-
ConocoPhillips Global NVE Greenland LTD. 2012 Program Block 2
(Qamut)
2D-Seismic Survey
Final Environmental Impact Assessment
For submission to: Bureau of Minerals and Petroleum Imaneq 29
Post-box 930 3900 Nuuk Greenland Distribution: BMP: 1 Electronic
Copy and 1 Hard Copy ConcocPhillips: 1 Electronic Copy DONG
E&P: 1 Electronic Copy Nunaoil : 1 Electronic Copy 08 JUNE 2012
1113340084
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ConocoPhillips Global NVE Greenland Ltd - i - Environmental
Impact Assessment
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TABLE OF CONTENTS
SECTION PAGE
1 Introduction
..........................................................................................................................................................
1 1.1 Project Overview
......................................................................................................................................
1 1.2 Purpose and Structure of the Preliminary and Final EIA
........................................................................
1
2 Legal and Regulatory Setting
..............................................................................................................................
2 3 Project Description
..............................................................................................................................................
2
3.1 Scope of Work
.........................................................................................................................................
3 3.2 Alternatives Considered
..........................................................................................................................
6
4 Environmental
Baseline.......................................................................................................................................
7 4.1 Physical Environment
..............................................................................................................................
7
4.1.1 Introduction
.............................................................................................................................
7 4.1.2 Regional Setting
.....................................................................................................................
7 4.1.3 Marine Weather
......................................................................................................................
8 4.1.4 Oceanography
......................................................................................................................
10 4.1.5 Ice Climatology
.....................................................................................................................
16
4.2 Biological Environment
..........................................................................................................................
20 4.2.1 Plankton
...............................................................................................................................
20 4.2.2 Invertebrates
........................................................................................................................
21 4.2.3 Marine Fish
...........................................................................................................................
21 4.2.4 Seabirds
...............................................................................................................................
22 4.2.5 Marine Mammals
..................................................................................................................
23 4.2.6 Protected Areas
...................................................................................................................
28 4.2.7 Species of Concern
..............................................................................................................
29
4.3 Land and Sea Use
.................................................................................................................................
29 4.3.1 Commercial Fisheries
..........................................................................................................
29 4.3.2 Subsistence Fishing
.............................................................................................................
30 4.3.3 Subsistence Hunting
............................................................................................................
30 4.3.4 Other Vessel Traffic
.............................................................................................................
31
5 Methods Used for the Environmental Impact Assessment
...............................................................................
32 5.1 Purpose and Approach
..........................................................................................................................
32 5.2 Scope of Assessment
............................................................................................................................
33
5.2.1 Selection of Valued Ecosystem Component
.......................................................................
33 5.2.2 Interaction of Project with the Environment
.........................................................................
33 5.2.3 Temporal and Spatial Boundaries of the Assessment
........................................................ 34 5.2.4
Determining Impact Significance
.........................................................................................
34
6 Potential Impacts and Project Mitigation
...........................................................................................................
35 6.1 Effects of Airborne Emissions from Project Vessels
.............................................................................
35 6.2 Effects of Discharges from Project Vessels
..........................................................................................
37 6.3 Effects of Underwater Sound on the Marine
Environment....................................................................
40
6.3.1 Introduction
...........................................................................................................................
40 6.3.2 Overview of Sound Terminology
..........................................................................................
40 6.3.3 Project Sound Sources
........................................................................................................
40 6.3.4 Acoustic Behaviour in Arctic Waters
....................................................................................
40 6.3.5 Underwater Acoustic Modelling
...........................................................................................
40 6.3.6 Marine Invertebrates
............................................................................................................
41 6.3.7 Marine Fish
...........................................................................................................................
42 6.3.8 Marine Birds
.........................................................................................................................
44 6.3.9 Commercial Fisheries
..........................................................................................................
44 6.3.10 Subsistence Hunting and Fishing
........................................................................................
45 6.3.11 Marine Mammals
..................................................................................................................
45
6.4 Effects of Vessel Traffic
.........................................................................................................................
58 6.5 Effects of Vessel Lighting
......................................................................................................................
61 6.6 Effects of Introduced Species from Ballast Water Exchange
............................................................... 62
6.7 Effects of Unplanned Events and Accidental Spills
..............................................................................
63
7 Cumulative Effects Assessment
.......................................................................................................................
67 7.1 Introduction
............................................................................................................................................
67 7.2 Methods
.................................................................................................................................................
68 7.3 Results
...................................................................................................................................................
69 7.4 Interpretation and Mitigation
..................................................................................................................
70
7.4.1 Identification of Mitigation Measures
...................................................................................
70 7.4.2 Determination of Significance
..............................................................................................
70
8 Environmental Protection Plan
..........................................................................................................................
74
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ConocoPhillips Global NVE Greenland Ltd - ii - Environmental
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8.1 Introduction
............................................................................................................................................
74 8.2 Environmental Policy during the Project
...............................................................................................
74 8.3 Standards, Controls, Consultation and Notification
..............................................................................
75 8.4 Plans Included in or Related to the Environmental Protection
Plan ..................................................... 76
8.4.1 Safe Operations Plan
...........................................................................................................
76 8.4.2 Simultaneous Operations Plan
............................................................................................
76 8.4.3 Waste Management Plan
.....................................................................................................
77 8.4.4 Ballast Water Management Plan
.........................................................................................
77 8.4.5 Fuel Spill Response Plan
.....................................................................................................
77 8.4.6 Marine Mammal and Seabird Observation Program
........................................................... 78
8.4.7 Passive Acoustic Monitoring Plan
........................................................................................
78 8.4.8 Ice Management Plan
..........................................................................................................
79 8.4.9 Emergency Response Plan
.................................................................................................
79 8.4.10 Fisheries Impact Management Plan
....................................................................................
80 8.4.11 Environmental Studies Plan
.................................................................................................
80 8.4.12 Mitigation Reporting/Oversight Plan
....................................................................................
80
9 Study Limitations and Future Research
............................................................................................................
80 9.1 Study Limitations and Data Gaps
..........................................................................................................
80 9.2 Future Research
....................................................................................................................................
81
LIST OF TABLES
Table 3.1-1 Survey Data
....................................................................................................................................
5 Table 3.1-2 Array Specification
..........................................................................................................................
5 Table 3.1-3 Acoustic Properties of the Airgun Array
.........................................................................................
6 Table 3.1-4 Specifications of PAM System
........................................................................................................
6 Table 4.1-1 Qamut Block Wind Statistics from MSC50 Hindcast Data
Node M3018543 ................................. 9 Table 4.1-2 Qamut
Block Wave Statistics from the MSC50 Hindcast Data Node M3018543
........................ 16 Table 4.2-1 Overview of Seabird Species
Found within the Qamut Block
...................................................... 24 Table
4.2-2 Overview of Marine Mammal Species found within the Qamut
Block ......................................... 27 Table 4.2-3
Summary of Species of Concern Potentially Occurring in the Qamut
Block ............................... 29 Table 5.2-1 Matrix
Combining Impact Consequence and Probability to Determine Overall
Impact
Significance
...................................................................................................................................
35 Table 6.1-1 Estimated Fuel Consumption for Seismic Survey and
Support Vessels during the
Proposed 2012 Program
...............................................................................................................
36 Table 6.1-2 Total Air Emissions for the Proposed 2012 Program
...................................................................
36 Table 6.1-3 Total Greenhouse Gas Emissions for the Proposed 2012
Program ........................................... 36 Table 6.1-4
Summary of Impacts from Airborne Emissions on Air Quality
..................................................... 37 Table
6.2-1 Types of Waste Potentially Generated from the Project Vessels
................................................ 38 Table 6.2-2
Summary of Impacts from Discharges on VECs
..........................................................................
39 Table 6.3-1 Summary of Impacts from Seismic Sound on Marine
Invertebrates, Marine Fish,
Seabirds, and Subsistence Hunting and Fishing
.........................................................................
44 Table 6.3-2 Summary of Impacts from Seismic Sound on Marine
Mammals ................................................. 54 Table
6.3-3 Summary of Impacts from Vessel Sounds on Marine Mammals
................................................. 58 Table 6.4-1
Summary of Impacts from Vessel Traffic on VECs
......................................................................
61 Table 6.5-1 Summary of Impacts from Vessel Lighting on Seabirds
.............................................................. 62
Table 6.6-1 Summary of Impacts from Ballast Water Exchange on VECs
..................................................... 63 Table
6.7-1 Summary of Impacts from Minor Unplanned Events and Accidental
Spills on VECs ................. 66 Table 6.7-2 Summary of Impact
from Major Unplanned Events and Accidental Spills on VECs
................... 67 Table 7.3-1 Areas Affected by cSEL in Qamut
Block and RSA
......................................................................
70 Table 7.4-1 Summary of Cumulative Impacts from Seismic Sound on
Marine Mammals and Fish on
a Regional Level
...........................................................................................................................
71
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LIST OF FIGURES
Figure 3.1-1 Proposed 2D Seismic Survey Location
........................................................................................
82 Figure 3.1-2 Seismic Source Layout
.................................................................................................................
83 Figure 3.1-3 Geometry of Airgun Array (Starboard)
.........................................................................................
84 Figure 3.1-4 3,940 in³ Array Far-field Pressure Signature
................................................................................
85 Figure 3.1-5 Frequency Spectrum Including Surface Ghost
............................................................................
86 Figure 4.1-1 Regional Setting for the Project
....................................................................................................
87 Figure 4.1-2 Mean Temperature for February (left) and August
(right)
............................................................ 88
Figure 4.1-3 Mean Annual Air Temperature at West Greenland Weather
Stations ......................................... 88 Figure 4.1-4
Time Series of the Winter (December to March) Index of the NAO from
1865/1866 to
2010/2011
.....................................................................................................................................
89 Figure 4.1-5 Wind Roses at Selected Locations in Northeast
Baffin Bay ........................................................
89 Figure 4.1-6: Qamut Block Wind Distribution from the MSC50
Hindcast Data Node M3018543 ..................... 90 Figure 4.1-7
Frequencies of Fog at Three West Greenland Stations
............................................................... 91
Figure 4.1-8 General Ocean Surface Circulation around Greenland
............................................................... 92
Figure 4.1-9 Model Currents at 50 Metres (Tang Model)
.................................................................................
93 Figure 4.1-10 Qamut Licence Area 29 Days Maximum Tidal Range
.................................................................
94 Figure 4.1-11 Qamut Licence Area 29 Days Maximum Tidal Current
Magnitude and Direction ....................... 94 Figure 4.1-12
Qamut Temperature and Salinity Profiles during Summer
.......................................................... 95
Figure 4.1-13 Fronts of West Greenland Shelf Large Marine
Ecosystems ........................................................
96 Figure 4.1-14 Sound Speed Profiles typical of Oceanic Conditions
in Arctic Waters ........................................ 97 Figure
4.1-15 Qamut Block Wave Distribution from the MSC50 Hindcast Data
Node M3018543 .................... 98 Figure 4.1-16 Mean Monthly
Extent of the North Water Polynya
.......................................................................
99 Figure 4.1-17 Major Iceberg Sources and General Drift Pattern in
West Greenland Waters .......................... 100 Figure 4.2-1
Distribution of Important Bird Species in Baffin Bay
..................................................................
101 Figure 4.2-2 Seasonal Distribution and Migratory Routes of
Narwhal in West Greenland and the
Eastern Canadian Arctic
.............................................................................................................
102 Figure 4.2-3 Beluga Migration Routes and Wintering Grounds in
Baffin Bay Region .................................... 103 Figure
4.2-4 Seasonal Distribution and Migratory Movements of Bowhead
Whales in Northwest
Greenland
...................................................................................................................................
104 Figure 4.2-5 Seasonal Distribution of Walrus in Baffin Bay
............................................................................
105 Figure 4.2-6 Summer (July to September) Home Range for Polar
Bears (Baffin Bay Sub-Population)
from 1991 to 1997
.......................................................................................................................
106 Figure 4.2-7 Protected Areas in Northwest Greenland
...................................................................................
107 Figure 4.3-1 Annual Revenue Generated by the Northern Shrimp
and Greenland Halibut Fisheries
in Greenlandic Waters between 2008 and 2010
........................................................................
108 Figure 4.3-2 Overview of Commercial Fisheries in Northeast
Baffin Bay ......................................................
109 Figure 6.3-1 Source-path-receiver Model
.......................................................................................................
110 Figure 6.3-2 Underwater Sound Propagation of a Marine Seismic
Survey .................................................... 110
Figure 7.2-1 Seismic Survey Lines (red lines) and VSP Source
Location (red circle) for the
Aggregate cSEL Scenario.
.........................................................................................................
110 Figure 7.2-2 Sources (red circles) and Receivers (green
triangles) for the Model Transects that
Extend beyond the RSA.
............................................................................................................
111
LIST OF APPENDICES
Appendix A Acronyms, Glossary and References Appendix B
International and Local Legal Framework Appendix C Physical
Environment Appendix Appendix D Acoustics Technical Report Appendix
E Summary of Selected Valued Ecosystem Components Appendix F
Environment Interaction Matrix Appendix G Impact Assessment
Terminology Appendix H Decision Tree for Assessment of Impact
Consequence Appendix I Summary of Project Mitigation and
Environmental Protection Plans Appendix J Marine Mammal and Seabird
Observation and Passive Acoustic Monitoring Plans
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1 Introduction
ConocoPhillips Global NVE Greenland Ltd., DONG E&P Grønland
A/S and Nunaoil A/S (referred to collectively as “ConocoPhillips”)
are pleased to submit an Environmental Impact Assessment (EIA) to
the Bureau of Minerals and Petroleum (BMP) for a proposed
2D-seismic survey in Block 2 (Qamut Block). This region is located
in northeast Baffin Bay, licence number 2011/11. The 2D-siesmic
survey would occur from early August to mid-September 2012, with
the option of extending to 1 October 2012 if ice conditions,
weather conditions, sea state or other factors delay the
program.
This report describes the “Final EIA”. It was prepared by
revising or amending the EIA that was submitted to BMP in mid-March
2012. A non-technical summary in English, Greenlandic and Danish
was submitted at the same time. That version of the EIA will be
referred to as the “Preliminary EIA”. BMP released the Preliminary
EIA Report to the public for a consultation period that was eight
weeks in length. ConocoPhillips’s responses to Information Requests
from this consultation with stakeholders and communities formed the
basis for producing the Final EIA.
The Final EIA Report has been prepared by Golder Associates A/S
and INUPLAN A/S, in consultation with ConocoPhillips. It was
produced in accordance with the January 2011 BMP “Guidelines for
preparing an Environmental Impact Assessment [EIA] report for
activities related to hydrocarbon exploration and exploitation
offshore Greenland” and December 2011 BMP “Guidelines for
application, execution and reporting of offshore hydrocarbon
exploration activities (excluding drilling) in Greenland”,
including Appendix G (“Guidelines to environmental impact
assessment of seismic activities in Greenland waters”, 3rd revised
edition) prepared by Danish Center for Environment and Energy
(DCE).
ConocoPhillips is aware that Block 2 (Qamut) is closer to the
Melville Bay Reserve than other licence areas. It also recognizes
that there is an overlap of the proposed seismic survey region with
Narwhal Protection Zone I (NPZ-I) in northeast Baffin Bay, where
“seismic activities shall be avoided or of limited extent (a few
widely spaced (>10 km) lines)”, and consequently, if operations
occur in NPZ-I between 1 June and 15 October, that “a detailed
shooting program is subject to BMP approval, and if approved,
impact studies on narwhal shall be considered” (NERI 2010).
ConocoPhillips is concerned about the possible effects of
underwater sound on marine mammals during the survey period
mentioned above. It will support programs carried out on these
effects by DCE and the Greenland Institute of Natural Resources
(GINR). ConocoPhillips understood before submission of the
Preliminary EIA that more discussion with BMP or DCE about seismic
operations in NPZ-I would be necessary during the application
process, and that it was important to address all aspects of this
subject in a proper and appropriate way. This situation was taken
into account during preparation of the Final EIA.
ConocoPhillips looks forward to applying its experience from
many years of operations in Alaska and other northern locations to
exploration activities in northeast Baffin Bay. It welcomes the
opportunity to interact and engage with members of communities, the
authorities, and other stakeholders about the seismic survey
proposed for 2012.
1.1 Project Overview
The proposed exploration program in northeast Baffin Bay during
2012 involves a 2D-seismic survey in the central part of Block 2
(Qamut). This program, referred to as “the Project” below, is
described in Section 3 of this report. ConocoPhillips Global NVE
Greenland Ltd is “Operator” during exploration activity in Qamut
Block. DONG E&P Grønland A/S is a “Partner”; Nunaoil A/S is a
“Partner” as well.
1.2 Purpose and Structure of the Preliminary and Final EIA
An EIA has been performed on the Project because BMP decided
that it has the potential to have significant impacts on the
environment, either by itself, or in combination with other planned
exploration activity, in northeast Baffin Bay this year. This
decision was made after ConocoPhillips submitted a detailed Scope
of Project Report to BMP on 1 February 2012.
The offshore setting of the Project, and the nature of the
exploration activity that would occur during the Project, have a
strong influence on the purpose and structure of the EIA. It has
three objectives: determine if the Project will have an effect on
the marine environment in a specific and broader sense of potential
impact; identify the
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ConocoPhillips Global NVE Greenland Ltd - 2 - Environmental
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extent of possible effects; and develop or specify means to
mitigate, or reduce where possible, the identified possible
effects. Possible effects of the environment on the Project are
also addressed.
To meet the objectives mentioned above, the physical and
biological environments, and land & sea use in Qamut Block,
were described from a local and regional point of view. A project
description was also developed. A summary of the national and
international legal frameworks that provide guidance and set limits
on the Project, and on methodology used for impact assessment, was
prepared. An assessment was performed on the Project, including
potential impacts of the exploration program on the marine
environment at local and regional scale, as well as cumulative
effects and trans-boundary effects. Other work was conducted during
preparation of the Preliminary EIA, including acoustic modeling to
investigate cumulative effects from multiple operations occurring
at the same time in northeast Baffin Bay, and assembly of an
Environmental Protection Plan (EPP) for the Project. This plan was
based on the assessment, on regulatory requirements in Greenland,
and on “best practice” in other jurisdictions.
After the Preliminary EIA Report was submitted to BMP in
mid-March 2012, it was released to communities, agencies, and other
stakeholders by posting on for a review and consultation process
that was eight weeks long. Responses to Supplemental Information
Requests that resulted from this process were used to prepare the
Final EIA. BMP will make a recommendation about the Final EIA to
the Greenland Government. A decision will be made by the Greenland
Government to approve the Project, in whole or in part, with or
without conditions, and grant a licence for it to proceed.
The Final EIA Report is structured as follows:
• Section 2 provides a brief overview of the Greenland and
International legal and regulatory frameworks.
• Section 3 introduces the Project activities, location, survey
plan and other details; provides BMP’s required tables (four in
total), and describes alternatives considered during design of the
Project.
• Section 4 presents the exisiting physical and biological
environment as well as land & sea use in the Project area.
• Section 5 describes the impact assessment methodology, and how
the assessment was performed.
• Section 6 presents the impact assessment on the residual
effects from project activities on valued ecosystem components
(VECs).
• Section 7 describes acoustic modeling and assessment of
cumulative effects of underwater sound on marine mammals and fish
in a regional setting.
• Section 8 contains the Environmental Protection Plan (EPP),
including the mitigation measures that ConocoPhillips will be
applying to Project activities.
• Section 9 describes data gaps and subjects for research that
were identified during the assessment process.
Figures are located at end of the main text before a series of
appendices. Please refer to these appendices for references, a list
of acronyms and abbreviations, a glossary,a summary of the legal
and regulatory frameworks, a technical report on acoustic
modelling, supporting information on EIA methodology, a summary of
project mitigation measures, a Marine Mammal and Seabird
Observation (MMSO) Plan, and a table with attachments containing
ConocoPhillips’s responses to Supplemental Information
Requests.
2 Legal and Regulatory Setting
Greenlandic legislation, regulations and guidelines applicable
to the Project are listed in Appendix B. Table B-1.
Greenland and Denmark are signatories to a number of
international agreements and thus have obligations under several
international conventions with regards to the use, administration,
and protection of the environment and wildlife. Those potentially
applicable to seismic surveys in Greenlandic waters are described
in Appendix B, Table B-2.
3 Project Description
The section provides, in accordance with BMP Guidelines
(December 2011 version, including Appendix G), a description of the
proposed exploration activity, the area where this work will occur,
schedule, and equipment and materials for the 2D-seismic survey
that ConocoPhillips is proposing to undertake in Qamut Block. Table
3.1-1
http://www.nanoq.gl/�
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ConocoPhillips Global NVE Greenland Ltd - 3 - Environmental
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08 June 2012
contains the details that BMP has requested on the seismic
survey. This table, and the other three tables that are specified
in the Guidelines, are found at the end of Section 3.1. The
location of the survey is shown in Figure 3-1, including a lay-out
of the planned seismic lines. This survey grid is a modification of
the survey grid that was included in the Preliminary EIA Report.
This change was agreed to at a meeting between ConocoPhillips and
DCE in Copenhagen on 22 May 2012. The reasons for this change are
described in more detail below.
3.1 Scope of Work
The offshore exploration program that ConocoPhillips is
proposing for West Greenland in 2012 is a 2D-seismic survey in
northeast Baffin Bay, including collection of marine gravity and
magnetic data. Roughly 3,000 line-kilometres (line-km) of high
quality 2D-seismic reflection data, as well as marine gravity and
magnetic data, will be collected in the survey region during the
Project. ConocoPhillips will use this data to conduct a detailed
geological and geophysical evaluation of the license area.
The Project location will be in the central, eastern and
northern parts of the Qamut Block. The survey region extends into
the west-central part of Narwhal Protection Zone I (NPZ-I) and
northern part of NPZ-II.
Four sail lines extend slightly north of the licence area
boundary for line-tie purposes. During preparation of the
Preliminary EIA, ConocoPhillips discussed the possibility of
obtaining a supplementary or additional exploration licence for the
tie-in lines with BMP. It was decided that an extra licence would
not be required for this part of the survey.
The portion of the survey that is located in NPZ-I was discussed
at a meeting between ConocoPhillips and DCE in Copenhagen on 22 May
2012. This part of the survey has been changed, which
ConocoPhillips brought to BMP’s attention after the meeting with
DCE. It was agreed that modifying the survey grid in NPZ-I would
address concerns about proximity to the Melville Bay Reserve, line
spacing in NPZ-I, and possible impacts of underwater sound on
narwhals during the seismic survey period.
The background and basis for the modification is as follows:
ConocoPhillips believes that two of the primary sub-surface targets
(possible hydrocarbon reservoirs) in the Qamut licence area extend
into the region that is part of NPZ-I. To mature these leads, and
determine whether or not an exploration well is justified,
additional seismic data in the form of either a 3D survey or an
approximately one km by one km 2D-seismic survey is required.
ConocoPhillips decided to pursue the 2D solution. In order to limit
exposure to underwater sound in the NPZ-I area, the 2D survey plan
has been altered to cover only the area occupied by the identified
leads, leaving a small number of widely-spaced 2D lines for
regional mapping. Two measures are being implemented in this
regard:
• The total amount of seismic data within NPZ-I will be reduced
by removing every other north-south line in the area between the
mapped leads. This effectively removes roughly 100 line-km of
acquisition from the survey. To meet the licence obligation of
acquiring 3,000 line-km of 2D-seismic data, ConocoPhillips will add
roughly 100 line-km of acquisition to the area southwest of the
NPZ-I boundary.
• Great effort will be expended to execute a shooting pattern
that alternates operations inside NPZ-I with operations outside
NPZ-I. The goal is to not operate continuously in NPZ-I for long
periods of time.
The proposed schedule for the Project is early August to
mid-September, with an option of extending it to 1 October if the
seismic survey is delayed by weather conditions, ice conditions,
sea state, or other factors. It would proceed for four to six
weeks, and take place 24 hours per day, seven days per week based
on safe operations when sea ice is not present.
Three vessels have been chartered to carry out the Project,
including: one ice-class seismic survey ship; one ice-class chase
vessel; and one support and re-supply vessel. The CGGVeritas M/V
Princess will be used to conduct the 2D-seismic survey (including
collection of marine gravity and magnetic data). The chase ship and
support/re-supply ship will be the M/V Thor Supplier and the M/V
Thor Beamer, respectively. This information was mentioned in the
Preliminary EIA. In early June 2012, it was necessary for
ConocoPhillips to change these ships. They have been replaced by
equivalent vessels, including the Artemis Angler as the seismic
ship, F/F Meredian as the chase ship, and MV Arctic Star as the
support/re-supply ship (which may act as a second chase ship). The
airgun array and single streamer that will be used by the Artemis
Angler will be identical to the airgun array and single streamer
that would have been used by the Princess. CGGVeritas will also
continue to be the seismic contractor for the survey.
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ConocoPhillips decided that the Final EIA would not be altered
to reflect this change in the fleet, since it was an operations
planning adjustment that is not uncommon during seismic surveys
when release of a ship, or ships, from a previous charter has been
delayed, or when any or all of the proposed ships are not available
for other reasons. The change is not regarded as material or
significant for environmental assessment purposes. It will be
addressed by ConocoPhillips as part of the “Application Package”
process for the 2012 program in Qamut Block (which is distinct or
separate from the EIA process described in Section 1.2), or in a
Supplementary Filing or Submission to BMP. Consequently, mention of
the Princess, Thor Supplier or Thor Beamer in the rest of Section
3, or in other sections of the Final EIA, was left as is.
Health, Safety & Environment (HSE) performance was taken
into account during selection of CGGVeritas as the contractor for
the seismic survey, including policies, procedures, vessels, and
equipment that were “fit for purpose” in Arctic environments,
including conditions in northeast Baffin Bay. This factor was
included in the evaluation to lower the likelihood, as much as
possible, of the seismic survey having impacts on the environment
in the survey region.
The Princess is a dual-source, multi-streamer seismic ship
well-suited for performing the 2D seismic survey described below.
This vessel has integrated geophysical and navigation data
acquisition systems, full quality assurance capabilities and
onboard positioning and seismic data processing facilities. The
seismic source on the ship consist of tuned arrays of G-gun II
airguns. The Princess is equipped with a full acoustic system to
position the in-water seismic equipment. Standard quality control
products available in real-time include brute stacks,
signal-to-acoustic ratio analyses on shot gathers, and near-trace
displays.
The Princess will be using or deploying a single airgun array
for seismic signal generation. A seismic receiver cable (or
streamer) will be towed behind the vessel for recording the
reflected signal. Details of the air gun array are provided in
Tables 3.1-2 and 3.1-3 at the end of this section. The M/V Princess
will sail along a total of 50 pre-planned sail lines and release
high pressure air to provide a down-going pressure wave at regular
intervals. The sail lines are planned to infill the existing
license database in order to obtain a regular grid of seismic data
to allow an adequate definition of subsurface structures. A line
change plan for the seismic survey will be developed. This plan
needs to be flexible, and take sea ice and glacial ice conditions,
weather conditions, sea state and other factors at the time of
survey into account. The survey vessels, equipment and material
brought into Qamut Block will leave the licence area at the end of
the survey. CGGVeritas has a strict “no spill” policy during
operations in Arctic waters. There are no planned discharges into
the sea, with the exception of normal discharges permitted by the
authorities under Greenlandic regulations or international
conventions. No waste disposal is planned, on land, during port
calls. No ballast water discharge is contemplated, unless
re-ballasting to set or establish an ice draft for any of the
ships, or related to re-fuelling, is needed. Re-fuelling may or may
not occur during the survey period. It is possible that
ship-to-ship transfer from the support/re-supply vessel will be
done if re-fuelling is required.
The marine gravity and magnetic measurements will be recorded
along the sail lines. The system for collecting gravity data is
hull-mounted; the magnetic data is obtained with a submerged system
that is towed behind the Princess. No energy or sound is emitted by
either system when the data are obtained. Equipment for these
measurements will be provided by Austin Exploration Inc. The survey
ship will not deviate from the sail lines to collect this
information. It is normal industry practice to collect gravity and
magnetic data during seismic surveys. The ship will use two systems
for depth measurements during the survey. The Princess is equipped
with an Atlas Echograph 461 echosounder for navigation and safety
purposes. A single-beam bathymetry system will be used for survey
purposes only, to accurately measure water depths along the sail
lines. This system is a Kongsberg EA600 echosounder that operates
at a frequency of 12 kHz, 32 kHz or 200 kHz. The two echosounders
are the only active (hull-mounted) sound sources on the Princess
that ConocoPhillips is aware of.
It is noted that a simultaneous operations plan, with mitigation
added that is related to reducing effects of underwater sound on
marine mammals in a regional setting, will be developed and
implemented by the three operators in northeast Baffin Bay before
their programs, if approved, begin in 2012. The usual purpose of
this plan, in addition to safety related to transit and manoeuvring
when several ships are operating in one area, is to minimize
problems with data quality or integrity when two or more seismic
surveys are occurring at the same time. Addition of mitigation to a
simultaneous operations plan is not a standard practice. It is one
of the actions that the operators will be taking to reduce possible
impacts of underwater sound on marine mammals from a cumulative
effects point of view. This situation is also discussed in Section
7 and 8 of the Final EIA.
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All of the steps outlined in the BMP Guidelines (December 2011
version, including Appendix G), involving operation of an airgun
array during a seismic survey, will be followed. These steps,
including any survey-specific procedures and measures developed by
ConocoPhillips for the Project, are being implemented to reduce or
mitigate the effects of underwater sound on the marine environment
that are related to operation of the airgun array.“Best Practice”
during seismic surveys at sea will be employed throughout.
A Safe Operations Plan, or equivalent, including an Emergency
Response Plan (for example, procedures for responding to accidental
discharges and environmental incidents), is being developed by
ConocoPhillips and CGGVeritas. This plan is mentioned in the EPP
for the Project (Section 8), but it is not attached to the Final
EIA at this time. An Ice Management Plan for the Project is also
being developed by ConocoPhillips, assisted by CGGVeritas and other
companies. A multi-tier or multiple-level approach, involving
actions or procedures before, during and after the survey, will be
followed. An important part of this plan, which is summarized in
the EPP (Section 8), but not attached to the Final EIA at this time
either, will be “ice avoidance” at tactical (near-ship) level.
Towing of bergy bits and small icebergs is not anticipated during
the survey.
A Marine Mammal and Seabird Observation (MMSO) Plan has been be
developed by ConocoPhillips, and will be carried out during the
seismic survey. This plan is summarized in the EPP (Section 8), and
attached in Appendix J (Marine Mammal Management Plan). The
Princess will be using a Passive Acoustic Monitoring (PAM) system
during the survey period. Table 3.1-4 contains the details
requested by BMP on this system. A plan or approach for PAM during
seismic operations is discussed in the EPP (Section 8). A
mitigation airgun will also be used. It is part of the approach
that will be implemented by ConocoPhillips to mitigate impacts of
underwater sound on marine mammals.
Table 3.1-1 Survey Data
Specify Description Provided Type of survey (2D, high resolution
(3D), well testing, other) 2D seismic survey ConocoPhillips
Map of the area with all transect lines shown please refer to
Figure 3.1-1 ConocoPhillips
Start and end dates for the survey Planned operation is from the
beginning of August 2012 to middle of September; however,
ConocoPhillips requests an option to operate until 1 October 2012
in case of delay caused by weather, sea ice, sea state, or other
issues.
ConocoPhillips
Expected duration of seismic program four (4) to six (6) weeks
ConocoPhillips
Duty cycle of operation (in hours/24 hours); number of hours in
the dark per 24 hours
24 hours per day, 7 days per week, based on safe operations when
sea ice is not present (i.e., when conditions are “open water” or
ice-free” only, and ships can operate safely)
ConocoPhillips
Number and types of accompanying vessels two (2) chase vessels
ConocoPhillips
Intended use of icebreakers. Will survey be carried out in
ice?
Icebreaker will not be used. Seismic survey will not occur when
sea ice is present – “open water” or “ice-free” conditions only.
Ice management plan being developed (mostly involves glacial ice,
but sea ice will not be overlooked in this plan, or at sea).
ConocoPhillips
Table 3.1-2 Array Specification
Specify Description Provided Number and names of vessels towing
airgun arrays one (1) vessel; CGGVeritas M/V Princess
ConocoPhillips For each vessel provide geometric layout of complete
airgun array with individual volume specified (in PSI per airgun
and in3 per airgun) please refer to Figure 3.1-2 and 3.1-3
CGGVeritas
Size of total array (in3 and PSI for the entire array) 3,940 in³
(one array consisting of three sub-arrays, as shown in attached
diagram), CGGVeritas
Firing rate in shots/sec. Will sub arrays fire simultaneously or
alternate? firing rate: 10 sec/shot; the sub-arrays will fire
simultaneously CGGVeritas
Operation speed of the vessel in km/hours or knots.
approximately 5 kt over bottom CGGVeritas
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Table 3.1-3 Acoustic Properties of the Airgun Array
Specify Description Provided Far field pressure signature of
total airgun output (provide figure) please refer to Figure 3.1-4
JASCO Frequency spectrum of the far field airgun signature
(broadband) (provide figure) please refer to Figure 3.1-5 JASCO
Source level (source factor) of airgun array on acoustic axis below
array given in all of the following units dB re 1 μPa peak- peak
(broadband) 262.4 dB re 1 Pa JASCO
dB re 1 μPa rms (Over 90%* pulse duration) (provide duration for
rms calculation) *as defined in Malme et al., 1986; Blackwell et
al., 2004
247.1 dB re 1 μPa, duration is 33.5 milliseconds (ms) JASCO
dB re: 1 μPa2s. per pulse 232.8 dB re: 1 Pa2s JASCO Energy,
joule/m2 per airgun pulse 9,643 J/m² JASCO
Signal duration. (Define how it is measured) 33.5 ms (90% rms
pulse duration as defined in Malme et al., 1986) JASCO
Map showing modeled sound pressure levels (rms*), peak-peak and
sound exposure level (μPa2s) for the survey area and surroundings
(to levels likely to affect marine mammals or nearest land) * rms
calculated by the 90% energy approach for derivation of the
duration (Malme et al., 1986; Blackwell et al., 2004).
please refer to Appendix D JASCO
Provide description of the acoustic propagation model, including
assumptions of sound speed profiles. please refer to Appendix D
JASCO
Table 3.1-4 Specifications of PAM System
Specify Description Provided
Number of hydrophones 4 Seiche Measurements Ltd. Threshold of
the recording system band width20Hz to 200kHz +/–3dB
Seiche Measurements Ltd.
Sample rate of the recording system
low frequency cetaceans samples up to 98kHz higher frequency
cetaceans (such as porpoises) sampling rate of 500kHz
Seiche Measurements Ltd.
Where will hydrophones be placed?
behind the vessel mounted on the trailing equipment (rigging /
lead-ins), the exact distance aft has not been determined by
CGGVeritas
Seiche Measurements Ltd.
Will there be duty cycling of recordings? In that case when will
the PAM system be used?
equipment will be recording and manned continuously CGGVeritas /
ConocoPhillips
Name of software WindowsXP,“Ishmael”, Pamguard Sigview Seiche
Measurements Ltd.
Species covered all vocalizing species Seiche Measurements
Ltd.
Estimated range accuracy, m. as per manufacturer’s
specifications Seiche Measurements Ltd.
3.2 Alternatives Considered
ConocoPhillips is committed to acquiring additional seismic data
as part of its license requirements. It has an obligation to obtain
a minimum of 3,000 line-km of 2D-seismic data during Exploration
Phase 1.
A number of methods have been evaluated for accessing the Qamut
sub-surface configuration and hydrocarbon potential. Different
geophysical methods can be applied to an area to evaluate its
sub-surface geology, including marine gravity surveys, marine
magnetic surveys, and marine controlled source electromagnetic
surveys, in addition to marine seismic data acquisition. However,
seismic surveys are the only viable means of providing enough
detail of the sub-surface to better understand the hydrocarbon
potential of the licence region, and identify locations for
possible drilling sites. Investigating the Qamut Block without
acquiring additional seismic data is not possible, and a “no
activity” option in 2012 cannot be considered at this time.
ConocoPhillips has evaluated the need for 2D- versus 3D-seismic
acquisition for the Qamut license. It was concluded that
acquisition of additional 2D lines would provide sufficient data
coverage to allow interpretation of the strata and structural
configuration at this point in the exploration phase. The
interpretation of the 2012 seismic data would help to highlight the
areas with significant hydrocarbon potential.
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The seismic source will generate an elevated sound level in the
northeast Baffin Bay area. ConocoPhillips evaluated alternatives to
determine if a solution existed to mitigate the elevated sound
levels from a seismic survey in this region. All commercially
available seismic airgun systems produce a broadband signal, even
though only the lower parts of the frequency spectrum is being
recorded in the reflected signal. Methods for reducing the high
frequency content have been investigated during Joint Industry
Projects (JIPs), but no successful methods have been developed.
Alternative seismic signal generation has also been investigated.
However, both the watergun and the marine seismic vibrator are not
commercially available. The current prototypes appear to produce a
frequency spectrum that cannot be used for seismic imaging of deep
basins. ConocoPhillips concluded that an airgun system is the only
available seismic source for the Qamut seismic survey.
ConocoPhillips evaluated different options for airgun volume to
see which volume was needed to produce the required data quality
for the proposed 2012 survey. Several seismic surveys have been
undertaken in the Baffin Bay area; different airgun volumes have
been used during these surveys. For example, employing up to 5,016
in3, as in the Kanumas 1992 seismic survey, does not appear to
provide uplift compared to the 4,100 in3 volume used in 2009 and
2010. Reducing the volume to 2,050 in3 in volume, as in the 2000
survey, has an effect on data quality, especially in the deeper
parts of the area, and would reduce the value of the seismic data
for understanding the structural development of the basins and
structures. The proposed airgun volume of 3,940 in3 will produce
the best seismic image.
The seismic acquisition lines proposed for the 2012 seismic
survey are pre-planned to in-fill existing seismic data to provide
sufficient data coverage over the most prospective sub-surface
areas. The current survey layout is the most effective based on the
current data base. Other layouts are possible, but these lines
would lead to an irregular grid pattern. This pattern could create
a requirement for more data, and consequently, a longer survey
period, which is not desirable.
With respect to timing of the proposed survey, early August 2012
to mid-September 2012 was deemed the most appropriate period. The
actual duration will be dependent on ice conditions, weather
conditions, sea state, and other factors at time of survey, but
deploying a streamer up to 10 km in length means that data
acquisition must occur during a period when sea ice is absent or at
a minimum in Qamut Block.
4 Environmental Baseline
4.1 Physical Environment
4.1.1 Introduction
This section of the EIA describes the physical environment of
northeast Baffin Bay. It includes information that is relevant to
assessment from a regional point of view, as well as information
that applies at local (block or licence) level. The following
subjects are covered: the setting in Baffin Bay; marine weather;
oceanography (including acoustic conditions and bathymetry/seabed);
and ice climatology (including sea ice and glacial ice). The
Strategic EIA on northeast Baffin Bay (NERI 2011) is not as
comprehensive on physical environment as it is on biological
environment, and consequently, the approach taken below is detailed
and thorough to support the assessment on the Project.
4.1.2 Regional Setting
Baffin Bay is situated between the Arctic Ocean and the Labrador
Sea (northwest Atlantic Ocean), between the west coast of Greenland
and the east coast of Baffin Island (Canada). The coastal features
around Baffin Bay are mountainous, and contain many ice sheets and
glaciers, particularly the massive Greenland Ice Sheet (or the
“Inland Ice”).
Baffin Bay is about 1,400 km long by 550 km wide and is
characterized by relatively shallow sills at its connections with
the Arctic and Atlantic Oceans, and by a deep and large abyssal
plain in its center. Three narrow (width of the order of 50 km or
less) channels connect Baffin Bay to the Arctic Ocean: Smith Sound
(through Nares Strait) to the north, Jones Sound to the northwest,
and Lancaster Sound to the west (Figure 4.1-1) with sill depths of
250, 120 and 125 m, respectively. On its southern boundary, Baffin
Bay is connected to the Atlantic Ocean (via the Labrador Sea) by
the much wider and deeper Davis Strait, which has a sill depth of
about 650 m and a width of about 170 km at the 500 m isobath, or
contour of equal depth.
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4.1.3 Marine Weather
4.1.3.1 Atmospheric Circulation
The pattern of atmospheric circulation over Baffin Bay exhibits
large changes between winter and summer, and may vary from year to
year. In January (winter), in addition to a high pressure system
over and north of northern Greenland), a high pressure system,
often referred to as the “polar vortex”, covers the eastern
Canadian Arctic, centered over Baffin Island (Cappelen et al.
2001). A low pressure region develops south and east of Greenland,
focused on the Icelandic Low, extending over the Norwegian Sea
toward northern Europe. As a result of this pressure pattern,
northerly winds will typically prevail over most of Baffin Bay. The
pattern usually lasts from November until April or May. In July
(summer), the mean pressure gradients are weak, especially around
Greenland, resulting in variable wind conditions determined by
passing cyclones. Cyclonic activity can occur anywhere in the
Greenland area, with most storms or cyclones affecting Baffin Bay
arriving from the south to southwest. In winter, if storms follow
this track frequently, a warmer, wetter period results,
contributing to less severe sea ice conditions along the northwest
Greenland coast. A good summary of the regional meteorology and
energy balance is found in DMI-DTU (2011).
4.1.3.2 Air Temperature
Maps of air temperature compiled by the Danish Meteorological
Institute (DMI) reveal a large west to east gradient in winter,
with colder temperatures in western Baffin Bay, while in summer, an
almost uniform distribution of temperatures occurs over Baffin Bay
(Figure 4.1-2). Mean temperatures in winter are about -20°C, with
lows of about -40°C occurring in late winter over unbroken,
snow-covered ice in Melville Bay and near the coast of Baffin
Island. In summer, the air temperatures are similar to ocean
surface temperature in these areas, though the local air
temperature, at sea, can be as low as -5°C from time to time during
this period. Summer temperatures as high as +5°C, or greater, have
been observed at reporting stations along the northwest Greenland
coast Valeur et al., 1996).
4.1.3.3 Inter-Annual Variability: North Atlantic Oscillation
Air temperature, wind and other meteorological parameters
exhibit large amounts of year-to-year or inter-annual variability
in northeast Baffin Bay. Air temperature measurements at coastal
weather stations along the west coast of Greenland reveal large
variations over time scales ranging over periods of two or three to
many years (Figure 4.1-3). The inter-annual variability in annual
air temperatures are associated with the North Atlantic Oscillation
(NAO) index, computed as the normalized difference in sea level
pressure between southwest Iceland and Gibraltar (Figure 4.1-4).
Above (below) normal air temperatures off West Greenland are
associated with below (above) normal values of the NAO index. A
persistent and strong negative North Atlantic Oscillation (NAO)
index was responsible for southerly air flow along the west of
Greenland (northerly winds, in winter, are the long-term norm),
which caused anomalously warm weather in winter 2010 to 2011 and
summer 2011 (Box et al. 2011).
4.1.3.4 Wind
Due to the atmospheric circulation pattern noted above,
northerly to northwest winds occur frequently in western and
central Baffin Bay. Inflow takes place mainly through Smith Sound,
Lancaster Sound and Jones Sound, while outflow is through Davis
Strait. In both the north-western and north-eastern portions of
Baffin Bay regions, gale-force winds often occur. In contrast to
this pattern, Melville Bay is in somewhat sheltered by northern
Greenland while the coastal area further to the southeast is
exposed to south-southeast winds. In summer, south-southeast winds
are dominant, particularly near the Greenland coast (Valeur et al.
1996).
A comprehensive wind-wave hindcast dataset (MSC50) prepared by
Environment Canada (2012) was used to characterize the wind
conditions of northeast Baffin Bay. This is shown in Figure 4.1-5.
The time-series data were processed with a time-step of three
hours, and provide continuous data for the period 1958 to 2008
inclusive. A complete description of the dataset and the hindcast
method is provided by Swail et al. (2006). North-westerly winds are
dominant in the western portion of northeast Baffin Bay, while
winds are primarily from the southeast in the eastern part of the
area. In between, at roughly long. 64°W, a transitional regime
occurs. The wind intensifies toward the coast with more frequent
wind at speeds greater than 10 m/s at the two sites closest to the
Greenland coast. These results are consistent with the results
reported by Valeur et al. (1996). Similar results are reported by
DMI-DTU (2011), based on DMI’s High Resolution Area Model.
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The Environment Canada MSC50 datset was also used to
characterize the winds in the vicinity of the Qamut Block. The
diagram in Figure 4.1-5 was derived from the entire time-series
(1958 to 2008); a summary table can be found in Table 4.1-1. The
yearly rose demonstrates a wind dominantly from the east to
southeast with little contribution from other quadrants. The
seasonal pattern, from January to December, features dominant east
to southeast winds that veer to southerly winds in spring and
summer (May, June and July) with a light winds from the north to
northwest sector on Figure 4.1-6 occur mainly in May and June. The
winds return to more easterly in the fall to winter period
(September to December) with a stronger regime in October. The most
energetic period is the fall and winter (October to March), when
the mean wind speeds are above 4 m/s, and estimated maximum speeds,
above 20 m/s, in November, December and February. Lower mean and
maximum wind speeds are seen during summer (June to August) with a
lower mean speeds of 2.9 m/s in June and lower maximum speeds of
16.2 m/s in July.
Table 4.1-1 Qamut Block Wind Statistics from MSC50 Hindcast Data
Node M3018543
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year Mean wind
speed 3.8 3.8 3.6 3.4 3.2 2.5 2.8 3.4 4.4 5.5 4.5 3.8 3.7 Dominant
direction WNW WNW WNW WNW WNW SE SE SE ESE SE WNW WNW WNW
Maximum wind speed 14.6 17.0 13.2 11.3 12.5 13.0 14.3 13.5 15.6
16.5 17.1 16.0 17.1
Direction of max. wind SE SE SSE SSE ESE ESE SE ESE E SE SE SE
SE
4.1.3.5 Precipitation
Due to the low moisture content of the air masses involved,
precipitation in the Baffin Bay area is small, about 200 mm/yr,
according to Valeur et al. (1996). Precipitation falls mostly in
summer and fall along the northwest Greenland coast, occasionally
as rain, but mainly as snow, based on observations at Upernavik
(Valeur et al. 1996). The precipitation events result from passage
of storms associated with atmospheric fronts. In summer, light snow
or drizzle may fall from low stratus clouds. In winter, light
snowfall occurs near leads and polynyas in the established ice
cover. Before this ice cover is fully developed, heavy snow showers
typically occur (Valeur et al. 1996).
4.1.3.6 Visibility
The predominant cause of reduced visibility in Baffin Bay is
fog, which occurs mainly during the summer months. The frequency of
fog events will increase during the spring, and peaks in June/July.
The frequency of fog decreases by late August (Valeur et al., 1996)
and through September to October as the sea surface temperatures
warm following the clearing of sea ice. Coastal weather station
data at Aasiaat, Nuuk and Paamiut (Figure 10 in Hansen and Buch,
2004) indicates that the highest frequency of fog occurs in July
(10-18%). Fog conditions tend to decrease in August (8-5%) and
further decrease in September (3-8%) and October (
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The two icing nomograms in Overland et al. (1986), or the four
used by the US Navy, showing light, moderate and heavy icing as a
function of air temperature and wind speed at specified sea surface
temperatures, are often referred to. The first set is shown in
DMI-DTU (2011), and not reproduced here.
4.1.4 Oceanography
4.1.4.1 Bathymetry and Seabed
The bathymetry of northeast Baffin Bay is relatively well-known
at regional scale. It is shown on appropriate small-scale Danish
and Canadian charts, and is available in digital form as the
General Bathymetric Chart of the Ocean (GEBCO) and International
Bathymetric Chart of the Arctic Ocean (IBCAO) gridded data. A
value-added version of the IBCAO has been used for regional mapping
and acoustic modeling during the EIA. This information, including
isobaths derived from the elevation surface, appears to be more
accurate, and more extensive, than isobath polygons available in
digital format from DCE. Water depths are shown on Danish charts
1600, 1700, 3100 and 3200 at 1:250,000 scale, and consist of track
or line soundings augmented by spot soundings over the historical
period of charting by Danish authorities. The region is
characterized by a complex continental shelf of varying width along
the coast north of Disko Island. This shelf has been deeply incised
by submarine valleys or canyons that were formed by glacial action
(outflow from the Inland Ice) in the past.
The most prominent seabed feature in Qamut Block is Isfjeldbanke
(Iceberg Bank), centered roughly 90 to 100 km south-southeast of
Savissivik, in the central and eastern part of the licence area,
bounded on the east by a deep submarine canyon and on the north
(between the coast and the licence boundary) by a similarly deep
depression. This bank has minimum depths of less than 100 m on
Danish chart 3100, and occupies a large area that is less than 200
m deep. The outline of the bank is not entirely accurate compared
to ConocoPhillips bathymetry derived from proprietary seismic
surveys carried out by TGS Nopec and other companies, but minimum
water depths are similar, and it is satisfactory for planning and
assessment purposes during the EIA.
Sediment properties and benthic ecology at and below bottom on
the continental shelf and slope, and on the abyssal plain at depths
of 2,000 m or greater, are not well-known in northeast Baffin Bay,
with the possible exception of the North Water region in northern
Baffin Bay between northwest Greenland and Devon and Ellesmere
Islands in northern Canada. Some reconnaissance box coring and
piston or gravity coring has been done by Canadian, American and
Danish scientists during international expeditions, in addition to
more detailed (site-specific) work carried out by Shell Kanumas A/S
during summer/fall 2011 at and near locations proposed for
stratigraphic drilling in 2012.
It is very likely that frequent scouring (or gouging) of the
seabed by icebergs is a key process that affects sediment
properties and benthic ecology on the shelf and upper slope in
northeast Baffin Bay when the keels of these icebergs come into
contact with the bottom. This suggestion is based on the high
numbers of icebergs in these waters, discussed further in Section
4.1.5, that could produce scours during drift or movement in
response to currents and the surface wind field. This scouring will
typically occur when depths are varying and become shallow, but
also, it can happen when the keel depth increases as a result of
rotation (roll-over) or other motion of the iceberg. Ice scours
have been mapped in several offshore areas where hydrocarbon
exploration or production occurs. It is almost certain that
scouring takes place along the east Greenland coast, and
especially, along the west Greenland coast north of Davis Strait,
where high numbers of large icebergs are calved, and transported by
the West Greenland Current across banks and other shallow areas on
the shelf. Depending of the draft of the large icebergs involved,
scouring could occur down to water depths of 250 m on the upper
slope. The scours could be as deep as four to six metres in some
locations (K Been, pers. comm. 2012) if soft clay sediment is
present.
The scours in-fill over time with material that settles through
the water column to the bottom, or from boundary layer transport
along the seafloor. Depend on the amount of scouring that takes
place, it can lead to an upper seabed that consists of mostly or
only scoured/in-filled material over periods as short as 50 or 60
to a few hundred years in areas prone to frequent scouring (Smale
et al. 2007). The pattern of past and present scours that cross
each other can have an important impact on the seabed. When silt or
clay soils are disturbed, they generally lose some of their
strength, and may absorb water. This process is known as
“remoulding”. It can take a long time for the clay soil to regain
its strength after remoulding. Sands also lose strength and become
looser when they are disturbed, but strength gain can be relatively
rapid under wave or other hydrodynamic loading. These observations
are related to scouring in the Beaufort Sea, off Sakhalin Island,
and off Newfoundland and Labrador, but it is likely the same
situation applies in northeast Baffin Bay. Other aspects of
scouring by icebergs are discussed in Appendix C.
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4.1.4.2 Circulation
The surface circulation of Baffin Bay is primarily cyclonic
(counter-clockwise) with an inflow of warm and more saline water
(the West Greenland Current) on the east side of Davis Strait, and
a broader outflow of cold and less saline water (the Baffin
Current) on the west side of the strait. This pattern is shown in
Figure 4.1-8.
The West Greenland Current that enters eastern Baffin Bay
consists of two components (Buch 2000, 2002 and Myers 2009):
• a modified East Greenland Current component, closest to the
coast, carrying water of polar origin (from the Arctic Ocean)
northward, after it rounds Cape Farewell; and
• a current component originating from the Irminger Sea and
North Atlantic Current, located to the west of and below the East
Greenland Current component.
The Atlantic Water component (Irminger Current and North
Atlantic water from the Labrador Sea) is significantly larger than
the East Greenland Current component. Clarke and Johnson (1984)
estimated 11 Sverdrup (Sv, equal to 106 m3/s) of volume transport
for the Atlantic Water versus 3 Sv for East Greenland Current
component, for example. As it moves north, a significant portion of
the West Greenland Current turns offshore when it encounters the
Davis Strait sill, which diverts this water to the interior of the
Labrador Sea (Myer et al. 2009). The remaining water continues to
flow north, and enters Baffin Bay through Davis Strait. The
remaining East Greenland Current component (on the shelf), at this
point, is greatly decreased in volume. The properties of this water
have been significantly modified by local run-off and interaction
with the slope water component (Buch 2000, 2002, NERI 2009). The
relatively warm and saline water forming the slope current
component flows along the slope and outer shelf, and can be traced
as far north as Thule (Buch 1990, 2000, 2002).
A recent estimate of transport by the West Greenland Current
indicates that the inflow of the warmer and more saline sub-surface
component along the slope is about 1.5 Sv, and that the inflow of
the colder and less saline surface component, on the shelf, is
about 0.4 Sv (Curry et al. 2011). Seasonality is important; a
stronger influx of water from the slope component occurs during
fall and early winter (Curry et al. 2011, Tang et al. 2004).
Variability from year to year and decade to decade appears to be
significant as well. Myer et al (2009), for example, described
quasi-decadal variability with the longest consistent period of
enhanced transport over a 50-year record taking place during the
2000s. This longer-term variability is probably influenced by the
North Atlantic Oscillation (Buch 2002).
As it flows northward along the east coast of Baffin Bay, the
West Greenland Current is strongly affected by the topography of
the shelf. The West Greenland shelf is deeply incised by large
fjords and canyons. Using a numerical circulation model, Tang et
al. (2004) described the topographic control and spatial variation
of the currents. The results of their simulations illustrate
stronger currents along the southern part of the northwest
Greenland shelf, and weaker and more variable currents north of
lat. 72° N. Canyons divert part the flow toward the coast and off
the shelf, particularly to the south and north of Disko Island.
When it enters northern Baffin Bay near the North Water Region (see
“Sea Ice by Seasonal Period” below), the West Greenland Current
mixes with Arctic Ocean outflow that enters Smith Sound from Nares
Strait, and essentially ends as a distinct ocean current (Buch
1990, 2000, and Ingram et al. 2002). The combined outflow through
Smith, Jones and Lancaster Sounds then drives the south-setting
Baffin Current, with estimated volume transport ranging from 0.7 to
2.1 Sv (Tang et al. 2004). Other aspects of regional circulation in
Baffin Bay are described in Appendix C.
Except for a small number of moorings deployed by the Bedford
Institute of Oceanography (BIO) operational model atlas (Wu and
Tang 2011) were retrieved from the BIO database (DFO ODI database
2012). A summary of the analysis is presented below.
The results from the southernmost mooring located in deep water
demonstrate both velocity maxima and means that increase with
depth, while the second mooring, located further north on the slope
and in shallower water, demonstrate similar current strength from
surface to bottom. Currents are not strong in general (mean
speed
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deep measurement does not demonstrate as much seasonality, but
summer currents are still stronger than winter ones overall.
4.1.4.3 Tides
The tides of Baffin Bay are predominantly semi-diurnal and the
major semi-diurnal constituent M2 is characterized by an
amphidromic point located at about lat. 70° N, almost in the middle
of Baffin Bay (Greisman et al. 1986). Both semi-diurnal (components
of the tide that occur twice each day) and diurnal (components of
the tide that occur once each day) tidal waves propagate
anticlockwise (cyclonically) from this amphidromic point.
Tidal amplitudes increase away from the amphidromic point and
are higher in the Davis Strait and Smith Sound regions where the M2
constituent of the tidal heights reaches amplitudes of the order of
a meter and more. Strong fortnightly modulation (spring and neap)
in the tidal elevations is observed in northern Baffin Bay and Kane
Basin (Ingram et al. 2002).
No tidal gauge or other tidal records for the Qamut Block were
found in the public domain. The closest record on the northwest
Greenland coast is from Foulke-Havn about 300 km north of the area,
on the east coast of Smith Sound. Recent modeling studies
undertaken by the Bedford Institute of Oceanography (Collins et al.
2011) can be used to provide quantitative estimates of the tides in
the Qamut Block. A map of the tidal heights over the region,
including the license area, was obtained by running and extracting
a 29-day prediction at regular intervals (every 0.1 degree) from
lat. 74.5° N to 76.5° N and from long. 70.75° W to 61.25 °W. The
results were combined to represent maximum (spring tides) tidal
range and the current magnitude that can be expected in this
region, as shown in Figure 4.1-10 and Figure 4.1-11. The model
results indicate that the tidal range and tidal currents increase
toward the northwest, as described above. The maximum tidal
currents (Figure 4.1-11) also exhibit a substantial increase of
current strength over the Qamut Block due to shallower depth, and
particularly on the eastern side, with magnitudes above 20
cm/s.
4.1.4.4 Water Mass Distribution and Structure
The water column of northern Baffin Bay, following Tang et al
(2004), consists of three layers:
• a colder and relatively fresh surface layer (temperature 0 to
-1°C, salinity less than 33.5 practical salinity units(psu)
equivalent to parts per thousand) in the upper 100 to 300 m of the
water column;
• a warmer and more saline intermediate layer (temperature +1 to
+2°C, salinity up to 34.5 psu) from about 300 to 800 m; and
• a colder and slightly less saline (compared to intermediate
water) deep layer (temperature less than 0°C, salinity greater than
34 psu) from 1,200 m down to the bottom.
There is a northward deepening of isopycnals (contours of equal
density) in the upper 200 m, supporting the existence of a
west-setting current in northern Baffin Bay, as well as a
temperature minimum at roughly 100 m depth (which is a remnant of
winter cooling), and a temperature maximum at 500 to 800 m depth
(Tang et al. 2004).
The upper layer consists of inflow from the Arctic Ocean through
Nares Strait and other passages to the west and northwest, and to a
lesser extent, inflow along the West Greenland shelf (Tang el al.
2004). The on-shelf component of the West Greenland Current,
described in Section 4.1.4.2, carries the latter water north. The
middle layer, known as West Greenland Intermediate Water, is
related to influx of relatively warm and saline water from the
northwest Atlantic Ocean. This water is also transported north,
along the slope and outer shelf, by the West Greenland Current. It
is warmer during winter compared to the summer period. The
temperature of this water mass is not uniform, and is reduced as it
circulates (Tang et al. 2004). The origin and fate of the deep
layer in Baffin Bay, over the abyssal plain, known as Baffin Bay
Deep Water from 1,200 to 1,800 m, then as Baffin Bay Bottom Water
from 1,800 m to the bottom, involves vertical processes in the
basin itself, rather than advection (inflow) from external areas,
such as the Labrador Sea. Deep water exchange with other basins
does not occur. Other aspects of water column structure and water
mass properties in Baffin Bay are described in Appendix C.
To examine the water column structure of the Qamut Block in more
detail, data from the World Ocean Atlas (NOAA 2012) were extracted
and processed. The data represent a composite of profiles (a mean
or average) collected over a number of years, sometimes back to the
early 1900s or eariler. The temperature and salinity profiles
provided represent “climatology”, rather than a given profile at a
specific date and time in northeast Baffin
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Bay. A one-degree latitude, west to east longitudinal profile
from long. 70°W to 62°W centred on lat. 75.25° N, was extracted
from the 0.25 degree resolution available dataset and averaged to
create the profile. Temperature and salinity profiles during summer
can be found in Figure 4.1-212.
From July to September, the Qamut Block is characterized by a
thin surface layer (roughly, the upper 25 m of the water column) of
warm (about 1.5°C) and fresh (less than 33 psu) water above the
three water masses, mentioned above, that Tang et al. (2004)
described. The lower (deep) water mass, is not present in the
licence area, since only a small region in the northeast part of
the block has water depths approaching the upper limit of this
water mass.
Overall, the water column is slightly colder westward except for
the thin surface layer in which warmer temperatures occur from west
to east. It is also generally fresher, to the west, in the upper
200 m of the water column. According to Buch (1990, 2000), this
surface mixed layer originates from the melting of (winter) sea
ice, together with run-off from land, and the melting of glacier
ice. This forms a thin, less saline layer of water during spring.
Due to the intensification of solar radiation in summer and to the
vertical salinity stratification, the heat is stored within this
thin layer and temperatures increase significantly.
The water structure is more strongly stratified during the
summer from west to east in the licence area, with higher
temperatures at the surface and lower sub-surface temperatures.
This could be due to higher sea ice melting volume on the western
part of the area and/or stronger vertical mixing over the shallow
banks present on the eastern part.
No upwelling areas were identified by NERI (2006, 2011) along
the northwest Greenland coast, but strong vertical advection due to
the tides along or across the steep slopes of banks can occur. This
is supported by the temperature profile data reported by Valeur et
al. (1996). These vertical mixing areas would be located where the
tidal currents are strongest.
4.1.4.5 Large-Scale Variability due to Winds, Air-Sea Fluxes and
Fronts
In the upper layer of the water column, from the time of sea ice
break-up in late June through to ice freeze-up in early November,
there are large temperature and salinity gradients in both the
vertical and horizontal domain. An example of this situation is the
vertical temperature-salinity distribution at an oceanographic
station off Upernavik in July 2009 (Ribergaard 2010). The vertical
gradients in this section, in the form of elevated water
temperatures of up to 5°C in a thin layer at the surface, develop
from the vertical exchanges of heat between the ocean and the
atmosphere, in this case, during summer after melting of sea ice.
Winds are also important in northeast Baffin Bay. Strong winds
result in vertical mixing of water properties to greater depths;
when winds are weak, the water column can be more stratified,
causing larger vertical gradients. In addition, depending on
direction, winds can drive the upwelling of nutrient-rich deeper
water to the surface. West or north-westerly winds can lead to
upwelling at the shelf edge off northwest Greenland and also along
ice edges, when the ice edge is laying to the west. Precipitation
and evaporation can decrease or increase the salinity of surface
and near-surface waters as well. However, these vertical exchanges
result in smaller changes to salinity than those due to ice melt
and formation processes in northeast Baffin Bay. Variability of
water column properties, which can be considerable in this region,
has important effects on the presence and abundance of marine
life.
Oceanic fronts, or large horizontal gradients in water
properties, are also important biologically active zones in
northeast Baffin Bay. Munk et al. (2003) reported that “...the
establishment of hydrographical fronts are of primary importance to
the plankton communities in the West Greenland shelf area,
influencing the early life of fish and the recruitment to the
important fisheries resources”. Mossbech et al. (2002) also noted
that “fronts, upwelling areas and marginal ice zones are examples
of...hydrodynamic discontinuities [in Greenland waters] where high
surface concentrations of phytoplankton, zooplankton, and shrimp
and fish larvae can be expected”.
The West Greenland Current Front (WGCF) closely follows the
shelf break and the steep upper slope along the northwest Greenland
shelf until it reaches long. 52° W where the slope becomes notably
less steep and therefore no longer stabilizes the WGCF (Aquarone et
al., 2009). This is shown in Figure 4.1-313. This front results in
eddy generation that enhances cross-frontal exchange of heat, salt
and nutrients, as well as zooplankton and juvenile fish. The
Mid-Shelf Front (MSF) is found over the mid-shelf roughly parallel
to the coast. It roughly separates the two components of the West
Greenland Current, described above in Section 4.1.4.2, from each
other as both continue to flow north and the on-shelf component is
modified during summer and fall by fresh water from various
sources, including meltwater from the Inland Ice. The front between
these two components of
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the West Greenland Current is weak from January to May and
relatively strong the remaining part of the year, with maximum
strength in September and October (Hansen et al. 2004).
Other frontal features occur in northern Baffin Bay, such as
those measured off Cape York at the boundary between the relatively
warm waters of the remaining West Greenland Current in this area
and the cold Arctic waters exiting Smith Sound (Melling et al.
2001). The current measurements reveal large-scale or deeply
penetrating horizontal gradients, or frontal features, as well as
smaller frontal features occurring near the surface.
4.1.4.6 Sea Ice Melt and Upwelling
The near-surface frontal features in the upper layer of
northeast Baffin Bay are primarily associated with sea ice break-up
and melting, iceberg movement and melting, and direct meltwater
run-off along the northwest coast of Greenland. The contribution of
the first process to surface and near-surface water column
properties is described in this section.
The melting of sea ice in early summer results in reduced
salinity waters at the surface of northeast Baffin Bay, since the
salinity of first-year sea ice is typically about 8 psu, which is
considerably less than the surface water salinities of about 30 psu
in this region. The average thickness of the sea ice during the
melt season is in the range of 1.5 to 2.0 m (NERI 2011).
In summary, a significant amount of fresh water enters the upper
part of the water column in northeast Baffin Bay when this ice
melts during the break-up and clearing process on the northwest
Greenland shelf. This pattern is described in more detail in
Section 4.1.5.1. The volume of water involved is roughly
1.1x1011m3. Appendix C describes how this estimate was calculated,
and contains other details on the significance of fresh water input
from sea ice melting.
Another important attribute of sea ice break-up and melting in
early summer is the location of the remaining West Ice in central
Baffin Bay through June and into July. Upwelling along the pack ice
edge has been shown in other Arctic regions to be an important
mechanism. This was noted, for example, by Buckley et al. (1979)
and Dumont et al. (2010), involving enrichment of nutrients in the
upper layer of the ocean due to transport of the surface waters
away from the ice edge under favourable wind conditions which are
replaced by higher nutrient waters from depth, and also from
beneath the ice itself. In the case of Middle Ice Pack, this means
upwelling could occur during periods of westerly to northwest
winds, which are not as prevalent as south-easterly winds in
northeast Baffin Bay during summer, but still common (DMI-DTU
2011). The importance of ice-edge upwelling to increased ocean
productivity levels has been noted in northwest Baffin Bay by
Borstad and Gower (1984) and off southwest Greenland by Pederson et
al. (2003).
A novel form of localized “upwelling” is possible in northeast
Baffin Bay. It does not involve ice-edge processes, but rather, the
effect an iceberg has on the upper part of the water column when it
is moved by wind or surface currents through the ocean, including
the momentum “wake” of glacial ice it creates, which trails behind
the iceberg when it is drifting. The water column is locally
displaced, bringing up deeper water that is nutrient-rich. Ice in
the wake, and the iceberg itself, will continue to melt,
contributing fresh water to the surface layer, which continues to
be locally altered and mixed, but on a diminishing basis, until the
ice disappears. Other aspects of this situation are described in
Appendix C.
4.1.4.7 Freshwater Run-off from Land and Icebergs
Freshwater inputs to the sea from land sources are important to
the oceanography of northeast Baffin Bay, especially the inshore
and shelf regions. Freshwater of land origin can take three forms:
direct run-off from rivers and streams along the West Greenland
coast, including the extensive fjords; melting of outflow glaciers
at tidewater (including drainage via meltwater channels in these
glaciers that enters the ocean directly); and the export of glacial
ice to the sea in the form of icebergs, which subsequently melt as
they move away from the coast.
The total mass loss of Greenland glacial ice will result in
considerable amounts of freshwater inputs to Baffin Bay in summer
months. The total freshwater volume discharge for all of West
Greenland, resulting from loss of ice sheet mass, has been
estimated as approximately 2x1011 m3/yr. This total is derived from
ice sheet volume reductions (Box et al. 2011) and from iceberg
volume fluxes (Valeur et al. 1996). The total freshwater discharge
occurs as both run-off and melt into the ocean at the shoreline and
at tidewater glaciers, as well as from iceberg calving. Nearly all
of this freshwater would be released during the period from mid-May
to mid-September during
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times of above zero degree air temperature and clearing of sea
ice cover. The total volume of freshwater released from land
sources of 2x1011 m3 is approximately twice that of freshwater
input from sea ice melt over the shelf areas for all of eastern
Baffin Bay. This input was estimated to be 1.1x1011 m3; it was
described in Section 4.1.4.6.
Direct meltwater run-off occurs from late spring to late summer
(Box et a