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Shallow Hazards Survey Former Gas Light Company MGP Project Area
Gloucester Harbor, Gloucester, Massachusetts
Magnetic Contour Map Gloucester, Massachusetts
Prepared for:
ANCHOR QEA
26300 La Alameda, Suite 240 Mission Viejo, California 92691
Prepared by:
CR Environmental, Inc. 639 Boxberry Hill Road
East Falmouth, MA 02536
December 2013
2013 Shallow Hazards Survey December 2013 Gloucester Harbor MGP Project Area
639 Boxberry Hill Road, East Falmouth, MA 02536 Phone/Fax 508 563-7970 www.crenvironmental.com
i
TABLE OF CONTENTS
Page Number 1.0 INTRODUCTION…………………………………………………………………… 1 2.0 VESSEL & NAVIGATION ………………………................................................ 1 3.0 ACQUISITION AND DATA PROCESSING METHODS………………………. 2
3.1 Side Scan Sonar Acquisition ………………………………………………. 2 3.2 Side Scan Sonar Processing …….…………………………………............. 2
3.3 Sub-Bottom Profiling Acquisition ............................................................... 2 3.4 Sub-bottom Processing ……………………………………………………… 2
3.5 Magnetic Data Acquisition ………………………………………………….. 3
3.6 Magnetic Data Processing ...………………………………………………… 3
4.0 GIS PROCESSING AND DATA VISUALIZATION …………………………….. 3 5.0 SURVEY RESULTS ………………………………………….................................. 4 5.1 Side Scan Sonar Results …………………………………………………… 4
5.2 Sub-bottom Results ………………………………. ……………………….. 5
5.3 Magnetic Results …………………………………………………………… 6 6.0 CONCLUSIONS AND RECOMMENDATIONS ………………………………… 6 REFERENCES
2013 Shallow Hazards Survey December 2013 Gloucester Harbor MGP Project Area
639 Boxberry Hill Road, East Falmouth, MA 02536 Phone/Fax 508 563-7970 www.crenvironmental.com
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TABLE 1 Magnetic Anomalies Gloucester, MA FIGURES Figure 1 Survey Locus
Gloucester Inner Harbor, MA Figures 2 Side Scan Sonar Mosaic and Contacts Proposed Project Area,
Gloucester MGP Remediation Figure 3 Side Scan Sonar Mosaic and Contacts Remediation Support Area,
Gloucester MGP Remediation Figure 4 Depth to First Acoustic Reflector Overlaying Bathymetric Relief
Gloucester MGP Remediation
Figure 5 Total Field Magnetism Overlaying Bathymetric Relief Gloucester MGP Remediation APPENDIX A Side Scan Sonar Contact Report Gloucester, MA APPENDIX B Geophysical Survey Limitations
2013 Shallow Hazards Survey December 2013 Gloucester Harbor MGP Project Area
639 Boxberry Hill Road, East Falmouth, MA 02536 Phone/Fax 508 563-7970 www.crenvironmental.com
1
1.0 INTRODUCTION
Gophysical surveys of Gloucester Inner Harbor were conducted by CR Environmental, Inc. of East Falmouth, MA to support Massachusetts Contingency Plan Remediation for the former Gloucester Gas Light Company Manufactured Gas Plant. The geophysical investigations were conducted within the former Gloucester MGP Remediation Proposed Project Area Limit of Work and property to the north proposed for use as a Remediation Support Area on October 8 and 9, 2013 (Figure 1). Additional focused investigations of a charted wreck and two historic marine railways (one abandoned and one active) were conducted on October 10 and 11, 2013 (Figure 1).
Remote sensing technologies included: side scan sonar, sub-bottom profiling and magnetometry. Only side scan sonar was conducted at the proposed Remediation Support Area. CR also provided support for archaeological diver inspections and a sediment probing effort by DSRA in the vicinity of the marine railways.
The following Sections detail remote sensing data acquisition and processing methods and provide a summary of the survey results. All data have been delivered digitally in GIS compatible formats (where applicable) and have been projected to Massachusetts State Plane, NAD83, US Foot.
2.0 VESSEL AND NAVIGATION
Survey operations and diving support were performed from the 26-foot aluminum survey boat, RV Lophius equipped with a bow-mounted hydraulic A-frame, stern pilothouse, over-the-side transducer mount, and 12 volt power supplies.
Navigation for the surveys was accomplished using a Hemisphere VS-110 12-channel Differential Global Positioning System (DGPS) and Digital Compass system capable of receiving satellite-based differential corrections (SBAS) and U.S. Coast Guard (USCG) Beacon corrections. Trimble DGPS systems were available as necessary as backups. Both systems are capable of sub-meter horizontal position accuracy. The DGPS system was interfaced to a laptop computer running HYPACK MAX® hydrographic survey software. HYPACK MAX® continually recorded vessel position and DGPS satellite quality and provided a steering display for the vessel captain to accurately maintain the position of the vessel along pre-established survey transects and targets.
2013 Shallow Hazards Survey December 2013 Gloucester Harbor MGP Project Area
639 Boxberry Hill Road, East Falmouth, MA 02536 Phone/Fax 508 563-7970 www.crenvironmental.com
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3.0 ACQUISITION AND PROCESSING METHODS
3.1 Side Scan Sonar Acquisition
Side scan sonar data were acquired using an Edgetech, Inc., Model 4125 400/900-kHz system. Sonar controls and digital recording were conducted using Edgetech Discover software. Side scan data were recorded in both Edgetech .JSF and standard .XTF formats.
The majority of sonar data were collected using an 82 foot (25 meter) range scale. Survey transects spacing was set to 50 feet, resulting in a coverage of more than 200-percent (i.e., all portions of the seafloor imaged at least two times). Narrower swath settings were utilized for inspections of the reported wreck and marine railways. Swath width in the northern dredge area was set to 164 feet (50 meters) to allow imaging of portions of the area too shallow for safe navigation. Layback position offsets were recorded to the nearest foot and applied to data during post-processing. A draft sonar mosaic was produced in near real-time during the survey to ensure adequate survey coverage and to allow identification of noteworthy features.
3.2 Side Scan Sonar Processing
JSF side scan data were imported to Chesapeake Technology’s SonarWizMAP-Pro software. Bottom tracking was confirmed and moderate Time Varied Gain (TVG) adjustments were made to sonar data. Mosaics of side scan data were created and exported in georeferenced TIF format using a resolution of 0.2 feet per pixel. Individual GEOTIF files were generated for each file to facilitate construction of area-specific mosaics.
3.3 Sub-Bottom Profiling Acquisition
Sub-bottom sonar data were acquired along transects spaced 25 feet apart using an Edgetech 3200-XS (FSSB) profiling system interfaced to an SB-216S towfish. The transmit signal was a frequency modulated Chirp swept from 2 to 12 kHz using a 20 millisecond pulse. The offset between the towfish and the DGPS antenna was recorded to aid position correction during post-processing.
3.4 Sub-Bottom Profiling Processing
Sub-bottom data were processed using Chesapeake Technology’s SonarWizMAP-Pro software. Appropriate adjustments to TVG were made during processing. Sub-bottom profiles were exported in JPG format with accompanying GIS shapefiles (polylines) of transect navigation data.
2013 Shallow Hazards Survey December 2013 Gloucester Harbor MGP Project Area
639 Boxberry Hill Road, East Falmouth, MA 02536 Phone/Fax 508 563-7970 www.crenvironmental.com
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In order to characterize variations in surficial sediment thickness, the distance between the sediment surface and the first strong subsurface reflector was digitized, extracted in ASCII format and used to create georeferenced maps. The data from this effort has been delivered in grid and TIF formats.
3.5 Magnetic Data Acquisition
Magnetic data were collected simultaneously with the side scan and sub-bottom sonar data along the same survey transects. Magnetic data were acquired using a Marine Magnetics, Inc. Explorer high resolution marine magnetometer system. The magnetic data acquisition system consisted of a towfish-mounted Overhauser magnetic sensor and pressure/depth sensor, an onboard power supply and serial interface, and a data acquisition computer. The 1 Hz data stream from the magnetic sensor was routed to the HYPACK navigation computer via a serial port, and HYPACK recorded magnetic readings in nanoTeslas (1.0 gamma = 1 nanoTesla) as a separate field within the same raw data files containing navigation data. The position of the magnetometer towfish was calculated in real-time using a HYPACK mobile device driver which considered “cable out” relative to the DGPS antenna, the cable catenary curve, and the effects of vessel course corrections.
3.6 Magnetic Data Processing
Magnetometer data were processed using HYPACK’s Single-Beam Processor Module. Each magnetic survey transect was first inspected in profile format for characteristic signals which indicate the presence of ferrous anomalies (objects). Observed or suspected magnetic anomalies were digitized and used to create a GIS database which included the approximate anomaly location, amplitude and duration. After inspecting each data file, magnetic measurements were merged into a single ASCII comma-delimited database containing all total field (TF) magnetic intensity measurements. The database contained fields for Northing, Easting, and magnitude. This combined data set was imported to Golden Software, Inc. Surfer V.11 Surface Modeling Software. Grids of magnetic intensity were created using interpolation methods constrained by a search radius of 75 feet (>3 survey transects) and a 5 foot node interval. Contour maps were created from these grids depicting TF magnetism using a 2.0 nT contour interval and the maps were exported in SHP, TIF and ESRI FLT Raster formats.
4.0 GIS PROCESSING AND DATA VISUALIZATION
Processed data from each of the three sensors were imported to ESRI ArcGIS projects created for each sensor type. Relationships between digitized Contacts (side scan and sub-bottom), magnetic anomalies and textural variations suggested by side scan sonar were qualitatively assessed by
2013 Shallow Hazards Survey December 2013 Gloucester Harbor MGP Project Area
639 Boxberry Hill Road, East Falmouth, MA 02536 Phone/Fax 508 563-7970 www.crenvironmental.com
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redundantly adjusting each layer’s transparency or display order. The extensive overlap between side scan sonar data files allowed iterative data review at the approximate locations of digitized sonar Contacts and magnetic anomalies. This review was conducted through fine-scale (e.g., <1:200) review of individual georeferenced side scan sonar swaths in conjunction with contoured magnetic data.
Anchor QEA provided CR with a database of bathymetric sounding data which included coverage for the survey area. CR used these data to create a bathymetric surface suitable for analysis and visualization using GIS and IVS3D Fledermaus software. This bathymetric surface was used as a base layer upon which georeferenced side scan sonar and magnetic imagery were draped, and facilitated the characterization of textural and magnetic anomalies.
5.0 SURVEY RESULTS
The Sections below summarize remote sensing data results. Ground truth data such as, core sample characterizations, were not provided to aid the analysis of seabed conditions.
5.1 Side Scan Sonar Results
Side scan sonar data is invaluable for identification of objects which pose a hazard to remediation efforts or safe navigation. Side scan sonar data may also be used for semi-quantitative mapping of substrate characteristics when coupled with adequate ground truth data.
Sonar Interpretation Guide
Side scan sonar results are presented as mosaics of gray shaded imagery. The shade of gray corresponds to the strength of the returning signal and is used to infer bottom type (sediment texture) and to identify underwater structures or debris. A key to sonar shading is provided below.
Key to Side-scan Sonar Image Shading
Sonar shadow------------ Weak Signal Return-------------------------Strong Signal Return
2013 Shallow Hazards Survey December 2013 Gloucester Harbor MGP Project Area
639 Boxberry Hill Road, East Falmouth, MA 02536 Phone/Fax 508 563-7970 www.crenvironmental.com
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In general, weak signal returns correspond to smooth substrates (e.g., fine sediments with little microtopography), soft materials that absorb the signal, or topography that slopes away from the signal source (towfish). These features appear lighter gray in sonar imagery. Strong signal returns correspond to rough substrates (e.g., gravel, cobble), highly reflective materials, or to a topography that slopes towards the signal source. These features appear as dark gray to black in the sonar imagery.
Features that rise above the bed (e.g., boulders) reflect more of the sonar energy than the surrounding substrate resulting in strong signal returns due to the decreased angle of incidence. These features often prevent insonification of the area opposite the signal source, resulting in a sonar “shadow” (white imagery). The length of these shadows can be used to calculate the approximate height of the feature above the bed.
Mosaics of the 900 kHz side scan sonar data are shown on Figures 2 and 3 for the Proposed Remediation Project Area Limit of Work and the Remediation Support Area to the north, respectively. Digitized sonar Contacts and fish/lobster traps are identified on these Figures. High resolution imagery and mensuration for each Contact is provided in Appendix A. Debris, traps and tires were widespread throughout the survey areas. Debris density appeared highest in the nearshore northwestern portion of the Remediation Project Area Limit of Work. Anchor and chain scours are clearly visible in the anchorage area at the northeastern edge of the proposed project area limit of work.
Sonar data indicated that the charted wreck adjacent to the USCG Station was a large rock or area of ledge (Figure 2, and Contacts 12 and 23 in Appendix A). Subsequent observations made by a DSRA diver confirmed this characterization.
Side scan records also allowed mapping of those portions of the abandoned and active marine railways present above the mudline (Figure 2, and Contacts 26, 28, 30, 31 and 32 in Appendix A). These data were used to guide DSRA’s archaeological dive inspection of the railways. Data were also used to guide a probing effort focused on detection of buried portions of the railways.
5.2 Sub-Bottom Sonar Results
Sub-bottom sonar penetration depth below the seafloor to the first strong reflector ranged from approximately 0.5 feet to 16 feet (Figure 4). Intermittent deeper reflectors with characteristics consistent with bedrock or lodgment till were infrequently observed at depths greater than 20 feet beneath the harbor bottom. Data suggest the presence of entrained natural gases (byproducts of microbial activity) throughout the majority of the survey area. Exceptions include the areas
2013 Shallow Hazards Survey December 2013 Gloucester Harbor MGP Project Area
639 Boxberry Hill Road, East Falmouth, MA 02536 Phone/Fax 508 563-7970 www.crenvironmental.com
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adjacent to the USCG Docks and the marine railways where frequent prop turbulence and hull contact have likely minimized gas entrainment.
5.3 Magnetic Results
Total field (TF) magnetism and digitized anomalies are shown on Figure 5. Many anomalies were approximately co-located with debris or fishing gear (lobster traps) observed in side scan data (Table 1). Data did not indicate the presence of utilities or wreckage.
Magnetic data quality appeared to be influenced by several parameters outside of the control of the survey team. First and foremost, strong magnetic field interferences were associated with shoreline structures (e.g., cranes, sheet piles) and may have obscured some features of potential interest. It is also important to note that temporal (e.g., diurnal) fluctuations in the Earth's magnetic field associated with a coronal mass ejection occurred during the survey.
Lastly, the Gloucester / Cape Ann region has been charted as an area with anomalously high magnetic intensities of concern for navigators (see NOAA Chart 13274_5 Local Magnetic Disturbance Note). These properties are thought to be associated with the Nahant Gabbro formation which is projected to lie beneath the surficial Cape Ann Granite (e.g., Brady and Cheney, 2004). Both formations are iron rich with varying and potentially significant concentrations of magnetite.
6.0 CONCLUSIONS AND RECOMMENDATIONS
Remote sensing data (side scan sonar, sub-bottom profiling, and magnetometry) were acquired to support remediation and archaeological investigations. Acquisition and processing methods conformed to Performance Standards published by the US Army Corps of Engineers, NOAA and the International Hydrographic Organization. Geophysical survey limitations are provided in Appendix B.
Remote sensing data did not suggest the presence of buried utilities. Side scan sonar data allowed characterization of man-made objects within the project area, including active and abandoned marine railways and debris of potential interest to dredging contractors. Importantly, side scan data indicated that a NOAA charted wreck was actually a large rock (area of ledge or boulder). This was subsequently corroborated by a diver’s visual inspection.
Sub-bottom sonar penetration was generally limited by the assumed presence of a sub-surface layer of entrained gases. CR strongly suggests that profile data be quantitatively compared to available geotechnical and laboratory analytical data from cores and borings to:
2013 Shallow Hazards Survey December 2013 Gloucester Harbor MGP Project Area
639 Boxberry Hill Road, East Falmouth, MA 02536 Phone/Fax 508 563-7970 www.crenvironmental.com
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(1) Corroborate the presence of the entrained gas layer;
(2) Investigate potential correlations between sonar intensity (backscatter) and sediment texture; and
(3) Identify potential correlations between sonar data and separate phase contaminants which may be present in sub-surface strata.
Magnetic data were shown to be of sufficient sensitivity to detect low-magnitude anomalies such as lobster traps. Linear anomalies indicative of utilities were not observed in magnetic data. As previously noted, magnetic data quality and sensitivity was at times adversely affected by large ferrous shoreline structures or a magnetic storm. Nonetheless, these interferences are not judged to have impacted the sensor’s ability to detect buried pipelines or cables. Magnetic data appear to indicate fine-scale variations in either sediment composition or depth to bedrock. CR suggests that the magnetic surface layer delivered digitally could be used to investigate potential correlations with geotechnical parameters (e.g., depth to bedrock), and transformed to allow mapping of correlated strata of interest
The re-processed raw multibeam bathymetric and backscatter data collected by others was used to investigate correlations between CR’s remote sensing data and seabed morphology. Future bathymetric mapping needs should be discussed as the current bathymetric data were found to be non-compliant with the least stringent Performance Standards and, therefore, would not be suitable for remedial dredging operations or dredge volume estimates.
REFERENCES
Brady, J.B., and Cheney, J.T. (2004). The Cape Ann Plutonic Suite: A field trip for petrology classes. In Hanson, L.S., ed., Guidebook, 96th Annual Meeting of the New England Intercollegiate Geological Conference, Salem, Massachusetts, B1-B25
TABLES
ID X Y File Minimum Maximum Range Signature Duration (ft) SSS Contact
M-1 882994.6 3048058 061_1111 52560.45 52633.56 73.11 DP 22 No SSS Contact at surfaceM-2 882665.4 3048442 041_1448 52579.93 52612.68 32.75 DP 23 Near trap-like objectsM-3 882800.5 3048557 041_1448 52641.47 52663.07 21.6 DP- 12 Near trap-like objects and debris clusterM-4 882885 3048620 041_1448 52589.39 52649.77 60.38 MP- 18 No SSS Contact at surfaceM-5 882824 3048607 041_1512 52650.61 52687.3 36.69 MP- 17 No SSS Contact at surfaceM-6 883255.6 3048355 058_1055 52625.25 52670.67 45.42 DP 38 Fine debrisM-7 883147.6 3048151 062_1121 52575.64 52599.82 24.18 MP- Complex 45 Near trap-like objectsM-8 883102 3048114 062_1121 52593.3 52630.45 37.15 MP+ Complex 34 No SSS Contact at surfaceM-9 883183.8 3048507 052_1216 52655.79 52705.62 49.83 DP Complex 55 Fine debrisM-10 882960.2 3048546 045_1424 52655.05 52672.79 17.74 MP+ 20 Fine debrisM-11 882833.1 3048461 045_1424 52655.97 52677.53 21.56 MP+ 20 Near trap-like objects and debris M-12 883082.7 3048531 049_1428 52659.67 52695.1 35.43 DP 29 No SSS Contact but surrounded by debris and trapsM-13 883033.2 3048633 044_1432 52603.51 52654.31 50.8 DP 30 Fine debrisM-14 882706.2 3048453 042_1439 52603.68 52669.21 65.53 DP 28 Near trap-like objectsM-15 882836.5 3048621 040_1446 52625.03 52646.22 21.19 MP- 15 Co-Located with Probe P-16
Notes:
1. Magnetic values reported as nanoTeslas (nT).2. Grid: Massachusetts State Plane, NAD83, US Foot.
TABLE 1
Magnetic Anomalies Digitized from Raw ProfilesGloucester Inner Harbor Gloucester, Massachusetts
FIGURES
Survey LocusGloucester Inner Harbor, Massachusetts
881908
881908
882408
882408
882908
882908
883408
883408
883908
883908 3047
546
3048
046
3048
046
3048
546
3048
546
3049
046
3049
046
3049
546
3049
546
Figure 10 200 400
FeetNOTES:
1) Surveys conducted October 2013.2) Grid MA State Plane, NAD 83, US Foot.
:
Marine Railways
Designated Survey Area
")
")
")
")
")")
")
")
")
")
")
")
")
")
")
")
")
")")
")")
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")")
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")")
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")")
")")
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")")
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")") ")")
")")
")")
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#0
#0
#0
#0
#0#0
#0
#0
#0
#0
#0
#0
#0
#0#0#0
#0
#0
#0
#0
#0
#0 #0#0
Contact 9
Contact 8
Contact 7
Contact 6Contact 5
Contact 4
Contact 3
Contact 2
Contact 1
Contact 32 Contact 31Contact 30
Contact 28
Contact 26
Contact 24
Contact 23
Contact 18
Contact 16Contact 15
Contact 14
Contact 13
Contact 12
Contact 10Contact 17
882469
882469
882569
882569
882669
882669
882769
882769
882869
882869
882969
882969
883069
883069
883169
883169
883269
883269
883369
883369 3047
905
3048
005
3048
005
3048
105
3048
105
3048
205
3048
205
3048
305
3048
305
3048
405
3048
405
3048
505
3048
505
3048
605
3048
605
3048
705
3048
705
3048
805
3048
805
3048
905
3048
905
Figure 20 50 100FeetNOTES:
1) Survey conducted October 2013.2) Grid MA State Plane, NAD 83, US Foot.
:
#0 Sonar Contacts") Lobster Traps
Survey Area
900-kHz Side Scan Sonar Mosaic and ContactsProposed Project Area
Gloucester MGP Remediation
900-kHz Side Scan Sonar Mosaic and ContactsRemediation Support Area
Gloucester MGP Remediation
#0 #0
#0#0
Contact 22Contact 21
Contact 20Contact 19
882888
882888
882988
882988
883088
883088
883188
883188
883288
883288 3049
369
3049
469
3049
469
3049
569
3049
569
3049
669
3049
669
3049
769
3049
769
3049
869
3049
869
Figure 30 50Feet
NOTES:
1) Survey conducted October 2013.2) Grid MA State Plane, NAD 83, US Foot.
:
#0 Sonar ContactsSurvey Area
Depth Below Sediment Surface to First Acoustic Reflector(1.0 foot contour interval)
Overlaying Bathymetric Relief Gloucester MGP Remediation
882500
882500
882600
882600
882700
882700
882800
882800
882900
882900
883000
883000
883100
883100
883200
883200
883300
883300
3048
000
3048
000
3048
100
3048
100
3048
200
3048
200
3048
300
3048
300
3048
400
3048
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3048
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3048
500
3048
600
3048
600
3048
700
3048
700
3048
800
3048
800
3048
900
3048
900
Figure 40 50 100Feet
NOTES:
1) Survey conducted October 8, 2013.2) Grid MA State Plane, NAD 83, US Foot.
:
Survey Area
Total Field Magnetism(2.0 nT contour interval)
Overlaying Bathymetric ReliefGloucester MGP Remediation
#0
#0
#0
#0#0
#0
#0
#0
#0
#0
#0
#0
#0
#0
#0
M-9
M-8
M-7
M-6
M-5 M-4
M-3
M-2
M-1
M-14
M-13
M-12
M-11
M-10
882500
882500
882600
882600
882700
882700
882800
882800
882900
882900
883000
883000
883100
883100
883200
883200
883300
883300
3047
900
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3048
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3048
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3048
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3048
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3048
700
3048
700
3048
800
3048
800
3048
900
3048
900
Figure 50 50 100Feet
NOTES:
1) Survey conducted October 8, 2013.2) Grid MA State Plane, NAD 83, US Foot.3) Magnetic survey tracklines spaced 25 feet apart.
:
Survey Area#0 Magnetic Anomalies
2.0 nT Contours
APPENDIX A
Side Scan Sonar Contacts Gloucester MGP Remediation Study Area
Gloucester Side Scan Sonar
Contact Report
(Projection: MA83F)
Contacts in this report:
Contact 1 10/08/2013 12:14:32 42.6090783876 Lat -70.6567124906 Lon
Contact 2 10/08/2013 12:14:59 42.6094686342 Lat -70.6567861934 Lon
Contact 3 10/08/2013 12:15:44 42.6097150368 Lat -70.6562179306 Lon
Contact 4 10/08/2013 12:25:09 42.6101799827 Lat -70.6562705919 Lon
Contact 5 10/08/2013 12:31:02 42.6095821769 Lat -70.6575500587 Lon
Contact 6 10/08/2013 12:35:45 42.6095682576 Lat -70.6575648049 Lon
Contact 7 10/08/2013 12:39:26 42.6097102397 Lat -70.6574682647 Lon
Contact 8 10/08/2013 12:42:21 42.6103127550 Lat -70.6571518778 Lon
Contact 9 10/08/2013 12:43:07 42.6099807719 Lat -70.6579344366 Lon
Contact 10 10/08/2013 12:48:15 42.6104895342 Lat -70.6571474383 Lon
Contact 12 10/08/2013 12:53:56 42.6102069939 Lat -70.6583726962 Lon
Contact 13 10/08/2013 12:54:36 42.6103988542 Lat -70.6577724755 Lon
Contact 14 10/08/2013 12:58:40 42.6107324493 Lat -70.6579023564 Lon
Contact 15 10/08/2013 12:59:22 42.6104426578 Lat -70.6582505902 Lon
Contact 16 10/08/2013 12:59:38 42.6103867813 Lat -70.6584362977 Lon
Contact 17 10/08/2013 13:03:53 42.6103697391 Lat -70.6586366294 Lon
Contact 18 10/08/2013 13:03:40 42.6103043180 Lat -70.6588264600 Lon
Contact 19 10/08/2013 17:29:41 42.6132457134 Lat -70.6571890855 Lon
Contact 20 10/08/2013 17:29:57 42.6132394228 Lat -70.6569048357 Lon
Contact 21 10/08/2013 17:29:24 42.6131130315 Lat -70.6568737124 Lon
Contact 22 10/08/2013 17:30:31 42.6131443404 Lat -70.6564930513 Lon
Contact 23 10/08/2013 17:42:45 42.6101832887 Lat -70.6584108604 Lon
Contact 24 10/09/2013 18:34:58 42.6103807806 Lat -70.6588421968 Lon
Contact 26 10/09/2013 18:42:52 42.6108757436 Lat -70.6583848942 Lon
Contact 28 10/09/2013 18:46:05 42.6110215843 Lat -70.6583802266 Lon
Contact 30 10/09/2013 18:50:28 42.6109124159 Lat -70.6584144987 Lon
Contact 31 10/09/2013 18:52:46 42.6109072474 Lat -70.6582443358 Lon
Contact 32 10/09/2013 19:19:14 42.6109850097 Lat -70.6584065452 Lon
Contact 1
Contact Info: Contact 1 User Entered Info
• Sonar Time at Target: 10/08/2013 12:14:32
• Click Position (Lat/Lon Coordinates)
42.6090783876 -70.6567124906 (WGS84)
• Click Position (Projected Coordinates)
(X) 883183.82 (Y) 3048108.43
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008121414.jsf
• Ping Number: 4544
• Range to Target: 12.88 US Feet
• Fish Height: 4.02 US Feet
• Heading: 52.290 degrees
• Event Number: 0
• Water Depth: 2.99
• Line Name: 20131008121414
Target Height: = 0.6 US Feet
Target Length: 2.4 US Feet
Target Shadow: 1.9 US Feet
Target Width: 1.9 US Feet
Classification 1: trap
Classification 2:
Area:
Description: Typical lobster trap
Contact 2
Contact Info: Contact 2 User Entered Info
• Sonar Time at Target: 10/08/2013 12:14:59
• Click Position (Lat/Lon Coordinates)
42.6094686342 -70.6567861934 (WGS84)
• Click Position (Projected Coordinates)
(X) 883162.57 (Y) 3048250.45
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008121414.jsf
• Ping Number: 5299
• Range to Target: 20.63 US Feet
• Fish Height: 3.95 US Feet
• Heading: 56.290 degrees
• Event Number: 0
• Water Depth: 2.99
• Line Name: 20131008121414
Target Height: = 0.3 US Feet
Target Length: 9.0 US Feet
Target Shadow: 1.6 US Feet
Target Width: 5.3 US Feet
Classification 1: debris
Classification 2:
Area:
Description:
Contact 3
Contact Info: Contact 3 User Entered Info
• Sonar Time at Target: 10/08/2013 12:15:44
• Click Position (Lat/Lon Coordinates)
42.6097150368 -70.6562179306 (WGS84)
• Click Position (Projected Coordinates)
(X) 883314.66 (Y) 3048341.76
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008121414.jsf
• Ping Number: 6574
• Range to Target: 13.77 US Feet
• Fish Height: 4.14 US Feet
• Heading: 62.290 degrees
• Event Number: 0
• Water Depth: 3.00
• Line Name: 20131008121414
Target Height: = 0.3 US Feet
Target Length: 3.6 US Feet
Target Shadow: 1.0 US Feet
Target Width: 1.7 US Feet
Classification 1: trap
Classification 2:
Area:
Description: Typical lobster trap
Contact 4
Contact Info: Contact 4 User Entered Info
• Sonar Time at Target: 10/08/2013 12:25:09
• Click Position (Lat/Lon Coordinates)
42.6101799827 -70.6562705919 (WGS84)
• Click Position (Projected Coordinates)
(X) 883298.81 (Y) 3048511.06
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008122457.jsf
• Ping Number: 22596
• Range to Target: 14.21 US Feet
• Fish Height: 4.24 US Feet
• Heading: 250.300 degrees
• Event Number: 0
• Water Depth: 2.88
• Line Name: 20131008122457
Target Height: = 1.0 US Feet
Target Length: 6.8 US Feet
Target Shadow: 3.9 US Feet
Target Width: 1.0 US Feet
Classification 1: debris
Classification 2:
Area:
Description:
Contact 5
Contact Info: Contact 5 User Entered Info
• Sonar Time at Target: 10/08/2013 12:31:02
• Click Position (Lat/Lon Coordinates)
42.6095821769 -70.6575500587 (WGS84)
• Click Position (Projected Coordinates)
(X) 882956.54 (Y) 3048289.80
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008122958.jsf
• Ping Number: 30239
• Range to Target: 10.17 US Feet
• Fish Height: 5.01 US Feet
• Heading: 61.090 degrees
• Event Number: 0
• Water Depth: 2.66
• Line Name: 20131008122958
Target Height: = 0.0 US Feet
Target Length: 0.0 US Feet
Target Shadow: 0.0 US Feet
Target Width: 0.0 US Feet
Classification 1: buoy
Classification 2:
Area:
Description: Bouy mooring with chain and surface line
Contact 6
Contact Info: Contact 6 User Entered Info
• Sonar Time at Target: 10/08/2013 12:35:45
• Click Position (Lat/Lon Coordinates)
42.6095682576 -70.6575648049 (WGS84)
• Click Position (Projected Coordinates)
(X) 882952.62 (Y) 3048284.69
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008123340.jsf
• Ping Number: 34200
• Range to Target: 9.48 US Feet
• Fish Height: 4.38 US Feet
• Heading: 238.800 degrees
• Event Number: 0
• Water Depth: 2.73
• Line Name: 20131008123340
Target Height: = 0.0 US Feet
Target Length: 0.0 US Feet
Target Shadow: 0.0 US Feet
Target Width: 0.0 US Feet
Classification 1: buoy
Classification 2:
Area:
Description: Mooring and chain
Contact 7
Contact Info: Contact 7 User Entered Info
• Sonar Time at Target: 10/08/2013 12:39:26
• Click Position (Lat/Lon Coordinates)
42.6097102397 -70.6574682647 (WGS84)
• Click Position (Projected Coordinates)
(X) 882978.09 (Y) 3048336.69
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008123800.jsf
• Ping Number: 37335
• Range to Target: 18.24 US Feet
• Fish Height: 4.56 US Feet
• Heading: 68.800 degrees
• Event Number: 0
• Water Depth: 2.58
• Line Name: 20131008123800
Target Height: = 0.7 US Feet
Target Length: 8.2 US Feet
Target Shadow: 3.1 US Feet
Target Width: 4.2 US Feet
Classification 1: debris
Classification 2:
Area:
Description: Debris cluster. Likey tires and traps
Contact 8
Contact Info: Contact 8 User Entered Info
• Sonar Time at Target: 10/08/2013 12:42:21
• Click Position (Lat/Lon Coordinates)
42.6103127550 -70.6571518778 (WGS84)
• Click Position (Projected Coordinates)
(X) 883061.09 (Y) 3048557.10
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008124142.jsf
• Ping Number: 39804
• Range to Target: 5.66 US Feet
• Fish Height: 4.58 US Feet
• Heading: 238.300 degrees
• Event Number: 0
• Water Depth: 2.65
• Line Name: 20131008124142
Target Height: = 0.8 US Feet
Target Length: 5.6 US Feet
Target Shadow: 1.3 US Feet
Target Width: 5.4 US Feet
Classification 1: Mooring
Classification 2:
Area:
Description: Debris or mooring
Contact 9
Contact Info: Contact 9 User Entered Info
• Sonar Time at Target: 10/08/2013 12:43:07
• Click Position (Lat/Lon Coordinates)
42.6099807719 -70.6579344366 (WGS84)
• Click Position (Projected Coordinates)
(X) 882851.63 (Y) 3048434.04
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008124142.jsf
• Ping Number: 40446
• Range to Target: 16.88 US Feet
• Fish Height: 4.71 US Feet
• Heading: 244.600 degrees
• Event Number: 0
• Water Depth: 2.60
• Line Name: 20131008124142
Target Height: = 0.8 US Feet
Target Length: 8.6 US Feet
Target Shadow: 3.2 US Feet
Target Width: 6.7 US Feet
Classification 1: debris
Classification 2:
Area:
Description: Likely metallic debris
Contact 10
Contact Info: Contact 10 User Entered Info
• Sonar Time at Target: 10/08/2013 12:48:15
• Click Position (Lat/Lon Coordinates)
42.6104895342 -70.6571474383 (WGS84)
• Click Position (Projected Coordinates)
(X) 883061.65 (Y) 3048621.54
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008124607.jsf
• Ping Number: 44780
• Range to Target: 5.11 US Feet
• Fish Height: 4.41 US Feet
• Heading: 61.700 degrees
• Event Number: 0
• Water Depth: 2.75
• Line Name: 20131008124607
Target Height: = 0.6 US Feet
Target Length: 17.5 US Feet
Target Shadow: 0.9 US Feet
Target Width: 1.1 US Feet
Classification 1: debris
Classification 2:
Area:
Description:
Contact 12
Contact Info: Contact 12 User Entered Info
• Sonar Time at Target: 10/08/2013 12:53:56
• Click Position (Lat/Lon Coordinates)
42.6102069939 -70.6583726962 (WGS84)
• Click Position (Projected Coordinates)
(X) 882732.84 (Y) 3048515.32
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008125308.jsf
• Ping Number: 49583
• Range to Target: 8.97 US Feet
• Fish Height: 4.06 US Feet
• Heading: 66.190 degrees
• Event Number: 0
• Water Depth: 2.74
• Line Name: 20131008125308
Target Height: = 3.7 US Feet
Target Length: 8.5 US Feet
Target Shadow: 12.5 US Feet
Target Width: 6.3 US Feet
Classification 1: rock
Classification 2:
Area:
Description:
Contact 13
Contact Info: Contact 13 User Entered Info
• Sonar Time at Target: 10/08/2013 12:54:36
• Click Position (Lat/Lon Coordinates)
42.6103988542 -70.6577724755 (WGS84)
• Click Position (Projected Coordinates)
(X) 882893.73 (Y) 3048586.83
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008125308.jsf
• Ping Number: 50146
• Range to Target: 4.21 US Feet
• Fish Height: 4.36 US Feet
• Heading: 66.190 degrees
• Event Number: 0
• Water Depth: 2.86
• Line Name: 20131008125308
Target Height: = 0.0 US Feet
Target Length: 3.9 US Feet
Target Shadow: 0.0 US Feet
Target Width: 4.2 US Feet
Classification 1: tires
Classification 2:
Area:
Description: Typical tire
Contact 14
Contact Info: Contact 14 User Entered Info
• Sonar Time at Target: 10/08/2013 12:58:40
• Click Position (Lat/Lon Coordinates)
42.6107324493 -70.6579023564 (WGS84)
• Click Position (Projected Coordinates)
(X) 882857.56 (Y) 3048708.06
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008125805.jsf
• Ping Number: 53584
• Range to Target: 23.20 US Feet
• Fish Height: 4.28 US Feet
• Heading: 247.690 degrees
• Event Number: 0
• Water Depth: 2.96
• Line Name: 20131008125805
Target Height: >= 0.7 US Feet
Target Length: 8.1 US Feet
Target Shadow: 3.9 US Feet
Target Width: 3.9 US Feet
Classification 1: debris
Classification 2:
Area:
Description:
Contact 15
Contact Info: Contact 15 User Entered Info
• Sonar Time at Target: 10/08/2013 12:59:22
• Click Position (Lat/Lon Coordinates)
42.6104426578 -70.6582505902 (WGS84)
• Click Position (Projected Coordinates)
(X) 882764.86 (Y) 3048601.52
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008125805.jsf
• Ping Number: 54177
• Range to Target: 14.03 US Feet
• Fish Height: 4.18 US Feet
• Heading: 248.300 degrees
• Event Number: 0
• Water Depth: 2.96
• Line Name: 20131008125805
Target Height: = 0.0 US Feet
Target Length: 0.0 US Feet
Target Shadow: 0.0 US Feet
Target Width: 0.0 US Feet
Classification 1: debris
Classification 2:
Area:
Description: Debris cluster at end of pier
Contact 16
Contact Info: Contact 16 User Entered Info
• Sonar Time at Target: 10/08/2013 12:59:38
• Click Position (Lat/Lon Coordinates)
42.6103867813 -70.6584362977 (WGS84)
• Click Position (Projected Coordinates)
(X) 882715.07 (Y) 3048580.67
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008125805.jsf
• Ping Number: 54409
• Range to Target: 16.63 US Feet
• Fish Height: 3.33 US Feet
• Heading: 247.890 degrees
• Event Number: 0
• Water Depth: 2.95
• Line Name: 20131008125805
Target Height: >= 3.6 US Feet
Target Length: 6.4 US Feet
Target Shadow: 27.5 US Feet
Target Width: 6.9 US Feet
Classification 1: debris or rock
Classification 2:
Area:
Description:
Contact 17
Contact Info: Contact 17 User Entered Info
• Sonar Time at Target: 10/08/2013 13:03:53
• Click Position (Lat/Lon Coordinates)
42.6103697391 -70.6586366294 (WGS84)
• Click Position (Projected Coordinates)
(X) 882661.21 (Y) 3048573.93
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008130233.jsf
• Ping Number: 57990
• Range to Target: 13.11 US Feet
• Fish Height: 2.88 US Feet
• Heading: 71.590 degrees
• Event Number: 0
• Water Depth: 2.92
• Line Name: 20131008130233
Target Height: >= 3.4 US Feet
Target Length: 10.9 US Feet
Target Shadow: 24.8 US Feet
Target Width: 7.4 US Feet
Classification 1: rock and debris
Classification 2:
Area:
Description:
Contact 18
Contact Info: Contact 18 User Entered Info
• Sonar Time at Target: 10/08/2013 13:03:40
• Click Position (Lat/Lon Coordinates)
42.6103043180 -70.6588264600 (WGS84)
• Click Position (Projected Coordinates)
(X) 882610.34 (Y) 3048549.58
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008130233.jsf
• Ping Number: 57815
• Range to Target: 15.89 US Feet
• Fish Height: 2.10 US Feet
• Heading: 68.590 degrees
• Event Number: 0
• Water Depth: 2.95
• Line Name: 20131008130233
Target Height: = 0.0 US Feet
Target Length: 0.0 US Feet
Target Shadow: 0.0 US Feet
Target Width: 0.0 US Feet
Classification 1: debris
Classification 2:
Area:
Description: debris cluster and derelict pilings
Contact 19
Contact Info: Contact 19 User Entered Info
• Sonar Time at Target: 10/08/2013 17:29:41
• Click Position (Lat/Lon Coordinates)
42.6132457134 -70.6571890855 (WGS84)
• Click Position (Projected Coordinates)
(X) 883040.52 (Y) 3049625.87
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008172836.jsf
• Ping Number: 2744
• Range to Target: 21.24 US Feet
• Fish Height: 2.91 US Feet
• Heading: 48.090 degrees
• Event Number: 0
• Water Depth: 1.82
• Line Name: 20131008172836
Target Height: = 0.6 US Feet
Target Length: 29.2 US Feet
Target Shadow: 4.9 US Feet
Target Width: 0.0 US Feet
Classification 1: debris
Classification 2:
Area:
Description:
Contact 20
Contact Info: Contact 20 User Entered Info
• Sonar Time at Target: 10/08/2013 17:29:57
• Click Position (Lat/Lon Coordinates)
42.6132394228 -70.6569048357 (WGS84)
• Click Position (Projected Coordinates)
(X) 883117.05 (Y) 3049624.33
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008172836.jsf
• Ping Number: 2896
• Range to Target: 4.83 US Feet
• Fish Height: 4.66 US Feet
• Heading: 70.090 degrees
• Event Number: 0
• Water Depth: 1.80
• Line Name: 20131008172836
Target Height: = 2.1 US Feet
Target Length: 25.4 US Feet
Target Shadow: 3.6 US Feet
Target Width: 0.0 US Feet
Classification 1: debris
Classification 2:
Area:
Description: likely fallen pilings
Contact 21
Contact Info: Contact 21 User Entered Info
• Sonar Time at Target: 10/08/2013 17:29:24
• Click Position (Lat/Lon Coordinates)
42.6131130315 -70.6568737124 (WGS84)
• Click Position (Projected Coordinates)
(X) 883125.89 (Y) 3049578.35
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008172836.jsf
• Ping Number: 2585
• Range to Target: 14.47 US Feet
• Fish Height: 3.26 US Feet
• Heading: 353.100 degrees
• Event Number: 0
• Water Depth: 1.79
• Line Name: 20131008172836
Target Height: = 2.7 US Feet
Target Length: 6.5 US Feet
Target Shadow: 16.3 US Feet
Target Width: 1.8 US Feet
Classification 1: debris or rock
Classification 2:
Area:
Description:
Contact 22
Contact Info: Contact 22 User Entered Info
• Sonar Time at Target: 10/08/2013 17:30:31
• Click Position (Lat/Lon Coordinates)
42.6131443404 -70.6564930513 (WGS84)
• Click Position (Projected Coordinates)
(X) 883228.24 (Y) 3049590.77
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008172836.jsf
• Ping Number: 3216
• Range to Target: 22.00 US Feet
• Fish Height: 6.16 US Feet
• Heading: 73.900 degrees
• Event Number: 0
• Water Depth: 1.79
• Line Name: 20131008172836
Target Height: = 2.5 US Feet
Target Length: 19.7 US Feet
Target Shadow: 10.7 US Feet
Target Width: 10.2 US Feet
Classification 1: debris
Classification 2:
Area:
Description:
Contact 23
Contact Info: Contact 23 User Entered Info
• Sonar Time at Target: 10/08/2013 17:42:45
• Click Position (Lat/Lon Coordinates)
42.6101832887 -70.6584108604 (WGS84)
• Click Position (Projected Coordinates)
(X) 882722.65 (Y) 3048506.58
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131008174228.jsf
• Ping Number: 19060
• Range to Target: 3.69 US Feet
• Fish Height: 6.16 US Feet
• Heading: 284.700 degrees
• Event Number: 0
• Water Depth: 3.62
• Line Name: 20131008174228
Target Height: = 5.5 US Feet
Target Length: 10.4 US Feet
Target Shadow: 8.8 US Feet
Target Width: 8.8 US Feet
Classification 1: rock
Classification 2:
Area:
Description:
Contact 24
Contact Info: Contact 24 User Entered Info
• Sonar Time at Target: 10/09/2013 18:34:58
• Click Position (Lat/Lon Coordinates)
42.6103807806 -70.6588421968 (WGS84)
• Click Position (Projected Coordinates)
(X) 882605.83 (Y) 3048577.40
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131009183329.jsf
• Ping Number: 6130
• Range to Target: 9.07 US Feet
• Fish Height: 4.57 US Feet
• Heading: 267.790 degrees
• Event Number: 0
• Water Depth: 2.62
• Line Name: 20131009183329
Target Height: >= 7.4 US Feet
Target Length: 0.0 US Feet
Target Shadow: 32.6 US Feet
Target Width: 0.0 US Feet
Classification 1: piling
Classification 2:
Area:
Description: series of pilings
Contact 26
Contact Info: Contact 26 User Entered Info
• Sonar Time at Target: 10/09/2013 18:42:52
• Click Position (Lat/Lon Coordinates)
42.6108757436 -70.6583848942 (WGS84)
• Click Position (Projected Coordinates)
(X) 882727.15 (Y) 3048759.00
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131009184203.jsf
• Ping Number: 22479
• Range to Target: 10.74 US Feet
• Fish Height: 3.12 US Feet
• Heading: 342.790 degrees
• Event Number: 0
• Water Depth: 2.60
• Line Name: 20131009184203
Target Height: = 0.0 US Feet
Target Length: 0.0 US Feet
Target Shadow: 0.0 US Feet
Target Width: 0.0 US Feet
Classification 1: railway
Classification 2:
Area:
Description: Southwestern marine railway remnants
Contact 28
Contact Info: Contact 28 User Entered Info
• Sonar Time at Target: 10/09/2013 18:46:05
• Click Position (Lat/Lon Coordinates)
42.6110215843 -70.6583802266 (WGS84)
• Click Position (Projected Coordinates)
(X) 882727.88 (Y) 3048812.16
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131009184503.jsf
• Ping Number: 26512
• Range to Target: 3.25 US Feet
• Fish Height: 2.14 US Feet
• Heading: 331.700 degrees
• Event Number: 0
• Water Depth: 2.77
• Line Name: 20131009184503
Target Height: = 0.0 US Feet
Target Length: 0.0 US Feet
Target Shadow: 0.0 US Feet
Target Width: 0.0 US Feet
Classification 1: railway
Classification 2:
Area:
Description: Existing marine railway
Contact 30
Contact Info: Contact 30 User Entered Info
• Sonar Time at Target: 10/09/2013 18:50:28
• Click Position (Lat/Lon Coordinates)
42.6109124159 -70.6584144987 (WGS84)
• Click Position (Projected Coordinates)
(X) 882719.05 (Y) 3048772.28
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131009185009.jsf
• Ping Number: 33495
• Range to Target: 12.14 US Feet
• Fish Height: 3.13 US Feet
• Heading: 168.100 degrees
• Event Number: 0
• Water Depth: 2.73
• Line Name: 20131009185009
Target Height: = 0.0 US Feet
Target Length: 0.0 US Feet
Target Shadow: 0.0 US Feet
Target Width: 0.0 US Feet
Classification 1: railway
Classification 2:
Area:
Description: Southwestern marine railway remnants
Contact 31
Contact Info: Contact 31 User Entered Info
• Sonar Time at Target: 10/09/2013 18:52:46
• Click Position (Lat/Lon Coordinates)
42.6109072474 -70.6582443358 (WGS84)
• Click Position (Projected Coordinates)
(X) 882764.88 (Y) 3048770.85
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131009185159.jsf
• Ping Number: 37464
• Range to Target: 10.46 US Feet
• Fish Height: 2.82 US Feet
• Heading: 279.000 degrees
• Event Number: 0
• Water Depth: 2.88
• Line Name: 20131009185159
Target Height: = 0.0 US Feet
Target Length: 0.0 US Feet
Target Shadow: 0.0 US Feet
Target Width: 0.0 US Feet
Classification 1: railway
Classification 2:
Area:
Description: Existing marine railway
Contact 32
Contact Info: Contact 32 User Entered Info
• Sonar Time at Target: 10/09/2013 19:19:14
• Click Position (Lat/Lon Coordinates)
42.6109850097 -70.6584065452 (WGS84)
• Click Position (Projected Coordinates)
(X) 882720.93 (Y) 3048798.76
• Map Proj: MA83F
• Acoustic Source File: E:\Projects\DR-Gloucester\Glo-
SSS\All_Lophius_JSF\20131009191829.jsf
• Ping Number: 1043
• Range to Target: 19.68 US Feet
• Fish Height: 5.94 US Feet
• Heading: 322.500 degrees
• Event Number: 0
• Water Depth: 1.60
• Line Name: 20131009191829
Target Height: = 0.0 US Feet
Target Length: 0.0 US Feet
Target Shadow: 0.0 US Feet
Target Width: 10.3 US Feet
Classification 1: railways
Classification 2:
Area:
Description: Point between southwestern railway (left)
and existing railway (right). Upper portion of image is
southeast, bottom is shoreward. Width between rails is
approximately 10 ft.
APPENDIX B
Geophysical Survey Limitations
i
APPENDIX B
CR ENVIRONMENTAL, INC. LIMITATIONS FOR GEOPHYSICAL SURVEYS
The following general limitations apply to all geophysical surveys conducted by CR Environmental, Inc. or its subcontractors: Every attempt has been made to conduct this survey in such a fashion so as to maximize the quality of the data collected and the interpretations rendered. However, a geophysical investigation is an indirect method of exploration whereby subsurface characteristics are inferred or interpreted from measurements collected at the sediment surface. Many variables may affect these measurements. Due to the indirect, interpretive nature of geophysics, findings are generally considered precursory and subject to verification by more direct methods of investigation such as coring, test borings, drilling, etc. The following general limitations are considered when evaluating geophysical data. (1) Subsurface features can be interpreted from the appropriate geophysical methods only insofar as they produce a discernable geophysical signature. They must have adequate homogeneity, size, and appropriate physical or chemical properties sufficient to contrast with the surrounding medium and be within reasonable proximity to the sensors. Additionally, their signature must be distinguishable from and not masked by background noise or interference. (2) Lithologic data inferred on the basis of geophysical data may not be identical to geologic data. Some complex geological configurations may be impossible to resolve with surface geophysical methods. (3) CR cannot be responsible for losses caused through any misrepresentation of the data presented or the interpretation rendered for this project. CR has provided the data and interpretations presented in the report in good faith. CR is not responsible for any misuse of the data by the Client, its affiliates and/ or subcontractors. Use and Limitations of Survey Technologies Each of the three remote sensing technologies (i.e. , side-scan sonar, sub-bottom sonar, and magnetometer) has detection capabilities and limitations. Understanding these systems’ capabilities and limitations is essential to understanding how they affect data interpretation, and conclusions that may be drawn from the data. Co-located evidence of bottom features or anomalies using different technologies provides added detail and certainty. Generally surficial debris < 1 ft in any dimension is difficult to distinguish. In addition, small buried ferrous objects between magnetometer survey transect lines, and buried non-ferrous objects between sub-bottom survey lines cannot be detected.
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Side-scan sonar The towed side-scan sonar system provides complete coverage of the bottom in varying swath widths depending on the instrument’s frequency and water column characteristics. These swaths of data are pieced together to create mosaics providing a shaded image of the bottom based on the amplitude of the return signal and showing habitat features and substrate roughness and hardness. Side-scan sonar is an ideal instrument for identifying surficial obstructions and debris at the sediment surface. The forms and materials that make up obstructions and debris at the sediment mudline (the sediment-water interface) can be detected with side-scan sonar. Groundtruthing with grab sampling or video is important for substrate and image confirmation. The high frequency signal of the side-scan system does not substantially penetrate surficial sediments. Side-scan sonar data can be used to estimate the approximate dimensions of detected objects on the seabed, including object height above the mudline. These height measurements are made by measuring the length of sonar “shadows” behind objects, considering the height of the towfish and the corrected range to the object. The ability of the side-scan system to detect bottom features is related to several characteristics of the sonar system and the method of deployment. Integral system characteristics which influence image resolution include signal frequency, horizontal and vertical beam angles, signal (ping) duration, swath range selection, and operator adjustments of signal gain controls. The resolution and quality of sonar imagery is also influenced by towfish depth, vessel survey speed, the degree of overlap between survey transects, and water column characteristics. Based on the operations procedure detailed in this report, the approximate resolution of the side-scan sonar data collected for this project ranges from approximately 5 cm to 50 cm (about 2 to 20 inches), depending on the transect-specific settings. The positions reported for Contacts identified using side-scan sonar are subject to two uncertainties. The first uncertainty is associated with post-processing correction for the towfish layback (i.e., the distance between the DGPS antenna and the towfish). This correction has been applied to all data with demonstrable success. However, minor variations in vessel speed and towfish altitude can introduce some position uncertainty. The second Contact position uncertainty is integral to all side-scan sonar systems. The side-scan sonograph is a two-dimensional record of the strength of the return sonar signal. Raw sonar data is “slant-range” corrected by removing the water column portion of the sonograph. However, the two-dimensional nature of the data and the slant-range correction methods necessitate a geometric assumption of a flat seabed (horizontal bottom). For instance, consider a sonar transect which runs parallel to the shoreline near the toe of a substantially steep slope. Assume that the port channel is facing shoreward up the slope and that the sonar range is set to 82 feet. Because the sonar is recording the positions of bottom features using a range-calculation based on signal travel time, the reported “across-track” dimensions and position of a Contact observed mid-slope may be different than the actual position. Similarly, two objects at equal distance from the towfish (e.g., one object mid-slope at 50-foot range, another at the toe of the slope at 50-
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foot range) will overlap on the data record even though the true across-ground distance may be substantially different. This effect can introduce unwanted artifacts into the data. Sonar data acquired “up-slope” also results in decreased bottom grazing angles, shortening shadows associated with objects and skewing calculations of object height towards lower values. Additionally, more acoustic energy can be received on the up-slope channel, complicating classification of substrate reflectance relative to flat bottom areas The inverse of the uncertainties associated with the “flat-bottom” assumptions occurs with the down-slope oriented sonar channel. Sub-Bottom Sonar Sub-bottom sonar systems can be used to estimate the depth of various sediment strata or depth to bedrock, and can detect larger objects at or near the sediment surface. .The system used for this survey has been shown to penetrate and image up to 120 ft of sediment under ideal conditions. Sediment composition and geotechnical properties play a major role in determining sonar penetration. The acoustical impedance and sound absorption coefficient of sediments varies with grain size, pore space and several other characteristics, each of which influences penetration. Magnetometer A magnetometer was used to identify ferrous containing objects both above and below the sediment surface, and to determine if features identified by side-scan sonar (above the sediment surface) contained iron. The magnetometer employed for this survey allows discrimination of magnetic variations as low as 1 gamma. The magnitude of a magnetic anomaly detected depends on the ferrous mass of an object and its distance from the magnetometer. A list of common objects and the typical maximum magnetic anomaly that would be detected is provided below for reference: OBJECT NEAR DISTANCE FAR DISTANCE Ship (1000 tons) 300 to 700 gammas @100 ft 1 gamma @ 800 ft Automobile (1 ton) 40 gammas @ 30 ft 2 gammas @ 40 ft Pipeline (12 inch diameter) 50 to 200 gammas @ 25 ft 12 to 50 gammas @ 50 ft Fenceline 15 gammas @ 10 ft 1 to 2 gammas @ 25 ft File (10 inches long) 50 to 100 gammas @ 5 ft 5 to 10 gammas @ 10 ft (From G-881 Operating Manual 25831-OM, 2001) In addition to ferrous mass and distance, the orientation, composition and shape of a ferrous object influence the magnitude of the detected anomaly. For instance, a 12-inch pipeline will have a similar magnetic effect as 1 ton of iron at a range of about 50 ft. The position of the sensor relative to the object’s magnetic field and the orientation of the object on the seabed will influence the “shape” of the anomaly. For instance, consider an iron pipe lying flat on the seabed. If the magnetometer intersects only one lobe of the pipe’s magnetic field, the magnetic signature will likely be monopolar (i.e., in profile view, a positive or negative parabola), with the duration, response magnitude and tangent of the curve reflecting the size and proximity of the object. If the sensor intersects both
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lobes of the field, the response curve will appear dipolar (i.e., sinusoidal), with the actual position of the object corresponding to the midpoint between positive and negative responses. However, if the same pipe were embedded vertically in the sediment, even if the sensor is towed directly above the pipe, it is likely that the “shape” of the response in profile will be monopolar.