ACCESS NUMBER: 30998 TO-10905

STUDY TITLE: Arctic Nearshore Impact Monitoring in the Development Area (ANIMIDA) Program Phase

- Sources, Concentrations and Dispersion Pathways for Suspended Sediment in Areas of Oil and Gas

Development along the Coastal Beaufort Sea

REPORT TITLE: ANIMIDA Task 5 Sources, Concentrations and Dispersion Pathways for Suspended

Sediment in the Coastal Beaufort Sea

CONTRACT NUMBER: 1435-01-99-CT-30998; TASK ORDER (TO): 10905

SPONSORING OCS REGION: Alaska

APPLICABLE PLANNING AREA: Beaufort Sea

FISCAL YEARS OF PROJECT FUNDING: FY 2000-FY2003

COMPLETION DATE OF REPORT: May 2004

COSTS BY FY: FY 2000: $70,000; FY 2001: $70,000; FY 2002: $140,000; FY 2003: $24,627

CUMULATIVE PROJECT COST: $304,627

PROJECT MANAGER: John H. Trefry

AFFILIATION: Florida Institute of Technology

ADDRESS: Florida Institute of Technology, Department of Marine & Environmental Systems, 150 West

University Boulevard, Melbourne FL 32901

PRINCIPAL INVESTIGATOR: John H. Trefry

KEY WORDS: ANIMIDA, nearshore Beaufort Sea, Sagavanirktok River, Colville River, Kuparuk River,

total suspended sediments, turbidity, source, monitoring, trace metals, Arctic, Alaska,

BACKGROUND:

The Arctic Nearshore Impact Monitoring in Development Area (ANIMIDA), a five-year study started in

1999, has provided baseline data and monitoring results for chemical contamination, turbidity, and

subsistence whaling in the vicinity of Northstar and Liberty development sites. Northstar is in State

waters, but includes production of some OCS oil through directional drilling. Liberty, if approved, would

be the first offshore OCS development project in the Beaufort Sea or elsewhere in the Alaska OCS. This

Task Order sought to determine sources, concentrations and dispersion pathways for suspended

sediment in the ANIMIDA study area.

OBJECTIVES:

(1) Determine the annual amount of suspended sediment carried to the coastal Beaufort Sea by the

Sagavanirktok, Kuparuk and Colville rivers, (2) determine the major element, trace element and organic

carbon content of river-borne particles, (3) continue to develop a picture of the concentrations, distribution

patterns and composition of suspended particles in the coastal Beaufort Sea, (4) monitor the distribution

and composition of suspended particles in the area of Northstar Island during the period of start-up and

continuing operation, and (5) identify the fate of river-borne suspended sediment in the coastal Beaufort

Sea.

DESCRIPTION

Field activities for ANIMIDA Task 5 included sampling rivers during spring breakup in May-June 2001 and

2002, through ice sampling of the Beaufort Sea during spring floods (2001 and 2002) and sampling rivers

and offshore waters during the open-water periods of June-August 2000, 2001 and 2002. Laboratory

analyses included the following: total suspended solids (TSS), particulate aluminum (Al), arsenic (As),
ACCESS NUMBER: 30998 TO-i 0905

barium (Ba), calcium (Ca), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn),

sodium (Na), nickel (Ni), lead (Pb), zinc (Zn) and organic carbon.

Samples of suspended sediment also were collected under the ice, seaward of the rivers during the early

days of spring runoff in 2001 and 2002 when the coastal Beaufort Sea was still ice covered. Vertical

profiles of conductivity-temperature were collected at each site along with samples for TSS, particutate

metals and particulate organic carbon.

During the open-water period in 1999-2002, numerous vertical casts and horizontal tows in the water

column were made throughout the coastal Beaufort Sea to measure turbidity, salinity, temperature and

current speed and direction. Turbidity was measured by in situ turbidimeter, by laboratory turbidimeter

using discrete samples and by filtration/gravimetry using discrete samples. Samples were analyzed for

the same particulate elements listed above for rivers.

SIGNIFICANT CONCLUSIONS:

About 87% of the annual transport of suspended sediment by the Sagavanirktok River (-0.33 million

metric tons/yr) occurred during just 12 days in June2001. About 90% of the total transport of suspended

sediment by the Kuparuk River (-0.02 million metric tons/yr) was carried during just three days in June

2001.

The large burdens of suspended sediment carried by rivers during a brief period in May-June are

delivered to a coastal Beaufort Sea with 2-m thick ice. The suspended sediment flows out over and under

the ice. Suspended sediment carried out under the ice is entrained in surface, low-salinity water directly

under the ice. The fresher, more turbid water can be tracked under the ice more than 10 km offshore.

Overall, no significant differences in concentrations of TSS that could be directly linked to oil and gas

operations were observed in the ANIMIDA area. Periodic enhancement in levels of TSS in the coastal

Beaufort Sea was related to river runoff and resuspension of bottom sediment by strong winds. Natural

inputs of suspended sediment from runoff and erosion were large relative to any anthropogenic inputs of

sediment.

The ANIMIDA area appears to be a net erosional environment with respect to sediment at this time.

Based on our observations, much of the large sediment load of the rivers is carried across the nearshore

environment to deeper waters of the Beaufort Sea along the freshwater channel under the ice during

spring or with summer and fall storms. Therefore, sediment monitoring for potential anthropoenic

chemicals must be coordinated with measurements of radionuclides such as 137Cs, excess 21 Pb, 234Th or

7Be that help ensure that samples are recent and not relict deposits.

STUDY RESULTS:

Concentrations of total suspended solids (TSS) in the Sagavanirktok River near the Prudhoe Bay

Operations Center (PBOC) increased from -40 mg/L on June 1 when flow began to 600 mg/L on June

12, 2001, and then decreased to -30 mg/L by June 18. During late July and August 2001, concentrations

of TSS were -2 mg/L. Concentrations of TSS followed similar trends for the Colville River with maximum

levels of about 600 mg/L on June 13, 2001. In contrast, concentrations of TSS reached peak values of

only 60 mg/L in the Kuparuk River on June 10, 2001 and decreased to <5 rng/L after June 16, 2001.

Peak flow recorded for the Kuparuk River was about 600 m3/sec on June 12, 2001, decreasing to <50

m3/sec after June 28, 2001. During 2002, the same trend of increasing concentrations of TSS was

observed; however, freezing temperatures led to refreezing of the rivers and put a hiatus in the spring

flood for the Sagavanirktok River. However, the dramatic two-day flood of the Kuparuk River in 2002

occurred during the period prior to refreezing.

Concentrations of TSS averaged -40 mg/L in a 2-rn thick lens of freshwater immediately under the ice

that extended >10 km offshore. The suspended sediment was very rich in fine-grained aluminosilicates

as shown by the levels of Al and other metals in the particles. Metal/Al ratios in suspended particles

collected under the ice showed that the composition of river-borne particles was similar to that found for

bottom sediment.
ACCESS NUMBER: 30998 TO-i 0905

The day-to-day turbidity and distribution of TSS in the coastal Beaufort Sea were dependent on river flow,

ice cover and sea state. In the protected, relatively quiescent waters under ice during most of the year,

levels of TSS were low at a few tenths of a milligram per liter relative to average levels of -40 mg/L in

surface waters under the ice during the spring floods. During the brief open-water period, after the spring

floods, concentrations of TSS were typically <20 mg/L and varied as a function of river inputs, sea state

and the presence of floating sea ice. Sea state was directly related to the strength and duration of winds.

Concentrations of TSS increased to >50 mg/L during the summer only following a period of several days

with winds greater than 20 knots was necessary. In contrast, levels of TSS <2 mg/L were observed under

conditions where calm water had prevailed for several days. No significant deviations in levels of turbidity

were observed adjacent to Northstar Island during 2000-2002 while towing a turbidimeter-CTD package

along transects at distances as close as 100-500 m from the island.

Differences in the elemental composition of suspended sediment were observed among rivers. The

Colville River contained greater amounts of particulate Al, Fe and trace metals relative to the more Carich particles of the Sagavanirktok River and the more organic carbon-rich particles of the Kuparuk River.

However, the metal/Al ratios for all elements, except Ca, were not significantly different among rivers and

bottom sediment from the coastal Beaufort Sea.

Concentrations of trace metals also were determined for samples of suspended matter collected from the

coastal Beaufort Sea. The fine-grained aluminosilicates suspended in the water column were enriched

with Al and trace metals. However, concentrations of most metals in suspended sediment for 2000 and

2001 plotted within the 99% prediction intervals for metals versus Al that were developed using data for

bottom sediment. Thus, in most instances, concentrations of trace metals associated with suspended

particles were within the limits established for uncontaminated sediment.

STUDY PRODUCTS:

Trefry, J. H.; Rember, R. D.; Trocine, A. P.; and M. Savole. 2004. ANIMIDA Task 5 Sources,

Concentrations and Dispersion Pathways for Suspended Sediment in the Coastal Beaufort Sea.

OCS Study MMS 2004-032. Final Report 1435-01-99-CT-30998, TO 10905. Prepared by Florida

Institute of Technology and Kinnetic Laboratories, Inc. for Minerals Management Service Alaska OCS

Region. Anchorage, AK.

Rember, R.D.; and Trefry, J.H. 2004 Increased concentrations of dissolved trace metals and organic

carbon during snowmelt in rivers of the Alaskan Arctic. Geochimica et Cosmochimica Acta 68:477-

489.

Trefry, J. H.; et al. 2003. Concentrations, Composition, & Dispersion Pathways for Suspended Sediment

in the Coastal Beaufort Sea. Presented at SETAC 24th Annual Meeting in North America. Austin, TX:

SETAC.

Rember, R. D.; Trefry, J. H.; and A. P. Trocine. 2003. Concentrations and Dispersion Pathways for

Suspended Sediment. In: Alaska OCS Region Ninth Information Transfer Meeting And Barrow

Information Update Meeting Final Proceedings, OCS Study MMS 2003-42, p 23. Prepared by MBC

Applied Environmental Sciences. Anchorage, AK.: United States, DOl, MMS, Alaska OCS Region.

Trefry, J. H.; et al. 2003. Concentrations, Composition, & Dispersion Pathways for Suspended Sediment

in the Coastal Beaufort Sea. Presented at SETAC 24th Annual Meeting in North America. Austin, TX:

SETAC.

Trefry, J.H.; Rember, R.D.; Trocine, R.P.; and Brown, J.S. 2003. Trace metals in sediments near offshore

oil exploration and production sites in the Alaskan Arctic. Environmental Geology 45:149-1 60.

Rember, R.D. 2002. Composition of dissolved and suspended matter transported by the

Sagavanirktok, Kuparuk and Colville rivers in the Alaskan arctic. Ph.D. Dissertation, Florida

Institute of Technology, 106 pp.
ITOUTE hUE 00 ISO KIL000TEMO 50 000

CHLJKCHI SEA

0157 MOPE

55' ISO' III' 40' ARCTIC SUBREGI 0H

A LAS A /

ASOTA COSOL

BEAUFORT SEA

ACCESS NUMBER: 30998 TO-i 0905

TO.-

Focus area for Arctic Nearshore Impact Monitoring in the Development Area (ANIMIDA) Program.

I,,. I70 MO.
zN

z

F152W l5ow l48W

ACCESS NUMBER: 30998 TO-10905

l46W 144GW 142W

D Cape

llaYkett ?

78 6 8F 8C

68 Harrison Bay. rv

0 3 6 9 12 15Kilometers

Beaufort Sea

SE

Northstar

N21 5F N1 N14 N5D1

Liberty

Lil

L12

Camden

10

Griffin

Point

Study Area

_-I /4':.'--

Map showing the western portion of the coastal Beaufort Sea with inset maps of Alaska, the oil

production site at Northstar Island and a possible future drilling site at Liberty Prospect. The

ANIMIDA study focused mainly on the area shown in the shaded box.

NOl NA2 NO2 NA3

t116 NO4*5 °(oa.No9 NOSN18 NA4 N1O.Nfl S N1ISN2O Nl2

5(10

El

4B LA2 L01

L02

L03

L L06a L13L08

°4L05'LM

LA4

L09

.4 38

PruJoe Bay 4A A

2E 2CIC

lB
ACCESS NUMBER: 30998 TO-10905

Map showing locations of sampling sites in the Sagavanirktok, Kuparuk and Colville rivers with

inset map showing study area in northern Alaska.