Flow Patterns and Current Structure at

the USS Arizona Memorial: April, 2005

U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2005-1334

Photograph courtesy of the National Park Service

Flow Patterns and Current Structure at

the USS Arizona Memorial: April, 2005

Curt D. Storlazzi1, Matthew A. Russell2, M. Katherine Presto1 and Jennifer E. Burbank3

1

US Geological Survey, Pacific Science Center, Santa Cruz, CA

2

National Park Service, Submerged Resources Center, Santa Fe, NM

3

National Park Service, USS Arizona Memorial, Pearl Harbor, Oahu, HI

U.S. GEOLOGICAL SURVEY

Open-File Report 2005-1334

2005
LIST OF TABLES

TABLE 1. Experiment personnel.

TABLE 2. ADCP deployment log.

LIST OF FIGURES

FIGURE 1. Map of the study area location in relation to the main Hawaiian Island

chain.

FIGURE 2. Map showing location of instrument packages in the study area.

FIGURE 3. Photograph of one of the instrument packages.

FIGURE 4. Relationship between tides, flow and temperature off the starboard side.

FIGURE 5. Mean flow and its variability at different heights above the seafloor off the

starboard side.

FIGURE 6. Relationship between tides, flow and temperature off the port side.

FIGURE 7. Mean flow and its variability at different heights above the seafloor off the

port side.

FIGURE 8. Relationship between tides, flow and vertical shear off the starboard side.

FIGURE 9. Relationship between tides, flow and vertical shear off the port side.

FIGURE 10. Vertical profiles of current velocity and the resulting current-induced force

on the starboard hull.

FIGURE 11. Vertical profiles of current velocity and the resulting current-induced force

on the port hull.

FIGURE 12. Concurrent water temperatures of the port and starboard sides of the hull

and the resulting thermal gradient.

LIST OF APPENDICES

APPENDIX 1. Acoustic Doppler Current Profiler (ADCP) Information.
ADDITIONAL DIGITAL INFORMATION

For additional information on the instrument deployments, please see:

http://walrus.wr.usgs.gov/infobank/a/a105oa/html/a-1-05-oa.meta.html

For an online PDF version of this report, please see:

http://pubs.usgs.gov/of/2005/1334/

For more information on the U.S. Geological Survey Western Region’s Coastal and

Marine Geology Team, please see:

http://walrus.wr.usgs.gov/

For more information on the National Park Service’s Submerged Resources Center,

(NPS-SRC) please see:

http://www.nps.gov/submerged

For more information on the National Park Service’s Submerged Resources Center’s

USS Arizona Memorial Project, please see:

http://www.pastfoundation.org/Arizona

For general information on the USS Arizona National Memorial please see:

http://www.nps.gov/usar/

DIRECT CONTACT INFORMATION

Regarding this Report

Dr. Curt D. Storlazzi, Oceanographer: cstorlazzi@usgs.gov

USS Arizona Memorial Project Information

Matthew A. Russell, Project Director: matthew_russell@nps.gov

Larry E. Murphy, Chief, NPS-SRC: larry_murphy@nps.gov

REPORT REFERENCE

Storlazzi, C.D., Russell, M.A., Presto, M.K. and Burbank, J.E., 2005. “Flow Patterns and

Current Structure at the USS Arizona Memorial: April, 2005” U.S. Geological Survey

Open-File Report 2005-1334, 24 p.
INTRODUCTION

U.S. Geological Survey (USGS) and National Park Service (NPS) personnel

collected short-term (1 month), high-resolution physical oceanographic measurements

at the USS Arizona Memorial (USAR) in April, 2005, to better understand the nature of

flow surrounding the mostly submerged historic ship. Scientists deployed two bottommounted oceanographic instruments in water depths less than 10 m on either side of

the USS Arizona’s hull. This study supports the National Park Service’s Submerged

Resources Center (NPS-SRC) research directed at understanding and characterizing

the nature and rate of natural processes affecting deterioration of the National Historic

Landmark (NHL) USS Arizona. The purpose of these measurements was to collect

high-resolution and spatially-extensive hydrographic data to better constrain the nature

of fluid flow around the submerged vessel’s hull and near the Memorial.

This project represents a multi-agency approach to acquiring sound scientific

data requisite for future stewardship-based management actions. Several organizations

cooperatively funded this project: USGS, Department of Defense Legacy Resources

Management Fund, NPS Systemwide Archeological Inventory Program, USS Arizona

Memorial, Arizona Memorial Museum Association, and NPS Submerged Resources

Center.

Project Objectives:

The objective of the instrument deployments was to understand how currents

and temperature in the vicinity of the Memorial vary over 2 spring-neap tidal cycles.

These data supplemented the long-term single-point measurements made between

2002 and 2004 by Storlazzi et al., (2004). The oceanographic data were collected to

support the NPS-SRC research to understand and characterize the nature and rate of

natural processes affecting deterioration of USS Arizona. The USS Arizona, along with

USS Utah, was designated as a NHL, the nation’s highest recognition of historic

significance, on May 5, 1989. The NPS-SRC project was designed to be multi-year,

interdisciplinary and cumulative, with each element contributing to developing an overall

management strategy designed to provide the basic research required to make

informed management decisions for long-term preservation of these NHL sites.

Understanding the nature and rate of natural processes affecting deterioration of the

vessels is required for sound management decisions regarding long-term preservation

of these sites. In addition, the NPS-SRC research program will have global application

to the many sunken steel heritage vessels, and it will serve as a management model for

NPS and partners who have stewardship responsibility for these sites. As part of this

research program, flow patterns close to Arizona’s hull were investigated. The two

instrument packages were deployed for a period spanning 1 month to investigate both

horizontal and vertical spatial variability in flow.

Study Area:

Instrument deployments were conducted off the northwest corner of Ford Island

in the East Loch of Pearl Harbor, South-central Oahu, Hawaii, USA (FIGURE 1). One

instrument was deployed in 10 m of water roughly 25 m southeast of Arizona’s port

beam below the Number 1 turret. The other instrument package was deployed in 9 m of

water roughly 25 m northwest of Arizona’s starboard beam below the Number 1 turret
U.S. DEPARTMENT OF THE INTERIOR–U.S. GEOLOGICAL SURVEY–RESTON

Albers Equal Area Projection

Principal Islands of Hawaii

0 20 40 60 80 100

0 50 100 150

MILES

KILOMETERS

Hawaii

Maui

Oahu

Kauai

Molokini

P A C I F I C O C E A N

Hilo

Waimea

Kailua

Honolulu Molokai

157

160 159

158 156 155

20

21

22 Lihue

Niihau

Lehua Island

Kaula Island

Kahoolawe

Lanai

Wailuku

Hana

Lahaina

Kaunakakai

19

Study

Area

USS

Arizona

Makalapa

Crater

Aliamanu Crater

Main 

Channel

West

Loch

East

Middle Loch

Loch

Ford Island

Southeast

Loch

PEARL HARBOR, HAWAII

Walawa

Spring

Walau 

Spring

Salt

Lake

Honouliuli

Stream

Waikele

Stream

Kipapa

Stream Walawa

Stream Punanani Gulch

Waimalo Stream

Kalauao Stream

Aiea Stream

Halawa Stream

0 0.5 1 2

0 0.5 1 2 3

MILES

KILOMETERS

N

a)

b)

FIGURE 1. Map of the study area. a) Location of Pearl Harbor in relation to the 

main Hawaiian Island chain. b) Location of the USAR in Pearl Harbor relative to 

Ford Island, the main Lochs and sources of freshwater that empty into the harbor.
just to the southwest of the mooring quay (FIGURE 2). The seafloor at these sites

consists of an organic-rich mud. All diving, mobilization and demobilization were based

from the USAR dock on the eastern side of the East Loch of Pearl Harbor, South-central

Oahu, Hawaii.

OPERATIONS

This section provides information about personnel, equipment and vessels used

during equipment deployments. See TABLE 1 for personnel involved in this experiment

and TABLE 2 for complete deployment information.

Equipment and Data Review:

The primary instruments used to acquire data during the deployments were two

RD Instruments 600 kHz Acoustic Doppler Current profilers (ADCP). These collected

three-dimensional vertical profile measurements of current speed and direction in 0.5 m

bins (sampling volumes) every 0.5 m from 1.0 m above the seafloor up to the water

surface and single-point measurements of water temperature 0.5 m above the seafloor;

a pressure sensor on the ADCP measured water level data (FIGURE 3). The ADCP

sampled mean currents, water level and water temperature by averaging over a 1-min

window every 4 min. The instrument package deployment and recovery log is

presented in TABLE 2; the instrument specifics and sampling scheme is listed in

APPENDIX 1.

Deployment/Recovery Operations:

The US Navy operates launches to transport visitors between USAR

headquarters and the Memorial about every 15 minutes. The Navy launches

transported project scientists and instruments to the USAR dock. Prior to deployment,

diving scientists established a secure guideline from Arizona’s hull out to the location

where the instruments would be deployed. The ADCPs and their semi-permanent

mount were deployed by initially lowering them just below the water’s surface. At this

point the scuba divers attached a lift bag and detached the lifting line. The divers

followed a marker line to the sea floor to move the instrument packages into place.

They secured the instrument packages with cables attached to sand anchors embedded

in the seafloor. Recovery and redeployment operations involved the same procedures.

DATA ACQUISITION AND QUALITY

Current speed, current direction and near-bed water temperature data were

acquired for 30 days between April 2 and May 1, 2005, yielding 100% coverage over

the entire experiment period. Each ADCP made more than 10,400 observations of

current speed, current velocity and acoustic backscatter from each of the 28 bins

(>290,000 total samples per instrument) over the study period. Data quality was very

high. The ADCP data near the surface displayed slightly lower correlation due to

bubble interference with the transducers. This loss of data from the bins closest to the

surface is common to most upward-looking ADCPs and was expected. The raw ADCP

data were archived and copies of the data were post-processed to remove all “ghost”
FIGURE 2. Map showing the spatial distribution of instrument packages 

in the study area relative to the USAR’s hull and Ford Island.

Depth (m)

High : -1

Low : -15

0 10 20 40 60 80

Meters

USS Arizona

Ford

Island

port

starboard

bow

stern

N
FIGURE 3. Photograph of one of the instrument packages and its mount.

The ADCP transducers and the pressure and temperature sensors are

under the yellow protective cap (~20 cm diameter for scale).
data from above the surface. All data collected when the beam correlation dropped

below 70% were discarded for visualization and analysis. Post-processed data were

saved and copies were desampled to hourly intervals to identify longer-term variability;

these desampled copies of the data were also saved and archived.

RESULTS AND DISCUSSION

This section reviews data collected by both systems during deployment and

addresses significance of the findings to characterizing local oceanographic conditions

in the study area.

Tides

Pearl Harbor tides are mixed, microtidal (< 2m) and semi-diurnal with two uneven

high tides and two uneven low tides per day; thus the tides change just over every 6

hours. The mean daily tidal range during the study was roughly 0.6 m, while the

minimum and maximum daily tidal ranges are 0.4 m and 0.9 m, respectively.

Currents

Most daily variability in current speed and direction at the study site is due to the

semi-diurnal (12.4 hour) and diurnal (24.8 hour) tides. As the tide rises (floods),

currents in Pearl Harbor flow to the north; conversely, as the tide falls (ebbs), the

currents flow to the south. Mean current speeds ± one standard deviation 1 m above

the seafloor are 0.010 ± 0.007 m/sec off the starboard (northwestern) side of the hull

(FIGURES 4-5) and 0.027 ± 0.015 m/sec off the port (southeastern) side of the hull

(FIGURES 6-7). Higher up in the water column, approximately 1 m below the water

surface, mean current speeds ± one standard deviation are 0.028 ± 0.019 m/sec off the

starboard (northwestern) side of the hull and 0.023 ± 0.013 m/sec off the port

(southeastern) side of the hull. Of note are the slightly different orientations in both

instantaneous and net flow to the port and starboard sides of the Arizona’s hull. Off the

starboard side, the flow is predominantly oriented north-northeast or south-southwest,

roughly parallel Ford Island’s shoreline in the vicinity of the Arizona. Off the port side,

however, the flow is predominantly oriented east-northeast or west-southwest, roughly

parallel to the main trend of the East Loch of Pearl Harbor. These differences in

orientation imply steering, not only by the bathymetry, but also by the Arizona’s hull.

The differences in current speed, both vertically and from one side of the hull to

the other, result in velocity shear, which, in turn, likely increases turbulence and mixing.

The values of vertical shear varied from 0.025 ± 0.015 1/sec off the starboard

(northwestern) side of the hull (FIGURE 8) and 0.038 ± 0.023 1/sec off the port

(southeastern) side of the hull (FIGURE 9). The shear was generally highest during the

falling tides. The vertical velocity shear, by moving seawater of a given density, would

impart a vertical variation in current-induced force on the hull. Seeing that seawater in

Pearl Harbor has a density around 1023 kg/m3

 (temperature~25 °C and a salinity~33

PSU), the mean current-induced force on the starboard (northwestern) side of the hull is

0.175 ± 0.131 N/m2 (FIGURE 10) and 0.291 ± 0.259 N/m2 on the port (southeastern)

side of the hull (FIGURE 11).
95 100 105 110 115 120

-0.5

0

0.5

95 100 105 110 115 120

-0.05

0

0.05

95 100 105 110 115 120

-0.05

0

0.05

95 100 105 110 115 120

-0.05

0

0.05

95 100 105 110 115 120

24

25

26

Year Day 2005

Tide [m]

z = 8.0m z = 4.5m z = 1.0m

Temp [deg C] Current [m/sec]

FIGURE 4. Relationship between tides, flow and temperature off the starboard side. The vectors are pointing in the direction of flow and are 

oriented geographically, with north up and east to the right; z-values are heights above the seafloor. Note the tide ebbs to the southeast and 

floods to the northwest.
v (m/sec)

-0.1 0 0.1

-0.1

-0.05

0

0.05

0.1

z = 8m

-0.1 0 0.1

-0.1

-0.05

0

0.05

0.1

v (m/sec)

z = 7m

-0.1 0 0.1

-0.1

-0.05

0

0.05

0.1

z = 6m

-0.1 0 0.1

-0.1

-0.05

0

0.05

0.1

z = 5m

-0.1 0 0.1

-0.1

-0.05

0

0.05

0.1

u (m/sec)

v (m/sec)

z = 4m

-0.1 0 0.1

-0.1

-0.05

0

0.05

0.1

u (m/sec)

z = 3m

Principal Axes of Currents

-0.1 0 0.1

-0.1

-0.05

0

0.05

0.1

u (m/sec)

z = 2m

FIGURE 5. Mean flow and its variability at different heights above the seafloor off the starboard side. 

The measurements are oriented geographically, with north (+v) up and east (+u) to the right; z-values are 

heights above the seafloor. Note the major axis of the current ellipse and mean flow is oriented parallel to 

the USAR’s hull, Ford Island and the southwest-northeast trend of the East Loch. Also note that the flow 

is weaker and more variable near the seafloor.
95 100 105 110 115 120

-0.5

0

0.5

95 100 105 110 115 120

-0.05

0

0.05

95 100 105 110 115 120

-0.05

0

0.05

95 100 105 110 115 120

-0.05

0

0.05

95 100 105 110 115 120

24

25

26

Year Day 2005

Tide [m]

z = 8.0m z = 4.5m z = 1.0m

Temp [deg C] Current [m/sec]

FIGURE 6. Relationship between tides, flow and temperature off the port side. The vectors are pointing in the direction of flow and are 

oriented geographically, with north up and east to the right; z-values are heights above the seafloor. Note the tide ebbs to the southeast 

and floods to the northwest.
v (m/sec)

-0.1 0 0.1

-0.1

-0.05

0

0.05

0.1

z = 9m

-0.1 0 0.1

-0.1

-0.05

0

0.05

0.1

z = 8m

-0.1 0 0.1

-0.1

-0.05

0

0.05

0.1

v (m/sec)

z = 7m

-0.1 0 0.1

-0.1

-0.05

0

0.05

0.1

z = 6m

-0.1 0 0.1

-0.1

-0.05

0

0.05

0.1

z = 5m

-0.1 0 0.1

-0.1

-0.05

0

0.05

0.1

u (m/sec)

v (m/sec)

z = 4m

-0.1 0 0.1

-0.1

-0.05

0

0.05

0.1

u (m/sec)

z = 3m

Principal Axes of Currents

-0.1 0 0.1

-0.1

-0.05

0

0.05

0.1

u (m/sec)

z = 2m

FIGURE 7. Mean flow and its variability at different heights above the seafloor off the port side. The 

measurements are oriented geographically, with north (+v) up and east (+u) to the right; z-values are 

heights above the seafloor. Note the major axis of the current ellipse and mean flow is oriented parallel 

to the USAR’s hull, Ford Island and the southwest-northeast trend of the East Loch. Also note that the 

flow is weaker and more variable near the seafloor. 
95 100 105 110 115 120

-0.5

0

0.5

95 100 105 110 115 120

-0.05

0

0.05 red = 8m, blue = 1m

95 100 105 110 115 120

0

0.05

0.10

Year Day 2005

Tide [m] Current [m/sec] Shear [1/sec]

FIGURE 8. Relationship between tides, flow and vertical shear off the starboard side. The current speeds are parallel to the hull; 

z-values are heights above the seafloor. Note that the shear is due to the strong gradient in current speed through the water column, 

with the near-surface speeds almost an order of magnitude greater than those near the seafloor.
95 100 105 110 115 120

-0.5

0

0.5

95 100 105 110 115 120

-0.05

0

0.05

95 100 105 110 115 120

0

0.05

0.10

red = 8m, blue = 1m

Year Day 2005

Tide [m] Current [m/sec] Shear [1/sec]

FIGURE 9. Relationship between tides, flow and vertical shear off the port side. The current speeds are parallel to the hull; z-values 

are heights above the seafloor. Note that unlike of the starboard side of the hull, the shear off the port side is due to the strong gradient 

in current direction through the water column, with the near-surface speeds often in the opposite direction of those near the seafloor.
-0.04 -0.03 -0.02 -0.01 0 0.01 0.02 0.03 0.04

1

2

3

4

5

6

7

8

Hull-ward Current Velocity [m/sec]

Elevation above the Seafloor [m]

0 0.5 1 1.5 2 2.5 3 3.5 4

1

2

3

4

5

6

7

8

Current-induced Force per Area [N/m ]2

Elevation above the Seafloor [m]

FIGURE 10. Vertical profiles of current velocity and the resulting current-induced force on the starboard hull. Dashed red lines are ± 1 

standard deviation. Note that flow is towards the hull throughout most of the water column but is away from the hull at the surface. 
-0.04 -0.03 -0.02 -0.01 0 0.01 0.02 0.03 0.04

1

2

3

4

5

6

7

8

0 0.5 1 1.5 2 2.5 3 3.5 4

1

2

3

4

5

6

7

8

Hull-ward Current Velocity [m/sec]

Elevation above the Seafloor [m]

Current-induced Force per Area [N/m ]2

Elevation above the Seafloor [m]

FIGURE 11. Vertical profiles of current velocity and the resulting current-induced force on the port hull. Dashed red lines are ± 1 

standard deviation. Note that flow is towards the hull throughout the entire water column except near the bed.
Assuming flow speeds remained constant, the mean current s measured would

result in a total replacement of water along the 185 m length of the hull in 1.84 to 5.14

hours off the starboard (northwestern) side of the hull at the surface and the seafloor,

respectively, and 2.23 to 1.90 hours off the port (southeastern) side of the hull at the

surface and the seafloor, respectively. Because the shear-induced turbulence

enhances these mean flow speeds, the actual replenishment time would probably be

shorter. The orientation of greatest flow variability and mean flow is approximately

parallel to the hull, Ford Island and the southwest-northeast trend of the East Loch

throughout most of the water column. Close to the bed, however, the orientation of flow

becomes less distinct and sometime orthogonal to the hull (trending east-west), similar

to the long-term near-bed observations made by Storlazzi et al. (2004).

The lunar tidal cycle drives the magnitude of the tidal currents, with the highest

tidal current speeds occurring during spring tides (new and full moons) and the weakest

during neap tides (quarter moons). While tides control the majority of the variability in

current speed and direction, insolation-driven Trade wind intensification also appears to

slightly influence daily variability. When the Trade winds blow at high speed in the early

to late afternoon, the net flow appears to take on a more northerly component. This

shift might be due to the Trade winds blowing obliquely onshore to the northwest along

Oahu’s southern shoreline, which forces oceanic water up into Pearl Harbor. We do not

have information at this time that indicates which process or combination of processes

is responsible for the observed intensification of northeasterly flow during the afternoon.

Temperature

Over the period of study, the water off the starboard (northwestern) side of the

hull at a depth of 9 m had a mean temperature ± one standard deviation of 25.11 ± 0.35

°C and at a depth of 10 m off the port (southeastern) side of the hull the mean

temperature ± one standard deviation was 25.10 ± 0.29 °C (FIGURE 12). Overall, the

variability in water temperature was greater off the starboard (northwestern) side of the

hull between the hull and Ford Island. In general, the near-bed water off the starboard

(northwestern) side of the hull was slightly (0.02 ± 0.10 °C) warmer that off the port

(southeastern) side of the hull. The greater stability off the port (southeastern) side of

the hull is likely caused by greater mixing due to currents, which act to minimize

temperature fluctuations caused by insolation or submarine groundwater discharge. We

do not have information at this time that indicates that these processes are the cause of

the temperature differences between the two sites. At both sites, insolation typically

warmed the water during the day by approximately 0.1 °C.

CONCLUSIONS

In all, more than 580,000 observations of currents and near-bed water

temperatures were collected during April, 2005, in Pearl Harbor, Oahu, Hawaii, USA.

Significant findings based upon these measurements and analyses include:

(1) Tides are of mixed, semi-diurnal type with a minimum, mean and maximum tidal

range of 0.4 m, 0.6 m and 0.9 m, respectively.
95 100 105 110 115 120

24.2

24.4

24.6

24.8

25.0

25.2

25.4

25.6

95 100 105 110 115 120

-0.5

0

0.5

Year Day 2005

red = starboard side of hull

blue = port side of hull

Temp [deg C] Starboard Temp - Port Temp [deg C]

FIGURE 12. Concurrent water temperatures off the port and starboard sides of the hull and the 

resulting thermal gradient. While both the port and starboard temperatures both follow the same 

long-term trends, note the greater fluctuations in water temperature off the starboard side; this 

likely results from less mixing of the water column off the starboard side.
(2) Flow along the hull is dominated by semi-diurnal and diurnal tidal motions, which

are modulated to some degree by what appears to be wind forcing during the

mid- to late afternoon. Flow throughout most of the water column is primarily

parallel to the Arizona’s hull at ~ 0.02 m/sec and net flow is to the northeast.

Flow within a meter of the seafloor, however, is weaker and more variable in

direction.

(3) Flow speeds are faster off the port side than the starboard side, and thus the

water replenishment times on the port side of the hull are shorter than off the

starboard side.

(4) Shear, both vertically in the water column and across the hull, was observed.

This results in vertical variations in replenishment times and current-induced

forces on the hull. This shear also likely increases vertical mixing of the water

column.

(5) Water temperatures were generally cooler and less variable off the port side of

the hull than off the starboard side, possibly due to faster replenishment times

and greater mixing of the water column.

These data provide us with a much clearer picture of the nature of and controls

on the fluid flow around USS Arizona’s hull in Pearl Harbor, Oahu, Hawaii. The

complexity of the physical environment surrounding and influencing Arizona is reflected

in the number of interesting phenomena observed during this one month study.

ACKNOWLEDGEMENTS

This work was carried out as part of a NPS-USGS partnership as part of an effort

in the U.S. and its trust territories to better understand and characterize the nature of

and variability in coastal processes. NPS-SRC Chief Larry Murphy and USGS Project

Chief Michael Field deserve thanks for providing us with the patience, opportunity and

support to carry out this work. Joshua Logan (USGS) assimilated the NPS GIS data

and produced the maps presented in this report. We would also like to thank Jodi

Eshleman (USGS) and Ann Gibbs (USGS), who contributed numerous excellent

suggestions and a timely review of our work.

REFERENCES

Storlazzi, C.D., Russell, M.A., Owens, M.D., Field, M.E. and Murphy, L.E., 2004.

“Dynamics of the Physical Environment at the USS Arizona Memorial: 2002-2004” U.S.

Geological Survey Open-File Report 2004-1353, 28 p.

http://pubs.usgs.gov/of/2004/1353/
TABLE 1. Experiment personnel

Person Affiliation Responsibilities

Curt Storlazzi USGS Chief scientist, scuba diver

Matthew Russell NPS-SRC Co-chief scientist, led scuba diving operations

Kathy Presto USGS Scientist, lead instrument technician

Jennifer Burbank NPS-USAR Memorial USAR Memorial ranger, diver, led recovery operations

Joshua Logan USGS Scientist, diver, GIS tecchnician

Thomas Reiss USGS Scientist, dive safety officer

TABLE 2. ADCP deployment log

Instrument Island ID Depth

(m)

Deployment

Date

Recovery

Date

Latitude

(dd)

Longitude

(dd)

Starboard OA 9 4/2/2005 5/1/2005 21.364684 -157.950756

Port OA 10 4/2/2005 5/1/2005 21.364206 -157.950550
APPENDIX 1

Acoustic Doppler Current Profiler (ADCP) Information

Instrument:

RD Instruments 600 kHz Workhorse Monitor; s/n: 2074

RD Instruments 600 kHz Workhorse Monitor; s/n: 2432

Transmitting Frequency: 614 kHz

Depth of Transducer: 10 m

Blanking Distance: 0.30 m

Height of First Bin above Bed: 0.80 m

Bin Size: 0.5 m

Number of Bins: 28

Operating Mode: High-resolution, broad bandwidth

Sampling Frequency: 4 Hz

Beam Angle: 20 deg

Time per Ping: 00:00:00.30

Pings per Ensemble: 1

Ensemble Interval: 00:04:00.00

Sound Speed Calculation: Set salinity, updating temperature

via sensor

Data Processing:

The data were averaged over 20-bin (1 hour) ensembles, all of the

spurious data above the water surface were removed and all of the data in bins

where the beam correlation dropped below 70% were removed for visualization

and analysis.

Position Information:

Garmin GPS-76 GPS; s/n: 80207465; USGS/CRP unit#1

RDI internal compass/gyroscope, set to –10 deg magnetic offset