T3004 - Exhibit #4 ACOE Hydrographic Surveying Manual 9.27.24.pdf

EM 1110-2-1003

30 November 2013

US Army Corps of Engineers

ENGINEERING AND DESIGN

Hydrographic Surveying

ENGINEER MANUAL

25DPP01080 T3004 - Waterway Debris Assessment Services for Disasters Exhibit #4

30 Nov 13

THIS PAGE INTENTIONALLY LEFT BLANK

CECW-CE I CECW-OD

DEPARTMENT OF THE ARMY

U.S. Army Corps of Engineers Washington, DC 20314-1000

Manual No. 1110-2-1003 30 November 2013

Engineering and Design

HYDROGRAPHIC SURVEYING

1. Purpose. This manual provides technical guidance for specifying requirements and performing hydrographic surveys of USACE river and harbor navigation projects, water control projects, and shore protection projects.

2. Applicability. This manual applies to all USACE commands having responsibility for civil works navigation, dredging, flood risk management, multi-purpose water supply/control, coastal storm damage reduction, hurricane protection, and hydropower projects.

3. Distribution Statement. This publication is approved for public release; distribution is unlimited.

4. Discussion. Hydrographic surveys are performed to provide underwater site plan data for nearly all USACE civil works activities. These projects primarily include channel condition, measurement, payment, and clearance surveys of coastal Federal navigation channels, inland river and intracoastal navigation projects, reservoirs, and underwater structural surveys at locks and dams. Also included are surveys for various coastal engineering projects, beach renourishment and restoration projects, shoreline protection structure construction (breakwaters and jetties), and river stabilization structures. Hydrographic survey systems developed during the past decade have become increasingly complex, requiring the integration of acoustic multibeam sonar systems with differential GPS positioning systems and inertial vessel orientation/alignment systems. Acoustic depth measurements now utilize sophisticated beam forming phase detection, interferometric, synthetic aperture, and backscatter signal processing methods. The quality control and quality assurance guidance in this manual is intended to increase the overall confidence in reported navigation project clearances and the measured elevations of water control and shore protection projects.

FOR THE COMMANDER:

18 Appendixes (See Table of Contents)

R. MARK TOY, P.E

Colonel, Corps of En Chief of Staff

This manual supersedes EM 1110-2-1003, dated 1 January 2002.

i

DEPARTMENT OF THE ARMY EM 1110-2-1003

US Army Corps of Engineers

CECW-CE/CECW-OD Washington, DC 20314-1000

Manual No. 1110-2-1003 30 November 2013

Engineering and Design

HYDROGRAPHIC SURVEYING

TABLE OF CONTENTS

Paragraph Page Chapter 1. Introduction

Purpose ...........................................................................................1-1 1-1 Applicability ....................................................................................1-2 1-1 Distribution ......................................................................................1-3 1-1 References .......................................................................................1-4 1-1 Discussion........................................................................................1-5 1-1 Abbreviations and Acronyms .........................................................1-6 1-1 Hydrographic Survey Support to Corps Civil Works Activities..1-7 1-1 Use and Scope of Manual ...............................................................1-8 1-3 Hydrographic Surveying Requirements during Project Phases ...1-9 1-4 Geospatial Data Policy ...................................................................1-10 1-4 Metrics .............................................................................................1-11 1-5 Trade Name Exclusions ..................................................................1-12 1-5 Manual Development......................................................................1-13 1-5 Proponency ......................................................................................1-14 1-6

Chapter 2. Overview of Hydrographic Surveys for Civil Works Navigation and Water Control Projects

Required Supplemental References ...............................................2-1 2-1

Section I: Overview of Hydrographic Survey Techniques General Hydrographic Survey Methods ........................................2-2 2-1 Survey Coverage Options ..............................................................2-3 2-2 Survey Line Spacing and Alignment Specifications ....................2-4 2-3 Horizontal Positioning Methods and Datum Specifications ........2-5 2-5 Vertical Datum Specifications .......................................................2-6 2-6 Water Surface Elevation Measurement Specifications.................2-7 2-6 Vessel Motion and Orientation Requirements ..............................2-8 2-7 Quality Control and Quality Assurance.........................................2-9 2-8 Miscellaneous Survey Requirements .............................................2-10 2-8 ii

Section II: General Planning Considerations General .............................................................................................2-11 2-9 Determining Project Accuracy Requirements ...............................2-12 2-11 Determining Required Data Density..............................................2-13 2-12

Section III: Vessel Selection Considerations General Considerations...................................................................2-14 2-13 Vessel and Equipment Acquisition ................................................2-15 2-15

Section IV: Data Processing, Editing, Depth Selection, and Plotting Options Hydrographic Data Processing Flow .............................................2-16 2-15 Initial Field Data Review and Editing ...........................................2-17 2-16 Office Data Editing and Processing ...............................................2-18 2-17 Depth Selection Options .................................................................2-19 2-18 Hard Copy Plot Options .................................................................2-20 2-20 Selecting Representative Depths on Plan Drawings .....................2-21 2-21 Terrain Modeling ............................................................................2-22 2-22 Data Submittal to District Office Project/Design Engineer .........2-23 2-22 Retention of Hard-Copy Depth Records .......................................2-24 2-23

Section V: Estimating Costs for Hydrographic Surveys of Navigation Projects Factors to Consider in Estimating Survey Time ...........................2-25 2-23 Plant Rental Rates ...........................................................................2-26 2-25 Crew Labor Rates............................................................................2-27 2-25 Effective Daily Field Survey Crew Rates .....................................2-28 2-25 Survey Time and Cost Estimates ...................................................2-29 2-25

Section VI: Decision Matrix: Single Beam v Multibeam Surveys

Chapter 3. Recommended USACE Accuracy Standards for Federal Navigation Projects

Purpose and Scope ........................................................................3-1 3-1 Discussion ......................................................................................3-2 3-2 Quality Assurance Performance Tests ........................................3-3 3-2 Total Propagated Uncertainty Accuracy Estimates ....................3-4 3-4 Recommended USACE Depth Accuracy Standards for Engineering and Construction Surveys.....................................3-5 3-4 Horizontal Accuracy Standards ....................................................3-6 3-7 IHO Standards for Hydrographic Surveys ...................................3-7 3-7 iii

Chapter 4. Single Beam Depth Measurement Systems

General Scope and Applications ..................................................4-1 4-1 References ......................................................................................4-2 4-1

Section I: Principles of Acoustic Single Beam Depth Measurement Overview ........................................................................................4-3 4-1 Single Beam Transducer and Frequency Specifications .............4-4 4-3 Echo-Sounder Control Settings ....................................................4-5 4-5 Single Beam Power and Receiver Sensitivity Effects ................4-6 4-7

Section II: Single Beam Echo Sounders and Auxiliary Sensors Single Beam Echo Sounding Evolution in USACE ....................4-7 4-9 Single Beam Transducer Mounting Locations ............................4-8 4-10 Motion Correction on Single Beam Systems--Vessel Heave, Roll, Pitch, and Yaw ..................................................................4-9 4-10

Section III: Single Beam Quality Control Calibrations Bar Check Calibration of Single Beam Echo Sounders..............4-10 4-15 Depth Corrections Based on Bar Check Data .............................4-11 4-20 Velocity Meter Calibration ...........................................................4-12 4-24 Squat and Settlement Calibration .................................................4-13 4-27 Vessel Dynamic Draft Calibrations..............................................4-14 4-29 Latency Calibrations .....................................................................4-15 4-29

Section IV: Data Collection, Editing, and Processing Single Beam Survey Methods ......................................................4-16 4-30 Depth Collection Density and Bottom Coverage ........................4-17 4-30 Field Collection of Single Beam Survey Data.............................4-18 4-33 Editing and Processing Single Beam Data ..................................4-19 4-34 Depth Selection and Thinning Options on Single Beam Data ...4-20 4-34

Section V: Single Beam System Quality Assurance Performance Tests Depth Quality Assurance Techniques for Single Beam Surveys .................................................................4-21 4-36

Section VI: Summary of Quality Control and Quality Assurance Criteria for Single Beam Surveys iv

Chapter 5. Multiple Transducer Channel Sweep Systems for Shallow Draft Navigation Projects

General Overview..........................................................................5-1 5-1 Background ....................................................................................5-2 5-1 Design of Channel Sweep Systems ..............................................5-3 5-2 General Survey Operation ............................................................5-4 5-4 Multiple Transducer System Quality Control and Quality Assurance. ...................................................................5-5 5-5 Selecting Recorded Depths and Estimated Accuracies...............5-6 5-8

Section I: Examples of Corps Multiple Transducer Survey Systems Mobile District Tuscaloosa Site Office Sweep Systems.............5-7 5-9 St. Louis District Ross 875-4 Shallow Water Portable Sweep System ..............................................................5-8 5-12 New York District Sweep System ................................................5-9 5-13 St. Paul District Sweep System ....................................................5-10 5-13 Rock Island District Sweep System ............................................5-11 5-15 Philadelphia District Sweep System. ...........................................5-12 5-15 Jacksonville District Raytheon 719 CSS (Channel Sweep System) ...........................................................5-13 5-16 Detroit District 120-Ft Strike Detection Systems. ......................5-14 5-16

Section II: Recommended Quality Control Checklist for Multiple Transducer Sweep Systems

Chapter 6. Acoustic Multibeam Survey Systems

General Scope and Applications ..................................................6-1 6-1 Background ....................................................................................6-2 6-1 General USACE Applications ......................................................6-3 6-2

Section I: Principles of Multibeam Depth Measurement General ..........................................................................................6-4 6-2 Depth Measurement Principles.....................................................6-5 6-2 Overall System Requirements ......................................................6-6 6-7 References ......................................................................................6-7 6-8 v

Section II: Multibeam Applications and Utilization on USACE Civil Works Projects General ...........................................................................................6-8 6-9 Project Condition Surveys ............................................................6-9 6-9 Dredging Measurement and Payment Surveys............................6-10 6-9 Shoal or Strike Detection Applications ........................................6-11 6-10 Underwater Structure Investigation Surveys ...............................6-12 6-11 Multibeam Sidescan Imagery .......................................................6-13 6-11 Miscellaneous Considerations ......................................................6-14 6-11

Section III: Configuring Multibeam Transducers on Corps Floating Plant General ...........................................................................................6-15 6-12 Fixed Hull-Mounted Systems .......................................................6-16 6-13 Through-Hull Transducer Mountings ..........................................6-17 6-14 Bow-Mounted Transducers ..........................................................6-18 6-14 Side Mounted Transducers ...........................................................6-19 6-15 Stern-Mounted Multibeam Transducers ......................................6-20 6-20

Section IV: Quality Control Procedures for Multibeam Systems Background ....................................................................................6-21 6-22 Initial Installation Alignment and Static Offset Measurements .6-22 6-23 Vessel Squat/Settlement, Draft, and Datum Variations ..............6-23 6-26 Patch Test (Residual Bias Calibration) .......................................6-24 6-26 Velocity Measurements.................................................................6-25 6-30 Vessel Draft and Index Measurements (Bar Checks) ................6-26 6-32 Beam Width Restrictions on Multibeam Systems.......................6-27 6-33

SectionV: Multibeam Survey Data Collection, Editing, and Processing Determining Coverage and Overlap.............................................6-28 6-34 Editing and Processing Multibeam Data......................................6-29 6-36 Editing and Filtering Data.............................................................6-30 6-37 Thinning and Binning Multibeam Datasets ................................6-31 6-38 Recommended Bin Sizes and Depth Selection for USACE Navigation Surveys .....................................................6-32 6-38 Depth Selection Options from Binned Multibeam Data .............6-33 6-39 vi

Section VI: Quality Assurance Performance Tests on Multibeam Systems General ...........................................................................................6-34 6-39 Performance Test Procedures .......................................................6-35 6-42 Multibeam versus Single Beam Performance Tests....................6-36 6-45 Real-time Quality Assurance Tests ..............................................6-37 6-45 Sample Performance Test—Survey Vessel Shuman (Philadelphia District) ................................................................6-38 6-45 Fixed Calibration Barge (Louisville District) .............................6-39 6-46

SECTION VII: Summary of Multibeam QC and QA Criteria

Chapter 7. GPS Positioning, Orientation, and Water Surface Elevation Measurement

Purpose ...........................................................................................7-1 7-1 Scope ..............................................................................................7-2 7-1 Required References .....................................................................7-3 7-1 GPS Background and Applications in USACE ..........................7-4 7-2 GPS Accuracies .............................................................................7-5 7-3 Reference Datums .........................................................................7-6 7-3

Section I: Code Phase Differential GPS Positioning Real-Time Code Phase DGPS ......................................................7-7 7-3 USCG Code Phase DGPS Radiobeacon Navigation Service .....7-8 7-4 Commercial Differential Navigation and Positioning Systems..7-9 7-5 Position Quality Control Tolerance Checks ................................7-10 7-7

Section II: Real-Time Kinematic Carrier Phase GPS Positioning Real-Time Kinematic (RTK) ........................................................7-11 7-8 RTK System Requirements ..........................................................7-12 7-9 Real-Time Networks (RTN) .........................................................7-13 7-10 Inertial-Aided Post-Processed Kinematic (IAPPK) Position and Elevation Computations .......................................7-14 7-10

Section III: RTK Water Surface Elevation Measurement RTK Surface Elevation Requirements in Coastal Navigation Projects.......................................................7-15 7-12 RTK Tide Corrections ...................................................................7-16 7-13 Heave Correction Options from RTK Measurements.................7-17 7-16 KTD File Generation from VDatum ............................................7-18 7-16 vii

Section IV: Vessel Motion and Orientation Measurement Motion Reference Units (MRUs) .................................................7-19 7-17 Inertial Aided GPS Motion Measurement ...................................7-20 7-18 Vessel Heave Corrections and Considerations ............................7-21 7-20 Recommended Quality Control Criteria for GPS Positioning Methods .........................................................7-22 7-22

Chapter 8. Coastal Navigation Project Channel Condition Surveys

Purpose ...........................................................................................8-1 8-1 Scope ..............................................................................................8-2 8-1 References ......................................................................................8-3 8-1 Overview ........................................................................................8-4 8-2 Condition Survey Standards and Specifications..........................8-5 8-2 Topographic Feature Standards for Condition Surveys ..............8-6 8-3 Hard Copy Map Scales and Formats ............................................8-7 8-4 Feature Content and Digital Data File Standards. .......................8-8 8-7 Internet Posting of Project Condition Surveys ............................8-9 8-7 Channel Framework Data .............................................................8-10 8-8 Channel Condition Survey Drawing Notes .................................8-11 8-8 Tabular Channel Condition and Controlling Depth Reports ......8-12 8-10 HYPACK Channel Condition Reporter (CCR) ...........................8-13 8-11

Chapter 9. Surveys of Navigable Inland Rivers, Locks and Dams, River Stabilization Structures, and Reservoir Surveys

General Applications .....................................................................9-1 9-1 Survey Equipment, Vessels, and Methods...................................9-2 9-2 Inland River Charting Surveys. ....................................................9-3 9-4 River Lock and Dam Investigation Surveys ................................9-4 9-6 River Stabilization Structure Surveys ..........................................9-5 9-8 Underwater Structure and Revetment Surveys............................9-6 9-8 Levee Breech Surveys ...................................................................9-7 9-9 Mississippi River Sand Wave Mapping .......................................9-8 9-9

Section I: Hydrographic Surveys for River Hydraulics Studies Background ....................................................................................9-9 9-11 Cross-Sections for Hydraulic Studies ..........................................9-10 9-12 Hydraulic Engineering Guidance on Cross-Section Locations ..9-11 9-16 Hydraulic Cross-Sections Adjacent to Bridges or Culverts .......9-12 9-18 Required Accuracy of Hydraulic Cross-Section Data ................9-13 9-20 viii

Section II: Hydrographic Surveys of Reservoirs and other Impounded Areas Reservoir Surveys..........................................................................9-14 9-22 Surveys of an Earth and Rockfill Dam. .......................................9-15 9-27

Section III: Summary of Recommended Accuracy and Performance Standards for Inland Surveys

Chapter 10. Construction Dredging Measurement, Payment, and Clearance Surveys

General Scope ................................................................................10-1 10-1 Background ....................................................................................10-2 10-1 Types of Dredging Support Surveys ............................................10-3 10-2 Dredge Contracting and Production Measurement Methods .....10-4 10-4 Definitions of Dredging Grades ...................................................10-5 10-6 Factors Impacting Survey Coverage and Accuracy Requirements .............................................................10-6 10-8 Measurement, Payment, and Acceptance Survey Contract Specifications ..............................................................10-7 10-9 Measurement and Payment Surveys Performed by Other than Corps Hired-Labor...................................................10-8 10-11

Section I: Channel Clearance Surveys Definitions .......................................................................................10-9 10-12 Channel Clearance Bar Sweeps ....................................................10-10 10-13 Acoustic Evaluation of Clearances on Dredging Projects ..........10-11 10-16 Evaluating Clearance Grades in Unconsolidated Material .........10-12 10-23 Side Scan Sonar .............................................................................10-13 10-23 Combined Uncertainty and Bathymetry Estimator (CUBE) ......10-14 10-23

Section II: Dredge Payment Volume Calculations Dredge Quantity Computation Techniques—Background .........10-15 10-25 Average End Area Method ...........................................................10-16 10-26 Surface Differencing Methods—“TIN Models” .........................10-17 10-27 Grid or Bin Vertical Projection Methods .....................................10-18 10-27 Average End Area Computation ..................................................10-19 10-27 Reference Surfaces and Payment Templates used in Corps .......10-20 10-28 ix

Section III: Average End Area Computation Methods Background ....................................................................................10-21 10-30 Box Cut Allowance .......................................................................10-22 10-31 Cross-Section End Area and Volume Computations ..................10-23 10-33 HYPACK Average End Area Dredge Volume Computations ...10-24 10-36 Average End Area Computations on Irregular Channels or Non-Parallel Sections.................................................................10-25 10-41

SectionIV: Surface Differing Volume Computations (Triangulated Irregular Networks) Background ....................................................................................10-26 10-44 Computing Dredge Volumes from TIN Models .........................10-27 10-47 Overdepth Dredging Statistics (HYPACK DREDGESTATS) ..10-28 10-57 Evaluation of Dredge Quantity Estimates Based on Depth Accuracy and Density ......................................................10-29 10-57

SectionV: Recommended Guidance for Dredging Surveys and Quantity Computations Recommended Dredge Quantity Computation Procedures. .......10-30 10-63 Contract Guide Specifications for Multibeam Measurement and Payment. .......................................................10-31 10-64

Chapter 11. Coastal Engineering Surveys for Beach Renourishment Projects and Shoreline Protection Structures

Introduction....................................................................................11-1 11-1 Required Supplemental Reference ...............................................11-2 11-1 General Procedures .......................................................................11-3 11-2

Section I: Coastal Engineering Survey Techniques Differential Leveling Methods .....................................................11-4 11-7 Total Station Methods ...................................................................11-5 11-9 Real Time Kinematic GPS Methods ............................................11-6 11-10 Coastal Research Amphibious Buggy (CRAB) ..........................11-7 11-11 Survey Sled Methods ....................................................................11-8 11-12 Nearshore and Offshore Profile Acoustic Measurement Methods ...............................................11-9 11-13 LIDAR Bathymetry and Topography Methods ...........................11-10 11-15

Section II: Coastal Project Applications Beach Renourishment Measurement and Payment Surveys ......11-11 11-17 Offshore Jetty, Breakwater, and Groin Surveys ..........................11-12 11-20 Subsurface Probings ......................................................................11-13 11-23 x

Offshore Confined Placement or Borrow Area Surveys.............11-14 11-26

Section III: General Guidance on Survey Requirements for Coastal Engineering Studies Coastal Engineering Studies .........................................................11-15 11-28 Accuracy Requirements for Studies .............................................11-16 11-30 Data Density, Formats, Processing and Archiving .....................11-17 11-30 Coastal Processes Affecting Surveys ...........................................11-18 11-31 Overview of Coastal Processes ....................................................11-19 11-32 Profile Closure ...............................................................................11-20 11-35 Tides and Other Water Level Changes ........................................11-21 11-35 Survey Planning Considerations ..................................................11-22 11-36 xi

Appendices Page

A References…………………………………………………………………...A-1

B Manual Depth Measurement Techniques……………………………………B-1

C Contracted Survey Procedures and Cost Estimates………………………….C-1

D General Background on Hydrographic Survey Accuracy Estimates………...D-1

E IHO Standards for Hydrographic Surveys (S-44)……………………………E-1

F Multibeam Quality Control and Quality Assurance Procedures (North Atlantic Division Multibeam User Group)………………...................F-1

G Terrestrial (Non-GPS) Positioning Methods…….…………………………...G-1

H Kings Bay Entrance Channel Tidal Modeling for RTK Surveys (Jacksonville District)………………………………………….…………….H-1

I Implementation of Inertial-Aided Post-Processed Kinematic GPS Cape Canaveral, FL (Jacksonville District)………………………………….I-1

J Field Survey Report: Project Condition Survey Tampa Harbor, Egmont Bar Channel and Mullet Key Channel (Jacksonville District)………………………………………………………..J-1

K Channel Framework Data for Coastal Navigation Projects………………….K-1

L Almond Lake Reservoir Survey and Area Capacity Curves (Baltimore District)……………………………………………………….….L-1

M 2010 Allegheny River Multibeam/Side Scan Sonar Scour Survey (Pittsburgh District)………………………………………………………….M-1

N Application Examples of Underwater Structural Investigation Surveys…….N-1

O Howard Hanson Dam Monitoring Survey Report-Seattle District………......O-1

P Depth Measurement and Construction Payment in Unconsolidated Material……………………………………………………………………....P-1

Q Navigation Project Object Detection--Side Scan Sonar……………………..Q-1

Glossary……………………………………………………………...Glossary-1 xii

1-1

CHAPTER 1

Introduction

1-1. Purpose. This manual provides technical guidance for specifying requirements and performing hydrographic surveys of USACE river and harbor navigation projects, water control projects, and shore protection projects.

1-2. Applicability. This manual applies to all USACE commands having responsibility for civil works navigation, flood risk management, multi-purpose water supply/control, coastal storm damage reduction, hurricane protection, multi-purpose water supply/control, and hydropower projects.

1-3. Distribution. This publication is approved for public release; distribution is unlimited.

1-4. References. Referenced USACE publications and related bibliographic information are listed in Appendix A. Where applicable, primary source material for individual chapters may be noted within that chapter. Any required supplemental references are noted in each chapter.

1-5. Discussion. Hydrographic surveys are performed to provide underwater site plan data in support of nearly all USACE civil works activities. These support surveys include periodic condition assessments of coastal Federal navigation channels, inland rivers, intracoastal navigation projects, water control reservoirs, and underwater structural surveys at locks and dams. Also included are surveys that support various coastal engineering studies, beach renourishment and restoration construction, shoreline protection structure construction (breakwaters and jetties), and river stabilization structures. Hydrographic survey systems developed during the past decade have become increasingly complex, requiring the integration of acoustic multibeam (swath) sonar systems with carrier-phase GPS positioning systems and inertial vessel orientation/alignment systems. Acoustic depth measurements now employ sophisticated beam forming phase detection, interferometric, synthetic aperture, and backscatter signal processing methods. To reflect these newer developments, this manual establishes recommended accuracy and quality control standards to ensure uniform hydrographic surveying products; especially for construction dredging measurement, payment, and channel clearance assessment. The guidance in this manual is intended to enhance the equitability of contracted construction administration, and increase the overall quality and confidence in reported clearance or protection elevations in federal navigation and related shore protection or water control projects.

1-6. Abbreviations and Acronyms. Abbreviations and acronyms used in this manual are listed in the Glossary. Some abbreviations may be spelled out in each chapter for clarity.

1-7. Hydrographic Survey Support to Corps Civil Works Activities. Hydrographic surveying activities covered in this manual supports a wide range of civil works engineering and construction activities, ranging from federal navigation project dredging to surveys of wetlands.

1-2

This section describes some of the more common USACE activities or projects requiring hydrographic survey support.

a. Project condition surveys of federal navigation projects. The Corps is responsible for operating and maintaining over 900 federally authorized coastal navigation projects plus another 12,000 miles of inland and intracoastal navigation system channels. Periodic hydrographic surveys are performed over these authorized projects to determine the current condition and clearance of the navigation channels. These condition surveys are primarily used to determine if project conditions (e.g., shoaling) have changed enough to warrant maintenance dredging, if condition surveys are required at more frequent intervals, or if a greater survey coverage density is necessary. Drawings and/or project condition reports derived from these surveys are furnished to local sponsors, pilots, commercial navigation interests, and to other federal agencies, such as the U.S. Coast Guard (USCG) and the NOAA National Ocean Service (NOS). Condition surveys of inland navigation projects are used to modify project depth conditions for the monthly updates to the Inland Electronic Navigational Charts (IENC).

b. Construction dredging measurement and payment surveys. Dredge measurement and payment surveys encompass all work associated with dredging construction activities in USACE, most particularly those surveys performed to measure the amount of excavated, deposited, and/or placed material in subsurface or upland confinement areas. These surveys also include investigative studies used for preparing contract bid documents (estimated quantities) and for directly monitoring and measuring subsequent contract performance, payment, and acceptance.

These surveys require a high level of accuracy in both positioning and depth measurement so that payments will be equitable and consistent with the actual work performed. A significant portion of the Corps' in-house hydrographic survey resources are engaged in direct support of dredging operations; in particular on coastal navigation projects. A wide variety of vessels and survey equipment are used, depending on water depth, inland or coastal location, payment method (in-place or daily rate), and the type of material being dredged.

c. Underwater obstruction and investigation surveys. Hydrographic surveys are performed to locate and assist in the removal of obstructions in Federal navigation channels.

Surveys of jetties, breakwaters, locks, revetments, dikes, levees, and other river control structures are performed at regular intervals to assess the subsurface condition of the structures, such as scour, shoal build up, rock voids, etc. They are used to support a variety of engineering requirements. Side-scan sonar and multibeam sonar are typically used to detect obstructions or objects on the navigation channel bottom; in particular, after major storm events or during search and rescue operations. Magnetometer surveys are performed to detect buried pipelines, locate archeological remains, and trace buried cables. Underwater investigation surveys are also performed adjacent to bridge piers, locks, and below hydroelectric power plants to assess scour or other conditions. Both acoustic and visual (camera) methods may be deployed.

d. Coastal engineering surveys. Coastal surveys are performed for a variety of engineering purposes. These surveys are used to evaluate the condition of beach renourishment and hurricane protection projects or to support coastal engineering research studies. Coastal surveys

1-3 are performed to study the effects of offshore protection structures (jetties, breakwaters, and groins), harbor entrances, estuaries, and coastlines in areas of suspected accretion, erosion, or other material movement or transport. They are also performed to develop, evaluate, and calibrate physical and numerical models used for planning and design of projects. During beach renourishment or offshore structure construction, coastal surveys are performed to measure placement and estimate payment.

e. Dam and reservoir sedimentation surveys. Periodic underwater condition surveys are performed at many of the 600 water control/supply dams managed by the Corps, including 75 hydropower projects. Reservoirs behind these dams are periodically surveyed to assess sedimentation rates and update area-capacity curves.

f. Inland navigation charting surveys. Hydrographic surveys are performed to update maps and charts of the Corps inland navigation projects--about 7,500 miles of waterways. Corps-wide, these charts involve hundreds of drawings. These surveys also include periodic updates to Inland Electronic Navigational Charts (IENC). IENC updates are performed as needed when river conditions warrant. Hydrographic, topographic, and facility features along the river are updated.

g. Miscellaneous surveys. Various other marine surveys are performed to support civil works water resources activities. These include: environmental/HTRW surveys/studies of underwater areas, periodic disposal area monitoring surveys during placement of material, offshore drill barge location, subsurface probings (wash or dry), tidal boundary surveys (e.g., MHW demarcation), river hydraulic section surveys, river current measurements, wetland surveys, and underwater archeological surveys.

1-8. Use and Scope of Manual. This manual should be used as a "best practices" technical guide in performing hydrographic surveys with USACE hired-labor forces or contracted survey forces.

It is also intended to support project managers, project engineers, or construction inspectors in preparing specifications for these surveys. It should be directly referenced in specifications for contracted construction, dredging, or Architect-Engineer services. This manual focuses on quality control calibration and quality assurance testing standards for acoustic single beam and multibeam survey systems. Field operation of particular hydrographic survey positioning systems and acoustic instrumentation are only minimally covered when reference can be made to more current NOAA manuals, data collection software manuals, or manufacturer operational manuals. The recommended quality control and quality assurance criteria in this manual should be considered in developing technical specifications for surveys supporting dredging measurement, payment, and acceptance functions. This manual may be referenced should hydrographic surveying functions be required as part of a USACE military construction or environmental restoration activity. It may also be referenced for surveys performed or procured by local interest groups under various cooperative or cost-sharing agreements.

a. Scope. Chapters 2 through 7 cover basic hydrographic surveying principles, to include:

an overview of general survey planning, data acquisition, and processing techniques (Chapter 2), 1-4 recommended accuracy standards (Chapter 3), single beam systems (Chapter 4), multiple transducer systems (Chapter 5), multibeam systems (Chapter 6), and GPS positioning systems (Chapter 7). The remaining chapters, along with their associated appendices, describe specific applications to Corps civil works projects. These include coastal navigation project condition surveys (Chapter 8), surveys of inland waterways, river control structures, locks, dams, and reservoirs (Chapter 9), dredging construction surveys (Chapter 10), and coastal engineering surveys (Chapter 11).

b. Recommended guidance versus mandatory standards. Previous versions of this manual contained rigid prescriptive criteria for performing all aspects of hydrographic surveys, including mandatory plant and survey instrumentation, equipment calibration procedures, accuracy standards, data collection procedures, and data plotting criteria. These "mandatory" requirements have been largely eliminated--this updated version now provides only recommended depth accuracy, quality control, and quality assurance criteria—i.e., best practices.

This change recognizes the fact that each District's navigation or water control project may have unique site conditions, and that no single accuracy, quality control, or quality assurance performance standard fits all Corps civil works projects. In addition, acoustic and satellite positioning improvements are expected to occur well before future updates to this manual are scheduled, potentially rendering some of the current guidance obsolete.

c. Instrumentation theory and principles. Theory of operation for various acoustic, GPS positioning, and inertial orientation systems is only briefly outlined in this manual—references are provided to other USACE engineer manuals or technical publications for more detailed information. Equipment configuration, calibration, operation, and procedural methods for performing and processing field hydrographic surveys are now sufficiently detailed in operation manuals provided by the various equipment and software vendors.

d. PROSPECT training. This manual is the primary reference document for use in USACE Learning Center (ULC) PROSPECT Course 056 (Hydrographic Survey Techniques).

1-9. Hydrographic Surveying Requirements during Project Phases. Hydrographic surveying support is required throughout most phases of civil works navigation and water resource projects.

During the early phases of a project, a comprehensive program should be developed to integrate and fund hydrographic surveying requirements throughout the various stages of a project's life.

Procedures for accomplishing this are contained in ER 1110-2-1150, Engineering and Design for Civil Works Projects. Hydrographic surveying support may be required during any of the five project phases outlined in ER 1110-2-1150: Reconnaissance phase, Feasibility phase, Preconstruction Engineering and Design (PED) phase, Construction phase, and Operation and Maintenance phase. Most survey support effort is required during the later three phases.

1-10. Geospatial Data Policy. ER 1110-1-8156, Policies, Guidance, and Requirements for Geospatial Data and Systems, details Army and Corps policies for processing, displaying, transferring, sharing, publishing, and archiving hydrographic survey data. This regulation applies to hydrographic survey data generated in Computer Aided Design (CAD), Site

1-5

Information Modeling (SIM), or Geographic Information System (GIS) file formats.

Supplemental implementation guidance is in EM 1110-1-2909, Geospatial Data and Systems.

1-11. Metrics. The use of both metric and English systems of measurement in this manual is predicated on the common use of both systems in engineering practice, and the exclusive use of English units by the navigation industry. Although most, if not all, electronic surveying and satellite measurement systems now acquire data in metric units, these data are readily converted to English units by the processing software. In the Corps, engineering project coordinates are normally in English units and water depths are expressed in feet and tenths. Construction units are normally measured in linear feet, square feet (sf), or cubic yards (cy). Exceptions may exist on some OCONUS or military construction projects.

a. Metric-English conversions. Due to the variety of mixed metric and English measurements, equivalent conversions are not shown in this manual; the most common measurement unit is used for example computations. Unless otherwise indicated, metric conversions are based on the U.S. Survey Foot, which equals (exactly) 1200/3937 m (or

3.280833333333 ft/m). Note that OCONUS (and some CONUS) jurisdictions, and some software platforms, use the SI conversion (30.48 m /100 International Foot exactly) instead of the U.S. Survey Foot conversion.

b. Statistics. Accuracy or uncertainty statistics, standards, and tolerances specified in this manual are defined at the 95% Root Mean Square (RMS) level (95% = 1.96-sigma for 1D depth measurements), unless otherwise indicated. The terms "Accuracy," "Error," and "Uncertainty" are often used interchangeably in this manual even though their precise statistical definitions may differ.

1-12. Trade Name Exclusions. The citation or illustration in this manual of trade names of commercially available products, including supporting surveying equipment, instrumentation, and software, does not constitute official endorsement or approval of the use of such products.

1-13. Manual Development. The original version of this manual was developed in the 1980s and first published in 1991, then revised in 1994, 2002, and 2004 (multibeam systems). Most of the standards and technical guidance in the 1991 and 1994 versions were designed to support older analog depth recording instruments, mechanical, visual, or microwave positioning, and manual data processing and drafting methods. The 2002 version added newer technologies, such as acoustic multibeam swath survey systems and differential GPS positioning techniques. Much of the visual/mechanical survey procedural methods in earlier versions was either eliminated or moved to appendices in this current version. This update covers the use of more advanced multibeam systems and enhanced vessel positioning and orientation systems using carrier phase GPS and inertial measurement systems. Field survey activities throughout the Corps participated in the development and review of this latest version of the manual.

1-6

1-14. Proponency. The joint proponents for this manual in the HQUSACE Directorate of Civil Works are the Engineering and Construction Community of Practice (CECW-CE) and the Operations and Regulatory Community of Practice (CECW-CO). Technical development and compilation of the manual was coordinated by the U.S. Army Geospatial Center (CEAGC-GSA).

Comments or recommended changes to this manual should be forwarded to HQUSACE (ATTN:

CECW-CE). Technical issues dealing with dredging operations should be forwarded to

HQUSACE (ATTN: CECW-OD).

2-1

CHAPTER 2

Overview of Hydrographic Surveys for Civil Works Navigation and Water Control Projects

This chapter provides a general overview of hydrographic surveys required for the engineering, construction, and maintenance of Corps civil works projects. It covers general survey planning, specification development, optional survey methods, vessel selection, reference datums, data processing and editing, and depth selection options. Time and cost estimating procedures are also outlined. The guidance in this chapter is primarily intended for USACE survey sections;

however, portions are also applicable for use by project managers or design engineers specifying hydrographic surveys for civil works navigation or water control projects.

2-1. Required Supplemental References. The following reference manuals are required to supplement the material in this chapter.

a. EM 1110-1-1003, NAVSTAR Global Positioning System Surveying.

b. EM 1110-1-1005, Control and Topographic Surveying.

c. EM 1110-1-2909, Geospatial Data and Systems.

d. EM 1110-2-6056, Standards and Procedures for Referencing Project Elevation Grades to Nationwide Vertical Datums.

SECTION I

Overview of Hydrographic Survey Techniques

This section provides an overview of basic hydrographic survey techniques and systems used on Corps civil works projects. It covers both historical and current survey techniques. Details on these techniques are covered in the referenced chapters and appendices in this manual. The following paragraphs in this section contain general guidance on procedural and equipment options that must be considered in developing specifications for a hydrographic survey. These specifications will ultimately determine the required or resultant accuracy of a survey, as further detailed in Chapter 3.

2-2. General Hydrographic Survey Methods. Up until the 1960s, the primary method in USACE for measuring water depths utilized manual techniques. These included lead lines, sounding poles, and topographic surveys (levels and transits). Depth measurements were positioned using a variety of visual survey methods, e.g., transits, sextants, tag lines. Manual depth measurement procedures are described in Appendix B and visual positioning techniques in Appendix G.

These manual and visual survey methods were gradually superseded when acoustic depth measurements (echo sounding) were implemented in the 1950s and GPS positioning in the 1990s. Echo sounders project a vertical beam from a single transducer to measure the water

2-2 depth. Single beam acoustic systems are described in Chapter 4. In the 1970s multiple transducer sweep systems were developed. These systems employ multiple single beam transducers on a boom array—see Chapter 5. Acoustic multibeam systems evolved in the early 1990s. These systems project an acoustic sweeping array beam from a single transducer.

Multibeam system operation is covered in Chapter 6.

2-3. Survey Coverage Options. A primary survey specification must evaluate the density of bottom coverage required for a particular project. This specification affects the engineering use of the data and survey cost. There are two survey coverage methods that may be specified for a project: (1) Cross-Sectioning, or (2) Full Bottom Coverage. Cross-section surveys are performed by lead line, topographic survey methods, and single beam echo sounders. Full bottom coverage surveys are obtained by either multiple transducer systems or multibeam sweep systems. These different survey methods have advantages and disadvantages as outlined in the paragraphs below, and summarized in Table 2-5 at the end of this chapter.

a. Cross-Sectioning surveys. Surveys of navigation and other shore protection projects have traditionally been performed by running cross-sections at some predefined spacing, e.g., every 100 ft. Depths are measured using manual methods (lead line) or acoustic methods (single beam). Cross-section methods are most effective in shallow draft projects and in deep draft projects where the bottom topography in a channel is relatively uniform. Single beam cross-section surveys are typically the most economical method, requiring a minimal amount of survey instrumentation on the survey vessel. Smaller survey boats with low plant rental rates are used.

Quality control calibration effort is usually minimal in comparison to multibeam systems. Data editing, processing, plotting, and volume computations are relatively easily and rapidly accomplished.

b. Full Coverage Surveys.

(1) Multiple transducer sweep systems. Multiple transducer boom systems provide full bottom coverage (technically ensonification). Multiple transducer sweep systems have application on shallow draft projects where full bottom coverage is required; thus, they are heavily used by USACE districts on inland navigation projects.