CO-OPS Current Meter Reconnaissance Procedures 

National Current Observation Program 

Center for Operational Oceanographic Products and Services 

National Ocean Service 

National Oceanic and Atmospheric Administration 
TABLE OF CONTENTS 

1. INTRODUCTION................................................................................................................. 1

2. BACKGROUND ................................................................................................................... 1

3. TYPES OF STATIONS........................................................................................................ 2

4. EQUIPMENT NEEDED ...................................................................................................... 2

5. OFFICE INFORMATION................................................................................................... 3

6. SITE VISIT............................................................................................................................ 3

7. DOCUMENTATION............................................................................................................ 4

APPENDIX A – SITE RECONNAISSANCE FIELD NOTES ................................................ 5
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1. Introduction 

The National Ocean Service (NOS), Center for Operational Oceanographic Products and 

Services (CO-OPS), operates a number of short and long term environmental monitoring 

systems. CO-OPS provides the infrastructure, science, and technical expertise to monitor, 

assess, and disseminate coastal oceanographic and Great Lakes products and services 

necessary to support NOS missions of environmental stewardship, assessment, and 

prediction; safe navigation; and hazard mitigation. 

In order to support the NOS and CO-OPS missions, new current meter stations are regularly 

required. The best method for assembling the information needed to deploy these stations is 

a reconnaissance. The primary objective of the reconnaissance is to determine where the best 

location for the current meter will be. It is necessary to obtain the longitude, latitude, bottom 

type, depth, salinity, and observe any coastal hazards/obstructions around the sites. The 

reconnaissance consists of personnel visiting the site sufficiently far in advance of site 

preparation to: 

• Locate an acceptable site. 

• Compare predictions to observations during the recon 

• Obtain measurements and information necessary to design the station. 

• Arrange for any permits/license agreements required. 

• Arrange for utilities (when needed for side-looking current meters). 

• Prepare a cost estimate and work schedule. 

• Allow time for the procurement and fabrication of special support components (if 

necessary). 

A proper field reconnaissance for current meter stations is accomplished on a boat, onsite, by 

taking bottom grab samples; observing tide stage and general current speed and direction; 

CTD (Conductivity-Temperature-Depth) measurements; GPS measurements; and fathometer 

readings. 

When applicable, property owners should be contacted in advance to obtain oral or written 

permission to use or modify the site; otherwise, meet with the property owner as soon as the 

site is visited. An advance letter of permission, permit, security clearance, or some other 

written instrument may be required by the owner. A license agreement may have to be 

executed before any work can be done. 

Once the reconnaissance information is collected and a report issued, the proper mount type 

is chosen, and a cost estimate and deployment schedule can be determined. 

2. Background 

NOS is a Federal agency devoted to exploring, understanding, conserving, and restoring the 

Nation's coasts and oceans. NOS promotes safe navigation, supports coastal communities, 

sustains coastal habitats, and mitigates coastal hazards. NOS balances environmental 
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Procedures, Updated April 2007

protection with economic prosperity and leads the effort to ensure that our Nation's coastal 

areas remain safe, healthy and productive. 

CO-OPS establishes standards for the acquisition and processing of water level and current 

data; collects and documents user requirements that serve as the foundation for all resulting 

program activities; designs new and/or improved oceanographic observing systems; develops 

software to improve data processing capabilities; maintains and operates oceanographic 

observing systems; performs operational data analysis/quality control; produces/disseminates 

oceanographic products; and archives the resulting oceanographic data. 

A standard current meter station is a stand alone station that is deployed on the ocean bottom, 

in a sub-surface platform, or attached to a pier or other structure for horizontal 

measurements. The primary requirement of a station is to accurately measure current speed 

and direction that is representative of the area’s flow with low power consumption and high 

reliability. The typical station includes a current meter housed in a trawl resistant bottom 

mount or subsurface float; an acoustic release; a transponding locator device; and either cable 

for mounting or line for recovery purposes. 

3. Types of Stations 

There are several types of stations that CO-OPS deploys that are dependent on different 

characteristics of the site, such as water depth and bottom type. They are: 

• Bottom Mounted Current Meter 

a) Trawl Resistant Bottom Mount 

b) Self-contained 

c) Acoustic release for deployment and recovery 

• Subsurface Float Current Meter 

a) Subsurface float 

b) Anchored to bottom 

c) Acoustic Releases for recovery 

• Side/Horizontal Looking Current Meter 

a) Mounted to pier or other hard substrate 

b) Measures one depth across the water basin 

c) Usually Real-time 

d) Utilities (phone and electric) needed 

e) Normally requires divers to install 

4. Equipment Needed 

The following equipment, forms, and information are needed to perform a complete 

reconnaissance: 

• Digital Camera/Videotape Recorder 

• Sample License Agreement/Letter of Permission (if applicable) 

• Bottom Grab Sampler with pan to dump sample 

• CTD unit with weights and line to cast to bottom 
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• Hand-held GPS 

• Compass 

• Chartlet 

• Depth Sounder/Fathometer 

• Range Finder 

• Site Reconnaissance Field Notes form (Appendix A) 

• Field Reconnaissance Log 

5. Office Information 

After a general region has been selected for the deployment of a current meter, the first step 

is to gather all relevant information. In many cases, the site is a previously occupied site and 

the latitude and longitude are known to a certain margin of error. In other cases, CO-OPS 

determines the latitude and longitude for the reconnaissance, and must make adjustments 

after the field reconnaissance either due to depth limitations or other obstructions. 

Some office information that can be gathered prior to the reconnaissance is general chartlet 

information about the site and the bottom characteristics. High resolution bathymetry of the 

area should be obtained either from NOS or USACE. Coast Pilot should be checked for 

relevant information, including hazards, tide type, currents, marinas, etc., as should any web 

sites about the area under consideration. 

Meters are not deployed while a waterway is undergoing dredging, unless it is maintenance 

dredging that will be completed before the reconnaissance and field deployments. 

An analysis of the existing predictions should be done and all historic data, analysis and 

reports from previous CO-OPS current surveys should be located and retrieved and taken 

into consideration. 

Other information of importance may include requests received by CO-OPS from pilots, 

USACE, USGS, HAZMAT or others for current measurements at specific locations. 

 

It is good to have an understanding of the weather, currents, ship traffic, or other obstacles 

you will encounter while on site and to make note of them on the logs once on site. 

6. Site Visit 

After compiling all information possible in the office, it is time to visit the site. Upon arrival 

at the general location, proceed to the precise site determined from the office documents. 

Use the Site Reconnaissance Field Notes form in Appendix A to record all information and 

fill out the Site Reconnaissance Field Log. The Log is embedded in this document for 

reference only. 

A separate fillable pdf file (ReconLog.pdf) should be filled out for every site (attached under 

separate cover). 
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All NOAA safety regulations will be followed. 

All fields in the Site Recon Log should be filled in as accurately as possible. 

A tentative name for the site should be recorded. This should be representative of the area 

and its surroundings. ( e.g. Approach to Juneau Harbor, or Seal Rock, SE of). CO-OPS will 

determine the final names after recon is complete. 

Record the time of observations in Greenwich Mean Time (GMT). Recon can occur at any 

stage of tide, as long as it is noted on the recon log what time of day and what stage of tide it 

is, and what the apparent current direction and speed are. 

The latitude and longitude will be recorded to at least 6 decimal places in decimal degree 

format. If degrees and decimal minutes are given, the requirement is three decimal places for 

minutes. 

A depth sounding in feet or meters will be recorded and units specified. CO-OPS typically 

does not deploy sub surface meters greater than 120 fathoms or bottom mounted meters 

greater than 120 ft (so a diver can reach the bottom safely if a diver-assisted recovery is 

necessary). 

A CTD cast will determine salinity for the location in question, which will be used to 

configure the current meter profiling settings. 

A bottom grab sample will be obtained to determine the bottom type for deciding what 

platform to use (these should conform to standard nautical chart conventions, i.e. soft mud, 

small pebbles, hard mud, large boulders, fine sand, shells, etc,). The sample should be 

photographed and observed and then discarded. There is no necessity for CO-OPS to have 

the physical sample after it is logged. CO-OPS does not typically deploy bottom mounts in 

extremely soft mud. If soft mud is encountered, it is suggested that the vessel move a few 

100 yards from the site and take another bottom grab to investigate the bottom substrate. 

Hazards should be observed and recorded. These include other vessel traffic, seafloor cable 

crossings, bridges, and USCG buoys. It should be reported if the seafloor bottom is uneven, 

or a canyon is encountered. 

Digital images should be taken of the bottom grab sample, buoys or large ships passing that 

characterize vessel traffic. In addition, if the current meter is going to be a side looking 

meter, photos of the pier and other structures should be taken. 

Other information that is helpful to the successful deployment of the current meter should be 

noted. 
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7. Documentation 

Submit the following documentation upon completion of the reconnaissance: 

• Site Reconnaissance Field Notes and Log 

• All digital photos 

• CTD data
Appendix A – Site Reconnaissance Field Notes 

National Oceanic and Atmospheric Administration 

National Ocean Service 

Center for Operational Oceanographic Products and Services 

National Current Observation Program 

Field Reconnaissance Log

Project:_____________________ CO-OPS Project Lead:__________________

Body of Water:_______________ Tentative name of site: ________________

Chartlet #: __________________ Nearest Landmark: ___________________

Date:_______________________ Time of Observations(GMT):____________

Latitude (°N):_________________Longitude (°W):______________________ 

Vessel:______________________ Captain:____________________________

Weather: _______________________________________________________

Field Party: 

_______________________________________________________________

_______________________________________________________________

Log Filled in By:__________________________________________________ 

Recorded Depth: (circle m or ft)________ Depth Source:_________________

General Current Direction: _________________________________________ 

Current Speed – if observable (knots):________________________________

Tide Stage (high, low, slack)__________ Nearest Tide Gauge: ____________ 

CTD file name:___________________________________________________

CTD observations: (include CTD make/model/SN) 

_______________________________________________________________

_______________________________________________________________

Bottom Grab description: (include Sampler make/model/SN) 

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

Vessel traffic observations: (i.e.: Cruise, Cargo, Ferries, Tugs, Pleasure, etc) 

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

Other (Descriptive characteristics of site, obstructions, buoys, cabling areas, 

local knowledge, etc..): 

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

Please attach any digital photos or sketches you make of the area.