Hydrographic Surveying
Rusli Othman Department of Geoinformation Faculty of Geoinformation Science & Engineering Universiti Teknologi Malaysia
Mapping the Seabed
Hydrography •
Traditionally surveying at sea is known as Hydrography
•
Science of Hydrography – Defined as “that branch of applied science which deals with the measurement and description of the physical features of the navigable portion of the Earth’s surface and adjoining coastal areas, with special reference to their use for the purpose of navigation”
Hydrographic Dictionary (1996), International Hydrographic Bureau
Stages of Hydrographic Survey 1. Data acquisition • on land or sea –Using various system and equipments –Software, HYDROpro,CARIS –Types of data observe: position (DGPS), depth (SBES/MBES), tidal obsrrvation
Stages of Hydrographic Survey 2. Processing using certain software • HYDROpro • AutoCAD • CDS • CARIS
Stages of Hydrographic Survey 3. Presentation • chart, • plan, • report, etc
Elements of Hydrographic Survey ■
Positioning System – Coordinate System
■
Depth Measurement System – MSL – Chart Datum LAT
■
Tidal observation – Conventional Method – Automated Tide Gauge – TLDM & JUPEM
Elements of Hydrographic Survey ■
Horizontal Controls
■
Preparation of control – Horizontal – Vertical
■ ■
Method and Planning in Hydrographic Survey Method to maintain accuracy and avoid error
History and Development of Hydrography ■
Production of marine maps/charts – showing coastline information + seabed topography + obstructions/dangers to navigation
■
To assist Navigation – (Latin: Navigare – navis = ship, gare = drive)
■
Development of sea-borne trade
■
Military requirements
■
France / Netherlands / UK / USA
Coastline Information - Traditional Nautical Chart
Seabed Topography
History and Development of Hydrography ■
Earliest evidence from 3000 BC
■ ■
Sailing directions – written descriptions of passages between ports Earliest charts of coastline in Chinese/Greek/Roman times
■
1st printed charts in 15th century
■
1st ‘true’ map using mathematical projection – Mercator
■
Dutch Government charts – published 17th century
■
French Chart Office – 1720
■
Admiralty Hydrographic Dept – 1795
■
Scientific Instruments development in 18th century
■
Organised Hydrographic surveys by most civilised countries from 19th century
■
Detailed charts showing seabed obtained from lead soundings /position provided by sextant
■
Many charts still show information dating back 80+ years
Chinese Navigation Diagram – 1371
Sketch Chart
Mercator
Shipping / Navigation
Major Developments in Modern Hydrography 1 / 4 ■
The echo so und er in 1930’s
Major Developments in Modern Hydrography 2 / 4 ■
Electronic position fixing developed in 1940’s
Major Developments in Modern Hydrography 3 / 4 ■
Satelli te Pos it io n fixing developed in 1960’s leading to GPS/DGPS replacing most other systems during 1990’s
Major Developments in Modern Hydrography 4 / 4 ■
Development of mul tib eam/swathe sou ndi ng systems in late 1980’s
SS Richard Montgomery
Markets for Hydrography
■
Until 1950’s almost entirely centred on the shipping and fishing industries. Navigation
■
Inshore Waters
■
Confined/Busy Waters
■
Deep water channels – Commerce
■
Since then remarkable increase in interest in the resources of the sea and sea floor. Oil & gas by far the biggest investor.
■
Hydrographic or Offshore Surveying ? ■
Offs hor e Sur veyin g – surveying activities in support of resource and infrastructure development. Conducted by commercial survey companies for industry, local government, etc.
■
Hydro gra phic Surveying – surveying for nautical charting, general trade and safety of life at sea. Largely a governmental organised and conducted activity. Some commercial activity, market is growing.
Applications of Hydrography ■
Shipping - Navigation Charts, wrecks and coastline surveys
■
Civil - Marinas, Bridges, Harbours, Outfalls, Sea Defences, Dredging
■
Military - Precise Navigation Charts for submarines, Special Forces, etc
■
Environmental- Coastal management and engineering
■
Mining - Diamonds and manganese nodules
■
Oil and Gas – Exploration (Seismic, Geo-technical, Geo-physical & Rigmoves) Construction (Pipelines, Platforms, Wells and Refineries) Monitoring (Seismic, Pipeline Inspections) Decommissioning.
Navigation Charts
• in open sea • ports • rivers • etc
Shipping - Navigation Charts, wrecks and coastline surveys
Civil
Jetties and breakwaters Dredging- shipping channel, port and habour
Environment
Environmental
- Coastal management and engineering
Marine Activities • Mining - Diamonds and manganese nodules • Oil and Gas – Exploration (Seismic, Geo-technical, Geo-physical & Rig-moves) • Construction (Pipelines, Platforms, Wells and Refineries) • Monitoring (Seismic, Pipeline inspections) Decommissioning
Mining
• Diamond mining at sea and the collection of manganese nodules • Performed by a ‘dredge’ or scoop deployed from a towing and recovery vessel •Use seismic interpretation for the identification of targets area
Mining - Diamonds and manganese nodules
Minerals • • • •
•
EEZ surveys Sand/Gravel deposits Diamond Mining Deep ocean – manganese nodules Political sensitivity
Oil and Gas Oil and Gas – Exploration (Seismic, Geo-technical, Geophysical & Rig-moves)
Construction (Pipelines, Platforms,
Wells and Refineries) Monitoring (Seismic, Pipeline inspections) Decommissioning
Oil and Gas
Oil and Gas - Exploration ■
Seismic Surveys
■
Geophysical Surveys
■
Rig Moves
Oil and Gas - Construction ■
Offshore Installation – Platforms – Subsea installations – Pipelines
Oil and Gas - Monitoring ■
IRM (Inspection, Repair & Maintenance) – GPS Subsidence monitoring • Contributes to platform safety case – Tilt measurements • Structural integrity – Pipeline inspection surveys • ROVs & Sonars – Base map maintenance • Detailed installation drawings
Oil and Gas - Decommissioning ■
Decommissioning or Abandonment
■
Removal of facilities and return to ‘natural’ environment
■
Political and Environmental Sensitivity
■
Requires survey services for – Seabed and facilities investigations – (De-)Construction support – Post Decommissioning surveys
Construction Positioning • Jacket installations • Well guide bases • Sub sea manifolds • Satellite wells • Pipeline Lay downs & Crossings
Underwater Positioning ■
For many offshore survey activities, positioning the surface vessel (i.e. ship, barge, rig) is only part of offshore positioning
■
In many projects, positioning underwater is also required
■
The positioning of survey sensors, underwater vehicles, subsea structures all require a means of solving position underwater, examples: Side scan sonar, ROV, pipelines
Drill ship
Jackup Rig Moves Shallow Water
Semi Submersible Rigmoves Deepwater
Jacket Installation
Pipe laying Fiber-optic and communication cables. The corridor is mere 100 m – but is used to determine a safe route through seabed hazards and involve deviations of many hundreds of km in order to locate a suitable path. Side scan sonar is used to determine the suitable route.
Multibeam & Side Scan Sonar Survey
Side Scan Sonar APPLICATIONS:
– Pipeline Inspection – Site Surveys – Wreck Hunting – Environmental & Sediment Classification – ROV Operations
Side Scan Sonar
Side Scan Sonar
Tow height = 10% range setting
Fix Mounting of SSS - Layout survey vessel with fixed mount side scan sonar. - The accuracy in this method is much better, better than 1m
Side Scan Sonar on ROV – Mounted on ROV: >For inspection, together with video recordings. – Mounted under a floating device (not possible to mount on the bow esp. small boat – not stable enough): >Small catamaran, surfboard, run at low speeds
Side Scan Sonar Surveys
Example of SSS Record
Shipwreck: “Menja”
Seismic Surveys
Sub Bottom Profile
Towing Configuration
Seismic Receiver
Hydrophones @ Streamer and Tail Buoy
ROV Surveys (Remote Operated Vehicle)
SBP Sample Image
Pinger profile (24 kHz)
Chirp profile (2-6 kHz)
SBP Sample Image
■
Boomer profile (500 Hz - 1.5 kHz)
SBP Sample Image
■
■
Pinger profile (28 kHz)
Air gun profile (~100 Hz)
Military
Solar
Energy Power Stations
Wind
Wave
Professional Courses Prof essi onal Cour ses – HYDRO I (Cat B) – HYDRO II (Cat A) – Cat B (Marine Cartography)
Gov ern ment Agenci es – TLDM – Chart, Tide Table, Notice to Mariner JUPEM- TideTable – Port Authorities – Marine Department
All Hydrographic Surveys should follow the IHO Stand ard S-44
