001. The BHNIP involved CAD cell creation, dredging, dredged material placement in Boston Harbor and limited blasting in the upper portion of Chelsea River. All the BMPs were utilized during the placement of dredged material into CAD cells that occurred between February 15, 1999 and June 15, 2000 and all the BMPs were used during the blasting that occurred in Chelsea Creek in August of 2001. A monitoring effort was employed to determine if the BMPs were effective (ENSR, 2002). During construction activities, a vessel equipped with sonar and the startle system surveyed the project area periodically. For placement events, the vessels surveyed the area around the CAD cell prior to placement. Very few fish were detected in the colder months, however, a number of harbor seals were noted periodically observing the construction effort. As temperatures warmed in the spring, more individual fish were noted with the sonar, however, large schools of fish known to be moving up the harbor were not observed within the dredging and disposal areas (ENSR, 2002). No observable impacts from the placement of material into Boston Harbor CAD cells were noted. Additionally, no fisheries impacts were noted during the Chelsea River blasting effort which was performed during the month of August 2001.

Boston Harbor Inner Harbor Maintenance Dredging Project (IHMDP): 2007-2008

The fisheries protection BMPs were used in the Boston Harbor Inner Harbor Maintenance Dredging Project (IHMDP) during the 2007-2008 effort. The IHMDP involved dredging, dredged material placement and blasting in inner Boston Harbor. While no formal monitoring was performed in association with the placement of dredged material into the CAD cells, no fisheries impacts were noted for that phase of work. However, four fisheries impact events (from a total of 14 blasting events) were noted during the blasting phase of the IHMDP. These impact events, problem assessments, and subsequent corrective prescriptive actions to prevent future fisheries impacts are detailed in the Final After Action Report on Fisheries Impacts resulting from Fall 2007 Blasting Activities for Rock Removal from the (Boston Harbor) Federal Navigation Project (Appendix Y of the 2013 Boston Harbor SEIS). This document is attached to this report for reference. The corrective actions detailed in this report serve as the basis for the monitoring SOPs that are described below for the upcoming CAD cell disposal events.

CAD cell capping 2010

Sandy material dredged during maintenance dredging of the eastern end of the Cape Cod Canal was used to cap the CAD cells in Boston Harbor in January to March 2010. No time of year restrictions or BMPs were required or implemented during this effort. About 20,800 cubic yards of sandy material was hauled by scow from the canal to Boston Harbor. This was similar to the 1999-2000 Canal maintenance dredging project when about 162,200 cubic yards of sandy material was dredged from the canal and hauled to Boston Harbor for capping the CAD cells in the Mystic River that were used for the main tributaries maintenance and deepening project.

Chelsea River Navigation Widening: 2012

The fisheries protection BMPs were used in the Chelsea River Navigation Widening effort in 2012. The Chelsea River widening involved dredging of about 33,100 cubic yards in the Chelsea River and dredged material placement into the Chelsea River CAD cell from February 2012-June 2012. While no formal monitoring was performed in association with the placement of dredged material into the Chelsea River CAD cells, no fisheries impacts were noted for that phase of work.

Boston Harbor Rock Removal: 2012

The fisheries protection BMPs as discussed above were used in the Boston Harbor Rock Removal Project in 2012. The rock removal project involved three blasting events in the Main Ship Channel of Boston Harbor in September of 2012. No fisheries impacts were noted during the blasting efforts.

Standard Operating Procedures

The following operating procedures will be followed during the placement of dredged material into the Main Ship Channel CAD cell in Boston Harbor between February 15 and July 15 of any given year:

1. A Fish Startle System

Fifteen (15) minutes prior to a disposal event, the Contractor will deploy the fish startle system on a vessel that allows for startle system coverage of the CAD cell area that will be used. The operation of the system will extend throughout the duration of the placement event. The fish startle equipment will be similar or approved equal to Electronic Fish Startle System (EFSS) produced by Sonalysts, Inc. (Waterford, CT). The fish startle system will be capable of deterring fish from the family Clupeidae (blueback herring, alewife) using high amplitude sound at specific frequencies.

2. Fisheries Observer & Sonar

A qualified fish observer will use hydroacoustic monitoring (i.e. side-scan sonar) prior to any placement event to ensure that schools of fish are not located within or transiting the placement area. The fish observer will scan the placement area from at least 30 minutes prior to a material placement event until the material is released from the scow. The scans will be performed 360o around the placement location. The side scan sonar generally covers 150 feet on either side of the vessel. The observer will make as many passes around the placement location as needed to feel confident there were no fish in the area. A minimum of two passes with no observed fish shall be conducted prior to approving the initiation of the placement.

The following plans will be followed before, during, and after placement events:

1. Fish Observer/Contractor Communication Plan

The contract specification on fish protection will clearly identify that it is the sole responsibility of the fish observer to determine when conditions are favorable for the placement of material into the CAD cell based on fishery observations. The fish observer will not give approval for initiation of the placement activity until s/he has determined, through use of appropriate technology, that no schools of fish are present in the placement area. However, it is recognized that the on-site safety officer has the authority and responsibility to override the fish observer’s determination at those times when either safety concerns or regulatory compliance becomes an issue. The specifications will outline required protocol and the need for clear and constant communication between the fish observer and the scow personnel.

2. Fish Observer Reports

The fish observer will prepare an after action report for all placement events monitored. The report will include the date and time monitoring was initiated, deployment and retrieval of the fish startle system, the time of the placement, current speed and direction, tidal conditions, and weather observations throughout the day, and other pertinent observations. The fish observer will note if fish were observed in the project area prior to placement and if there were any dead or injured fish after the event. If applicable, the fish observer will record the number of fish killed or injured, and species including representative sizes and weights. Any equipment or operational issues that may have contributed to the fish kill will also be noted.

The fish observer will report his/her findings to the Resident Engineer for each day of material placement. The Resident Engineer will compile the previous week’s reports and forward to the USACE Project Manager or Study Manager and the Environmental Resources Team Member. If a fish kill is observed, the Resident Engineer will notify the Project Manager or Study Manager and the Environmental Resources Team Member immediately. Pertinent information along with the fish observer’s report will be forwarded to the above parties as soon as possible. Based on the fish observer’s report, the Project Manager, or Study Manager, will convene a meeting with the Resident Engineer and appropriate personnel to discuss events and to determine what, if any, corrective actions can be taken to reduce the changes of further fish kills.

3. External Communication Plan

In the event of a fish kill, the Environmental Team Member will notify the appropriate resource agencies as soon as possible after the event. Additional communication will occur as soon as all pertinent facts and issues surrounding the event have been determined. In the case of the Boston Harbor Project, the NMFS, U.S. EPA, MA DEP, MA DMF, MA Coastal Zone Management Office, and Massport will receive a copy of the fish observers report along with other factual information. If determined necessary, a meeting and/or conference call will be scheduled between the Corps, Massport, and the resource agencies to discuss and identify potential corrective measures. These measures will then be forwarded along with the fish observer report to the agencies.

Assessment Summary

The fishery protection BMPs noted above, which were used to minimize impacts to fishery resources from the placement of dredged material into CAD cells in Boston Harbor, have proven effective in the BHNIP, IHMDP, and Chelsea River widening phases of the project. While the BMPs failed to fully protect fishery resources during four of the fourteen the blasting events associated with the IHMDP, changes in the methodology for the deployment of the fish startle system were effective in minimizing fisheries impacts in subsequent blasting events. The lessons learned from prior efforts in Boston Harbor have been incorporated into the existing SOPs and are anticipated to aid in the avoidance or minimization of impacts to fisheries resources in the project area.

References

Blaxtera1, J. H. S. and D. E. Hossa. 1981. Startle response in herring: The effect of sound stimulus frequency, size of fish and selective interference with the acoustico-lateralis system.

Journal of the Marine Biological Association of the United Kingdom, 61, pp 871-879.

D. Mann, D. Higgs, W. Tavolga, M.J. Souza, and A N. Popper. 2001. Ultrasound detection by clupeiform fishes. The Journal of the Acoustical Society of America. Vol. 109.6: 3048-3054.

ENSR, 2002. Boston Harbor Navigation Improvement Project Phase 2 Summary Report.

Prepares for US Army Corps of Engineers, 696 Virginia Road, Concord, MA 01742

USACE. April 2013. Final Supplemental Environmental Impact Statement (SEIS) for Boston Harbor. US Army Corps of Engineers, New England District, 696 Virginia Road, Concord, MA 01742.