Hydrographic survey

For a broader coverage related to this topic, see Hydrography.
A nostalgic 1985 sketch of hydrographic surveying in Alaska.
Neptune, a privately owned survey ship based in Chicago, Illinois.

Hydrographic survey is the science of measurement and description of features which affect maritime navigation, marine construction, dredging, offshore oil exploration/offshore oil drilling and related activities. Strong emphasis is placed on soundings, shorelines, tides, currents, seabed and submerged obstructions that relate to the previously mentioned activities. The term hydrography is sometimes used synonymously to describe maritime cartography, which in the final stages of the hydrographic process uses the raw data collected through hydrographic survey into information usable by the end user.

Hydrography is collected under rules which vary depending on the acceptance authority. Traditionally conducted by ships with a sounding line or echo sounding, surveys are increasingly conducted with the aid of aircraft and sophisticated electronic sensor systems in shallow waters.

National and International Maritime Hydrography

Main article: Hydrographic office

Hydrographic offices evolved from naval heritage and are usually found within national naval structures, for example Spain's Instituto Hidrográfico de la Marina.[1] Coordination of those organizations and product standardization is voluntarily joined with the goal of improving hydrography and safe navigation is conducted by the International Hydrographic Organization (IHO). The IHO publishes Standards and Specifications[2] followed by member states as well as Memoranda of Understanding and Co-operative Agreements[3] with hydrographic survey interests.

The product of such hydrography is most often seen on nautical charts published by the national agencies and required by the International Maritime Organization (IMO),[4] the Safety of Life at Sea (SOLAS)[5] and national regulations to be carried on vessels for safety purposes. Increasingly those charts are provided and used in electronic form unders IHO standards.

United Kingdom

The United Kingdom has a long hydrographic history officially begun with the 1683 appointment of Captain Grenville Collins as Hydrographer to the King.[6] With the Royal Navy dominating the seas hydrography grew to a worldwide hydrographic activity. That tradition extended to the nations with a common legacy in the Empire, for example, the Australian Hydrographic Service.[7] The British Admiralty Hydrographic Office became the United Kingdom Hydrographic Office which continues the legacy within the Ministry of Defence[8] with responsibility for the Admiralty Charts.[9] The Royal Navy maintains a number of hydrographic survey vessels[10] to continue the work today.

Argentina

The Argentine Hydrographic Service was established in 1879.

Australia

Hydrographic services are provided by the Royal Australian Navy Hydrographic Service.

Canada

Hydrographic services are provided by the Canadian Hydrographic Service.

France

Hydrographic services are provided by the Naval Hydrographic and Oceanographic Service.

Germany

Hydrographic services are provided by the Federal Maritime and Hydrographic Agency.

Iceland

Hydrographic services are provided by the Icelandic Coast Guard - Hydrographic department.

India

Hydrographic services are provided by the National Hydrographic Office. It operates a fleet of Eight Oceangoing Conventional Hull Survey Vessels and One Large Catamaran Hull Vessel INS Makar (J31) of the Alcock Ashdown Class, with 5 More of the class due to be commissioned soon.

The Indian Marine Survey Department was established at Calcutta in 1874, which became a part of the Royal Indian Marine in 1882. The Hydrographic Department of the Indian Navy derives its origin from the charting activities of the British East India Company, way back in the 17th century. John and Samuel Thornton, Hydrographers to the East India Company compiled the first chart and Sailing Directions for the Indian Ocean in 1703. During the next two centuries, the captains of the ships of the East India Company went on to pioneer the charting of the Eastern seas extending from Red Sea to Persian Gulf, Arabian Sea, across the Indian Ocean right up to the China Seas.

After India's independence from the United Kingdom, the Marine Survey Office was shifted to Dehradun on 1 June 1954 and was renamed as the Naval Hydrographic Office. The Naval Hydrographic Office was renamed in 1997 as the National Hydrographic Office in recognition of its national stature and increasing international role.[11][12]

Italy

Istituto Idrografico della Marina is the Italian Navy Hydrographic Office and is in charge of all the official nautical documentation published in Italy.[13]

The Netherlands

The Dutch Dienst der Hydrografie (Hydrographic Service) has been part of the Royal Netherlands Navy since 8 January 1488.[14]

United States

History

In 1807, the United States created the United States Survey of the Coast, the first United States Government scientific agency, giving it the responsibility for hydrographic surveys of the waters of the United States. Its surveying activities did not begin until 1816 and then were suspended completely when the United States Army and United States Navy were given the responsibility for surveys in 1818. Surveying responsibility returned to the Survey of the Coast in 1832, and it conducted the first official hydrographic survey in U.S. history in 1834. It was renamed the United States Coast Survey in 1836.[15]

Over time, the Coast Survey accumulated a small fleet of ships to employ in surveying work. In 1871, the Coast Survey was given the responsibility of conducting geodetic surveys in the interior of the United States, and in 1878 it was renamed the United States Coast and Geodetic Survey. In 1959, the Coast and Geodetic Survey was given the responsibility for U.S. Government hydrographic surveying activities worldwide.[16]

In 1965, the Coast and Geodetic Survey was subordinated to the new Environmental Science Services Administration (ESSA), although it retained its separate identity. On 3 October 1970, ESSA was expanded and reorganized to become the National Oceanic and Atmospheric Administration (NOAA), and at that time a number of U.S. Government scientific agencies, including the Coast and Geodetic Survey, merged and were reorganized to form NOAA. Among other things, NOAA took over the Coast and Geodetic Survey's responsibility for hydrographic surveys, and the Coast and Geodetic Survey's fleet merged with those of other U.S. government agencies to form the NOAA fleet, which includes survey ships that carry out hydrographic surveys.[16]

Today

In the United States, statutory authority for hydrographic surveys of territorial waters and the exclusive economic zone (EEZ) lies with the National Oceanic and Atmospheric Administration (NOAA).[17][18] NOAA hydrographic surveys are administered by the National Ocean Service[19][20] and carried out by the National Oceanic and Atmospheric Administration Commissioned Corps [21] and federal government civilians. The NOAA fleet survey vessels are based at the Atlantic Marine Center in Norfolk, Virginia, and the Pacific Marine Center in Seattle, Washington.[22] The organic survey assets are supplemented by other agencies [23] and contract surveys in order to survey the large areas – including 3,603 square miles (9,330 km2) classified as critical alone, according to the "NOAA Hydrographic Survey Priorities (NHSP) - East Coast"[24] – that fall under NOAA's responsibility. The 2009 status shows 29,412 square nautical miles (100,900 km2) out of 510,841 square nautical miles (1,752,000 km2) "Navigationally Significant" were completed.[17] – that fall under NOAA's responsibility. The NOAA Office of Coast Survey's Hydrographic Surveys Division estimates it has awarded approximately $250 million in contracts for hydrographic surveying and related support since 1994.[25]

For inland surface waters such as rivers, streams, and inland lakes the United States Geological Survey (USGS) has national responsibility. USGS coordinates survey data collection and publishes the National Hydrography Dataset[26][27] that is designed to be used with geographic information systems (GIS). Other federal agencies such as the United States Environmental Protection Agency[28] and the United States Fish and Wildlife Service use[29] these data and, along with state and local hydrographic collection organizations, contribute to the national hydrographic data base. The Environmental Protection Agency conducts or contracts for surveys on projects such as the GE/Hudson River Superfund site. The United States Coast Guard also conducts hydrographic survey operations, particularly in the polar regions.[30]

The National Geospatial-Intelligence Agency[31] (NGA) oversees the charting of international waters for United States Department of Defense purposes. The United States Navy's Naval Oceanographic Office[32] conducts many of these oceanic surveys. The United States Army Corps of Engineers conducts hydrographic surveys supporting its responsibility for the major waterway projects that include navigation and flood control. Hydrographic data from those surveys is published by districts.[33] Such data is incorporated into both NOAA and NGA products and the Corps engages in efforts to improve hydrographic collection methods.[34] Military combat organizations such as the U.S. Navy's SEALs and military engineering units have specialized hydrographic reconnaissance survey capabilities.

The NOAA Office of Coast Survey Web page (Coast Survey Partners) offers a useful list and summary of major hydrographic activities, government and private, with links to the Web sites of NOAA's partners.

Hydrographic survey conducted by non-national agencies

Governmental entities below the national level conduct or contract for hydrographic surveys for waters within their jurisdictions with both internal and contract assets. Such surveys commonly are conducted by national organizations or under their supervision or the standards they have approved, particularly when the use is for the purposes of chart making and distribution or the dredging of state-controlled waters.

In the United States, there is coordination with the National Hydrography Dataset in survey collection and publication.[35] State environmental organizations publish hydrographic data relating to their mission.[36]

Hydrographic survey by private organizations

Commercial entities also conduct large-scale hydrographic and geophysical surveying, particularly in the dredging, marine construction, oil exploration, and drilling industries. Industrial entities installing submarine communications cables[37] or power[38] require detailed surveys of cable routes prior to installation and increasingly use acoustic imagery equipment previously found only in military applications when conducting their surveys.[39] Specialized companies exist that haveboth the equipment and expertise to contract with both commercial and governmental entities to perform such surveys .

Companies, universities, and investment groups will often fund hydrographic surveys of public waterways prior to developing areas adjacent those waterways. Survey firms are also contracted to survey in support of design and engineering firms that are under contract for large public projects.[40] Private surveys are also conducted before dredging operations and after these operations are completed. Companies with large private slips, docks, or other waterfront installations have their facilities and the open water near their facilities surveyed regularly, as do islands in areas subject to variable erosion such as in the Maldives.

Hydrographic survey by crowdsourcing

Crowdsourcing also is entering hydrographic surveying, with projects such as OpenSeaMap,[41] TeamSurv and ARGUS. Here, volunteer vessels record position, depth, and time data using their standard navigation instruments, and then the data is post-processed to account for speed of sound, tidal, and other corrections. With this approach there is no need for a specific survey vessel, or for professionally qualified surveyors to be on board, as the expertise is in the data processing that occurs once the data is uploaded to the server after the voyage. Apart from obvious cost savings, this also gives a continuous survey of an area, but the drawbacks are time in recruiting observers and getting a high enough density and quality of data. Although sometimes accurate to 0.1 - 0.2m, this approach cannot substitute for a rigorous systematic survey, where this is required. Nevertheless, the results are often more than adequate for many requirements where high resolution, high accuracy surveys are not required or are unaffordable.

Methods

Lead lines, sounding poles, and single-beam echosounders

The history of hydrographic surveying dates almost as far back as that of sailing.[42] For many centuries, a hydrographic survey required the use of lead lines – ropes or lines with depth markings attached to lead weights to make one end sink to the bottom when lowered over the side of a ship or boat – and sounding poles, which were poles with depth markings which could be thrust over the side until they touched bottom. In either case, the depths measured had to be read manually and recorded, as did the position of each measurement with regard to mapped reference points as determined by three-point sextant fixes. The process was labor-intensive and time-consuming and, although each individual depth measurement could be accurate, even a thorough survey as a practical matter could include only a limited number of sounding measurements relative to the area being surveyed, inevitably leaving gaps in coverage between single soundings.[42]

Single-beam echosounders and fathometers began to enter service in the 1930s which used sonar to measure the depth beneath a vessel. This greatly increased the speed of acquiring sounding data over that possible with lead lines and sounding poles by allowing information on depths beneath a vessel to be gathered in a series of lines spaced at a specified distance. However, it shared the weakness of earlier methods by lacking depth information for areas in between the strips of sea bottom the vessel sounded.[42]

Wire-drag surveying

A U.S. Coast and Geodetic Survey diagram of wire-drag hydrographic survey operations, ca. 1920. The basic principle is to drag a wire attached to two vessels at set depth; if the wire encounters an obstruction it will come taut and form a "V."

In 1904, wire-drag surveys were introduced into hydrography. In the wire-drag method, a wire attached to two ships or boats and set at a certain depth by a system of weights and buoys was dragged between two points. If the wire encountered an obstruction, it would become taut and form a "V" shape. The location of the "V" revealed the position of submerged rocks, wrecks, and other obstructions, while the depth at which the wire was set showed the depth at which the obstruction was encountered.[42] This method revolutionized hydrographic surveying, as it allowed a quicker, less laborious, and far more complete survey of an area than did the use of lead lines and sounding poles.

So valuable was wire-drag surveying in the United States that for decades the U.S. Coast and Geodetic Survey, and later the National Oceanic and Atmospheric Administration, fielded a pair of sister ships of identical design specifically to work together on such surveys. USC&GS Marindin and USC&GS Ogden conducted wire-drag surveys together from 1919 to 1942, USC&GS Hilgard (ASV 82) and USC&GS Wainwright (ASV 83) took over from 1942 to 1967, and USC&GS Rude (AVS 90) (later NOAAS Rude (S 590)) and USC&GS Heck (ASV 91) (later NOAAS Heck (S 591)) worked together on wire-drag operations from 1967.[42][43][44][45][46][47]

The rise of new electronic technologies – sidescan sonar and multibeam swath systems – in the 1950s, 1960s and 1970s eventually made the wire-drag system obsolete. Sidescan sonar could create images of underwater obstructions with the same fidelity as aerial photography, while multibeam systems could generate depth data for 100 percent of the bottom in a surveyed area. These technologies allowed a single vessel to do what wire-drag surveying required two vessels to do, and wire-drag surveys finally came to an end in the late 1980s.[42] Vessels were freed from working together on wire-drag surveys, and in NOAA, for example, Rude and Heck operated independently in their later years.[46][47]

Modern surveying

In suitable shallow-water areas lidar (light detection and ranging) may be used.[17] Equipment can be installed on inflatable craft, such as Zodiacs, small craft, autonomous underwater vehicles (AUVs), unmanned underwater vehicles (UUVs) or large ships, and can include sidescan, single-beam and multibeam equipment. At one time different data collection methods and standards were used in collecting hydrographic data for maritime safety and for scientific or engineering bathymetric charts, but increasingly, with the aid of improved collection techniques and computer processing, the data is collected under one standard and extracted for specific use.

After data is collected, it has to undergo post-processing. A massive amount of data is collected during the typical hydrographic survey, often several soundings per square foot. Depending on the final use intended for the data (for example, navigation charts, Digital Terrain Model, volume calculation for dredging, topography, or bathymetry) this data must be thinned out. It must also be corrected for errors (i.e., bad soundings,) and for the effects of tides, waves/heave, water level and thermoclines (water temperature differences). Usually the surveyor has additional data collection equipment on site to record the data required for correcting the soundings. The final output of charts can be created with a combination of specialty charting software or a computer-aided design (CAD) package, usually Autocad.

With crowd-sourced surveying, although the accuracy of the individual measurements are not as accurate as with a traditional survey, the algorithms used rely on a high data density to produce final results that are more accurate than single measurements. A comparison of crowd-sourced surveys with multibeam surveys indicates an accuracy of crowd-sourced surveys of around plus or minus 0.1 to 0.2 meter (about 4 to 8 inches).

See also

References

  1. ↑ http://www.armada.mde.es/ArmadaPortal/page/Portal/ArmadaEspannola/ciencia_ihm_1/ | Armada Esapñola - Instituto Hidrográfico de la Marina
  2. ↑ http://www.iho-ohi.net/english/standards-publications/introduction.html | IHO Catalogue of Publications
  3. ↑ http://www.iho-ohi.net/english/letters-and-documents/mou-agreements.html | IHO Memoranda of Understanding and Co-operative Agreements
  4. ↑ http://www.imo.org/safety/mainframe.asp?topic_id=350 | IMO
  5. ↑ http://www.icomia.com/technical-info/docs/SOLASV.pdf | SOLAS CHAPTER V SAFETY OF NAVIGATION
  6. ↑ http://www.naval-history.net/xGM-Tech-HydrographicSurvey.htm | HYDROGRAPHIC SURVEY WORK IN THE ROYAL NAVY UP TO THE 1980s by Geoffrey B Mason, Lieutenant Commander, RN (Rtd)
  7. ↑ http://www.hydro.gov.au/aboutus/past.htm | Australian Hydrographic Service - The Past
  8. ↑ http://www.ukho.gov.uk/AboutUs/Pages/Corporate.aspx | UKHO - About Us
  9. ↑ http://www.ukho.gov.uk/PRODUCTSANDSERVICES/Pages/ChartAvailabilityList.aspx | UKHO - Admiralty Chart Availability List
  10. ↑ http://www.royalnavy.mod.uk/operations-and-support/surface-fleet/hydrographic-vessels/ | Royal Navy - Hydrographic Vessels
  11. ↑ http://www.hydrobharat.nic.in/brief_history.htm
  12. ↑ http://indiannavy.nic.in/book/naval-hydrographic-department
  13. ↑ http://www.marina.difesa.it/EN/Conosciamoci/hydroffice/Pagine/default.aspx
  14. ↑
  15. ↑ NOAA History: The Coast Survey 1807-1867
  16. 1 2 NOAA History: NOAA Corps and the Coast and Geodetic Survey
  17. 1 2 3 http://www.nauticalcharts.noaa.gov/hsd/docs/NHSP_2009_TextOnly.pdf | NOAA Hydrographic Survey Priorities 2009 Edition
  18. ↑ http://www.nauticalcharts.noaa.gov/hsd/NHSP.htm | NOAA Hydrographic Survey Priorities
  19. ↑ http://www.nauticalcharts.noaa.gov/hsd/hydrog.htm | NOS - Hydrographic Surveying
  20. ↑ http://oceanservice.noaa.gov/about/nos_org_chart.pdf | National Ocean Service Organization Chart
  21. ↑ http://www.careers.noaa.gov/career_fields.html | WELCOME TO NOAA CAREERS
  22. ↑ http://www.moc.noaa.gov/ | NOAA Marine Operations
  23. ↑ http://www.nauticalcharts.noaa.gov/staff/ocspartners.html | NOAA, Office of Coast Survey, Coast Survey Partners
  24. ↑ http://www.nauticalcharts.noaa.gov/hsd/east_priorities.html | Hydrographic Survey Priorities - East Coast
  25. ↑ http://www.nauticalcharts.noaa.gov/hsd/contrac.htm | Office of Coast Survey, Contract Hydrographic Surveys
  26. ↑ http://nhd.usgs.gov/ | National Hydrography Dataset
  27. ↑ http://pubs.usgs.gov/fs/2009/3054/ | The National Map—Hydrography
  28. ↑ http://www.epa.gov/waters/doc/nhd_flyer.pdf | EPA Site - National Hydrography Dataset
  29. ↑ http://www.fws.gov/data/gisconv/nhdtools.html | U.S. Fish and Wildlife Service - Documentation and Tools for Utilizing the National Hydrography Dataset
  30. ↑ http://www.star.nesdis.noaa.gov/star/documents/2009Ice/Day2/Mack_icebreaker_day2.pdf | U.S. Coast Guard - Polar Icebreaker Operations
  31. ↑ https://www1.nga.mil/ProductsServices/NauticalHydrographic/Pages/default.aspx | NGA - Nautical - Hydrographic and Bathymetric Product Descriptions
  32. ↑ https://oceanography.navy.mil/legacy/web/nipr_2006/capabilities.html | Naval Oceanographic Office - Capabilities
  33. ↑ http://www.sac.usace.army.mil/?action=navigation.surveymaps | US Army Corps of Engineers, Charleston District - Hydrographic Survey Maps
  34. ↑ http://www.informaworld.com/smpp/1528816525-68966095/content~db=all~content=a907651111 | http://www.informaworld.com/smpp/1528816525-68966095/content~db=all~content=a907651111
  35. ↑ http://www.dnr.state.wi.us/maps/gis/datahydro.html | Wisconsin DNR - Surface Water (Hydrography) Data - Conversion from Coverage to Geodatabase
  36. ↑ http://www.tceq.state.tx.us/implementation/water/tmdl/hydromaps.html | Texas Commission on Environmental Quality - Hydrography Maps and Data
  37. ↑ http://www.setech-uk.com/pdf/Paper2.pdf HYDROGRAPHIC INFORMATION AND THE SUBMARINE CABLE INDUSTRY
  38. ↑ http://sanpedrosun.net/old/belcable.html | BEL submarine cable survey complete
  39. ↑ http://www.hydro-international.com/news/id2826-Utec_Surveyor_Equipped_for_Deep_Ocean_Cable_Route_Surveys.html | Utec Surveyor Equipped for Deep Ocean Cable Route Surveys
  40. ↑ http://www.hydro-international.com/news/id3583-Infrastructure_Survey_in_Turkey.html | Infrastructure Survey in Turkey 14 December 2009
  41. ↑ Hydro International: Water Depths by Crowdsourcing
  42. 1 2 3 4 5 6 http://www.nauticalcharts.noaa.gov/hsd/hydro_history.html NOAA History: History of Hydrographic Surveying
  43. ↑ NOAA History: Coast and Geodetic Survey Ships: Marindin
  44. ↑ NOAA History: Coast and Geodetic Survey Ships: Ogden
  45. ↑ History: Coast and Geodetic Survey Ships: Hilgard
  46. 1 2 History: Coast and Geodetic Survey Ships: Rude
  47. 1 2 NOAA History: Coast and Geodetic Survey Ships: Heck

External links

NOAA maintains a massive database of survey results, charts, and data on the NOAA site.

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