**REPORT TITLE**: The Diapir Field Environment and Possible Consequences
of Planned Offshore Oil

and Gas Development.

**STUDY TITLE**: Outer Continental Shelf Environmental Assessment
Program-Management Functions-Synthesis Meetings.

CONTRACT NUMBER(S): Part of Outer Continental Shelf Environmental
Assessment Program (OCSEAP) interagency agreement(s).

SPONSORING OCS REGION: Alaska.

APPLICABLE PLANNING AREA(S): Beaufort Sea.

FISCAL YEAR(S) OF PROJECT FUNDING: 1983; 1984.

COMPLETION DATE OF REPORT: May 1987.

COST(S): Cost of meeting(s) and report development are part of OCSEAP
management costs.

PROJECT MANAGER(S): Outer Continental Shelf Environmental Assessment
Program (OCSEAP).

AFFILIATION: National Oceanic and Atmospheric Administration.

ADDRESS: 701 C Street, Box 56, Anchorage, Alaska 99513.

PRINCIPAL INVESTIGATOR(S)\*: P. Barnes, P. Becker, M. Bennett, D. Betts,
I. Buist, J. Burns, A. Carey, P. Connors, J. Craig, P. Craig, G. Divoky,
K. Dunton, K. Frost, R. Goodman, W. Griffiths, L. Hachmeister, D.
Hopkins, H. Hume, R. Meehan, D. Norton, G. Oliver, M. Pelto, R.
Phillips, D. Schell, P. Sellmann, S. Stringer, P. Tebeau, L.
Thorsteinson, J. Truett.

KEY WORDS: Beaufort Sea; Diapir Field; Alaska; synthesis; meetings;
biology; hazards; fates and effects; leasing; development; development
scenarios; ecosystem; risk assessment; coastal zone; socioeconomics;
subsistence; marine mammals; birds; fish; shellfish; modeling;
trajectory; oil spill; Chukchi Sea; Simpson Lagoon; lagoons; barrier
islands; habitat; pipeline; ice; currents; literature review.

ACCESS: NUMBER: SR-005

**BACKGROUND**: The Outer Continental Shelf Environmental Assessment
Program (OCSEAP) was established by basic agreement between the U.S.
Department of Commerce, National Oceanic and Atmospheric Administration
(NOAA) and the U.S. Department of the Interior (USDOI), Bureau of Land
Management \[presently Minerals Management Service (MMS)\] to conduct
environmental research on Alaskan Outer Continental Shelf (OCS) areas
identified by the USDOI for potential oil and gas development. OCSEAP
activities have included review of existing data, planning and
management of original studies of all aspects of marine science, and
transfer of information to MMS or other users. One method by which this
information transfer takes place is through interdisciplinary synthesis
meetings. This report represents the results of the fourth Beaufort Sea
synthesis meeting held at Chena Hot Springs, Alaska, 25‑28 January 1983.

**OBJECTIVES**: (1) To provide a synthesis of research, and address
environmental issues and resource use conflicts which may arise in
proposed oil and gas lease areas.

**DESCRIPTION**: Disciplinary workshops were conducted on the following
subjects: (1) pollution transport involving trajectory analysis using
scenarios of expected oil and gas related developments; (2) biological
resources, including primary production, invertebrates, fish, birds,
marine mammals, and characterizations of ecological zones on a seasonal
basis; (3) physical hazards, including sea ice, permafrost, and other
hazards; and (4) oil spill cleanup, including discussions oriented
toward technology available for spilled oil cleanup in broken ice
environments. Other sessions were conducted for interdisciplinary
discussions and analyses of the following issues: biologically sensitive
areas and times, subsistence, noise effects, causeways, sand and gravel
sources, subsea pipelines and landfalls, and cumulative effects.

**SIGNIFICANT CONCLUSIONS**: Sea ice has a large influence on physical
conditions and movement of biota into and out of the Diapir Field area
and is in itself the greatest hazard to offshore development in the
area. Currents in the Beaufort Sea include the anticyclonic gyre of the
Canadian Basin, the Beaufort Current, and predominantly wind driven
nearshore currents. Lagoon type and exchange with coastal waters vary
along the Beaufort coast.

The coastal areas of the Beaufort and Chukchi Seas are most active
biologically in terms of primary productivity, invertebrates, fishes,
birds, and marine mammals during the summer months and, at that time,
are most susceptible to alterations in nearshore coastal habitats and
oil spills. Biologically sensitive areas were delineated. The existence
of nearly year-round ice conditions has resulted in development of two
phased oil trajectory modeling for ice and open water conditions. Oil
spill response is also adapted for the changing conditions.

**STUDY RESULTS**: Information collected for Lease Sale 87, covering the
large area from the Chukchi Sea to the Canadian border, has provided
insight into ice properties including drift, pressure ridges, ice
override and pileup, ice gouging, and other factors. The polar ice pack,
active tectonism, seafloor instability, shallow gas concentrations,
overpressurized shale diapirs, natural gas hydrates, and subsea
permafrost are among the potential hazards to petroleum development in
the Beaufort and northeastern Chukchi Seas. Although ice occurrence and
movement present the greatest obstacle to offshore development, other
geologic conditions hamper platform siting and drilling operations. The
southern Beaufort Sea is generally portrayed as a region of mean
westward water and ice motion corresponding to the southern edge of the
anticyclonic gyre of the Canadian Basin. However, the Beaufort Current,
over the slope and shelf seaward of the 50-m isobath, has a strong mean
eastward motion. Lagoon-barrier island geometries vary between the
eastern and western Beaufort Sea shelf. Open lagoons are the dominant
form along the western Beaufort coast from Barter Island to Point
Barrow. Pulsing and limited exchange lagoons are dominant along the
eastern Beaufort and northeast Chukchi coast. Greatest flushing
efficiencies for the three lagoon types occur in the open lagoons, such
as Simpson Lagoon.

Nature and distribution of sand and gravel resources differ in various
Lease Sale 87 areas. Exploration and development may require movement of
considerable quantities of fill over long distances. Exploration beyond
the ice‑fast limit will require barging material in the open season.

The Beaufort and Chukchi Seas have a relatively narrow band of
seasonally high primary productivity. Two kinds of invertebrate food
webs occur in the Diapir Field: a nearshore regime including the coastal
embayments and lagoons, and a pelagic regime. Both are numerically
dominated by crustaceans, the nearshore by epibenthic species and the
pelagic by euphausiids and copepods. Lagoonal habitats and possibly
\"closed\" lagoons may be most sensitive to spilled oil. Sixty-two
species of fish have been recorded in the Beaufort Sea; most are
anadromous (e.g., char, ciscoes, whitefish) and marine species (e.g.,
cods, sculpins, eelpouts, and snailfish). The cumulative impact of
coastal petroleum development may affect anadromous fish populations
both directly (i.e., mortality of juveniles in seawater intakes) or
indirectly (i.e., habitat alteration due to artificial structures that
change nearshore circulation patterns). The regional avifauna are
transient, being present from May through September when they fulfil
various life-cycle functions (e.g., nesting, migrating, feeding, and
staging). Habitat alterations caused by OCS petroleum activities could
affect bird populations during summer months. The Beaufort Sea is a
traditional feeding ground for bowhead whales. Polar bears have a
patchy, transient distribution. Spotted seals, hooded seals, minke
whales, and harbor porpoises are other marine mammals that occur with
less regularity. Ringed seals, however, are very prominent and rank high
in the subsistence harvest. The effects of underwater noise on marine
mammals, particularly the bowhead whale, is a concern, but adequate data
are lacking upon which to draw conclusions.

If oil is spilled under ice, the ice will probably restrict the spill to
a very small area and oil movement will be determined by motion of the
ice. Therefore, oil spill trajectory modeling in the Beaufort Sea
consists largely of modeling ice motion. An open water spill may be
tracked during the short open water season. Oil spill response has been
adapted for thick, stable, level ice; dynamic, hummocky ice; and light
ice or open water conditions.

Biologically sensitive areas were delineated with emphasis on species or
groups of species that are significant resources from a commercial,
subsistence, recreational, or aesthetic standpoint, or that are unique,
threatened, or endangered. Areas were delineated sensitive if the area
is a place where individuals of the species habitually congregate or, in
the case of live-bottom communities, the community is rare or unique.

Three major topics concerning subsistence/wage economy were addressed:
(1) socioeconomic impacts of OCS oil and gas lease development on
participants in the subsistence/wage economy; (2) major fish and
wildlife resources harvested by subsistence users in the Beaufort Sea
region; and (3) possible impacts of OCS development on the major fish
and wildlife resources.

**STUDY PRODUCT(S)**: Becker, P. R. (ed.). 1987. The Diapir Field
Environment and Possible Consequences of Planned Offshore Oil and Gas
Development. A final report for the U.S. Department of the Interior,
Minerals Management Service Alaska OCS Region, Anchorage, AK and the
U.S. Department of Commerce, National Oceanic and Atmospheric
Administration, OCS Environmental Assessment Program, Anchorage, AK.
NTIS No. PB87‑209938/AS. MMS Report 85-0082. 285 pp.

\*P.I.\'s affiliation may be different than that listed for Project
Manager(s).