Hydrographic survey is the science of measurement and description of features which affect maritime navigation, marine construction, dredging, offshore oil exploration/drilling and related disciplines. Strong emphasis is placed on soundings, shorelines, tides, currents, sea floor 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.
HydrographyHydrography is the measurement of the depths, the tides and currents of a body of water and establishment of the sea, river or lake bed topography and morphology. Normally and historically for the purpose of charting a body of water for the safe navigation of shipping...
is collected under rules which vary depending on the acceptance authority. Traditionally conducted by vessels and with
Echo soundingEcho sounding is the technique of using sound pulses directed from the surface or from a submarine vertically down to measure the distance to the bottom by means of sound waves. This information is then typically used for navigation purposes or in order to obtain depths for charting purposes...
, surveys are increasingly conducted with the aid of aircraft and sophisticated electronic sensor systems in shallow waters.
National and International Maritime Hydrography
Hydrographic offices evolved from naval heritage and are usually found within national naval structures, for example Spain's Instituto Hidrográfico de la Marina. 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 OrganizationThe International Hydrographic Organization is the inter-governmental organisation representing the hydrographic community. It enjoys observer status at the UN and is the recognised competent authority on hydrographic surveying and nautical charting...
(IHO). The IHO publishes Standards and Specifications followed by member states as well as Memoranda of Understanding and Co-operative Agreements 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), the Safety of Life at Sea (SOLAS) and national regulations to be carried on vessels for safety purposes. Increasingly those charts are provided and used in electronic form unders IHO standards.
History and responsibilities
The
United KingdomThe United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
has a long hydrographic history officially begun with the 1683 appointment of Captain Grenville Collins as Hydrographer to the King.
[http://www.naval-history.net/xGM-Tech-HydrographicSurvey.htm | HYDROGRAPHIC SURVEY WORK IN THE ROYAL NAVY UP TO THE 1980's by Geoffrey B Mason, Lieutenant Commander, RN (Rtd)] With the
Royal NavyThe Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
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. The British Admiralty Hydrographic Office became the
United Kingdom Hydrographic OfficeThe United Kingdom Hydrographic Office is an organisation within the UK government responsible for providing navigational and other hydrographic information for national, civil and defence requirements...
which continues the legacy within the Ministry of Defence with responsibility for the Admiralty Charts. The Royal Navy maintains a number of hydrographic survey vessels to continue the work today.
Australia
Hydrographic services are provided by the
Royal Australian Navy Hydrographic ServiceThe Australian Hydrographic Service is the Australian Commonwealth Government agency responsible for providing hydrographic services that meet Australia's obligations under the SOLAS convention and the national interest; enabling safe navigation, maritime trade and supporting protection of the...
.
Republic of Ireland
The Republic of Ireland is actively undertaking the largest civilian seabed mapping programme in the world; the INFOMAR programme. The INtegrated Mapping FOr the Sustainable Development of Ireland’s MArine Resource (INFOMAR) programme is a joint venture between the Geological Survey of Ireland and the Marine Institute. The programme is a successor to the Irish National Seabed Survey (INSS) and concentrates on creating a range of integrated mapping products of the physical, chemical and biological features of the seabed in the near-shore area. The programme is being funded by the Irish Government through the Department of Communications, Energy and Natural Resources as part of the National Development Plan, 2007 – 2013 .
Total mapping coverage of the INSS to end of 2005 was 432,000 km² and taken along with an earlier DCENR Petroleum Affairs Division, over 81% of the Irish designated seabed area (at end 2005) has been mapped. The INSS mapped to approximately the 200m contour and delivered a national asset that has provided Ireland with a data set to underpin present and future economic, environmental, infrastructural, social and policy issues. In addition significant capacity building has taken place both in terms of Irish marine surveying infrastructure and the development of personnel skilled in the design, planning, implementation and management of a large scale integrated marine resource evaluation programme.There remains a crucially important body of work to follow in mapping commercially valuable inshore and other waters outside the scope of that achieved by the INSS. A range of diverse navigation, environmental and cultural international legislative obligations must also be addressed. The INFOMAR Programme is intended to address these outstanding issues while also delivering an enhanced data management and delivery service for data gathered under both the INSS and INFOMAR. This data delivery strategy is intended to promote the creation of value added products.
United States
In United States statutory authority for hydrographic surveys of territorial waters and the Exclusive Economic Zone (EEZ) lies with the National Oceanographic and Atmospheric Administration (NOAA).
[http://www.nauticalcharts.noaa.gov/hsd/docs/NHSP_2009_TextOnly.pdf | NOAA Hydrographic Survey Priorities 2009 Edition] NOAA hydrographic surveys are conducted by the
National Ocean ServiceThe National Ocean Service , an office within the U.S. Department of Commerce National Oceanic and Atmospheric Administration, is responsible for preserving and enhancing the nation’s coastal resources and ecosystems along of shoreline bordering of coastal, Great Lakes, and ocean waters...
, a uniformed corps within NOAA and a fleet of survey vessels based at two major centers. The organic survey assets are supplemented by other agencies
[http://www.nauticalcharts.noaa.gov/staff/ocspartners.html | NOAA, Office of Coast Survey, Coast Survey Partners] and contract surveys in order to survey the large areas within its responsibility. Those were identified in the NOAA Hydrographic Survey Priorities (NHSP) - East Coast alone as being 3603 square miles (9,331.7 km²) classified as critical. The 2009 status shows 29412 sqnmi out of 510841 sqnmi "Navigationally Significant" were completed.
The NOAA Office of Coast Survey, Hydrographic Surveys Division estimates it has awarded approximately $250 million in contracts for hydrographic surveying and related support since 1994.
For inland surface waters such as rivers, streams and inland lakes the U.S. Geological Survey (USGS) has national responsibility. USGS coordinates survey data collection and publishes a National Hydrography Dataset that is designed to be used with geographic information systems (GIS). Other federal agencies such as the Environmental Protection Agency and the U.S. Fish and Wildlife Service use 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 Super Fund site.
The U.S. Coast Guard conducts hydrographic survey operations, particularly in the Polar regions.
The National Geospatial Intelligence Agency (NGA) oversees charting of international waters for
Department of DefenseThe United States Department of Defense is the U.S...
purposes. The Navy's
Naval Oceanographic OfficeThe Naval Oceanographic Office , located at John C. Stennis Space Center in south Mississippi, comprises approximately 1,000 civilian, military and contract personnel responsible for providing oceanographic products and services to all elements within the Department of Defense.Valued by maritime...
conducts many the oceanic surveys. The U.S. 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. Such data is incorporated into both NOAA and NGIA products and the Corps engages in efforts to improve hydrographic collection methods. Military combat organizations such as the Navy's
SEALThe United States Navy's Sea, Air and Land Teams, commonly known as Navy SEALs, are the U.S. Navy's principal special operations force and a part of the Naval Special Warfare Command as well as the maritime component of the United States Special Operations Command.The acronym is derived from their...
and engineering units have specialized hydrographic reconnaissance survey capability.
The NOAA Office of Coast Survey,
Coast Survey Partners web page offers a useful list and summary of major player activities, government and private, with links to those partner web sites.
Hydrograpic survey conducted by non-national agencies
Governmental entities below national level conduct or contract for hydrographic surveys for waters within their jurisdiction with both internal and contract assets. Such surveys are
commonly conducted by or under the standards approved by or the supervision of national
organizationsA hydrographic office is an organization which is devoted to acquiring and publishing hydrographic information.Historically, the main tasks of hydrographic offices were the conduction of hydrographic surveys and the publication of nautical charts...
, particularly when the use is for the purposes of chart making/distribution or dredging of state controlled waters.
In the United States there is coordination with the National Hydrography Dataset in survey collection and publication. State environmental organizations publish hydrographic data relating to their mission.
Hydrograpic survey conducted by private organizations
Large scale hydrographic and geophysical survey is conducted by commercial entities, particularly in the dredging, marine construction, oil exploration & drilling industries. Industry installing submarine cable for communications or power require detailed surveys of cable routes prior to installation with increased use of acoustic imagery equipment previously found only in military applications. There are specialized companies with both the assets and expertise to contract for such surveys with both commercial and governmental entities.
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. Private surveys are also conducted before dredging operations and after these operations are completed. Companies with large private slips, docks or other water front installations have their facilities and the open water near their facilities surveyed regularly.
Crowd sourcing is also entering hydrographic surveying, with projects such as TeamSurv and ARGUS. Here, volunteer vessels record position, depth and time data using their standard navigation instruments, and then the d ata is processed on the server for speed of sound, tidal and other corrections. With this approach there is no need for a spercific 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 loggers and getting a high enough density of data. Also, although accurate to 0.1 - 0.2m, this approach does not have the accuracy and coverage of a multi-beam survey.
Process
Modern surveying relies as much on software as hardware. In suitable shallow water areas Light Detection and Ranging (LIDAR) may be used.
Equipment can be installed on inflatable craft, such as Zodiacs, small craft, AUVs (Autonomous Underwater Vehicles), UUVs (Unmanned Underwater Vehicles) 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. Increasingly with aid of improved collection techniques and computer processing the data is collected under one standard and extracted for the 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 (navigation charts, Digital Terrain Model, volume calculation for dredging,
topographyTopography is the study of Earth's surface shape and features or those ofplanets, moons, and asteroids...
,
BathymetryBathymetry is the study of underwater depth of lake or ocean floors. In other words, bathymetry is the underwater equivalent to hypsometry. The name comes from Greek βαθύς , "deep", and μέτρον , "measure"...
) this data must be thinned out. It must also be error corrected (bad soundings,) and corrected for the effects of tides,
waves/
heave,
water level and water temperature differences (
thermoclineA thermocline is a thin but distinct layer in a large body of fluid , in which temperature changes more rapidly with depth than it does in the layers above or below...
s.) Usually the surveyor has additional data collection equipment on site to record the data required for correcting the soundings. Final output of charts can be created in a combination of specialty charting software or a CAD package, usually
AutocadAutoCAD is a software application for computer-aided design and drafting in both 2D and 3D. It is developed and sold by Autodesk, Inc. First released in December 1982, AutoCAD was one of the first CAD programs to run on personal computers, notably the IBM PC...
.
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 the single measurements. Comparison against multi-beam surveys indicates an accuracy of around +/- 0.1 - 0.2m.
External links
NOAA maintains a massive database of survey results, charts, and data
on the NOAA site.
See also
- National Irrigation Congress
The National Irrigation Congress was held periodically in the Western United States beginning in 1891 and ending in 1916, by which time the organization had changed its name to International Irrigation Congress. It was a "powerful pressure group."...
- Echo Sounding
Echo sounding is the technique of using sound pulses directed from the surface or from a submarine vertically down to measure the distance to the bottom by means of sound waves. This information is then typically used for navigation purposes or in order to obtain depths for charting purposes...